Effect of Visual Biofeedback Using the Iowa Oral Performance Instrument and Auditory Feedback on Floor-of-the-Mouth Muscle Activation and Oral Pressure During Effortful Swallowing in Healthy Older Adults.

Effortful swallowing (ES) is a promising exercise option for patients with dysphagia due to reduced tongue base retraction. However, studies confirming how exercise physiology changes when performing ES continuously over multiple sets in clinical practice are limited. This study aimed to determine the effect of visual biofeedback using the Iowa Oral Performance Instrument (IOPI) on the muscle activity of the floor-of-the-mouth (FOM) and oral swallowing pressure during ES exercise. Forty-five healthy older adults (mean age 76.1 ± 4.48y) participated in this randomized crossover study with two conditions. In the visual biofeedback condition using the IOPI, the participants were presented with a value corresponding to 80% of the maximum isometric pressure of the posterior oral tongue measured at baseline and asked to exceed the target value while performing ES. In the no-feedback condition, the IOPI screen was blocked to ensure that information regarding the swallowing pressure during ES was not provided. In the biofeedback condition, participants showed a significantly higher oral swallowing pressure from Sets 3-8 compared with the no-feedback condition (p < 0.05). In the no feedback condition, FOM muscle activity was significantly lower in Set 4 than in the Set 1 (p < 0.05). To improve the strength of the tongue and FOM muscles through ES exercise, providing biofeedback using the IOPI may be beneficial for maintaining a consistently high level of exercise intensity. Further research is required to enable the application of this study's finding to patients with dysphagia.