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

Abstract

Background The effects of expiratory muscle strength training (EMST) has not yet been investigated in MSA patients. Objective The 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. Methods This 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. Results Fifteen 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. Conclusions These 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.

Hypotussic cough in persons with dysphagia: biobehavioral interventions and pathways to clinical implementation

“…Of clinical significance, however, EMST with natural expiratory flow rate increased PEFR from a mean of 8.4 (SD: 2.3) L/s to 8.9 (SD: 1.3) L/s post-training. Pilot investigations on EMST in multiple systems atrophy ( 89 ) have found direct improvements in MEPs, yet did not find statistically significant changes in PEFR. Similar limitations and/or findings have been observed in head and neck cancer patients ( 83 , 87 , 88 ).…”

“…There is a paucity of data on the impact of IMST alone on objective cough outcomes. Comprehensive RST protocols which combine or assess both EMST and IMST have been investigated in stroke ( 86 – 89 , 91 , 92 ), ALS ( 76 ), Huntington's disease ( 78 ), and preoperative cardiac surgical patients ( 35 ). Kulnik et al ( 82 ), aimed to examine the effect of expiratory muscle training, inspiratory muscle training, and a sham training protocol on cough airflow in acute stroke patients.…”

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“…Of clinical significance, however, EMST with natural expiratory flow rate increased PEFR from a mean of 8.4 (SD: 2.3) L/s to 8.9 (SD: 1.3) L/s post-training. Pilot investigations on EMST in multiple systems atrophy (89) have found direct improvements in MEPs, yet did not find statistically significant changes in PEFR. Similar limitations and/or findings have been observed in head and neck cancer patients (83, 87, 88).…”