Repetitive Peripheral Magnetic Stimulation for Strengthening of the Suprahyoid Muscles: A Randomized Controlled Trial

Abstract

Head lift exercise is a widely known form of training in the rehabilitation of patients with dysphagia. This study aimed to compare muscular strength reinforcement training of the suprahyoid muscles using repetitive peripheral magnetic stimulation (rPMS) with head lift exercises in a randomized controlled trial. Twenty-four healthy adults were randomly assigned to either the magnetic stimulation group (M group) or the head lift exercise group (H group). Both groups underwent training five days a week for two weeks. The primary outcome was the cervical flexor strength, and secondary outcomes were jaw-opening force, tongue pressure, muscle fatigue of the hyoid and laryngeal muscles, displacement of the hyoid bone and opening width of the upper esophageal sphincter (UES) while swallowing 10 mL of liquid, training performance rate, and pain. No dropouts were reported during the two-week intervention period. Cervical flexor strength significantly increased solely in the M group. Tongue pressure significantly improved in both groups. There were no significant differences in the jaw-opening force, median frequency rate of the anterior belly of the digastric muscle, sternohyoid muscle, sternocleidomastoid muscle, anterior and superior hyoid bone displacement, and UES opening width in both groups. Two-week rPMS of the suprahyoid muscles increased the strength of these muscles compared with the head lift exercise during the same period.