Suprahyoid Muscle Strengthening Using a Novel Exercise Device in Older Adults With Oral Hypofunction: A Randomised Placebo-Controlled Trial.

Background: Strengthening of the suprahyoid muscles plays a critical role in swallowing rehabilitation for older adults with oral hypofunction. Therefore, the development of diverse exercise devices and the accumulation of evidence supporting their effectiveness are essential.

Objective: The aim of this study was to evaluate the effectiveness of a novel neck-collar exercise device designed to strengthen the suprahyoid muscles in older adults with oral hypofunction.

Methods: Thirty older adults with oral hypofunction were enrolled and randomly assigned to the experimental or placebo group. The experimental group performed suprahyoid muscle-strengthening exercises using the neck-collar device developed for this study. The exercises incorporated isometric and isotonic movements. The placebo group performed the same exercises using a sham device identical in appearance but lacking an internal resistance spring, thus providing minimal resistance. The primary outcomes were suprahyoid muscle activation, recorded using surface electromyography with bipolar electrodes placed submentally, and suprahyoid muscle thickness, measured on ultrasound images. The secondary outcome was swallowing function, evaluated using videofluoroscopic swallowing studies and scored using the penetration-aspiration scale.

Results: The experimental group showed significantly greater improvements in suprahyoid muscle activation and thickness, along with significantly lower penetration-aspiration scale scores than the placebo group (all p < 0.05).

Conclusion: These findings suggest that the novel neck-collar exercise device is effective in enhancing suprahyoid muscle activation and thickness, and in reducing the risk of airway penetration and aspiration in older adults with oral hypofunction.