Updated on 2025/09/18

写真a

 
MAGARA Jin
 
Organization
University Medical and Dental Hospital Unit of Dysphagia Rehabilitation Lecturer
Title
Lecturer
External link

Degree

  • 歯学博士 ( 2012.3   新潟大学 )

Research Interests

  • Oral function

  • Dysphagia

  • Transcranial Magnetic Stimulation

  • Rehabilitation

Research Areas

  • Life Science / Oral biological science

  • Life Science / Prosthodontics

Research History (researchmap)

  • Niigata University Medical and Dental Hospital   Unit of Dysphagia Rehabilitation   Lecturer

    2015.4

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  • University of Manchester   Neurogastroenterology, Faculty of Biology, Medicine and Health,   Research fellow

    2014.6 - 2015.5

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  • Niigata University Medical and Dental Hospital   Unit of Dysphagia Rehabilitation   Assistant Professor

    2012.4 - 2015.3

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Research History

  • Niigata University   University Medical and Dental Hospital Unit of Dysphagia Rehabilitation   Lecturer

    2015.4

  • Niigata University   Graduate School of Medical and Dental Sciences Oral Life Science   Assistant Professor

    2012.4 - 2015.3

  • Niigata University   University Medical and Dental Hospital Unit of Dysphagia Rehabilitation   Assistant Professor

    2012.4 - 2015.3

Education

  • Niigata University   Graduate School of Medical and Dental Sciences

    2008.4 - 2012.3

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  • Niigata University   Faculty of Dentistry

    2000.4 - 2006.3

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Professional Memberships

  • 日本嚥下医学会

    2013.1

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  • Japanese Society of Stomatognathic Function

    2012.4

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  • The Japanese Society of Dysphagia Rehabiitation

    2012.4

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  • JAPAN PROSTHODONTIC SOCIETY

    2008.4

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  • 日本老年歯科医学会

    2016.4

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  • European Society for Swallowing Disorders

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Committee Memberships

  • 日本老年歯科医学会   倫理委員会  

    2024.4   

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  • 日本顎口腔機能学会   理事,会計担当幹事,評議員  

    2022.4   

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    Committee type:Academic society

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  • 日本摂食嚥下リハビリテーション学会   評議員  

    2017.9   

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Studying abroad experiences

  • University of Manchester  

    2015.6 - 2016.5

 

Papers

  • Enhancing swallowing initiation: The facilitatory role of crystalline oil and fat Reviewed

    Chisato Aizawa, Eri Takei, Jin Magara, Yasunobu Saito, Koki Noda, Yukiko Orihara, Mengjie Zhang, Takanori Tsujimura, Makoto Inoue

    Journal of Functional Foods   121   2024.10

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    Authorship:Corresponding author   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.jff.2024.106423

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  • Effect of carbonation and thickening on voluntary swallow in healthy humans. Reviewed International journal

    Hajime Iwamori, Jin Magara, Wakana Onuki, Reiko Ita, Anna Sasa, Takanori Tsujimura, Makoto Inoue

    Journal of oral rehabilitation   2024.7

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    Authorship:Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

    BACKGROUND: Liquid modification is a widely established strategy of treatment for patients with dysphagia. The modification of liquid particularly by thickening or carbonation is a common approach to promote safe swallowing. OBJECTIVE: This study sought to investigate how carbonated and/or thickened water modulates swallowing behaviours during swallowing in healthy young individuals. METHODS: Thirty-one healthy volunteers (9 men, 22 women; mean age ± standard deviation [SD], 25.7 ± 6.2 years) were instructed to swallow 20 mL of water, carbonated water and carbonated juice with and without added thickening agent. Electromyograms (EMGs) of the suprahyoid (S-hyo) muscles were recorded to evaluate swallowing behaviours. Obtained S-hyo EMG bursts was analysed using the following outcome parameters: onset latency, the time between swallowing que to onset of EMG burst; rising time and falling time, defined as the time between onset and peak, and between peak and offset, respectively; duration, defined as the time between onset and offset of EMG burst; and area integral value under the waveform. RESULTS: Effects of thickening demonstrated the extended onset latency, EMG burst duration including falling time and the larger area of EMG in thickened liquid compared to thin liquid, but there was not much difference between thin and thickened carbonated liquids. Carbonation significantly decreased the duration including falling time for thickened but not for thin liquids. CONCLUSION: Patients with dysphagia can benefit from use of carbonated or thickened water while the effects on swallowing physiology may differ between carbonation and thickening.

    DOI: 10.1111/joor.13793

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  • A Case of Dysphagia Rehabilitation in a Patient in the Chronic Stage of Lateral Medullary Syndrome Reviewed International journal

    Jin Magara, Reiko Ita, Yuhei Tsutsui, Haruka Sakai, Mengjie Zhang, Makoto Inoue

    Dysphagia   39 ( 3 )   534 - 539   2024.3

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    DOI: 10.1007/s00455-024-10690-6

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    Other Link: https://link.springer.com/article/10.1007/s00455-024-10690-6/fulltext.html

  • Use of suction electrodes for measurement of intrinsic tongue muscular endurance during lingual pressure generation. Reviewed International journal

    Reiko Ita, Jin Magara, Yuto Ochiai, Takanori Tsujimura, Makoto Inoue

    Journal of oral rehabilitation   51 ( 3 )   566 - 573   2023.10

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    Authorship:Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

    BACKGROUND: Lingual pressure (LP) generation is cooperatively controlled not only by the intrinsic tongue (I-ton) muscles but also by hyoid muscle activation. However, the measurement of endurance and fatigue properties of I-ton muscles is difficult due to the instability of electrodes. OBJECTIVE: The purpose of this study was to apply suction electrodes to measure electromyograms (EMGs) of I-ton muscle and to evaluate integrated EMG amplitude (iEMG) and mean power frequency (MPF) of EMG in the I-ton and hyoid muscles performing continuous LP. METHODS: Twenty healthy adult volunteers (10 males, 10 females, mean age 28.8 years) were instructed to perform 10-s LP generation tasks at 25%, 50%, 75% and 100% of maximum LP in randomised order with visual feedback. During each task, EMGs of the I-ton, suprahyoid (S-hyo), infrahyoid (I-hyo) and masseter (Mass) muscles were simultaneously recorded. The iEMG and MPF of EMG burst during 10-s LP tasks were compared. The recording period was divided into three substages to analyse temporal changes with the Friedman test. RESULTS: During the 10-s task, the iEMG significantly increased as the LP strength increased (p < .001). There was no time-dependent change in the I-ton iEMG; however, the MPF of the I-ton EMG burst decreased in all tasks (p < .05). The S-hyo and I-hyo iEMGs gradually increased, especially with strong LP (p < .01). CONCLUSION: While I-ton muscles may easily fatigue during 10-s LP generation, S-hyo and I-hyo muscles may help compensate for the weakened I-ton muscle activity by increasing their activity to maintain LP.

    DOI: 10.1111/joor.13612

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  • Evaluating the effect of management on patients with oral hypofunction: A longitudinal study. Reviewed International journal

    Wakana Onuki, Jin Magara, Kayoko Ito, Reiko Ita, Satomi Kawada, Yuhei Tsutsui, Yuta Nakajima, Haruka Sakai, Takanori Tsujimura, Makoto Inoue

    Gerodontology   40 ( 3 )   308 - 316   2023.9

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    Authorship:Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

    INTRODUCTION: Declining oral function may affect subsequent physical frailty in the older population. The aim of this longitudinal study was to summarise data on patients who underwent functional oral examination and evaluate the impact of management on patients with oral hypofunction (OHF). METHODS: Dental outpatients aged over 65 years at their initial visit to the Niigata University Hospital received detailed assessment of seven oral function items to diagnose oral hypofunction using diagnostic criteria defined by the Japanese Society of Gerodontology. Patients with OHF at the first assessment received management including oral health guidance for low function and dental treatment. They were re-evaluated approximately 6 months later and the two assessments were compared. According to the results of the second assessment, the patients were divided into two groups: OHF improved and OHF re-diagnosed. RESULTS: Of the 273 patients who underwent the first assessment, 86 (31.5%) were diagnosed with OHF and received management. Of those, 42 (48.8%) completed the second assessment. Comparing the first and second assessment, significant improvement was observed in oral hygiene, occlusal force, tongue-lip motor function of /pa/, mastication and swallowing. The change in values from the first assessment demonstrated a significant difference between the OHF improved and re-diagnosed groups only in occlusal force. CONCLUSION: Management for patients with OHF can contribute to the improvement of poor oral function, and an increase in occlusal force was notable in the recovery from OHF.

    DOI: 10.1111/ger.12655

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  • Chewing modulates the human cortical swallowing motor pathways. Reviewed International journal

    Jin Magara, Wakana Onuki, Reiko Ita, Takanori Tsujimura, Makoto Inoue

    Physiology & behavior   249   113763 - 113763   2022.5

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    When eating, mastication is always followed by swallowing. The present study assessed the effect of mastication on swallowing-related neural pathways in humans. Twenty healthy volunteers participated and underwent baseline transcranial magnetic stimulation to evaluate cortico-pharyngeal and cortico-hand motor-evoked potentials (MEPs). Next, they performed a chewing task and a swallowing task. Repeated-measures ANOVA revealed that pharyngeal MEPs were significantly higher after the swallowing task than after the chewing task, even though the number of swallows across tasks was matched. This implies that chewing movements suppress swallowing-related activity in the pharyngeal motor circuit.

    DOI: 10.1016/j.physbeh.2022.113763

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  • Survey of oral hypofunction in older outpatients at a dental hospital. Reviewed International journal

    Wakana Onuki, Jin Magara, Takanori Tsujimura, Kayoko Ito, Haruka Sakai, Sirima Kulvanich, Yuta Nakajima, Nobuaki Saka, Makoto Inoue

    Journal of oral rehabilitation   48 ( 10 )   1173 - 1182.   2021.8

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    BACKGROUND: Oral hypofunction is defined as the reversible stage preceding oral dysfunction. However, its assessment and management need further examination and consideration. OBJECTIVE: The present study aimed to examine the current state of oral hypofunction among outpatients at the university hospital. METHODS: New outpatients underwent medical interviews and detailed assessment of oral hypofunction at their initial visit to our dental department. Oral hypofunction was diagnosed if the results of three of the following seven assessment items were below cut-off values: poor oral hygiene, oral dryness, reduced occlusal force, decreased tongue-lip motor function, decreased tongue pressure, decreased masticatory function and deterioration of swallowing function. The relationships between factors used to diagnose oral hypofunction as well as the distributions of assessment values were clarified. RESULTS: Seventy-five of 209 patients (35.9%) were finally diagnosed with oral hypofunction. Diagnosis of oral hypofunction was significantly related to patient age, Eichner index, a chief complaint of dental or periodontal disease or ill-fitting dentures and a history of neurodegenerative disease. The lowest quintile values for poor oral hygiene, oral dryness and decreased masticatory performance were all above current cut-off values. Reduced occlusal force contributed strongly to the diagnosis of oral hypofunction. CONCLUSION: Oral hypofunction in dental outpatients at a university hospital was associated with patient age, medical history and chief complaint at presentation. Diagnosis of oral hypofunction can be closely related to reduced occlusal force. The validity of cut-off values for assessments of oral hypofunction needs further consideration.

    DOI: 10.1111/joor.13237

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  • Lasting modulation of human cortical swallowing motor pathways following thermal tongue stimulation. Reviewed International journal

    Jin Magara, Masahiro Watanabe, Takanori Tsujimura, Shaheen Hamdy, Makoto Inoue

    Neurogastroenterology and motility   33 ( 1 )   e13938   2021.1

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    BACKGROUND: Thermal tactile oropharyngeal stimulation has been clinically used to facilitate swallowing initiation in dysphagic patients. We previously demonstrated that thermal stimulation applied to the oral cavity provokes an immediate excitability in pharyngeal motor cortex. The aim of the current study was to investigate whether thermal stimulation can produce longer lasting effects on the corticopharyngeal neural pathway. METHODS: Healthy volunteers (n = 8/12) underwent baseline pharyngeal motor evoked potential (PMEP) measurements evoked by transcranial magnetic stimulation. In the first experiment, subjects received thermal stimulation alternating 30 seconds of 15 and 36°C applied to the tongue surface for either 10 minutes, 5 minutes, or sham. In the second experiment, one of three intermittent thermal stimulus patterns was delivered: cold (alternating 30 seconds of 15 and 36°C), warm (continuous 36°C), or hot (alternating 30 seconds of 45 and 36°C) for 10 minutes. In both experiments, PMEP were remeasured every 15 minutes up to 60 minutes following thermal stimulation. KEY RESULTS: Repeated measures ANOVA for each stimulus time in the first experiment showed a significant increased change in PMEP amplitude at 30 minutes following only 10-minute stimulation compared with sham (P < .05). In the second experiment, we found that cold stimulation was more effective than the other stimulation (P < .05) at increasing PMEP amplitudes. CONCLUSIONS AND INFERENCES: Ten-minute cold stimulation on the tongue can induce a delayed (30 minutes) increase in pharyngeal cortical excitability, providing a clinically useful therapeutic window for its application in dysphagic patients.

    DOI: 10.1111/nmo.13938

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  • Endurance measurement of hyoid muscle activity and hyoid-laryngeal position during tongue lift movement. Reviewed International journal

    Yukako Sunada, Jin Magara, Takanori Tsujimura, Kazuhiro Ono, Makoto Inoue

    Journal of oral rehabilitation   47 ( 8 )   967 - 976   2020.8

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    Authorship:Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

    BACKGROUND: Tongue lift movement (TLM) is used as a therapy to improve tongue pressure against the hard palate for dysphagic patients. OBJECTIVE: The present study aimed to characterize the time-dependent endurance changes in hyoid muscle activity and hyoid-laryngeal displacement during TLM in different ways. METHODS: Sixteen young healthy volunteers were instructed to perform TLM at maximum effort (100%) against the anterior and posterior parts of the hard palate using a balloon-type tongue pressure instrument, followed by a 10-second recording during anterior 80% TLM, anterior 100% TLM, posterior 80% TLM and posterior 100% TLM with visual feedback. Electromyography (EMG) of suprahyoid (S-Hyo) and infrahyoid (I-Hyo) muscles and videofluorography were simultaneously recorded. To evaluate temporal changes, the recording period was divided into three substages: early, middle and late. Tongue pressure, integrated EMG (iEMG), power frequency of EMG burst and hyoid-laryngeal position were compared among the conditions (80% vs 100%, anterior vs posterior and early vs middle vs late). RESULTS: Tongue pressure was stably maintained for 10 seconds in all conditions. S-Hyo iEMG and I-Hyo iEMG were significantly greater at 100% than at 80%, while no significant difference was observed between positions. S-Hyo iEMG and I-Hyo iEMG significantly increased at the late stage, while power frequency of EMG burst gradually decreased. Significant temporal changes in laryngeal elevation were observed only in posterior 100% TLM. CONCLUSION: The current results suggested that isometric posterior TLM may be more useful compared with anterior TLM in clinical situations for dysphagic patients to elevate the hyolaryngeal complex.

