Upper-limb movement smoothness after stroke and its relationship with measures of body function/structure and activity - A cross-sectional study.

INTRODUCTION: After a stroke, upper limb (UL) motor impairments interfere with functional activities and quality of life. Even though a range of assessment tools has been developed to assess UL, few studies explore the interfaces between different levels of functioning after stroke. OBJECTIVES: (a) verify the correlation between movement smoothness and other measures of body function/structure [UL - Fugl-Meyer Assessment (FMA), and handgrip strength]; (b) verify which body function/structure [UL-FMA and/or handgrip strength] could predict UL movement smoothness; and (c) verify if movement smoothness could predict levels of activity, as assessed by the Box and Block Test (BBT). MATERIALS AND METHODS: Cross-sectional study. Thirty-four individuals with chronic hemiparesis after stroke were enrolled. Measurements of body function/structure included FMA, handgrip strength and kinematic measure of movement smoothness. Levels of activity were measured using the Box and Block Test (BBT). RESULTS: Movement smoothness showed strong correlation with FMA (r = 0.70, p < .001) and moderate correlation with handgrip strength (r = 0.63, p < .001). FMA explained 46.4% of the variation in movement smoothness. Movement smoothness was moderately correlated with BBT (r = -0.560, p < .005) and predicted 31% of the variation in BBT. CONCLUSION: We recommend the use of UL-FMA to predict movement smoothness in chronic post-stroke subjects. This study also showed that movement smoothness influences the level of activity. Then, movement smoothness may be emphasized during stroke rehabilitation to enhance the UL level of activity in chronic post-stroke subjects.