Comparison of Unilateral Versus Bilateral Upper Extremity Task Performance After Stroke

Abstract

Background: Previous studies have suggested that practicing functional tasks bilaterally instead of unilaterally may improve paretic limb performance after stroke. Objective: The purposes of this study were to determine whether the bilateral movement condition alters paretic limb performance of a functional task in people with poststroke hemiparesis and to identify specifically which parameters of performance may be affected. Methods: In this single-session study, we examined immediate effects of the bilateral versus unilateral movement condition on performance of a reach-grasp-lift-release task at preferred speed in 16 people with mild to moderate poststroke hemiparesis and in 12 healthy control subjects. Performance was quantified by using motion analysis variables, including duration of the reach and grasp phases, reach path straightness, maximum thumb-index finger aperture, efficiency of finger movement, peak grip force, and timing of release. Results: We found no evidence of immediate improvement in paretic limb performance in the bilateral condition. In both groups, release timing occurred later when participants moved bilaterally instead of unilaterally, possibly representing a divided attention effect. Other variables did not differ across conditions. Conclusions: Our findings suggest little immediate impact of the bilateral condition on motor performance of a reach-grasp-lift-release task at preferred speed in people with mild to moderate hemiparesis.

Keywords:

• bilateral
• grasp
• hemiparesis
• kinematic
• motor control
• reach