    DOI: 10.1111/joor.12988

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  • Cold thermal oral stimulation produces immediate excitability in human pharyngeal motor cortex. Reviewed

    Jin Magara, Masahiro Watanabe, Takanori Tsujimura, Shaheen Hamdy, Makoto Inoue

    Neurogastroenterology and motility   e13384   2018.6

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    DOI: 10.1111/nmo.13384

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  • Exploring the effects of synchronous pharyngeal electrical stimulation with swallowing carbonated water on cortical excitability in the human pharyngeal motor system Reviewed

    Jin Magara, Emilia Michou, Alicia Raginis-Zborowska, Makoto Inoue, Shaheen Hamdy

    Neurogastroenterology and motility   28 ( 9 )   1391 - 1400   2016.9

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    DOI: 10.1111/nmo.12839

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  • Effect of Hyposalivation on Bread Mastication in Healthy Individuals. Reviewed International journal

    Yuto Ochiai, Reiko Ita, Kazhihiro Ono, Takanori Tsujimura, Jin Magara, Makoto Inoue

    Journal of oral rehabilitation   2025.5

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    BACKGROUND: Solid foods mix with saliva during mastication to form a bolus. The water content of the food bolus and lubrication in the oral cavity are critical factors that determine the dynamics of the masticatory muscles. Among other factors, fat is believed to affect masticatory behaviour by lubricating foods. OBJECTIVES: The effects of artificially induced hyposalivation on masticatory behaviour and bolus properties were investigated using bread with varying water content and spreads to evaluate how these properties affect masticatory behaviour with hyposalivation. METHODS: Twenty healthy volunteers were instructed to eat bread with and without spreads. Before and after atropine administration, electromyographic activity was recorded in the masseter, suprahyoid and infrahyoid muscles. Masticatory movements and bolus properties were compared between breads, oral cavity conditions and spreads. RESULTS: Hyposalivation directly affected mastication behaviour only for dry bread, with masticatory duration and cycle time, and suprahyoid muscle activity increasing. These effects were primarily observed during the middle and late stages of mastication, particularly in the absence of spreads. The effect of spreads was significant only on dry bread with hyposalivation, decreasing masticatory cycle time and masseter and suprahyoid activity at the middle-to-late stage. Hyposalivation decreased the water content and increased the hardness of the bolus in dry bread, both with and without spreads. CONCLUSION: Bolus formation and transport during the mastication of dry bread are interrupted by hyposalivation. The addition of spreads can compensate for the affected masticatory movements without significant changes in bolus properties.

    DOI: 10.1111/joor.13987

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  • Effects of potassium on laryngeal induced swallowing rate in rats Reviewed

    Satomi Kawada, Titi Chotirungsan, Charng-Rong Pan, Yuhei Tsutsui, Keiichiro Okamoto, Jin Magara, Takanori Tsujimura, Makoto Inoue

    American Journal of Physiology-Gastrointestinal and Liver Physiology   2025.4

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    The swallowing reflex can be induced by peripheral stimulation of the larynx. Although previous studies have suggested that potassium ions exert facilitatory effects on the initiation of swallowing, little information is available on the mechanism underlying the potassium ion-evoked swallowing reflex. In this study, we evaluated the effects of potassium ions on peripheral afferent responses and the initiation of swallowing in conscious and anesthetized rats. Furthermore, the possible receptors involved were explored. The topical application of potassium chloride (KCl) significantly facilitated the swallowing reflex; these facilitatory effects were more prominent than those of distilled water (DW) or sodium chloride (NaCl). This phenomenon depended not on the concentrations of anions but on those of potassium ions. The potassium ion-induced response in the superior laryngeal nerve was most prominent after treatment with KCl, especially at the early stage. In chronic rats, without differences in licking behavior between DW, NaCl, and KCl, the intervals between swallows were the smallest during KCl-associated licking. Inward rectifier potassium channel (Kir)3.1- and Kir6.2-positive cells were detected in the nodose ganglion and vocal folds. The rate of expression of these molecules in immunoreactive cells was relatively high at 74.1% for Kir3.1 and 75.3% for Kir6.2. Kir3.1- and Kir6.2- blockers significantly decreased the number of KCl-induced swallows. Possible mechanisms underlying potassium ion-induced swallowing are discussed. Our findings suggest that Kir3.1 and Kir6.2 are involved in K ion-induced swallowing in rats.

    DOI: 10.1152/ajpgi.00012.2025

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  • Characterization of Beverage Viscosity Based on the International Dysphagia Diet Standardisation Initiative and Its Correspondence to the Japanese Dysphagia Diet 2021. Reviewed International journal

    Mari Nakao-Kato, Aya Takahashi, Jin Magara

    Nutrients   17 ( 6 )   2025.3

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    Background/Objective: The International Dysphagia Diet Standardisation Initiative (IDDSI) and the Japanese Dysphagia Diet 2021 (JDD2021) are prominent systems that classify thickened beverages for dysphagia management. We herein aim to establish a correspondence between these systems through systematic viscosity measurements. Methods: We analyzed 49 thickened beverage samples using an E-type viscometer, IDDSI flow test, and JDD syringe test. Results: Receiver operating characteristic analysis revealed the following viscosity cutoffs for IDDSI levels: 0-1 at 72.0 mPa·s (area under the curve [AUC] 0.94), 1-2 at 112.0 mPa·s (AUC 0.95), and 2-3 at 303.0 mPa·s (AUC 0.97). Multiple regression analysis revealed that beverage characteristics, including fat, sodium content, and settling time, significantly influenced viscosity (R2 = 0.803). The findings established that IDDSI Level 0 corresponds to a thinner viscosity than JDD Stage 1 and Stage 1 (0-72 mPa·s), Level 1 to Stage 1 (72-112 mPa·s), Level 2 to Stages 1-2 (112-303 mPa·s), and Level 3 to Stage 3 (>303 mPa·s). Moreover, the measurement methods had high correlations (r = 0.83-0.93, p < 0.001). Conclusions: The comprehensive map between IDDSI and JDD2021 classifications developed from the results of this study enables healthcare providers to translate between the classification systems, improving dysphagia management internationally while supporting evidence-based care and global research.

    DOI: 10.3390/nu17061051

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  • The central neural control of the posterior belly of the digastric muscles during swallowing in rats Reviewed International journal

    Yuhei Tsutsui, Titi Chotirungsan, Charng-Rong Pan, Satomi Kawada, Jin Magara, Takanori Tsujimura, Keiichiro Okamoto, Makoto Inoue

    American Journal of Physiology-Gastrointestinal and Liver Physiology   328 ( 3 )   G277-G288   2025.2

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    The aim of this study was to clarify whether the posterior belly of the digastric (post-Dig) muscle is activated during the swallowing reflex and whether the post-Dig muscle is directly controlled by the swallowing central pattern generator (CPG) in anesthetized rats, using physiological and immunohistochemical approaches. In physiological study, electromyograms (EMGs) of the post-Dig, sternohyoid and thyrohyoid muscles, and the diaphragm were recorded during respiration and swallowing with and without airway stenosis. In the immunohistochemical study, c-Fos immunoreactivity for expression of cells during swallowing was analyzed. Motoneurons were identified using immunohistochemistry with Fluoro-gold (FG). EMG bursts were observed in the hyoid muscles during the inspiratory phase and swallowing. With airway stenosis, the swallowing EMG activity was facilitated in terms of duration and area only in the post-Dig muscle. The coordination of these EMG activities during swallowing was maintained with airway stenosis. In contrast, the offset of the post-Dig EMG burst was delayed with airway stenosis. c-Fos-positive cells were observed in the accessory facial nucleus (Acs7), but only in the rostral portion. FG-labeled cells were observed in Acs7. Several c-Fos/FG double-labeled cells were observed only in the rostral Acs7. These results suggested that the post-Dig muscle is activated during swallowing, the activation of which is controlled by the swallowing CPG, and that the distribution of Acs7 neurons, which innervate the post-Dig muscle, was uneven in the nucleus. In addition, the modulation of post-Dig muscle activity during inspiration might be due to changes in peripheral conditions via respiratory CPG.

    DOI: 10.1152/ajpgi.00374.2024

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  • Physiological analyses of swallowing changes due to chronic obstructive pulmonary disease in anesthetized male rats Reviewed International journal

    Kouta Nagoya, Takanori Tsujimura, Midori Yoshihara, Masahiro Watanabe, Jin Magara, Katsushige Kawasaki, Makoto Inoue

    Frontiers in Physiology   15   1445336 - 1445336   2024.8

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    Chronic obstructive pulmonary disease (COPD) was previously known as chronic bronchitis and emphysema. It has various main symptoms, such as dyspnea, chronic cough, and sputum, and is often accompanied by dysphagia. Although many published clinical reports have described COPD-related dysphagia, the physiological mechanisms underlying swallowing changes due to COPD remain unclear. Therefore, we analyzed how COPD affects the swallowing reflex using COPD model rats. We performed an electrophysiological study of respiration and swallowing using COPD model induced by intratracheal administration of porcine pancreatic elastase and lipopolysaccharide in Sprague-Dawley male rats. To identify the respiration and swallowing responses, electromyographic activity was recorded from the diaphragm, digastric (Dig), and thyrohyoid (TH) muscles. We confirmed COPD using micro-computed tomography analysis and hematoxylin and eosin staining of the lungs. The duty cycle was defined as the ratio of the inspiration duration to the total respiratory duration. In COPD model rats, the duty cycle was significantly higher than that in control rats. The frequency of the swallowing reflex evoked by electrical stimulation of the superior laryngeal nerve during the inspiration phase was higher in COPD model rats than in control rats. Furthermore, long-term COPD altered Dig and TH muscle activity without pathological muscle change. Our results suggest that COPD increases the frequency of swallowing initiation during the inspiration phase. Furthermore, long-term COPD affects swallowing-related muscle activity without pathological muscle changes. These physiological changes may increase the risk of developing dysphagia. Further studies are necessary to clarify the mechanisms contributing to the functional changes in respiration and swallowing in COPD.

    DOI: 10.3389/fphys.2024.1445336

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  • Functional involvement of the sternohyoid muscle during breathing and swallowing in rats. Reviewed International journal

    Nobuaki Saka, Titi Chotirungsan, Midori Yoshihara, Charng-Rong Pan, Yuhei Tsutsui, Nozomi Dewa, Jin Magara, Takanori Tsujimura, Makoto Inoue

    American journal of physiology. Gastrointestinal and liver physiology   327 ( 4 )   G598-G607   2024.8

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    The sternohyoid muscle depresses the hyoid bone, but it is unclear whether the muscle contributes to respiratory and swallowing mechanisms. This study aimed to clarify whether the sternohyoid muscle participates in the respiration and swallowing reflex and how the activity is modulated in two conditions: with airway stenosis and with a fixed sternohyoid muscle length. Electromyographic activity in the sternohyoid, digastric, thyrohyoid, and diaphragm muscles was recorded in anesthetized rats. The sternohyoid muscle activity was observed in the inspiratory phase and during swallowing, and was well coordinated with digastric and thyrohyoid muscle activity. With airway stenosis, the respiratory activity per respiratory cycle was facilitated in all assessed muscles but the facilitation of activity per second occurred only in the digastric, thyrohyoid, and sternohyoid muscles. With airway stenosis, the swallowing activity was facilitated only in the digastric muscle but not in the thyrohyoid and sternohyoid muscles. Swallowing activity was not observed in the sternohyoid muscle in the condition with the sternohyoid muscle length fixed, although increased inspiratory activity remained. The current results suggest that (1) the sternohyoid muscle is slightly activated in the inspiratory phase, (2) the effect of airway stenosis on respiratory function may differ between the upper airway muscles and diaphragm, and (3) swallowing activity in the sternohyoid muscle is not dominantly controlled by the swallowing central pattern generator but instead occurs as a myotatic reflex.

    DOI: 10.1152/ajpgi.00138.2024

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  • Impact of salivary flow inhibition on masticatory behaviours in healthy individuals. Reviewed International journal

    Rie Goto, Yuto Ochiai, Eri Takei, Reiko Ita, Kazhihiro Ono, Ryo Takei, Hideaki Washio, Hajime Takahashi, Takanori Tsujimura, Jin Magara, Makoto Inoue

    Journal of oral rehabilitation   2024.6

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    BACKGROUND: It remains unclear how the salivary flow and the fat content of food affect bolus formation during mastication. OBJECTIVES: We aimed to clarify: (1) how hyposalivation affects jaw-closing and hyoid-elevating muscle activities in bolus formation, and (2) if the effect of hyposalivation on muscle activity depends on the fat content of food. METHODS: Eighteen healthy male volunteers were instructed to freely ingest four test foods: Plain, Fat without seasoning, Fat with seasoning, and Soft rice crackers. Masseter and suprahyoid electromyographic activities were recorded before and 30 min after the administration of atropine sulfate, a muscarinic receptor antagonist that induces hyposalivation. RESULTS: Hyposalivation extended the masticatory duration significantly in all the test foods except Fat with seasoning. Masticatory cycle time was significantly longer with vs without hyposalivation for the Soft (p = .011). Suprahyoid activity/cycle was significantly greater with vs without hyposalivation (p = .013). Masticatory cycle time was significantly longer at the late stage with vs without hyposalivation for the Soft (p < .001). Suprahyoid activity/cycle was significantly greater at the middle (p = .045) and late stages (p = .002) with vs without hyposalivation for the Soft and greater at the late stage with vs without hyposalivation for the Plain (p = .043). Changes in masticatory cycle time and suprahyoid activity/cycle for these foods had significantly positive relationship (p < .001). CONCLUSION: Hyposalivation-induced changes in masticatory behaviours resulted from the middle and late stage suprahyoid activity. Fat content and seasoning compensate for salivary flow inhibition.

    DOI: 10.1111/joor.13764

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  • Effect of bolus property on swallowing dynamics in patients with dysphagia Reviewed International journal

    Haruka Hino, Taku Suzuki, Kazuya Maekawa, Reiko Ita, Anna Sasa, Sirima Kulvanich, Eri Takei, Jin Magara, Takanori Tsujimura, Makoto Inoue

    Journal of Oral Rehabilitation   51 ( 8 )   1422 - 1432   2024.4

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    Abstract

    Background

    Modification of foods or liquids is commonly administered as part of dysphagia treatment. However, no consensus exists on the parameters for defining texture‐modified food for patients with dysphagia.

    Objectives

    The aim of this study was to evaluate the effect of food/liquid material on swallowing physiology in patients with dysphagia and to discuss the optimal food choice for direct swallowing therapy.

    Materials and Methods

    A total of 140 patients underwent a videofluoroscopic swallowing study using three test foods/liquids: 3 mL of mildly thick liquid (Thick liquid), jelly made of agar and polysaccharide (Jelly) and jelly made of pectin (Reset gel). Outcome measures of videofluoroscopic images, bolus transit time and hyoid movements were compared.

