Reach-to-grasp co-ordination in the paretic limbs of individuals with stroke: insight from a barrier paradigm

Abstract

Objective: Reach and grasp components must be co-ordinated to preserve the optimal reach-to grasp performance. However, conflicting results regarding the deficit in reach-to-grasp co-ordination has been reported in the paretic hand of individuals after stroke. Additionally, investigations have not been undertaken to study more challenging task constraints to induce the impairment of reach-to-grasp co-ordination. This study aimed to compare reach-to-grasp co-ordination while avoiding an obstacle in the paretic hand of individuals after stroke with matched non-disabled adults. Material and Method: Twenty-four participants having mild severity of upper extremity impairment were recruited with an equal number of non-disabled adults. Kinematic reach-to-grasp movements with obstacle avoidance were analyzed. Reachto-grasp co-ordination was quantified using cross-correlation analysis: maximum correlation coefficient represented the spatial aspect and the time lag represented the temporal aspects. Results: Individuals after stroke showed a significant disturbance in the temporal aspect of reach-to-grasp co-ordination, but not the spatial aspect as compared with non-disabled adults. Conclusion: Among participants, after stroke reach-to-grasp co-ordination was delayed in the temporal aspect of reach-tograsp with obstacle avoidance but preserved in the spatial aspect. Specific methods to assess reach-to-grasp co-ordination and to treat the time delay to improve co-ordination should be considered in individuals after stroke.