A goal of rehabilitation after stroke is to promote pre-stroke levels of arm use for every day, frequently bimanual, functional activities. We reasoned that, after a stroke, the choice to use one or both hands for bimanual tasks might depend not only on residual motor capacity, but also the specialized demands imposed by the task on the paretic hand. To capture spontaneous, task-specific choices, we covertly observed 50 pre-stroke right-handed chronic stroke survivors (25 each of left, LHD, and right-hemisphere damage, RHD) and 11 age-similar control adults and recorded their hand use strategies for two pairs of bimanual tasks with distinct demands: one with greater precision requirements (photo-album tasks), and another with greater stabilization requirements (letter-envelope tasks). The primary outcome was the choice to use one or both hands. Logistic regression was used to test the two hypotheses that the probability of choosing a bimanual strategy would be greater in those with less severe motor impairment and also in those with LHD. When collapsed across the four tasks, we found support for these hypotheses. Notably, however, the influence of these factors on bimanual choice varied based on task demands. For the photo–album pair, the probability of a bimanual strategy was greater for those with LHD compared to RHD, regardless of the degree of motor impairment. For the letter–envelope pair, we found a significant interaction between impairment and side of lesion in determining the likelihood of choosing both hands. Therefore, the manner in which side of lesion moderates the effect of impairment on hand use depends on the task.

中风后康复的目标是提高中风前每天使用手臂的水平，通常是双手的功能性活动。我们推断，在中风后，选择使用一只手还是两只手进行双手任务可能不仅取决于剩余运动能力，还取决于任务对麻痹手施加的特殊需求。为了捕捉自发的、针对特定任务的选择，我们秘密观察了 50 名中风前右手慢性中风幸存者（左、LHD 和右半球损伤，RHD 各 25 名）和 11 名年龄相似的对照成年人，并记录了他们的手部使用情况两对具有不同需求的双手任务的策略：一对具有更高的精度要求（相册任务），另一对具有更高的稳定性要求（信封任务）。主要结果是选择使用一只手还是两只手。Logistic 回归用于检验两个假设，即在运动障碍较轻的人和 LHD 的人中，选择双手策略的可能性更大。当在四项任务中崩溃时，我们发现对这些假设的支持。然而，值得注意的是，这些因素对双手选择的影响因任务需求而异。对于相册对，无论运动障碍程度如何，与 RHD 相比，LHD 患者双手策略的可能性更大。对于字母-信封对，我们发现在确定选择双手的可能性时，损伤和病变一侧之间存在显着的相互作用。因此，病变一侧减轻手部使用障碍影响的方式取决于任务。