    Results

    The frequency of chewing movements was highest for Jelly, followed by Reset gel and Thick liquid. While the probability of oral residue was the highest for Reset gel, pharyngeal residue after swallowing was high for Thick liquid as compared to Jelly and Reset gel. Oral transit time and pharyngeal transit time for Thick liquid were significantly smaller than that for Jelly and Reset gel. Pharyngeal delay time was significantly smaller for Thick liquid than that for Jelly and Reset gel. There was no difference in hyoid elevation time and hyoid movement time among the conditions.

    Conclusion

    Mildly thick liquid material may be optimal for patients with primarily oral motor function impairment and jelly, such as Reset gel, may be more suitable for patients with primarily pharyngeal motor function impairment or oral and pharyngeal coordinative motor function decline.

    DOI: 10.1111/joor.13709

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  • Chewing Well Modulates Pharyngeal Bolus Transit During Swallowing in Healthy Participants. Reviewed International journal

    Akira Okubo, Takanori Tsujimura, Rumi Ueha, Taku Suzuki, Yuhei Tsutsui, Yuta Nakajima, Nobuaki Saka, Anna Sasa, Eri Takei, Jin Magara, Makoto Inoue

    Dysphagia   2024.3

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    Mastication is controlled by central pattern generator in the brainstem and can be modulated by volition. The aim of this study was to investigate the effect of chewing well on swallowing. Twenty-six healthy participants were instructed to eat 8, 12, and/or 16 g of steamed rice with barium sulphate under the following two conditions: chewing freely task (CF; chewing naturally in their usual manner) and chewing well task (CW; chewing the food with a request to "chew well"). We evaluated bolus transport and swallowing movement using videofluoroscopy and electromyography of the masseter, suprahyoid and thyrohyoid muscles. The chewing time and pharyngeal transit time (PTT) at the first swallow showed high reproducibility in both CF and CW. PTT for CW was significantly shorter and longer than CF in 12 and 16 g, respectively. In 12 g, CW increased the pharyngeal bolus velocity and decreased thyrohyoid EMG activity during swallowing compared with CF. In 16 g, the difference between CW and CF in the estimated swallowed bolus volume was positively correlated with that in upper esophageal sphincter transit duration. We speculate that CW modulates PTT during swallowing depending on the mouthful volume.

    DOI: 10.1007/s00455-024-10689-z

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  • Continuous electrical stimulation of superior laryngeal nerve inhibits initiation of swallowing in anesthetized rats. Reviewed International journal

    Yuta Nakajima, Takanori Tsujimura, Kojun Tsuji, Jin Magara, Makoto Inoue

    Neuroscience letters   825   137672 - 137672   2024.3

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    Pharyngeal electrical stimulation (PES) applies electrical stimulation to pharyngeal mucosa (PhM) and represents a useful approach to improve swallowing function in patients with dysphagia. To determine the optimal PES modality to treat dysphagia, the mechanism underlying the effects of PES on swallowing function must be elucidated. In this study, we evaluated how PES and electrical stimulation of the superior laryngeal nerve (SLN) modulate the initiation of swallowing in anesthetized rats. A swallow was evoked by electrical stimulation of the PhM, SLN, and nucleus of the solitary tract (nTS) and pharyngeal mechanical stimulation using a von Frey filament. A swallow was identified by electromyographic bursts in mylohyoid and thyrohyoid muscles. Bilateral SLN transection abolished the swallows evoked by PhM electrical stimulation. PhM and SLN electrical stimulation decreased swallowing frequency in a similar time-dependent manner. Intravenous administration of the GABAA receptor antagonist bicuculine did not affect the time-dependent change in swallowing frequency during SLN electrical stimulation. Continuous SLN electrical stimulation significantly inhibited pharyngeal mechanically and nTS-electrically evoked swallows compared with before and 5 min after stimulation. The present findings suggest that the SLN plays a primary role in PES-evoked swallows. Additionally, continuous SLN electrical stimulation inhibits the initiation of swallowing, and the modulation of central network associated with swallowing might be partially involved in this inhibition.

    DOI: 10.1016/j.neulet.2024.137672

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  • Short-term and long-term effects of unilateral external carotid artery ligation on orofacial functions in rats. Reviewed International journal

    Titi Chotirungsan, Yuhei Tsutsui, Nobuaki Saka, Satomi Kawada, Nozomi Dewa, Jin Magara, Takanori Tsujimura, Makoto Inoue

    American journal of physiology. Gastrointestinal and liver physiology   326 ( 3 )   G318-G329   2024.3

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    The external carotid artery (ECA) plays a major role in supplying blood to the head and neck. Although impeded blood flow in the ECA is expected to affect orofacial functions, few studies have shown how blood flow obstruction in the ECA contributes to impairment of these functions, including chewing and swallowing. This study was performed to investigate the effects of ECA ligation (ECAL) on immediate and long-term changes in masticatory and swallowing functions as well as the jaw-opening reflex evoked in the digastric muscle. The experiments were carried out using male Sprague-Dawley rats. In the acute experiment, the digastric reflex evoked by low-threshold electrical stimulation of the inferior alveolar nerve and the swallow reflex, identified by digastric and thyrohyoid electromyographic (EMG) bursts, were compared between before and 1 h after ECAL. The chronic experiment was conducted on freely moving rats. EMGs of the masseter, digastric, and thyrohyoid muscles were chronically recorded. The long-term effects of ECAL on behavior and muscle histology were compared between rats with an intact ECA and rats with ECAL. In the acute experiment, the peak amplitude of the digastric reflex on the ECAL side was significantly decreased 1 h after ECAL. In the chronic experiment, although most parameters of the masticatory and swallowing EMGs were not significantly different between the groups, the results suggest wide variation of the effect of ECAL on the muscles. Blood supply compensation from collaterals of the internal carotid artery may be permanent in some animals.NEW & NOTEWORTHY The inhibitory effect of unilateral external carotid artery ligation (ECAL) on the ipsilateral digastric reflex was small but evident. Most parameters of masticatory and swallowing muscle activity were not significantly different after ECAL. Wide variation was noted in the effect of ECAL on the ipsilateral muscle activity. Blood supply compensation from collaterals of the internal carotid artery may occur in response to the impaired blood flow.

    DOI: 10.1152/ajpgi.00226.2023

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  • COVID-19感染症下での介護保険施設における歯科訪問診療の中断が肺炎の発症に与える影響について(Effect of COVID-19-related interruption of visiting dental services on pneumonia in nursing home residents)

    伊藤 加代子, 落合 勇人, 阿志賀 大和, 林 宏和, 飯泉 智子, 鈴木 拓, 道見 登, 花形 哲夫, Kulvanich Sirima, 那小屋 公太, 渡邊 賢礼, 真柄 仁, 辻村 恭憲, 井上 誠

    新潟歯学会雑誌   53 ( 2 )   73 - 80   2024.1

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  • 嚥下時胸骨舌骨筋の機能的役割

    坂 暢晃, Chotirungsan Titi, Pan Charng-Rong, 中嶋 優太, 真柄 仁, 辻村 恭憲, 井上 誠

    新潟歯学会雑誌   53 ( 2 )   102 - 102   2024.1

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  • 唾液分泌低下もたらす種々の食品咀嚼への影響

    池浦一樹, 落合勇人, 笹杏奈, 真柄仁, 辻村恭憲, 井上誠

    新潟歯学会雑誌   54 ( 2 )   2024

  • 唾液分泌低下及び油脂添加がパンの咀嚼・嚥下運動と食塊物性に与える影響

    落合勇人, 落合勇人, 板離子, 小貫和佳奈, 前川和也, 相澤知里, 真柄仁, 辻村恭憲, 井上誠

    新潟歯学会雑誌   54 ( 2 )   2024

  • ラットにおけるカリウムイオンの嚥下誘発促進メカニズム

    川田里美, TITI Chotirungsan, 筒井雄平, CHARNG-RONG Pan, 吉原翠, 真柄仁, 辻村恭憲, 井上誠

    新潟歯学会雑誌   54 ( 2 )   2024

  • Establishment of the swallowing function recovery support team system at a hospital

    山田真子, 落合勇人, 真柄仁, 那小屋公太, 小貫和佳奈, 坂井遥, 辻村恭憲, 井上誠

    日本摂食嚥下リハビリテーション学会学術大会抄録集(Web)   27 ( 3 )   S271 - S272   2023.12

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  • Modulation of reflex responses of the anterior and posterior bellies of the digastric muscle in freely moving rats. Reviewed International journal

    Titi Chotirungsan, Yuhei Tsutsui, Nobuaki Saka, Satomi Kawada, Nozomi Dewa, Taku Suzuki, Jin Magara, Takanori Tsujimura, Makoto Inoue

    Journal of oral rehabilitation   50 ( 11 )   1270 - 1278   2023.6

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    BACKGROUND: Chewing and licking are primarily activated by central pattern generator (CPG) neuronal circuits in the brainstem and when activated trigger repetitive rhythmic orofacial movements such as chewing, licking and swallowing. These CPGs are reported to modulate orofacial reflex responses in functions such as chewing. OBJECTIVE: This study explored the modulation of reflex responses in the anterior and posterior bellies (ant-Dig and post-Dig, respectively) of the digastric muscle evoked by low-intensity trigeminal stimulation in conscious rats. METHODS: The ant-Dig and post-Dig reflexes were evoked by using low-intensity electrical stimulation applied to either the right or left inferior alveolar nerve. Peak-to-peak amplitudes and onset latencies were measured. RESULTS: No difference was observed between threshold and onset latency for evoking ant-Dig and post-Dig reflexes, suggesting that the latter was also evoked disynaptically. The peak-to-peak amplitude of both reflexes was significantly reduced during chewing, licking and swallowing as compared to resting period and was lowest during the jaw-closing phase of chewing and licking. Onset latency was significantly largest during the jaw-closing phase. Inhibitory level was similar between the ant-Dig and post-Dig reflex responses and between the ipsilateral and contralateral sides. CONCLUSION: These results suggest that both the ant-Dig and post-Dig reflex responses were significantly inhibited, probably due to CPG activation during feeding behaviours to maintain coordination of jaw and hyoid movements and hence ensure smooth feeding mechanics.

    DOI: 10.1111/joor.13537

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  • Atropine facilitates water-evoked swallows via central muscarinic receptors in anesthetized rats. Reviewed International journal

    Yuta Nakajima, Takanori Tsujimura, Yuhei Tsutsui, Titi Chotirungsan, Satomi Kawada, Nozomi Dewa, Jin Magara, Makoto Inoue

    American journal of physiology. Gastrointestinal and liver physiology   325 ( 2 )   G109-G121   2023.5

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    Anticholinergic medication causes impaired swallowing with hyposalivation. However, the underlying mechanisms by which these drugs modulate the swallowing reflex remain unclear. This study investigated the effects of the muscarinic acetylcholine receptor (mAChR) non-specific antagonist atropine on the initiation of swallowing. Experiments were performed on 124 urethane-anesthetized rats. A swallow was evoked by either topical laryngeal application of a small amount of distilled water (DW), saline, citric acid, or capsaicin; upper airway distention with a continuous airflow; electrical stimulation of the superior laryngeal nerve (SLN); or focal microinjection of NMDAinto the lateral region of the nucleus of the solitary tract (L-nTS). Swallows were identified by electromyographic bursts of the suprahyoid and thyrohyoid muscles. Either atropine, the peripheral mAChR antagonist methylatropine, or antagonists of mAChR subtypes M1-M5 were intravenously delivered. Atropine at a dose of 1 mg/kg increased the number of DW-evoked swallows compared with baseline and did not affect the number of swallows evoked by saline, citric acid, capsaicin, or upper airway distention. Methylatropine and M1-M5 antagonists did not significantly change the number of DW-evoked swallows. Bilateral SLN transection completely abolished DW-evoked swallows, and atropine decreased the swallowing threshold of SLN electrical stimulation. Finally, microinjection of NMDA receptor antagonist AP-5 into the L-nTS inhibited DW-evoked swallows, and atropine facilitated the initiation of swallowing evoked by NMDA microinjection into this region. These results suggest that atropine facilitates DW-evoked swallows via central mAChR actions.

    DOI: 10.1152/ajpgi.00039.2023

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  • Effects of Head and Neck Alignment and Pharyngeal Anatomy on Epiglottic Inversion During Swallowing in Dysphagic Patients. Reviewed International journal

    Taku Suzuki, Haruka Hino, Jin Magara, Takanori Tsujimura, Kayoko Ito, Makoto Inoue

    Dysphagia   38 ( 6 )   1519 - 1527   2023.5

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    The effects of head and neck alignment and pharyngeal anatomy on epiglottic inversion remain unclear. This study investigated the factors involved in epiglottic inversion, including head and neck alignment and pharyngeal anatomy, in patients with dysphagia. Patients with a chief complaint of dysphagia and who underwent videofluoroscopic swallowing study at our hospital from January to July 2022 were enrolled. They were divided into three groups based on the degree of epiglottic inversion as the complete-inversion (CI), partial-inversion (PI), and non-inversion group (NI) groups. Data were compared among the three groups; a total of 113 patients were analyzed. The median age was 72.0 (IQR: 62.0-76.0) years; 41 (36.3%) and 72 (63.7%) were women and men, respectively. There were in 45 (39.8%) patients in the CI, 39 (34.5%) in the PI, and 29 (25.7%) in the NI groups, respectively. Single-variable analysis revealed significant relation to epiglottic inversion of Food Intake LEVEL Scale score, penetration-aspiration score with 3-mL thin liquid bolus, epiglottic vallecula and pyriform sinus residue, hyoid position and displacement during swallowing, pharyngeal inlet angle (PIA), epiglottis to posterior pharyngeal wall distance, and body mass index. Logistic regression analysis with complete epiglottic inversion as the dependent variable revealed the X coordinate at maximum hyoid elevation position during swallowing and PIA as significant explanatory variables. These results suggest that epiglottic inversion is constrained in patients with dysphagia who have poor head and neck alignment or posture and a narrow pharyngeal cavity just before swallowing.

