Expiratory Muscle Strength Training in Multiple System Atrophy: A Pilot Study

BackgroundThe effects of expiratory muscle strength training (EMST) has not yet been investigated in MSA patients. ObjectiveThe primary objective was to test the effects of EMST on expiratory muscle strength and voluntary peak cough flow (vPCF) in patients with multiple system atrophy (MSA). The secondary objective was to assess the suitability of the pulmonary dysfunction index as a tool for identifying MSA patients with expiratory muscle weakness and reduced voluntary peak cough flow. MethodsThis was an open label, non-controlled study, with an 8-week intensive home-based EMST protocol. The outcome measures included: maximal expiratory pressure (MEP) and vPCF. The sensitivity and specificity of the index of pulmonary dysfunction in the respiratory diagnostic process were assessed using receiver operating characteristic (ROC) analysis. ResultsFifteen MSA patients were enrolled in the study. Twelve MSA patients completed the training period. After the training period, MEP significantly increased (P = 0.006). Differences in vPCF were not significant (P = 0.845). ROC analysis indicated that the overall respiratory diagnostic accuracy of the index of pulmonary dysfunction had an outstanding capability to detect patients at risk of less effective coughing and an acceptable capability of detecting patients with decreased expiratory muscle strength. ConclusionsThese findings indicate non-significant differences in vPCF after 8 weeks of EMST. The index of pulmonary dysfunction appears to be a promising prognostic screening tool for identifying altered cough efficacy in MSA patients. Test cut-offs may be used to select an appropriate respiratory physiotherapy technique.

Automated summary

The effects of expiratory muscle strength training (EMST) on patients with multiple system atrophy (MSA) were investigated in this study. After an 8-week training period, the maximal expiratory pressure (MEP) significantly increased, indicating improved expiratory muscle strength. However, the voluntary peak cough flow (vPCF) did not show significant changes. The index of pulmonary dysfunction was found to be a useful tool for detecting altered cough efficacy and decreased expiratory muscle strength in MSA patients.