Pizzamiglio Gloria, Zhang Zuo, Duta Mihaela, Rounis Elisabeth
Wellcome Centre for Human Neuroimaging, Institute of Neurology, University College London, London, United Kingdom.
Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.
Front Hum Neurosci. 2020 Feb 11;13:465. doi: 10.3389/fnhum.2019.00465. eCollection 2019.
Previous studies have shown that hand actions to visual objects are affected both by perceptual factors and by action goals. Our aim was to study how these processes affected hand actions in chronic stroke patients, based on whether they had limb apraxia. Twenty-two left hemisphere, chronic stroke patients were measured on neuropsychological tasks of limb apraxia, which was identified in a subgroup of 10 patients. All patients underwent testing on a separate task of making simple reach and grasp actions to a cup. Their performance was compared to a group of 18 healthy age-matched volunteers. Participants were instructed to grasp the top or bottom of a cup to either lift or turn it over so as to end with a hand position that was either comfortable or uncomfortable. This task tested the influence of the compatibility of hand-cup orientation, as well as goals driven by the end-state comfort of the hand, on action selection for object manipulation. Participants' performance was measured in terms of error rates, and speed of initiation and reaching (movement time) to the object. The patients' performance was significantly delayed, and error rates increased when reaching to grasp a cup under conditions of poor compatibility and end-state comfort. The subgroup of patients with apraxia showed a decreased influence of compatibility of hand interaction with the cup, with increased error rates and delayed response times, compared to patients with no apraxia and healthy volunteers. This is despite the fact they did not display significant deficits on neuropsychological tasks of real object use. The study shows that patients with apraxia have difficulties in selecting elements of object-directed actions, pertaining to both habitual and goal-directed factors.
以往的研究表明，对视觉物体的手部动作会受到感知因素和动作目标的影响。我们的目的是基于慢性中风患者是否存在肢体失用症，来研究这些过程如何影响他们的手部动作。对22名左侧半球慢性中风患者进行了肢体失用症的神经心理学测试，其中10名患者被确定为失用症亚组。所有患者都接受了一项单独的任务测试，即对一个杯子进行简单的伸手抓取动作。将他们的表现与18名年龄匹配的健康志愿者组成的对照组进行比较。参与者被要求抓住杯子的顶部或底部，以提起或翻转杯子，最终手部位置要达到舒适或不舒适的状态。这项任务测试了手部与杯子方向的兼容性以及手部最终状态舒适度所驱动的目标对物体操作动作选择的影响。通过错误率、开始动作的速度和到达物体的速度（运动时间）来衡量参与者的表现。在兼容性差和最终状态舒适度低的情况下伸手抓取杯子时，患者的表现明显延迟，错误率增加。与无失用症的患者和健康志愿者相比，失用症患者亚组表现出手部与杯子交互兼容性的影响降低，错误率增加且反应时间延迟。尽管他们在实际物体使用的神经心理学任务中没有表现出明显的缺陷。该研究表明，失用症患者在选择与习惯和目标导向因素相关的目标导向动作要素方面存在困难。