    DOI: 10.1007/s00455-023-10579-w

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  • 口腔機能低下症患者における口腔機能管理の実施効果に関する縦断研究

    真柄仁, 小貫和佳奈, 井上誠

    8020   ( 22 )   139 - 142   2023.3

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  • 唾液分泌低下及びマーガリン添加がパンの咀嚼・嚥下運動と食塊特性にもたらす影響

    落合勇人, 板離子, 小貫和佳奈, 前川和也, 真柄仁, 辻村恭憲, 井上誠

    日本嚥下医学会抄録(Web)   46th   2023

  • Swallowing modulation by thickened texture and carbonated solution

    板離子, 真柄仁, 辻村恭憲, 井上誠

    日本顎口腔機能学会学術大会プログラム・事前抄録集   69th   2023

  • Dysphagia Rehabilitation Using Palatal Augmentation Prosthesis after Subtotal Glossectomy: A Case Report

    中嶋優太, 真柄仁, 坂井遥, 渡邊賢礼, 井上誠

    日本口腔リハビリテーション学会雑誌   35 ( 1 )   48 - 55   2022.12

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  • Effect of management on patients with oral hypofunction

    小貫和佳奈, 真柄仁, 辻村恭憲, 伊藤加代子, 中嶋優太, 板離子, 川田里美, 筒井雄平, 井上誠, 井上誠, 井上誠

    日本摂食嚥下リハビリテーション学会学術大会抄録集(Web)   26 ( 3 )   S138 - S138   2022.12

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  • 新たな素材の嚥下調整食品の臨床応用への可能性

    日野 遥香, 鈴木 拓, 板 離子, 坂井 遥, 山田 真子, 前川 和也, 真柄 仁, 辻村 恭憲, 井上 誠

    新潟歯学会雑誌   52 ( 2 )   94 - 94   2022.12

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  • Effects of various swallowing-adjusted foods on swallowing behavior: Examination in healthy people

    板離子, 笹杏奈, 真柄仁, 辻村恭憲, 井上誠

    日本摂食嚥下リハビリテーション学会学術大会抄録集(Web)   26 ( 3 )   S208 - S208   2022.12

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  • Effect of bolus condition on swallowing behaviors in dysphagic patients

    日野遥香, 笹杏奈, 坂井遥, 山田真子, 高波里帆, 前川和也, 真柄仁, 辻村恭憲, 井上誠, 井上誠

    日本摂食嚥下リハビリテーション学会学術大会抄録集(Web)   26 ( 3 )   S216 - S216   2022.12

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  • Evaluation of suprahyoid muscle activity in food bolus formation during solid food chewing

    笹杏奈, 笹杏奈, 羽尾直仁, 板離子, 鈴木拓, 真柄仁, 辻村恭憲, 井上誠

    日本摂食嚥下リハビリテーション学会学術大会抄録集(Web)   26 ( 3 )   S209 - S210   2022.12

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  • Functional evaluation of jaw and suprahyoid muscle activities during chewing Reviewed International journal

    Anna Sasa, Sirima Kulvanich, Naohito Hao, Reiko Ita, Masahiro Watanabe, Taku Suzuki, Jin Magara, Takanori Tsujimura, Makoto Inoue

    Journal of Oral Rehabilitation   49 ( 12 )   1127 - 1134   2022.9

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    BACKGROUND: It has not yet been clarified how the type of the chewing task affects related muscle activity and how the suprahyoid muscles contribute to masticatory function in humans. OBJECTIVES: This study aimed to investigate the difference in the suprahyoid muscle activity between the freely and unilaterally chewing tasks and between the working and non-working sides during chewing. MATERIALS AND METHODS: Twenty healthy volunteers were instructed to chew peanuts and two different types of rice crackers in two ways; freely and unilaterally while surface electromyograms of the masseter and suprahyoid muscles were recorded. The chewing duration, number of chewing cycles and chewing rate were compared between the tasks. Further, the masseter and suprahyoid muscle activities per chewing cycle were compared between the sides. RESULTS: The chewing duration was significantly longer and the chewing rate was significantly higher during unilaterally chewing than freely chewing. The chewing duration differed significantly among the different foods; the harder the food, the longer the duration. Chewing rate was significantly higher during soft rice cracker chewing as well as suprahyoid activity per chewing cycle. Masseter activity was higher on the chewing side than on the non-chewing side while there was no difference in suprahyoid activity between the sides. CONCLUSION: The current results demonstrate a difference in the masticatory efficacy between the chewing tasks and a functional role of the suprahyoid muscles during chewing, which does not differ between the chewing and non-chewing sides.

    DOI: 10.1111/joor.13373

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  • Inhibition of Water-Evoked Swallowing During Noxious Mechanical Stimulation of Tongue in Anesthetized Rats. Reviewed International journal

    Takanori Tsujimura, Yuta Nakajima, Titi Chotirungsan, Satomi Kawada, Yuhei Tsutsui, Midori Yoshihara, Taku Suzuki, Kouta Nagoya, Jin Magara, Makoto Inoue

    Dysphagia   38 ( 3 )   965 - 972   2022.9

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    Dysphagia is sometimes accompanied by pain. Because orofacial structures subserve mastication and swallowing, orofacial pain might impair both functions. Tongue biting can occur not only accidentally while eating but also in some pathological conditions. However, it remains unclear whether noxious mechanical stimulation of the tongue affects swallowing. To explore this question, we evaluated the effects of lingual pinch stimulation on the initiation of swallowing evoked by distilled water (DW) infusion with a flow rate of 5.0 µL/s for 20 s into the pharyngolaryngeal region in anesthetized rats. The swallowing reflex was identified by electromyographic (EMG) bursts in the suprahyoid muscles which include the anterior belly of the digastric muscle, mylohyoid and geniohyoid muscles, and laryngeal elevation by visual inspection. The number of DW-evoked swallows during pinch stimulation was significantly smaller than that in a control condition or during pressure stimulation. The onset latency of the first swallow during pinch stimulation was significantly longer than that in the control condition. DW-evoked swallowing was almost abolished following bilateral transection of the superior laryngeal nerve (SLN) compared with the control condition, suggesting that the SLN plays a crucial role in the initiation of DW-evoked swallowing. Finally, electrophysiological data indicated that some SLN-responsive neurons in the nucleus tractus solitarii (nTS) exhibited delayed latency from a single SLN stimulation during lingual pinch stimulation. These results suggest that noxious mechanical stimulation of the tongue inhibits the initiation of swallowing and modulates neuronal activity in the nTS.

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  • 食塊形成過程の新しい評価法の検討

    笹 杏奈, 羽尾 直仁, 真柄 仁, 辻村 恭憲, 井上 誠

    言語聴覚研究   19 ( 3 )   256 - 256   2022.9

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  • 固形食品の食塊形成過程における舌骨上筋群の機能的役割の検討

    笹 杏奈, 真柄 仁, 辻村 恭憲, 井上 誠

    老年歯科医学   37 ( 2 )   113 - 114   2022.9

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  • 咀嚼の評価法を再考する

    井上 誠, 辻村 恭憲, 真柄 仁, 伊藤 加代子, 高橋 肇, 竹井 亮, 高田 夏佳

    日本老年歯科医学会総会・学術大会プログラム・抄録集   33回   O6 - 05   2022.6

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  • 固形食品摂取時の食塊形成過程における舌骨上筋群の機能的役割の検討

    笹 杏奈, 真柄 仁, 辻村 恭憲, 井上 誠

    日本老年歯科医学会総会・学術大会プログラム・抄録集   33回   O6 - 04   2022.6

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  • Impact of oral function on regaining oral intake and adjusting diet forms for acute stroke patients. Reviewed International journal

    Sirima Kulvanich, Haruka Sakai, Riho Takanami, Mako Yamada, Anna Sasa, Kayoko Ito, Takanori Tsujimura, Jin Magara, Makoto Inoue

    Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association   31 ( 5 )   106401 - 106401   2022.5

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    BACKGROUND: Outcome prediction for dysphagia recovery is essential for rehabilitation treatment planning. Several studies have reported various predictors for resuming oral feeding after post-stroke dysphagia. However, evidence on oral health and function, a crucial part of feeding, has rarely been reported. Therefore, the goal of this study was to identify the oral status-related factors that could predict oral intake resumption in acute stroke patients. METHODS: 80 acute stroke patients with dysphagia were included. Clinical data, including the changes of general condition, oral and swallowing functions, were collected once a week until discharge. Patients were divided into two groups based on the outcome of the food intake level scale at discharge, and data were compared between the groups. RESULTS: 60 patients had regained complete oral intake before discharge. Multiple logistic regression showed that posterior tongue pressure could significantly predict complete oral intake recovery. Tongue pressure and modified water swallowing test score also significantly influenced diet forms. In addition, Spearman correlation analysis showed that improvement of other oral status-related factors, such as oral moisture and dentition status, also indicated the improvement of diet forms and swallowing function during the hospital stay. CONCLUSION: Tongue pressure measurement could be a useful oral status-related indicator for predicting complete oral intake and adjusting diet forms for acute stroke patients during hospitalization. Acute stroke patients should receive proper oral status evaluation and implementation to enhance functional recovery.

    DOI: 10.1016/j.jstrokecerebrovasdis.2022.106401

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  • 筋電図ならびに顎運動軌跡の記録を用いた食塊形成/移送過程の評価

    笹 杏奈, 羽尾 直仁, 真柄 仁, 辻村 恭憲, 井上 誠

    日本顎口腔機能学会雑誌   28 ( 2 )   90 - 91   2022.3

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  • Cause of Impairments of Bolus Transport and Epiglottis Inversion. Reviewed International journal

    Taku Suzuki, Sirima Kulvanich, Takanori Tsujimura, Jin Magara, Yasushi Ohnishi, Makoto Inoue

    Dysphagia   2022.2

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    DOI: 10.1007/s00455-022-10421-9

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  • Functional Role of Suprahyoid Muscles in Bolus Formation During Mastication. Reviewed International journal

    Anna Sasa, Sirima Kulvanich, Naohito Hao, Reiko Ita, Masahiro Watanabe, Taku Suzuki, Jin Magara, Takanori Tsujimura, Makoto Inoue

    Frontiers in physiology   13   881891 - 881891   2022

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    It still remains unclear how the suprahyoid muscles function in bolus formation during mastication. This study aimed to investigate the contributory role of the suprahyoid muscles during mastication. A total of 20 healthy young volunteers were asked to perform tongue pressure generation tasks and unilateral mastication tasks using peanuts and two different types of rice crackers. Surface electromyographic (EMG) activity of the masseter and suprahyoid muscles and mandibular kinematics were recorded. Suprahyoid activity increased with increasing tongue pressure. Masticatory duration until the first deglutition differed significantly among the different foods; the harder the food, the longer the duration. This was also the case in masseter activity per masticatory cycle. Masticatory rate and suprahyoid activity per masticatory cycle were significantly higher during soft rice cracker mastication. Masseter activity was higher on the masticatory side than on the non-masticatory side, however, there was no difference in suprahyoid activity between the sides. Suprahyoid activity and jaw gape showed significant positive correlation in the early stage on both the masticatory and non-masticatory sides. The suprahyoid muscles functioned dominantly for jaw-opening during peanut mastication, and for bolus formation, especially in the late stage during soft rice cracker mastication. Bolus formation was performed dominantly on the masticatory side during rice cracker mastication. These findings clearly demonstrate a functional role of the suprahyoid muscles during mastication of solid foods from assessments using both EMG activity and mandibular kinematic recordings.

    DOI: 10.3389/fphys.2022.881891

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  • 急性期の延髄外側症候群の嚥下障害に対し、頸部回旋を併用したバルーン単純引き抜き法を行った一例

    筒井 雄平, 真柄 仁, 小貫 和佳奈, 坂 暢晃, 坂井 遥, 井上 誠

    新潟歯学会雑誌   51 ( 2 )   89 - 94   2021.12

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  • 筋電図ならびに顎運動軌跡の記録を用いた食塊形成過程の評価

    笹 杏奈, 羽尾 直仁, 真柄 仁, 辻村 恭憲, 井上 誠

    新潟歯学会雑誌   51 ( 2 )   118 - 118   2021.12

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  • 呼吸、嚥下、咀嚼の協調を探る

    羽尾 直仁, 笹 杏奈, 真柄 仁, 辻村 恭憲, 井上 誠, 筒井 雄平, 中嶋 優太

    日本摂食・嚥下リハビリテーション学会雑誌   25 ( 3 )   S186 - S186   2021.12

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  • Effects of Carbonation and Temperature on Voluntary Swallowing in Healthy Humans. Reviewed International journal

    Chikako Takeuchi, Eri Takei, Kayoko Ito, Sirima Kulvanich, Jin Magara, Takanori Tsujimura, Makoto Inoue

    Dysphagia   36 ( 3 )   384 - 392   2021.6

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    We investigated how swallowing behaviors are affected by the temperature and carbonation of water in healthy humans. Twenty-nine healthy volunteers were instructed to drink as much natural water, carbonated water, or cider as they wanted, and we recorded the volume of solution swallowed and electromyographic (EMG) activity of the masseter and suprahyoid muscles. Sensory tests regarding the ease of holding the solution in the mouth and ease of swallowing were also performed. The volume of carbonated water swallowed was significantly lower than that of natural water and cider. The ease of holding and swallowing the solution significantly differed between solution types such that natural water was the easiest solution to hold and swallow, followed by cider and then carbonated water in both tests. EMG activity was also affected by the solution type. Masseter EMG activity was significantly lower when swallowing natural water compared with carbonated water. Suprahyoid EMG activity was significantly lower when swallowing natural water compared with carbonated water and cider. The volume of solution swallowed was significantly correlated with the ease of holding and swallowing the solution, but not with masseter or suprahyoid EMG activities. The ease of holding and swallowing the solution significantly affected masseter and suprahyoid EMG activities. The results suggested that when participants experienced difficulty holding and swallowing the solution, masseter and suprahyoid EMG activity increased. Considering our findings that mechanical stimulation with bubbles decreased the volume of solution swallowed and increased EMG activities, carbonated water swallowing may be useful in treating deglutition disorders.

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  • Changes of bolus properties and the triggering of swallowing in healthy humans. Reviewed International journal

    Izumi Kochi, Eri Takei, Rumiko Maeda, Kayoko Ito, Jin Magara, Takanori Tsujimura, Sirima Kulvanich, Makoto Inoue

    Journal of oral rehabilitation   48 ( 5 )   592 - 600   2021.5

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    There is wide variation in chewing behaviours, even among healthy humans. Further, the way in which humans determine swallowing initiation when chewing solid foods remains unclear. The current study sought to investigate how the bolus properties change over time during chewing, and to clarify which factors affect chewing and swallowing behaviours, including swallowing initiation, in healthy humans. Twenty-four healthy volunteers were instructed to chew 8 g of steamed rice and spit it out at 50%, 100% and 150% of their own chewing duration, defined as the time of chewing from onset of the first chewing cycle to onset of the first swallow. Chewing and swallowing behaviours were monitored and determined by visual inspection of video recordings. The physical properties such as hardness, cohesiveness and adhesiveness as well as water content of the bolus were measured. In each subject, maximum bite force, tongue pressure and stimulated salivary flow rate were also measured. Hardness gradually decreased, and the cohesiveness and water content of the bolus did not change up to 50% of chewing duration, followed by a slight but significant increase. The adhesiveness of the bolus rapidly decreased at the beginning of chewing. Chewing duration was significantly related to stimulated salivary flow rate; greater salivary flow rate was associated with shorter chewing duration. Variation of chewing duration and swallowing initiation was not dependent on bolus properties during the chewing of steamed rice, but mainly depended on the surface lubrication of the bolus.

