Transcutaneous electrical stimulation as a resistance force in lingual exercise: A preliminary proof-of-concept study

Background: Limited knowledge exists regarding whether transcutaneous electrical stimulation (TES)-based exercise can improve the lingual pressure generation. Objectives: To compare the effect of submental TES with two different pulse durations (PD) coupled with isometric lingual exercises on lingual pressure measures. Methods: Twenty-eight healthy volunteers were divided into two submental TES groups: short PD (300 μs) and long PD (700 μs). The Iowa Oral Performance Instrument (IOPI) was used for lingual pressure measurements and exercise. In total, participants attended six exercise sessions 3 days per week for 2 consecutive weeks. Maximum and swallowing lingual pressures were measured 1 h following each exercise session and 3 days after the final session to assess any detraining effect. Data were analysed using repeated measure ANOVA. Results: Mean maximum lingual pressure change was significantly greater in TES with short PD versus the long PD condition following the first week of exercise. Following the 2-week exercise, a significant increase was found in mean maximum lingual pressure for short and long PD conditions compared with the baseline. However, no significant difference was found between PD conditions for maximum lingual pressure. Likewise, no significant differences in swallowing lingual pressure were found compared with the baseline or across the two TES conditions. Conclusion: Although short PD induced greater gain in maximum lingual pressure than the long PD after week 1, the enhanced effect faded after week 2, leading to a comparable increase in maximum lingual pressure for both groups. However, increased gain in maximum lingual pressure was not transferred to lingual pressure during swallowing.