The use of expiratory muscle strength trainers improves parameters related to pulmonary function, speech, and cough in both
healthy and patient populations. Recently, it has been speculated that expiratory strength training may alter the force generation
of muscles used during the swallow process. Specifically, the use of the trainer may result in increased activation of the
submental muscle complex. Support for this hypothesis was tested by examining the timing and amplitude of submental muscle
activity obtained using surface EMG. These muscles are known to be important for normal swallow function. Twenty participants
(10 males, 10 females; mean age = 29 years) were recruited to participate in a one-session study. Participants were asked
to perform two swallows (saliva swallow and water swallow) and develop an expiratory pressure set at 25% and 75% of their
maximum expiratory pressure (MEP) using an expiratory muscle strength trainer. These tasks allowed comparison of muscle activity
during both the swallow and expiratory tasks completed with the trainer. Results indicated that the patterns of activation
in the submental muscle group while training on the expiratory device had longer duration of activation with higher amplitude
of EMG activity when compared with the swallowing condition. These findings indicate that expiratory muscle strength training
(EMST) increases motor unit recruitment of the submental muscle complex. Discussion centers on the potential benefit of EMST
as a treatment modality for dysphagia characterized by decreased amplitude of hyoid movement during swallowing.
Keywords Deglutition - Deglutition disorders - Surface electromyography - Expiratory muscle strength training - Submental muscles
This study was completed at the Oral Motor-Human Performance Laboratory of the Brain Rehabilitation Research Center, Malcom
Randall VA Medical Center, Gainesville, Florida