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  • Relationships Between Survival and Oral Status, Swallowing Function, and Oral Intake Level in Older Patients with Aspiration Pneumonia. Reviewed International journal

    Taku Suzuki, Takanori Tsujimura, Jin Magara, Naohito Hao, Naru Shiraishi, Kazuya Maekawa, Kazuo Matsushima, Makoto Inoue

    Dysphagia   37 ( 3 )   558 - 566   2021.4

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    The factors affecting the survival of patients with aspiration pneumonia (AP) remain unclear. This study aimed to determine whether factors, including oral status, swallowing function, and oral intake level, were related to survival outcomes in older patients hospitalized for AP. The study enrolled patients with AP who were admitted to our hospital between February 2017 and November 2019. Patients were divided into two groups based on the 90-day mortality after the first swallowing function evaluation: survivors and deceased. The data were compared between the two groups. A total of 29 patients were diagnosed with AP. Of these patients, 13 died within 90 days. The numbers of patients who could not use removable dentures and required sputum suctioning and had cough reflex at rest were significantly higher in the deceased than in the survivors. The salivary pooling and pharyngeal clearance scores evaluated by videoendoscopy, International Dysphagia Diet Standardisation Initiative Functional Diet Scale score determined after swallowing function evaluation, and consciousness level were significantly worse in the deceased than in the survivors. There were significant differences in patients' oral status, swallowing function, oral intake level, and consciousness level between the survivors and deceased.

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  • 健常者における呼吸と咀嚼/嚥下の協調

    羽尾 直仁, 笹 杏奈, 辻村 恭憲, 那小屋 公太, 真柄 仁, 井上 誠

    日本顎口腔機能学会雑誌   27 ( 1-2 )   32 - 33   2021.3

  • Impact of Oral and Swallowing Function on the Feeding Status of Older Adults in Nursing Homes. Reviewed International journal

    Sirima Kulvanich, Kayoko Ito, Eri Takei, Haruka Sakai, Risa Suzumi, Jin Magara, Takanori Tsujimura, Makoto Inoue

    Gerontology   67 ( 2 )   168 - 176   2021

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    BACKGROUND: To date, there have been few guidelines proposed for adjustment of the food consistency, particularly to match the oral function of older adults, which will guide clinicians and caregivers in appropriately modifying food. OBJECTIVE: We investigated how oral, swallowing, and cognitive conditions of older adults who required daily nursing care in a nursing home were associated with different dietary food consistencies. METHODS: Clinical examinations to record dentition status, swallowing, and cognitive functions were performed, and the feeding status, including the food consistencies and need for assistance at lunchtime, was evaluated in 37 older residents in nursing homes. The swallowing function was assessed by performing a modified water-swallowing test, and food swallowing was tested using pudding and rice crackers. The χ2 test was used to determine the relationships among the parameters. RESULTS: No participants were able to take cooked rice, nor regular and soft side dishes. There was no significant relationship between dentition status and feeding status. Of the participants, 95% ate pudding without any problems and 49% ate rice crackers without any signs of swallowing difficulty such as coughing or stopping chewing. There was a significant relationship between the food test score using a rice cracker and the level of food consistencies, and between the same test score and the level of mealtime assistance, whereby the better the score of the food test using a rice cracker, the better was the level of food consistencies including use of a thickening agent and the better was the level of mealtime assistance. CONCLUSION: The results strongly suggest that the food test using a rice cracker was associated with the level of food consistency and mealtime assistance for older adults in nursing homes.

    DOI: 10.1159/000511912

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  • Coordination of Respiration, Swallowing, and Chewing in Healthy Young Adults. Reviewed International journal

    Naohito Hao, Anna Sasa, Sirima Kulvanich, Yuta Nakajima, Kouta Nagoya, Jin Magara, Takanori Tsujimura, Makoto Inoue

    Frontiers in physiology   12   696071 - 696071   2021

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    Examining the coordination of respiration and swallowing is important for elucidating the mechanisms underlying these functions and assessing how respiration is linked to swallowing impairment in dysphagic patients. In this study, we assessed the coordination of respiration and swallowing to clarify how voluntary swallowing is coordinated with respiration and how mastication modulates the coordination of respiration and swallowing in healthy humans. Twenty-one healthy volunteers participated in three experiments. The participants were asked to swallow 3 ml of water with or without a cue, to drink 100 ml of water using a cup without breathing between swallows, and to eat a 4-g portion of corned beef. The major coordination pattern of respiration and swallowing was expiration-swallow-expiration (EE type) while swallowing 3 ml of water either with or without a cue, swallowing 100 ml of water, and chewing. Although cueing did not affect swallowing movements, the expiratory time was lengthened with the cue. During 100-ml water swallowing, the respiratory cycle time and expiratory time immediately before swallowing were significantly shorter compared with during and after swallowing, whereas the inspiratory time did not differ throughout the recording period. During chewing, the respiratory cycle time was decreased in a time-dependent manner, probably because of metabolic demand. The coordination of the two functions is maintained not only in voluntary swallowing but also in involuntary swallowing during chewing. Understanding the mechanisms underlying respiration and swallowing is important for evaluating how coordination affects physiological swallowing in dysphagic patients.

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  • Involvement of capsaicin-sensitive nerves in the initiation of swallowing evoked by carbonated water in anesthetized rats. Reviewed International journal

    Kojun Tsuji, Takanori Tsujimura, Shogo Sakai, Taku Suzuki, Midori Yoshihara, Kouta Nagoya, Jin Magara, Yoshihide Satoh, Makoto Inoue

    American journal of physiology. Gastrointestinal and liver physiology   319 ( 5 )   G564-G572   2020.11

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    Capsaicin powerfully evokes the swallowing reflex and is a known therapeutic agent for improving dysphagia and preventing aspiration pneumonia. However, the role of capsaicin-sensitive nerves in the initiation of swallowing evoked by various natural stimuli remains unclear. To explore this question, we blocked laryngeal capsaicin-sensitive nerves following the coapplication of QX-314 and capsaicin (QX/Cap), and investigated the effects on swallowing evoked by mechanical and chemical stimulation in anesthetized rats. Swallows were evoked by capsaicin, carbonated water (CW), distilled water (DW), and punctate mechanical stimulation using von Frey filaments applied topically to the larynx. Swallows were documented by recording electromyographic activation of the suprahyoid and thyrohyoid muscles. The initiation of swallowing by capsaicin was strongly suppressed at 5 min following QX/Cap treatment and returned in a time-dependent manner. CW-evoked swallows at 5 min following QX/Cap treatment were significantly diminished compared with before and 30 min after treatment. In contrast, DW-evoked and mechanically evoked swallows were unchanged by QX/Cap treatment. Furthermore, CW-evoked swallows were virtually abolished by transection of the superior laryngeal nerves and significantly decreased by the topical application of acid-sensing ion channel-3 (ASIC3) inhibitor APETx2, but they were not affected by the nonselective transient receptor potential channel inhibitor ruthenium red or the ASIC1 inhibitor mambalgin-1. Taken together, we speculate that capsaicin-sensitive nerves play an important role in the initiation of CW-evoked swallows.NEW & NOTEWORTHY The initiation of swallowing evoked by laryngeal capsaicin and carbonated water application was diminished by the coapplication of QX-314 and capsaicin. Carbonated water-evoked swallows were also abolished by transection of the superior laryngeal nerves and were inhibited by the acid-sensing ion channel-3 inhibitor. Capsaicin-sensitive nerves are involved in the initiation of carbonated water-evoked swallows.

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  • Age-related changes in functional adaptation to bolus characteristics during chewing. Reviewed International journal

    Eri Takei, Sirima Kulvanich, Takanori Tsujimura, Jin Magara, Kayoko Ito, Ryo Takei, Hideaki Washio, Hitoshi Arao, Makoto Inoue

    Physiology & behavior   225   113102 - 113102   2020.10

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    We investigated how the physical properties of food affect chewing kinematics, and examined the effects of aging on behavior. Twenty young and 21 older volunteers were asked to freely chew rice crackers and spit the food out at their average chewing duration. We compared chewing characteristics among the conditions (age × rice cracker), and examined the area of rectified masseter and suprahyoid electromyographic bursts per chewing cycle. We also evaluated temporal changes in those values. In addition, the bolus properties at the end of chewing were compared. The harder/larger the rice cracker, the longer the chewing duration and the greater the number of chewing cycles. These values also increased with age. Chewing cycle time was not affected by age and rice cracker properties, except in one condition: for the rice cracker with the lowest hardness and density, the chewing cycle time was longer than for the other rice crackers. Chewing cycle time decreased at the middle stage of chewing, followed by an increase, with increasing suprahyoid electromyographic activity at the late stage. The physical properties of the bolus at the end of chewing did not differ between age groups, and depended on the initial properties. The water absorption rate of the bolus was significantly greater for the rice cracker with the lowest hardness and density compared with other rice crackers. The results demonstrated that not only hardness, but also other factors, such as density, significantly affected chewing behaviors.

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  • Sustained laryngeal transient receptor potential vanilloid 1 activation inhibits mechanically induced swallowing in anesthetized rats. Reviewed International journal

    Midori Yoshihara, Takanori Tsujimura, Taku Suzuki, Kouta Nagoya, Naru Shiraishi, Jin Magara, Miho Terunuma, Makoto Inoue

    American journal of physiology. Gastrointestinal and liver physiology   319 ( 3 )   G412-G419   2020.9

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    A major component of gastric acid is hydrochloric acid (HCl), which can activate transient receptor potential vanilloid 1 (TRPV1). In the present study, we investigated how sustained laryngeal TRPV1 activation affects the frequency of the swallowing reflex. Experiments were carried out on 85 male Sprague-Dawley rats. The effects of short and sustained application of chemicals (3 µl of 0.1 N HCl or capsaicin) on the frequency of swallowing and on time-dependent changes in the occurrence of swallowing evoked by supralaryngeal nerve stimulation were determined. To evaluate vascular permeability of the larynx, Evans blue dye was intravenously injected after 5 or 60 min of sustained TRPV1 activation. SB366791 (a TRPV1 inhibitor) and Cap/QX-314 (a TRPV1-expressed neuronal inhibitor) significantly inhibited HCl/capsaicin-induced swallowing, but air flow-induced swallowing was not affected. Although the number of air flow-induced swallows followed by capsaicin stimulation was not affected within 5 min, it was significantly reduced by 60-min capsaicin or HCl application. The swallowing threshold associated with supralaryngeal nerve stimulation did not significantly change throughout the recording period. Evans blue dye concentrations in the larynx were significantly higher at 60 min in the 10-5 M capsaicin group than in the control group. Our results suggest that sustained TPRV1 activation not only desensitizes TRPV1 but also inactivates mechanoreceptors, which may be attributed to increases in vascular permeability and edema, as part of an inflammatory process.NEW & NOTEWORTHY Although a transient receptor potential vanilloid 1 (TRPV1) inhibitor or TRPV1-expressed neuronal inhibitor significantly inhibited HCl/capsaicin-evoked swallowing, air flow-induced swallowing was not affected. The number of air flow-induced swallows was significantly reduced within 60 min of TRPV1 activation. Evans blue dye concentration in the larynx increased 60 min after capsaicin application. TPRV1 activation not only desensitizes TRPV1 but also inactivates mechanoreceptors caused by increases in vascular permeability and edema.

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  • Inter-individual variation of bolus properties in triggering swallowing during chewing in healthy humans. Reviewed International journal

    Rumiko Maeda, Eri Takei, Kayoko Ito, Jin Magara, Takanori Tsujimura, Makoto Inoue

    Journal of oral rehabilitation   47 ( 9 )   1161 - 1170   2020.9

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    BACKGROUND: There is a wide variation of chewing behaviours even in healthy humans. The present study was aimed to clarify how the rheological properties of the bolus during chewing are different among individuals. We also investigated whether the swallowing threshold was consistent among the individuals and whether the difference in the bolus properties at the swallowing affected swallowing movement. METHODS: Twenty-nine healthy volunteers were asked to ingest 8 g of steamed rice. Based on the chewing duration defined by the time until first swallow, participants were asked to chew the food and then either spit it out or swallow it at 50%, 100% and 150% of chewing duration. In seven volunteers, the maximum bite force was measured. RESULTS: The hardness of the bolus gradually decreased throughout recording. Although the chewing duration varied widely, there was a significant negative correlation between time and hardness, regardless of the difference in individual chewing duration. The cohesiveness of the bolus was unchanged at the 100% time point, followed by a slight but significant increase. There was no significant correlation between the chewing duration and adhesiveness of the bolus. Swallowing-related bursts of Supra and Infra EMGs were not related to the chewing duration or bolus properties, and chewing duration did not affect swallowing function. CONCLUSION: The current results suggest that the bolus properties such as the hardness and cohesiveness during chewing are just dependent on the chewing duration and the difference in the bolus properties does not affect the swallowing initiation and movement.

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  • Properties of hyoid muscle contraction during tongue lift measurement. Reviewed International journal

    Naomi Koshi, Jin Magara, Shogo Sakai, Takanori Tsujimura, Kazuhiro Ono, Makoto Inoue

    Journal of oral rehabilitation   47 ( 3 )   332 - 338   2020.3

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    BACKGROUND: Tongue lift movement (TLM) task is considered a treatment strategy in dysphagic patients. However, there is no evidence of effect of sustained tongue movements on the related muscle contraction. OBJECTIVES: The present study aimed to characterise the properties and time-dependent changes of the electromyographic (EMG) features of suprahyoid muscles during TLM. METHODS: Twenty young healthy volunteers were instructed to perform TLM at maximum effort in either the anterior or the posterior position, during measurement of tongue pressure for 7 s. Supra- (S-hyo) and infra-hyoid (I-hyo) EMGs were recorded. The area and power frequency of EMG burst and the area under the curve of tongue pressure were compared among the conditions: trials (1st, 2nd vs 3rd trials); anterior vs posterior TLM; and early vs late 3 s of each trial. RESULTS: There was no difference in the tongue pressure among trials or between the early and late 3 s. Anterior tongue pressure was significantly higher than posterior tongue pressure (P < .001). The area of I-hyo EMG burst was significantly larger (P = .044), and the power frequency of I-hyo EMG burst was significantly smaller (P = .042) during posterior TLM than anterior TLM. A significant difference in the power frequency of both EMG bursts was observed between early and late stages during both anterior (P < .05) and posterior (P < .01) TLM. CONCLUSION: Hyoid muscles may compensate for rapid fatigue of the tongue muscle to maintain tongue pressure by changing their activity pattern during tongue pressure generation.

