The activation level of the floor-of-the-mouth muscles is systematically modulated using tongue-pressing and swallowing tasks in healthy elderly.

Abstract

Objective: This study aimed to examine how muscle activity of the floor-of-the-mouth (FOM) muscles changes with different target exercise intensities of 40 %, 60 %, 80 %, and 100 % of maximum isometric pressure (MIP) during tongue-pressing and swallowing tasks in healthy elderly.

Design: This prospective, repeated-measures within-participant study included 35 participants (mean age: 75.2 ± 4.8 years, 26 women). Each participant performed 16 tasks using the Iowa Oral Performance Instrument (IOPI) in a randomized order, with two repetitions per task (anterior/posterior tongue × pressing/swallowing task × 40/60/80/100 % of the MIP). Furthermore, FOM-muscle activity during the task was simultaneously measured using surface electromyography. Statistical analysis was conducted using repeated-measures analysis of variance (ANOVA).

Results: Significant differences in FOM-muscle activity were observed across most intensity levels during pressing tasks (p < 0.001), with fewer significant differences noted during swallowing tasks, particularly involving the posterior tongue. A significant correlation was found between tongue pressure of the anterior/posterior tongue and FOM-muscle activation level (p < 0.001 and r = 0.517 and 0.447 for the isometric tongue pressure of the anterior and posterior tongue, respectively; r = 0.370 for the swallowing pressure of the anterior tongue) except for posterior tongue swallowing task.

Conclusions: These findings suggest that healthy elderly can systematically modulate suprahyoid muscle activity using a tongue-pressure-measurement device when performing accuracy training. However, they may require personalized systematic feedback and sufficient practice. The study underscores the potential of the IOPI in swallowing rehabilitation for elderly, while also highlighting the need for further research on patients with dysphagia.