Department of Psychology, State University of New York Plattsburgh, 101 Broad Street, Plattsburgh, NY, 12901, USA.
Moss Rehabilitation Research Institute, Elkins Park, PA, USA.
Exp Brain Res. 2024 Dec;242(12):2785-2797. doi: 10.1007/s00221-024-06939-z. Epub 2024 Oct 12.
A vexing characteristic of motor disability after stroke is that many individuals fail to use their affected arm effectively despite having the capacity to do so, a phenomenon termed arm nonuse. Based on the hypothesis that nonuse is influenced by the competing cognitive demands of many daily activities, we examined the effects of cognitive load on arm choice and motor performance in individuals with stroke using a novel virtual reality paradigm that mimics the demands of real-life visual search, object selection, and reaching to targets. Twenty individuals with single left or right hemispheric chronic stroke (11 left cerebrovascular accident; 9 right cerebrovascular accident) and 10 age-matched neurotypical participants completed the Virtual Reality Arm Choice task, in which they reached for target objects in an array under varied cognitive demand. To manipulate cognitive demand, we varied the semantic similarity of objects in the reaching space and the presence or absence of a secondary task. The results showed reduced use of the paretic arm under increased demand. Under cognitive load, participants with stroke also showed slower reach initiation, slower movements, increased reach curvature, and increased performance differences between the paretic and non-paretic arms. The arm choice of neurotypical individuals was also modulated under cognitive load. These data indicate that cognitive factors influence arm choice and motor performance in naturalistic reaching tasks in individuals with chronic stroke. Performance decrements under cognitive load may in turn influence reduced paretic arm use during daily activities.
脑卒中后运动障碍的一个恼人特征是，许多患者尽管有能力，但仍无法有效地使用患侧上肢，这种现象称为上肢废用。基于非使用受许多日常活动认知需求竞争影响的假设，我们使用一种新的虚拟现实范式来检查认知负荷对脑卒中个体上肢选择和运动表现的影响，该范式模拟了现实生活中视觉搜索、物体选择和目标到达的需求。20 名单侧或双侧慢性脑卒中患者（11 名左侧脑血管意外；9 名右侧脑血管意外）和 10 名年龄匹配的神经典型参与者完成了虚拟现实上肢选择任务，他们在不同认知需求下到达阵列中的目标物体。为了操纵认知需求，我们改变了目标物体在到达空间中的语义相似性以及是否存在次要任务。结果表明，需求增加时，患侧上肢的使用减少。在认知负荷下，脑卒中患者的起始动作也变慢，运动速度变慢，运动轨迹变弯曲，患侧和非患侧上肢的运动表现差异增加。神经典型个体的上肢选择也在认知负荷下发生改变。这些数据表明，认知因素会影响慢性脑卒中患者在自然到达任务中的上肢选择和运动表现。认知负荷下的表现下降反过来可能会影响日常活动中患侧上肢的使用减少。