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  • Comparison of physical properties of voluntary coughing, huffing and swallowing in healthy subjects. Reviewed International journal

    Akiko Yawata, Takanori Tsujimura, Ryosuke Takeishi, Jin Magara, Li Yu, Makoto Inoue

    PloS one   15 ( 12 )   e0242810   2020

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    Coughing, huffing and swallowing protect the airway from aspiration. This study was conducted to compare the physical properties of voluntary coughing, huffing and swallowing in healthy subjects. Ten healthy men were asked to huff, cough and swallow repeatedly. Electromyograms (EMGs) were recorded from the left side of the external oblique (EO), sternocleidomastoid, suprahyoid (SH) and thyrohyoid muscles. Airflow was recorded using a face mask with two-way non-rebreathing valves. The expiratory velocity of huffing and coughing and the SH EMG of all actions presented high intraclass correlation coefficients (> 0.8). The inspiratory and expiratory velocities did not differ significantly between coughing and huffing. The expiratory acceleration of coughing was significantly higher than that of huffing, whereas the expiratory volume of coughing was significantly smaller than that of huffing. The EO EMG of coughing and huffing were significantly larger than that of swallowing. The EO EMG activity during the expiratory phase was significantly higher than that of the other phases of both coughing and huffing. The SH EMG of coughing and huffing were significantly smaller than that of swallowing. Correlation analysis revealed that the expiratory velocity of coughing was strongly positively correlated with that of huffing. The expiratory volume of huffing was significantly positively correlated with hand grip strength. These results suggest that EO and SH muscle activities during huffing or coughing differ those during swallowing, and huffing and coughing may work similarly in expiratory function.

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  • 嚥下誘発と咀嚼・嚥下の協調に関する神経機構(Neural mechanisms underlying swallowing initiation and coordination between chew and swallow)

    Inoue Makoto, Tsujimura Takanori, Magara Jin, Nagoya Kouta

    日本摂食・嚥下リハビリテーション学会雑誌   23 ( 3 )   S65 - S65   2019.12

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  • Involvement of the epithelial sodium channel in initiation of mechanically evoked swallows in anaesthetized rats. Reviewed International journal

    Takanori Tsujimura, Rumi Ueha, Midori Yoshihara, Eri Takei, Kouta Nagoya, Naru Shiraishi, Jin Magara, Makoto Inoue

    The Journal of physiology   597 ( 11 )   2949 - 2963   2019.6

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    KEY POINTS: Afferents carried by the superior laryngeal nerve play a primary role in the initiation of laryngeal mechanically evoked swallows in anaesthetized rats. Amiloride and its analogues inhibit swallowing evoked by mechanical stimulation, but not swallowing evoked by chemical and electrical stimulation. The epithelial sodium channel is probably involved in the initiation of laryngeal mechanically evoked swallows. ABSTRACT: The swallowing reflex plays a critical role in airway protection. Because impaired laryngeal mechanosensation is associated with food bolus aspiration, it is important to know how the laryngeal sensory system regulates swallowing initiation. This study was performed to clarify the neuronal mechanism of mechanically evoked swallows. Urethane-anaesthetized Sprague-Dawley male rats were used. A swallow was identified by activation of the suprahyoid and thyrohyoid muscles on electromyography. The swallowing threshold was measured by von Frey filament and electrical stimulation of the larynx. The number of swallows induced by upper airway distension and capsaicin application (0.03 nmol, 3 μl) to the vocal folds was counted. The effects of topical application (0.3-30 nmol, 3 μl) of the epithelial sodium channel (ENaC) blocker amiloride and its analogues (benzamil and dimethylamiloride), acid-sensing ion channel (ASIC) inhibitors (mambalgine-1 and diminazene) and gadolinium to the laryngeal mucosa on swallowing initiation were evaluated. A nerve transection study indicated that afferents carried by the superior laryngeal nerve play a primary role in the initiation of laryngeal mechanically evoked swallows. The mechanical threshold of swallowing was increased in a dose-dependent manner by amiloride and its analogues and gadolinium, but not by ASIC inhibitors. The number of swallows by upper airway distension was significantly decreased by benzamil application. However, the initiation of swallows evoked by capsaicin and electrical stimulation was not affected by benzamil application. We speculate that the ENaC is involved in the initiation of laryngeal mechanically evoked swallows.

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  • Cerebellar repetitive transcranial magnetic stimulation restores pharyngeal brain activity and swallowing behaviour after disruption by a cortical virtual lesion. Reviewed International journal

    Ayodele Sasegbon, Masahiro Watanabe, Andre Simons, Emilia Michou, Dipesh H Vasant, Jin Magara, Philip M Bath, John Rothwell, Makoto Inoue, Shaheen Hamdy

    The Journal of physiology   597 ( 9 )   2533 - 2546   2019.5

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    KEY POINTS: Despite evidence that the human cerebellum has an important role in swallowing neurophysiology, the effects of cerebellar stimulation on swallowing in the disrupted brain have not been explored. In this study, for the first time, the application of cerebellar neurostimulation is characterized in a human model of disrupted swallowing (using a cortical virtual lesion). It is demonstrated that cerebellar stimulation can reverse the suppressed activity in the cortical swallowing system and restore swallowing function in a challenging behavioural task, suggesting the findings may have important therapeutic implications. ABSTRACT: Repetitive transcranial magnetic stimulation (rTMS) can alter neuronal activity within the brain with therapeutic potential. Low frequency stimulation to the 'dominant' cortical swallowing projection induces a 'virtual-lesion' transiently suppressing cortical excitability and disrupting swallowing behaviour. Here, we compared the ability of ipsi-lesional, contra-lesional and sham cerebellar rTMS to reverse the effects of a 'virtual-lesion' in health. Two groups of healthy participants (n = 15/group) were intubated with pharyngeal catheters. Baseline pharyngeal motor evoked potentials (PMEPs) and swallowing performance (reaction task) were measured. Participants received 10 min of 1 Hz rTMS to the pharyngeal motor cortex which elicited the largest PMEPs to suppress cortical activity and disrupt swallowing behaviour. Over six visits, participants were randomized to receive 250 pulses of 10 Hz cerebellar rTMS to the ipsi-lesional side, contra-lesional side or sham while assessing PMEP amplitude or swallowing performance for an hour afterwards. Compared to sham, active cerebellar rTMS, whether administered ipsi-lesionally (P = 0.011) or contra-lesionally (P = 0.005), reversed the inhibitory effects of the cortical 'virtual-lesion' on PMEPs and swallowing accuracy (ipsi-lesional, P < 0.001, contra-lesional, P < 0.001). Cerebellar rTMS was able to reverse the disruptive effects of a 'virtual lesion'. These findings provide evidence for developing cerebellar rTMS into a treatment for post-stroke dysphagia.

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  • Effect of attention on chewing and swallowing behaviors in healthy humans. Reviewed International journal

    Hirokazu Ashiga, Eri Takei, Jin Magara, Ryosuke Takeishi, Takanori Tsujimura, Kouta Nagoya, Makoto Inoue

    Scientific reports   9 ( 1 )   6013 - 6013   2019.4

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    We examined how attention alters chewing and swallowing behaviors. Twenty-one healthy volunteers were asked to freely eat 8 g of steamed rice in three separate trials, and we obtained the average number of chewing cycles (N) and chewing duration (T) prior to the first swallow in each trial. We also conducted an N-limited test, in which participants chewed the food while independently counting the number of chewing cycles and swallowed the food when they reached N, and a T-limited test, in which they chewed the food for T sec and then swallowed. We recorded electromyograms (EMGs) from masseter and suprahyoid muscles and collected videoendoscopic images. In the N-limited test, chewing speed decreased, masseter muscle activity (area under the curve of the rectified EMG burst) per cycle increased, and suprahyoid muscle activity per cycle decreased. In the T-limited test, the chewing speed increased, muscle activities per cycle decreased, and the number of cycles increased. The occurrence frequency of bolus propulsion into the pharynx before swallowing was smaller in the N- and T-limited tests than in the free chewing test. Further, the whiteout time was longer in the T-limited test than in the free chewing test. Attentional chewing changes not only chewing but also swallowing behavior.

    DOI: 10.1038/s41598-019-42422-4

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  • Effect of peripherally and cortically evoked swallows on jaw reflex responses in anesthetized rabbits. Reviewed International journal

    Taku Suzuki, Midori Yoshihara, Shogo Sakai, Kojun Tsuji, Kouta Nagoya, Jin Magara, Takanori Tsujimura, Makoto Inoue

    Brain research   1694   19 - 28   2018.9

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    This study aimed to investigate whether the jaw-opening (JOR) and jaw-closing reflexes (JCR) are modulated during not only peripherally, but also centrally, evoked swallowing. Experiments were carried out on 24 adult male Japanese white rabbits. JORs were evoked by trigeminal stimulation at 1 Hz for 30 s. In the middle 10 s, either the superior laryngeal nerve (SLN) or cortical swallowing area (Cx) was simultaneously stimulated to evoke swallowing. The peak-to-peak JOR amplitude was reduced during the middle and late 10-s periods (i.e., during and after SLN or Cx stimulation), and the reduction was dependent on the current intensity of SLN/Cx stimulation: greater SLN/Cx stimulus current resulted in greater JOR inhibition. The reduction rate was significantly greater during Cx stimulation than during SLN stimulation. The amplitude returned to baseline 2 min after 10-s SLN/Cx stimulation. The effect of co-stimulation of SLN and Cx was significantly greater than that of SLN stimulation alone. There were no significant differences in any parameters of the JCR between conditions. These results clearly showed that JOR responses were significantly suppressed, not only during peripherally evoked swallowing but also during centrally evoked swallowing, and that the inhibitory effect is likely to be larger during centrally compared with peripherally evoked swallowing. The functional implications of these results are discussed.

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  • 聴神経腫瘍術後に脳幹・小脳出血を合併し摂食嚥下障害を認めた1症例 Reviewed

    笹 杏奈, 辻 光順, 渡邊 賢礼, 那小屋 公太, 伊藤 加代子, 真柄 仁, 辻村 恭憲, 井上 誠

    新潟歯学会雑誌   48 ( 1 )   37 - 41   2018.6

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  • Involvement of hypoglossal and recurrent laryngeal nerves on swallowing pressure. Reviewed International journal

    Takanori Tsujimura, Taku Suzuki, Midori Yoshihara, Shogo Sakai, Naomi Koshi, Hirokazu Ashiga, Naru Shiraishi, Kojun Tsuji, Jin Magara, Makoto Inoue

    Journal of applied physiology (Bethesda, Md. : 1985)   124 ( 5 )   1148 - 1154   2018.5

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    Swallowing pressure generation is important to ensure safe transport of an ingested bolus without aspiration or leaving residue in the pharynx. To clarify the mechanism, we measured swallowing pressure at the oropharynx (OP), upper esophageal sphincter (UES), and cervical esophagus (CE) using a specially designed manometric catheter in anesthetized rats. A swallow, evoked by punctate mechanical stimulation to the larynx, was identified by recording activation of the suprahyoid and thyrohyoid muscles using electromyography (EMG). Areas under the curve of the swallowing pressure at the OP, UES, and CE from two trials indicated high intrasubject reproducibility. Effects of transecting the hypoglossal nerve (12N) and recurrent laryngeal nerve (RLN) on swallowing were investigated. Following bilateral hypoglossal nerve transection (Bi-12Nx), OP pressure was significantly decreased, and time intervals between peaks of thyrohyoid EMG bursts and OP pressure were significantly shorter. Decreased OP pressure and shortened times between peaks of thyrohyoid EMG bursts and OP pressure following Bi-12Nx were significantly increased and longer, respectively, after covering the hard and soft palates with acrylic material. UES pressure was significantly decreased after bilateral RLN transection compared with that before transection. These results suggest that the 12N and RLN play crucial roles in OP and UES pressure during swallowing, respectively. We speculate that covering the palates with a palatal augmentation prosthesis may reverse the reduced swallowing pressure in patients with 12N or tongue damage by the changes of the sensory information and of the contact between the tongue and a palates. NEW & NOTEWORTHY Hypoglossal nerve transection reduced swallowing pressure at the oropharynx. Covering the hard and soft palates with acrylic material may reverse the reduced swallowing function caused by hypoglossal nerve damage. Recurrent laryngeal nerve transection reduced upper esophageal sphincter negative pressure during swallowing.

    DOI: 10.1152/japplphysiol.00944.2017

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  • Immediate effect of laryngeal surface electrical stimulation on swallowing performance. Reviewed International journal

    Keizo Takahashi, Kazuhiro Hori, Hirokazu Hayashi, Masako Fujiu-Kurachi, Takahiro Ono, Takanori Tsujimura, Jin Magara, Makoto Inoue

    Journal of applied physiology (Bethesda, Md. : 1985)   124 ( 1 )   10 - 15   2018.1

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    Surface electrical stimulation of the laryngeal region is used to improve swallowing in dysphagic patients. However, little is known about how electrical stimulation affects tongue movements and related functions. We investigated the effect of electrical stimulation on tongue pressure and hyoid movement, as well as suprahyoid and infrahyoid muscle activity, in 18 healthy young participants. Electrical stimulation (0.2-ms duration, 80 Hz, 80% of each participant's maximal tolerance) of the laryngeal region was applied. Each subject swallowed 5 ml of barium sulfate liquid 36 times at 10-s intervals. During the middle 2 min, electrical stimulation was delivered. Tongue pressure, electromyographic activity of the suprahyoid and infrahyoid muscles, and videofluorographic images were simultaneously recorded. Tongue pressure during stimulation was significantly lower than before or after stimulation and was significantly greater after stimulation than at baseline. Suprahyoid activity after stimulation was larger than at baseline, while infrahyoid muscle activity did not change. During stimulation, the position of the hyoid at rest was descended, the highest hyoid position was significantly inferior, and the vertical movement was greater than before or after stimulation. After stimulation, the positions of the hyoid at rest and at the maximum elevation were more superior than before stimulation. The deviation of the highest positions of the hyoid before and after stimulation corresponded to the differences in tongue pressures at those times. These results suggest that surface electrical stimulation applied to the laryngeal region during swallowing may facilitate subsequent hyoid movement and tongue pressure generation after stimulation. NEW & NOTEWORTHY Surface electrical stimulation applied to the laryngeal region during swallowing may facilitate subsequent hyoid movement and tongue pressure generation after stimulation. Tongue muscles may contribute to overshot recovery more than hyoid muscles.

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  • Effects of pharyngeal electrical stimulation on swallowing performance. Reviewed International journal

    Ryosuke Takeishi, Jin Magara, Masahiro Watanabe, Takanori Tsujimura, Hirokazu Hayashi, Kazuhiro Hori, Makoto Inoue

    PloS one   13 ( 1 )   e0190608   2018

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    Pharyngeal electrical stimulation (PEStim) has been found to facilitate voluntary swallowing. This study investigated how PEStim contributed to modulation of swallowing function in 15 healthy humans. In the involuntary swallowing test, water was injected onto the pharynx at 0.05 ml/s and the onset latency of the first swallow was measured. In the voluntary swallowing test, subjects swallowed their own saliva as quickly as possible for 30 s and the number of swallows was counted. Voluntary and involuntary swallowing was evaluated before (baseline), immediately after, and every 10 min after 10-min PEStim for 60 min. A voluntary swallowing test with simultaneous 30-s PEStim was also conducted before and 60 min after 10-min PEStim. The number of voluntary swallows with simultaneous PEStim significantly increased over 60 min after 10-min PEStim compared with the baseline. The onset latency of the first swallow in the involuntary swallowing test was not affected by 10-min PEStim. The results suggest that PEStim may have a long-term facilitatory effect on the initiation of voluntary swallowing in healthy humans, but not on peripherally-evoked swallowing. The physiological implications of this modulation are discussed.

