The effect of expiratory muscle strength training on the oral and respiratory functions of community-dwelling older people: An analysis using the swallowing, oral, phonatory, and respiratory muscle function indices.

Abstract

This study was performed to determine the effects of expiratory muscle strength training (EMST) on the oral and respiratory functions of community-dwelling older people. Older people using a visiting-rehabilitation center were divided into an intervention group of 31 subjects and a control group of 15 subjects. Those in the intervention group were assigned home training for 8 weeks, which included 5 sets of 5 breaths per day with a 75% load of the maximum expiratory pressure using an EMST device. The outcome indices included (1) oral functions, evaluated by the cumulative time spent swallowing three times and the maximum phonation time (MPT) and (2) respiratory functions, evaluated by the maximum expiratory pressure and maximum inspiratory pressure (MEP/MIP). An independent t-test and paired t-test were used to analyze the data. The cumulative time spent swallowing three times was lower in the intervention group than in the control group. This difference remained significant even after adjusting for sex, age, and baseline values. The MPT was 2.1 seconds higher than baseline in the intervention group but 0.4 seconds lower than baseline in the control group. An average increase of 5.7 cmH2O in the PEmax was observed in the intervention group compared with an average decrease of 4.6 cmH2O in the control group, indicating a significant difference. These results suggest that EMST improves the oral and respiratory functions of community elderly subjects. This may be explained by the fact that the pathway for swallowing is partially shared with that for phonation, which contributes to a shortened swallowing time by repeated suprahyoid muscle contractions.