Effects of neuromuscular electrical stimulation on submental muscle activity

Neuromuscular electrical stimulation (NMES) therapy has been proposed as a treatment option for pharyngeal dysphagia. However, little is known about the effects, if any, that NMES has on specific biomechanical aspects of the pharyngeal swallow. The purpose of this study was to determine if two weeks of NMES applied to the submental muscles increased myoelectric activity. Ten age- and gender-matched subjects participated, and eight completed the protocol. Treatment was delivered using an AB or BA design. No treatment was given during the A condition. Subjects received ten 1-h NMES treatments during the B condition. Results indicated that seven of eight subjects exhibited no significant gains in myoelectric activity of the submental muscles following NMES. Therefore, the benefit of NMES to the submental muscles with the goal of improving the pharyngeal swallow is not supported. Additional research investigating duration of treatment as well as frequency and amplitude modulation of NMES is needed to determine if, how, and why NMES applied to the submental muscles affects the biomechanical aspects of both the normal and disordered pharyngeal swallow.