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  • Relationship between bolus formation and swallowing initiation during chewing steamed rice

    Rumiko Maeda, Eri Takei, Jin Magara, Takanori Tsujimura, Ryousuke Takeishi, Makoto Inoue

    The Journal of Japanese Society of Stomatognathic Function   24 ( 2 )   130 - 131   2018

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  • Physical properties of bolus and muscle activities during rice chewing

    Eri Takei, Rumiko Maeda, Jin Magara, Takanori Tsujimura, Ryosuke Takeishi, Makoto Inoue

    The Journal of Japanese Society of Stomatognathic Function   25 ( 1 )   32 - 33   2018

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    DOI: 10.7144/sgf.25.32

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  • Changing mastication and swallowing by volitional chewing

    Hirokazu Ashiga, Taku Suzuki, Jin Magara, Ryosuke Takeishi, Takanori Tsujimura, Makoto Inoue

    The Journal of Japanese Society of Stomatognathic Function   24 ( 2 )   128 - 129   2018

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  • Effect of body posture on chewing behaviours in healthy volunteers Reviewed

    T. Iizumi, J. Magara, T. Tsujimura, M. Inoue

    JOURNAL OF ORAL REHABILITATION   44 ( 11 )   835 - 842   2017.11

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    DOI: 10.1111/joor.12555

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  • Central inhibition of initiation of swallowing by systemic administration of diazepam and baclofen in anaesthetized rats. Reviewed International journal

    Takanori Tsujimura, Shogo Sakai, Taku Suzuki, Izumi Ujihara, Kojun Tsuji, Jin Magara, Brendan J Canning, Makoto Inoue

    American journal of physiology. Gastrointestinal and liver physiology   312 ( 5 )   G498-G507 - G507   2017.5

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    DOI: 10.1152/ajpgi.00299.2016

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  • Impact of oral ingestion on oral health condition in dysphagic inpatients Reviewed

    Tejima Y, Ito K, Magara J, Tsujimura T, Inoue M

    Oral Health and Dental Management   16 ( 1 )   1 - 9   2017

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  • 歩行機能と摂食機能の比較 身体的フレイル患者における検討

    保田 麻里, 真柄 仁, 井上 誠

    日本口腔リハビリテーション学会雑誌   29 ( 1 )   60 - 61   2016.12

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  • 舌強化訓練により、嚥下機能改善を認めた一例

    佐藤 茜, 上村 由紀子, 林 宏和, 真柄 仁, 井上 誠

    日本摂食・嚥下リハビリテーション学会雑誌   20 ( 3 )   S266 - S266   2016.12

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  • Differential response properties of peripherally and cortically evoked swallows by electrical stimulation in anesthetized rats. Reviewed International journal

    Takanori Tsujimura, Kojun Tsuji, Jin Magara, Shogo Sakai, Taku Suzuki, Yuki Nakamura, Kayoko Nozawa-Inoue, Makoto Inoue

    Brain research bulletin   122   12 - 8   2016.4

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    DOI: 10.1016/j.brainresbull.2016.02.015

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  • Effect of body posture on involuntary swallow in healthy volunteers. Reviewed International journal

    Yoshitaka Shiino, Shogo Sakai, Ryosuke Takeishi, Hirokazu Hayashi, Masahiro Watanabe, Takanori Tsujimura, Jin Magara, Kayoko Ito, Tetsu Tsukada, Makoto Inoue

    Physiology & behavior   155   250 - 9   2016.3

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    DOI: 10.1016/j.physbeh.2015.12.024

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  • Contribution of synovial lining cells to synovial vascularization of the rat temporomandibular joint. Reviewed International journal

    Kayoko Nozawa-Inoue, Fumiko Harada, Jin Magara, Atsushi Ohazama, Takeyasu Maeda

    Journal of anatomy   228 ( 3 )   520 - 9   2016.3

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    DOI: 10.1111/joa.12426

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  • Changes in jaw muscle activity and the physical properties of foods with different textures during chewing behaviors. Reviewed International journal

    Hiroko Iguchi, Jin Magara, Yuki Nakamura, Takanori Tsujimura, Kayoko Ito, Makoto Inoue

    Physiology & behavior   152 ( Pt A )   217 - 24   2015.12

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    DOI: 10.1016/j.physbeh.2015.10.004

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  • 介護保険施設における本学研修医への口腔ケアおよび摂食指導

    船山 さおり, 伊藤 加代子, 辻村 恭憲, 真柄 仁, 林 宏和, 辻 光順, 酒井 翔悟, 井上 誠

    日本摂食・嚥下リハビリテーション学会雑誌   19 ( 3 )   S254 - S254   2015.12

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  • Peripheral and central control of swallowing initiation in healthy humans. Reviewed International journal

    Seiya Aida, Ryosuke Takeishi, Jin Magara, Masahiro Watanabe, Kayoko Ito, Yuki Nakamura, Takanori Tsujimura, Hirokazu Hayashi, Makoto Inoue

    Physiology & behavior   151   404 - 11   2015.11

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    DOI: 10.1016/j.physbeh.2015.08.003

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  • Comparison of mechanical analyses and tongue pressure analyses during squeezing and swallowing of gels Reviewed

    Kazuhiro Hori, Hirokazu Hayashi, Sumiko Yokoyama, Takahiro Ono, Sayaka Ishihara, Jin Magara, Hiroshige Taniguchi, Takahiro Funami, Yoshinobu Maeda, Makoto Inoue

    Food Hydrocolloids   44   145 - 155   2015.2

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Elsevier  

    DOI: 10.1016/j.foodhyd.2014.09.029

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  • Changes in the frequency of swallowing during electrical stimulation of superior laryngeal nerve in rats. Reviewed International journal

    Kojun Tsuji, Takanori Tsujimura, Jin Magara, Shogo Sakai, Yuki Nakamura, Makoto Inoue

    Brain research bulletin   111   53 - 61   2015.2

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    DOI: 10.1016/j.brainresbull.2014.12.008

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  • ガム咀嚼運動が嚥下反射惹起に与える影響

    谷口 裕重, 堀 一浩, 林 宏和, 辻村 恭憲, 真柄 仁, 竹石 龍右, 井上 誠

    日本摂食・嚥下リハビリテーション学会雑誌   18 ( 3 )   S210 - S210   2014.12

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  • 当院における小児摂食嚥下障害患者における過去5年間の臨床統計

    渡邊 賢礼, 中村 由紀, 辻村 恭憲, 谷口 裕重, 堀 一浩, 真柄 仁, 林 宏和, 井上 誠

    日本摂食・嚥下リハビリテーション学会雑誌   18 ( 3 )   S167 - S167   2014.12

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  • 咀嚼時の嚥下反射誘発抑制

    井上 誠, 竹石 龍右, 谷口 裕重, 堀 一浩, 真柄 仁, 林 宏和

    日本摂食・嚥下リハビリテーション学会雑誌   18 ( 3 )   S210 - S211   2014.12

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  • ヒト咽頭粘膜への電気刺激がもたらす嚥下機能の神経可塑性変化

    竹石 龍右, 真柄 仁, 谷口 裕重, 林 宏和, 辻村 恭憲, 堀 一浩, 井上 誠

    日本摂食・嚥下リハビリテーション学会雑誌   18 ( 3 )   S46 - S46   2014.12

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  • 食道癌術後患者における摂食嚥下障害の臨床統計

    林 宏和, 真柄 仁, 畠山 文, 谷口 裕重, 井上 誠

    日本摂食・嚥下リハビリテーション学会雑誌   18 ( 3 )   S114 - S114   2014.12

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  • 高齢者にも使いやすい紙パックの開発とその検証

    椎野 良隆, 谷口 裕重, 林 宏和, 酒井 翔悟, 真柄 仁, 井上 誠, 鈴木 絵里

    日本摂食・嚥下リハビリテーション学会雑誌   17 ( 3 )   S235 - S236   2013.12

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  • Role of tongue pressure production in oropharyngeal swallow biomechanics. Reviewed International journal

    Kazuhiro Hori, Hiroshige Taniguchi, Hirokazu Hayashi, Jin Magara, Yoshitomo Minagi, Qiang Li, Takahiro Ono, Makoto Inoue

    Physiological reports   1 ( 6 )   e00167   2013.11

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    The tongue is important for orofacial movements, including swallowing. Although numerous studies have focused on tongue pressure against the palate, its physiological role has not been fully evaluated. The tongue pressure generation may have the temporal coordination with the swallowing relational organs. The aim of this study was to clarify the physiological mechanisms of tongue pressure and to investigate the temporal relationship among tongue pressure, supra-hyoid muscle activity, and videofluorographic (VF) images during swallowing. Fifteen healthy young subjects participated. Tongue pressure measured using a sensor sheet with five channels, electromyographic EMG, and VF was recorded synchronously during 4-ml barium swallowing. Swallowing behavior in VF images with and without the sensor sheet was compared. Furthermore, the temporal relationship between events measured from tongue pressure, EMG, and VF was evaluated. Swallowing behavior on VF images was not affected by placement of the sensor sheet. Tongue pressure at the posterio-lateral point of the hard palate tended to have biphasic peaks. Tongue pressure production with a monophasic pattern appeared during the same period as the second peak in the biphasic pattern. The onset of tongue pressure was later than the start of hyoid movement and onset of EMG, and offset was observed between the hyoid at the up-forward position and reposition. Onset of tongue pressure at the anterior area was correlated with the start of slight hyoid elevation. Offset of tongue pressure at the posterio-lateral points was strongly time locked with the hyoid at the up-forward position. The present results suggested the temporal coordination of tongue pressure generation with the swallowing-related organs. That is, the tongue pressure was produced for bolus propulsion, and was closely related to hyoid movement temporally during swallowing. These results may contribute to clarify the clinical state with the disorder of tongue kinetics.

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  • Effects of chewing and swallowing behavior on jaw opening reflex responses in freely feeding rabbits. Reviewed International journal

    Aki Yamada, Yuka Kajii, Shogo Sakai, Takanori Tsujimura, Yuki Nakamura, Sajjiv Ariyasinghe, Jin Magara, Makoto Inoue

    Neuroscience letters   535   73 - 7   2013.2

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    DOI: 10.1016/j.neulet.2012.12.047

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  • Alterations in intermediate filaments expression in disc cells from the rat temporomandibular joint following exposure to continuous compressive force. Reviewed International journal

    Jin Magara, Kayoko Nozawa-Inoue, Akiko Suzuki, Yoshiro Kawano, Kazuhiro Ono, Shuichi Nomura, Takeyasu Maeda

    Journal of anatomy   220 ( 6 )   612 - 21   2012.6

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    DOI: 10.1111/j.1469-7580.2012.01501.x

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  • Phenotypes of articular disc cells in the rat temporomandibular joint as demonstrated by immunohistochemistry for nestin and GFAP. Reviewed International journal

    Hitoshi Miyako, Akiko Suzuki, Kayoko Nozawa-Inoue, Jin Magara, Yoshiro Kawano, Kazuhiro Ono, Takeyasu Maeda

    Journal of anatomy   219 ( 4 )   472 - 80   2011.10

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    DOI: 10.1111/j.1469-7580.2011.01404.x

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  • Factors Affecting the Satisfaction of Elderly Denture Wearers

    KON Haruka, SATOH Naoko, NOMURA Shuichi, SAKURAI Naoki, TANAKA Mikako, HOSOGAI Akiko, YAMADA Kazuho, KINJOH Atsushi, KAI Asako, YAMASHITA Emi, KANEKO Atsuro, MAGARA Zin, KOBAYASHI Hiroshi, MIYAZAKI Hideo, YOSHIHARA Akihiro, KOHNO Shoji

    Annals of Japan Prosthodontic Society   1 ( 4 )   361 - 369   2009.10

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    <B>Purpose:</B> This study aimed to define the relationship between satisfaction of wearing denture and three factors ("easy to chew", "retention in chewing", "absence of pain"), as well as the missing teeth pattern with Miyachi classification, the chewing ability.<br><B>Methods:</B> A total of 256 subjects (born in 1927) living in Niigata city, Japan who had answered a questionnaire survey in 2007 on the relationship between oral health and health status were selected for this study. Satisfaction with dentures and three factors ("easy to chew", "retention in chewing", and "absence of pain") were evaluated with the VAS score. This study also investigated grouping the pattern of missing teeth based on the Miyachi classification. In addition, a questionnaire was conducted to investigate whether the elderly people could chew around 15 different food items or not.<br><B>Result:</B> It was clearly shown that satisfaction with dentures was correlated with the three points of chewing easily, stability, and pain-free among elderly people. However, none of the three points showed a far stronger correlation than the others. The results also showed that there was no relation between the missing teeth pattern classified with the Miyachi classification and satisfaction with dentures. The results of the questionnaire revealed that the number of food items taken by the elderly people was significantly lower in the group not satisfied with dentures than the other groups (Excellent, good, poorly satisfaction group). <br><B>Conclusion:</B> It was confirmed that chewing easily, stability and pain-free enhance satisfaction with dentures. However, satisfaction with dentures was not ascribed to the pattern of missing teeth; accordingly, we consider that we can keep elderly people satisfied by fabricating good dentures and performing appropriate adjustments regardless of difficult patterns of missing teeth.

