Deficits in Performance on a Mechanically Coupled Asymmetrical Bilateral Task in Chronic Stroke Survivors with Mild Unilateral Paresis

Shanie A L Jayasinghe,Candice Maenza,David C Good,Robert L Sainburg

doi:10.3390/sym13081366

Abstract

Typical upper limb-mediated activities of daily living involve coordination of both arms, often requiring distributed contributions to mechanically coupled tasks, such as stabilizing a loaf of bread with one hand while slicing with the other. We sought to examine whether mild paresis in one arm results in deficits in performance on a bilateral mechanically coupled task. We designed a virtual reality-based task requiring one hand to stabilize against a spring load that varies with displacement of the other arm. We recruited 15 chronic stroke survivors with mild hemiparesis and 7 age-matched neurologically intact adults. We found that stroke survivors produced less linear reaching movements and larger initial direction errors compared to controls (p < 0.05), and that contralesional hand performance was less linear than that of ipsilesional hand. We found a hand × group interaction (p < 0.05) for peak acceleration of the stabilizing hand, such that the dominant right hand of controls stabilized less effectively than the nondominant left hand while stroke survivors showed no differences between the hands. Our results indicate that chronic stroke survivors with mild hemiparesis show significant deficits in reaching aspects of bilateral coordination, but no deficits in stabilizing against a movement-dependent spring load in this task.

Highlights

The range of activities of daily living (ADL) that require bilateral coordination suggests that bilateral coordination assessment and training should be an important focus of rehabilitation for stroke survivors who are able to use both arms for manipulation
Stroke survivors showed no differences in stabilizing performance between the two hands or when compared to performance of controls. These findings suggest that bilateral training is feasible in stroke survivors with mild paresis, and that remediation should focus on the movement, rather than the stabilization aspects of coordination
Our results suggest that the stroke survivors in this study produced deficits in movement planning and intersegmental coordination, regardless of which hand was used

Summary

Introduction

Bilateral training can increase activation of the ipsilesional primary motor cortex [6], and can result in larger gains in stroke-related recovery of arm function than unilateral training of the affected arm alone [7,8]. Both unilateral and bilateral training of upper-limb reaching tasks can improve paretic arm function [9], bilateral training was found to be more beneficial for improving proximal, but not distal, arm function related to bilateral descending motor pathways that support proximal limb function [10]. Unilateral training has been shown to improve paretic arm performance [11], but it may not provide the range of movement experiences required by functional activities [12] even though the therapeutic effects of bilateral training on stroke recovery remain incompletely understood [13]

Methods

Results

Conclusion