Recovery process of respiratory muscle strength in patients following stroke: A Pilot Study

Objective To determine the recovery process of respiratory muscle strength during 3 months following stroke, and to investigate the association of change in respiratory muscle strength and physical functions. Additionally, we compared respiratory muscle strength with those of healthy subjects. Method In this prospective, observational study, 19 stroke patients and 19 healthy subjects were enrolled. Maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), motricity index, trunk control test, 6-minute walk test (6MWT) and functional independence measure were assessed at 1, 2, and 3 months from stroke onset in stroke patients. MIP and MEP were assessed at arbitrary times in healthy subjects. Repeated one-way analysis of variance with Bonferroni post-hoc test was used to compare the change in respiratory muscle strength in each period in stroke patients. Pearson's correlation coefficient was computed for changes in respiratory muscle strength and physical functions. Student's t-test was used to compare respiratory muscle strength between stroke patients at 3 months from onset and healthy subjects. Results MIP was significantly increased at 3 months compared to 1 month. MEP was significantly increased in 2 months and 3 months, compared to 1 month. MIP changes associated with 6MWT changes. Compared to healthy subjects, MIP and MEP at 3 months were significantly lower in stroke patients. Conclusion Respiratory muscle strength significantly increased during 3 months following stroke. However, the trend of recovery may be different. MIP changes may associated with walking endurance changes. During 3 months following stroke, respiratory muscle strength did not recover to healthy subjects.