    DOI: 10.2186/ajps.1.361

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    Other Link: http://search.jamas.or.jp/link/ui/2010031506

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MISC

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Presentations

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Awards

  • 2023年度 学会賞

    2023.12   日本顎口腔機能学会  

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  • Oral presentation award

    2021.8   2nd World Dysphagia Summit  

    Jin Magara

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  • デンツプライシロナ賞

    2018.6   日本補綴歯科学会  

    真柄 仁

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  • 学術大会 優秀賞

    2014.4   日本顎口腔機能学会  

    真柄 仁

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Research Projects

  • 咀嚼嚥下時における舌運動ダイナミクスの解明

    Grant number:25K13123

    2025.4 - 2028.3

    System name:科学研究費助成事業

    Research category:基盤研究(C)

    Awarding organization:日本学術振興会

    真柄 仁

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    Grant amount:\4680000 ( Direct Cost: \3600000 、 Indirect Cost:\1080000 )

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  • Sensory motor integration in the recovery process of tongue function &#8211; exploring the active touch -

    Grant number:22K10053

    2022.4 - 2025.3

    System name:Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

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    Grant amount:\4160000 ( Direct Cost: \3200000 、 Indirect Cost:\960000 )

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  • 咀嚼が変える、嚥下調整食のこれから

    2021.4 - 2022.3

    Awarding organization:ロッテ財団 第8回 奨励研究助成

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    Authorship:Principal investigator 

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  • 口腔機能低下症患者における口腔機能管理の実施効果

    2021.4 - 2022.3

    System name:令和3年度8020財団研究事業

    Awarding organization:8020財団

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    Authorship:Principal investigator 

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  • 顎口腔運動学習による嚥下関連高次脳ネットワーク再構築を検証する

    2019.4 - 2022.3

    System name:基盤研究(C)

    Awarding organization:科学研究費助成事業

    真柄 仁

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    Authorship:Principal investigator  Grant type:Competitive

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  • 口腔への温度刺激がもたらす嚥下機能の変化 -感覚運動の統合機構の解明-

    2017.4 - 2019.3

    System name:若手研究(B)

    Awarding organization:科学研究費助成事業

    真柄 仁

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    Authorship:Principal investigator  Grant type:Competitive

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  • レオロジーの異なる炭酸飲料による嚥下機能への刺激効果の解明

    Grant number:23K01992

    2023.4 - 2027.3

    System name:科学研究費助成事業

    Research category:基盤研究(C)

    Awarding organization:日本学術振興会

    岩森 大, 澁谷 顕一, 真柄 仁

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    Grant amount:\4810000 ( Direct Cost: \3700000 、 Indirect Cost:\1110000 )

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  • Multiple approach to evaluate dysphagia condition using animal model

    Grant number:22KK0139

    2022.10 - 2025.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))

    Awarding organization:Japan Society for the Promotion of Science

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    Grant amount:\20150000 ( Direct Cost: \15500000 、 Indirect Cost:\4650000 )

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  • Functional role of anteiror cingulate cortex on feeding

    Grant number:22K19616

    2022.6 - 2025.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Challenging Research (Exploratory)

    Awarding organization:Japan Society for the Promotion of Science

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    Grant amount:\6500000 ( Direct Cost: \5000000 、 Indirect Cost:\1500000 )

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  • 脳可塑性変化に基づく口腔リハビリテーション効果の解析

    Grant number:22H03284

    2022.4 - 2025.3

    System name:科学研究費助成事業

    Research category:基盤研究(B)

    Awarding organization:日本学術振興会

    島田 明子, 高橋 一也, 佐々木 啓一, 松原 貴子, 村田 比呂司, 飯田 崇, 小見山 道, 鳥巣 哲朗, 真柄 仁

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    Grant amount:\17810000 ( Direct Cost: \13700000 、 Indirect Cost:\4110000 )

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  • Understanding fundamental masticatory function by evaluation of physiological and food science approaches

    Grant number:22K10073

    2022.4 - 2025.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

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    Grant amount:\4290000 ( Direct Cost: \3300000 、 Indirect Cost:\990000 )

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  • 脳可塑性変化に基づく口腔リハビリテーション効果の解析

    Grant number:23K24542

    2022.4 - 2025.3

    System name:科学研究費助成事業

    Research category:基盤研究(B)

    Awarding organization:日本学術振興会

    島田 明子, 高橋 一也, 佐々木 啓一, 松原 貴子, 村田 比呂司, 飯田 崇, 小見山 道, 鳥巣 哲朗, 真柄 仁

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    Grant amount:\17810000 ( Direct Cost: \13700000 、 Indirect Cost:\4110000 )

    本研究課題は,舌挙上訓練などの筋機能訓練により生じる中枢の神経可塑性変化と末梢の運動機能改善度の総合的な分析を目的としている.
    2023年度は,低舌圧を伴う口腔機能低下症高齢者を対象とし,経頭蓋磁気刺激(TMS)に対する舌筋の運動閾値(Motor Thresholds: MTs)などの神経可塑性変化パラメータと舌圧などの口腔機能パラメータを舌挙上訓練を用いた口腔リハビリテーション介入前後で総合的に分析し,舌に対する口腔リハビリテーションの効果および持続性を検討した.
    予備実験として,短期間の口腔リハビリテーションの効果を検証するため、5日連続で舌挙上訓練を低舌圧を伴う口腔機能低下症患者に実施し,1日目と5日目でTMSによる神経可塑性変化の評価を行った.若年健常者の口腔リハビリテーション介入前後の運動野における神経可塑性変化とは異なるデータが口腔機能低下高齢者にて示されたため,当初予定していた解析方法の改定を行った.
    現時点で収集されたデータの統計解析の結果,低舌圧を伴う口腔機能低下症高齢患者において,5日間連続の舌に対する口腔リハビリテーションにより,舌を司る運動野へのTMSに対するMTsの有意な減少が認められた.
    若年健常者で観察された舌に対する口腔リハビリテーションによる運動野の神経可塑性変化が、高齢者でも発現することが明らかとなり,高齢者においても若年者同様に末梢に対するリハビリテーションが脳可塑性変化をもたらす可能性が示唆された.

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  • Impact of orofacial function on recovery from dysphagia caused by cerebrovascular disorders

    Grant number:21H03128

    2021.4 - 2024.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (B)

    Awarding organization:Japan Society for the Promotion of Science

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    Grant amount:\17290000 ( Direct Cost: \13300000 、 Indirect Cost:\3990000 )

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  • 顎・舌運動と食塊移送から読みとく咀嚼機能評価

    Grant number:20K10265

    2020.4 - 2023.3

    System name:科学研究費助成事業

    Research category:基盤研究(C)

    Awarding organization:日本学術振興会

    渡邊 賢礼, 井上 誠, 真柄 仁

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    Grant amount:\4420000 ( Direct Cost: \3400000 、 Indirect Cost:\1020000 )

    健常者20名を対象として,口蓋への舌押し付け運動時の舌骨上筋群活動を表面筋電図にて記録した(実験1).油分と硬さが異なる2種の米菓(ハッピーターン,ハイハイン),ピーナツ各3 gを対象として,自由摂取ならびに片側咀嚼による筋電図(左右咬筋,左右舌骨上筋群,左側舌骨下筋群筋電図),嚥下内視鏡画像,VICONを用いた頭部ならび下顎の三次元運動軌跡の記録を行った(実験2).
    舌圧発揮の程度に依存して舌骨上筋群活動は有意に上昇し,最大舌圧発揮時には最大開口時に近い活動量が得られたことで,舌骨上筋群は舌全体を引き上げることで舌運動を補助していることが示された.実験2では,全量摂取時間,最初の嚥下までの咀嚼時間,咀嚼回数とも食品の硬さに応じて延長した.また,いずれの食品摂取時においても,自由咀嚼に比べて片側咀嚼では,咀嚼時間,咀嚼回数は延長し,咀嚼サイクル時間はわずかに延長した.一方,咬筋活動量は硬さに依存して増加したものの,舌骨上筋群活動には咀嚼タスクによる違い,咀嚼側と非咀嚼側による違いは認められず,開口や食塊形成における左右差は明らかではなかった.
    食品粉砕が主となる咀嚼前期においては,いずれの被験者においても舌骨上筋群活動量とこれに依存すると期待される開口量との間に高い正の相関が得られた.これらの値を用いて, 1咀嚼サイクルにおいて舌骨上筋群が開口優位に働いたサイクル(JO),食塊形成優位に働いたサイクル(De)を定義し,条件間で比較したところ,JOはピーナッツで有意にその回数,頻度ともに高かったのに対して,Deはハイハインにて有意に高い頻度だった.舌骨上筋群活動量/開口量を比較したところ,ハイハイン咀嚼時には咀嚼側,非咀嚼側ともに後期に上昇しており,咀嚼側で高かった.これらの関係を調べることが,食塊形成における舌骨上筋群の働きを明らかにするために有用であることが示唆された.

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  • 摂食嚥下機能評価をベースとした誤嚥性肺炎患者に対するクリニカルパス策定と有効性の検討

    2018.4 - 2020.3

    System name:(分担)

    Awarding organization:新潟市医師会地域医療研究助成

    建部 一毅

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    Grant type:Competitive

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  • 加齢に伴う摂食関連機能と形態変化ならびにその関係

    2017.4 - 2020.3

    System name:基盤研究(C)(分担)

    Awarding organization:科学研究費助成事業

    小野 和宏

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    Grant type:Competitive

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  • 消化器外科手術後の包括的嚥下機能評価に関する研究

    2017.4 - 2020.3

    System name:基盤研究(C)(分担)

    Awarding organization:科学研究費助成事業

    小杉 伸一

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    Grant type:Competitive

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  • Role of paratrigeminal nucleus connected to mouth and pharynx on chewing and swallowing functions

    Grant number:17K11775

    2017.4 - 2020.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

    Tsujimura Takanori

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    Grant amount:\4550000 ( Direct Cost: \3500000 、 Indirect Cost:\1050000 )

    The aim of this study was to investigate the role of paratrigeminal nucleus (Pa5) on chewing and swallowing functions. The swallowing reflexes evoked by electrical stimulation of superior laryngeal nerve (SLN) was inhibited during electrical stimulation of Pa5. We did not evoke any swallows by the focal microinjection of glutamate receptor agonists and GABAA receptor antagonist into the Pa5. On the other hand, many swallows were evoked following the microinjection of glutamate receptor agonists and GABAA receptor antagonist into the nucleus tractus solitarii. The SLN is a primary carrier of initiation of swallowing evoked by laryngeal mechanical stimulation. Furthermore, epithelial sodium channel is involved in those swallows.

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  • 摂食運動に関わる咀嚼と嚥下の機能連関

    2016.4 - 2019.3

    System name:基盤研究(B)(分担)

    Awarding organization:科学研究費助成事業

    井上 誠

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    Grant type:Competitive

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  • Multiple peripheral nerves stimulation induce the excitability on pharyngeal motor system

    Grant number:16K11885

    2016.4 - 2019.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

    Watanabe masahiro

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    Grant amount:\4680000 ( Direct Cost: \3600000 、 Indirect Cost:\1080000 )

    Dysphagia causes chest infection and malnutrition but the therapies for dysphagia remain limited. On the other hand, nasal inhalation of black pepper oil (BPO) is reported to possibly improve swallowing function in elderly people, but little is known about the effects of BPO on the motor cortex.
    We have examined how the BPO application affects excitability of pharyngeal motor cortex. Pharyngeal motor evoked potential showed significantly increase up to 30 min after 1-min 100% v/v BPO inhalation. Inhalation of 100% v/v BPO at least showed immediate and facilitatory effects on excitability of pharyngeal motor cortex in the healthy adults. Olfactory stimuli might be useful and safety methods for severe dysphagic patients.

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  • 咽頭電気刺激の嚥下誘発効果と神経・筋機構の解明

    2014.4 - 2017.3

    System name:若手研究(B)

    Awarding organization:科学研究費助成事業

    真柄 仁

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  • Relation between hyo-laryngeal position and swallowing function

    Grant number:25462992

    2013.4 - 2016.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (C)

    Awarding organization:Japan Society for the Promotion of Science

    Ono Kazuhiro, INOUE Makoto, MAGARA Jin

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    Grant amount:\5070000 ( Direct Cost: \3900000 、 Indirect Cost:\1170000 )

    Laryngoptosis or uncoordinated movement of hyoid and larynx in functions in elderly people and dysphagic patients may cause impaired transport of bolus and residues after swallowing, which leads to bolus penetration or aspiration. The present study was undertaken to validate the relationship between hyoid movement or tongue pressure production and swallowing function by evaluating spatial and temporal hyoid excursion, hyoid position and bolus transmission as well as voluntary generation of anterior and posterior tongue pressure in healthy and dysphagic humans.

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  • Assessment for peripheral and central controls of ingestion behavior

    Grant number:25670814

    2013.4 - 2016.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Challenging Exploratory Research

    Awarding organization:Japan Society for the Promotion of Science

    Makoto Inoue, TSUJIMURA Takanori, MAGARA Jin

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    Grant amount:\3770000 ( Direct Cost: \2900000 、 Indirect Cost:\870000 )

    We investigated how peripheral inputs might assist central inputs in the control of voluntary evoked swallowing and whether natural chewing behavior affects the initiation of involuntary swallowing in healthy humans. We delivered pharyngeal electrical stimulation (PES) to the laryngopharynx and compared the number of swallows that occurred with and without PES during chewing, voluntary swallowing or at rest. PES significantly increased the number of voluntary evoked swallows at rest and during voluntary swallowing and this facilitatory effect was larger at rest than during chewing. Based on the current results, we suggest that (1) peripheral inputs within a certain range appear to facilitate the central inputs that control voluntary swallowing, (2) inter-individual variations in swallowing initiation may arise from differences in the excitability of the common neural network, (3) during chewing, such that the neural network associated with chewing may regulate swallowing initiation.

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  • Central and peripheral control of ingestion function

    Grant number:24390431

    2012.4 - 2015.3

    System name:Grants-in-Aid for Scientific Research

    Research category:Grant-in-Aid for Scientific Research (B)

    Awarding organization:Japan Society for the Promotion of Science

    INOUE Makoto, HORI Kazuhiro, TANIGUCHI Hiroshige, TSUJIMURA Takanori, NAKAMURA Yuki, MAGARA Jin

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    Grant amount:\18070000 ( Direct Cost: \13900000 、 Indirect Cost:\4170000 )

    From human and animal studies, we successfully clarified the followings. 1) Initiation of reflex swallowing is not affected by oral inputs but by chewing behavior or activation of chewing central pattern generator. 2) Motor pattern of swallowing is not affected by conditioning stimulation such as peripheral stimulation. 3) Because there is a positive correlation between effect of central inputs and peripheral inputs on the initiation of swallow, inter-individual variation of initiation of swallow is dependent on the excitability of neural activity in the lower brain stem. 4) repetitive pharyngeal stimulation shortly inhibits the excitability involved in the swallowing center but facilitates that involved in voluntary swallow in the long term.

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  • 機械的負荷が顎関節円板内細胞に及ぼす影響―中間径フィラメントに着目して

    2012.4 - 2014.3

    System name:研究活動スタート支援

    Awarding organization:科学研究費助成事業

    真柄 仁

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    Authorship:Principal investigator  Grant type:Competitive

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Teaching Experience

  • 加齢歯科学

    2022
    Institution name:新潟大学

  • 歯科衛生学実習III

    2021
    Institution name:新潟大学

  • 摂食機能評価学演習IB

    2021
    Institution name:新潟大学

  • 摂食機能評価学演習IIA

    2021
    Institution name:新潟大学

  • 基礎・臨床連続講義II(摂食・嚥下機能評価学)

    2021
    Institution name:新潟大学

  • 摂食機能評価学演習IIB

    2021
    Institution name:新潟大学

  • 摂食機能評価学演習IA

    2021
    Institution name:新潟大学

  • 高齢者・障害者歯科学

    2020
    Institution name:新潟大学

  • 摂食嚥下障害学

    2020
    Institution name:新潟大学

  • 訪問歯科診療

    2019
    Institution name:新潟大学

  • 摂食機能評価学演習ⅡA

    2017
    -
    2018
    Institution name:新潟大学

  • 摂食機能評価学演習ⅠA

    2017
    -
    2018
    Institution name:新潟大学

  • 摂食機能評価学演習ⅡB

    2017
    Institution name:新潟大学

  • 摂食機能評価学演習ⅠB

    2017
    Institution name:新潟大学

  • 加齢歯科学Ⅱ

    2016
    -
    2018
    Institution name:新潟大学

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