Changes in the Activation Level of the Floor of the Mouth Muscles during Pressing and Swallowing Tasks According to the Degree of Tongue Pressure.

The suprahyoid muscles play an important role in protecting the airway by elevating both the hyoid bone and larynx superior-anteriorly during swallowing. However, providing systematic external resistance when performing exercises to improve suprahyoid muscle strength is practically difficult. This study attempted to confirm whether systematic resistance can be provided to the suprahyoid muscles using the Iowa Oral Performance Instrument (IOPI)-a representative tongue pressure measurement device. Thirty-one healthy adults participated in this study (20.6 ± 0.96 y, 19 females). The participants performed 16 exercise tasks using the IOPI three times each in random order (Anterior/posterior tongue × pressing/swallowing task × 40/60/80/100% maximum tongue pressure). Furthermore, the floor of the mouth (FOM) muscle activity during exercise was simultaneously measured using surface electromyography. During the pressing task, there were significant differences in FOM maximal muscle activity among the four exercise intensities for both the anterior and posterior oral tongue. For the swallowing task, a significant difference was found in FOM muscle activity among the four exercise intensities for the anterior tongue. For the posterior tongue, significant differences were identified among all conditions except for the comparison between 80% and 100% maximum tongue pressure. Significant correlations between the degree of tongue pressure and maximal FOM muscle activity were found in both the pressing and swallowing tasks at the anterior and posterior oral tongue. Overall, these results indicate that objective and systematic external resistance can be applied using the IOPI-a standard tongue pressure measurement device-during the program to improve suprahyoid muscle function.