Effect of expiratory muscle strength training on swallowing-related muscle strength in community-dwelling elderly individuals: a randomized controlled trial

Objective: This study aimed to investigate the effect of expiratory muscle strength training (EMST) on swallowing-related muscle strength in community-dwelling elderly individuals. Background: Expiratory muscle strength training is an intervention for patients with oropharyngeal dysphagia. This training is associated with respiration, coughing, speech and swallowing, and its effectiveness has been proven in previous studies. However, the effects of EMST on elderly individuals and evidence are still lacking. Materials and methods: This study included 24 community-dwelling senior citizens aged >= 65 years (12 men and 12 women). The experimental group trained at the 70% threshold value of the maximum expiratory pressure using an EMST device 5 days per week for 4 weeks and comprised five sets of five breaths through the device for 25 breaths per day. The placebo group trained with a resistance-free sham device. Post-intervention, muscle strength of the bilateral buccinator and the orbicularis oris muscles (OOM) was measured using the Iowa Oral Performance Instrument. Surface electromyography was used to measure activation of the suprahyoid muscles (SM). Results: After intervention, the strength of the buccinator and the OOM in the experimental group showed statistically significant improvement. There was also statistically significant activation of the SM. In the placebo group, the strength of the orbicularis oris muscle alone improved. No statistically significant differences between groups were found for the strength of the buccinator and the OOM and the activation of the SM. Conclusion: EMST had a positive effect on swallowing-related muscle strength in elderly participants.