Language：Japanese   Publisher：日本顎口腔機能学会  

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

BACKGROUND: The tongue functions by modulating according to bolus volume when swallowing; however, associated tongue dynamics are unclear. OBJECTIVE: We aimed to clarify how tongue motion and tongue pressure change with bolus volume during swallowing. METHODS: Sixteen healthy volunteers (age 29.5 ± 3.8 years; 12 males, 4 females) were recruited. Two electromagnetic articulography markers were attached, one each on the anterior and posterior parts of the tongue, to measure motion. A sensor sheet, with five pressure-sensitive points, was attached to the hard palate to measure tongue pressure. Participants were asked to swallow 3 ml and 10 ml of water. Motion trajectory, maximum velocity, vertical displacement just before contact with the hard palate, and maximum magnitude and duration of tongue pressure were analysed. RESULTS: Tongue rotation was observed in the sagittal plane; its rate of appearance was significantly higher when swallowing 3 ml of water than when swallowing 10 ml, and the rate of rotation at posterior part was significantly higher than at the anterior part. The maximum velocity and vertical displacement were significantly greater when swallowing 10 ml of water than those when swallowing 3 ml of water. There was no significant difference in either the maximum magnitude of tongue pressure or maximum duration of tongue pressure between 3 ml and 10 ml. CONCLUSION: Bolus volume influenced the pattern of tongue motion; however, there was no difference in tongue pressure.

DOI： 10.1111/joor.13248

PubMed

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

BACKGROUND: Although various training methods have been reported for improving oral function such as occlusal force, there are few reports that show the training effect of eating hard food on the oral functions. OBJECTIVE: To examine the training effects of habitually ating hard gummy candies on oral functions. METHODS: Participants of this cohort study were recruited into a training (six women, eight men; mean age 27.6 ± 3.5 years) and control group (two women, seven men; mean age 28.3 ± 4.9 years). The training group ate nine custom-developed hard gummy candies three times per week for 3 months. Training effects were evaluated by measuring the maximal occlusal force, masticatory performance, maximal tongue pressure, number of chewing cycles until swallowing the candy, duration of chewing and cycle time before training, after 1, 2 and 3 months of training, and 1 month after stopping training. The iEMG/force, which evaluates masseter muscle hypertrophy with electromyograms (EMG), was calculated. RESULTS: Masticatory performance after 1 month (p = 0.01), maximal occlusal force after 2 months (p < 0.01) and maximal tongue pressure after 3 months of training were significantly increased (p = 0.02), and the cycle time after 2 months of training (p = 0.02) was significantly decreased compared to before the intervention. Except for masticatory performance, the other effects were maintained for 1 month after stopping training. Changes in iEMG/force were not significant, but a tendency for muscle hypertrophy was observed in the training group. CONCLUSION: Habitual eating of hard gummy candies is a task-specific training that can improve overall masticatory function, including tongue pressure.

DOI： 10.1111/joor.13208

PubMed

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

BACKGROUND: Tongue motor biomechanics during swallowing was not fully elucidated due to the technical difficulty. OBJECTIVE: To evaluate the relationship between tongue motion and tongue pressure production by simultaneously measuring tongue motion and tongue pressure during water swallowing. METHODS: In 12 healthy male participants (mean age, 30.8 ± 4.2 years), tongue pressure and tongue motion trajectory during dipper- and tipper-type swallows of 3 mL of water were measured using a sensor sheet system equipped with five sensing points and an electromagnetic articulography, respectively. The temporal correlation between motion of anterior/posterior tongue and tongue pressure production during swallowing was evaluated on the synchronised waveforms. RESULTS: In the dipper-type swallow, a similar up-and-down motion pattern in vertical direction was observed among all participants before tongue pressure production. Those motion patterns were common at the anterior and posterior tongue locations with a temporal difference in some segment of tongue motion. On the other hand, tongue directly attached to hard palate with temporal synchronicity between the anterior and posterior parts. In both types of swallow, a strong temporal correlation was found between the timing of tongue-palate contact and the Onset of tongue pressure by intra-class correlation coefficients. CONCLUSION: From the simultaneous measurement of tongue motion and tongue pressure production, the tongue motion pattern during water swallowing and the temporal correlation between tongue motion and tongue pressure production were elucidated.

DOI： 10.1111/joor.13079

PubMed

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

BACKGROUND: Pharyngeal residue can trigger aspiration and choking after swallowing. Various studies to assess the amount of pharyngeal residue have been conducted; however, an easy and quantitative method is yet to be established. The aroma released from the pharyngeal residue is thought to be delivered from the pharynx to the nasal cavity via velopharynx by expiration, that is, retronasal pathway. OBJECTIVE: This study verified that the amount of pharyngeal residue could be estimated by aroma intensity. METHODS: Ten healthy adult subjects had tubes in from the oral cavity to the pharynx. Varying amounts of essence were dispensed into the pharynx through the tube either at rest or after swallowing the essence. Pharyngeal residue was simulated by retention essence in the pharynx without swallowing. An odour sensor was placed in the nostril, and the aroma intensity of the retained essence was measured over time. RESULTS: The aroma intensity level flattened after a certain period of time had elapsed, and a significant correlation was found between the amount of essence dispensed and the flattened aroma intensity, both at rest and after swallowing. Furthermore, to estimate in a short period of time, changes in aroma intensity over time were estimated by fitting to a decay curve. The estimated intensity at convergence, calculated from the fitted curve from 80 to 120 seconds after swallowing, was significantly correlated to the measured intensity. CONCLUSION: The amount of pharyngeal residue can be estimated in a short period of time by measuring the aroma intensity.

DOI： 10.1111/joor.12974

PubMed

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