Test-retest reliability of respiratory muscle testing in stroke

Abstract

Introduction: Although respiratory muscle strength tests are used in assessment post stroke, the reliability has not been tested. The aim was to evaluate test-retest reliability of Maximal Inspiratory (MIP), Expiratory (MEP) and Sniff Nasal Inspiratory Pressure (SNIP) in stroke patients.

Methods: MIP, MEP and SNIP were assessed in 3 sessions (S1-3) within 24-hour period. Baseline spirometry was taken. Mean Differences (MD) between sessions were analysed with SPSS using paired t-tests and intraclass correlation coefficient (ICC). The Bland-Altman method was used to describe 95% limits of agreement.

Results: Eighteen patients (11 male), mean (SD) age 59.1(14.5) years and with FEV₁ 2.81(0.78)L (88.2(12.2) % pred.) and FVC 3.46(1.02)L (87.6(14.6) % pred.) were assessed at median(range) 50(21-128) days post stroke. There was good reliability for all 3 measures, but there were significant differences between sessions for SNIP only (table 1). Limits of agreement for MIP S1-S2 were 22.2 to -23.0 and S2-S3 17.0 to -12.7; for MEP S1-S2 19.9 to -29.0 and S2-S3 24.9 to -24.3; for SNIP S1-S2 17.37 to -38.5 and S2-S3 15.2 to -27.3.

Conclusion: There was good test-retest reliability of MIP and MEP measures, but SNIP shows more variation and may require a practice session in stroke patients.