Community-dwelling individuals with stroke, who have inspiratory muscle weakness, report greater dyspnea and worse quality of life

Abstract

The objective of the present study was to investigate if different levels of inspiratory muscle strength would be associated with dyspnea, walking capacity, and quality of life after stroke. For this exploratory study, the dependent outcome was strength of the inspiratory muscles, measured by maximal inspiratory pressure. Individuals with maximal inspiratory pressure ≥80 cmH₂O were classified as non-weak, those with maximal inspiratory pressure between 45 and 80 cmH₂O were classified as weak, and those with maximal inspiratory pressure ≤45 cmH₂O were classified as very weak. Related outcomes included dyspnea, measured by the modified Medical Research Council scale; walking capacity, measured by the 6-minute walk test; and quality of life, measured by the Stroke-Specific Quality of Life scale. Fifty-three participants, who had a mean age of 62 years (SD 12) and a mean time since the onset of the stroke of 20 (SD 17) months were included. Significant differences were found only between the weak/very weak and non-weak groups. The mean differences between the non-weak and weak/very weak participants were −1.8 points (95% confidence interval −2.7 to −0.9) for dyspnea and 55 points (95% confidence interval 22–88) for quality of life. Significant correlations were found between measures of inspiratory strength and dyspnea (r = −0.54; P < 0.01) and quality of life (r = 0.56; P < 0.01). There were not found any significant differences or correlations regarding walking capacity. The findings demonstrated that individuals with stroke, who had weakness of the inspiratory muscles, reported greater dyspnea and worse quality of life, compared with those, who did not have weakness. The results regarding walking capacity remain unclear.