School of Psychology, University of Nottingham, Nottingham NG7 2RD, United Kingdom.
School of Psychology, University of Nottingham, Nottingham NG7 2RD, United Kingdom.
Neuropsychologia. 2011 Apr;49(5):1275-1286. doi: 10.1016/j.neuropsychologia.2011.01.020. Epub 2011 Jan 15.
Apraxia after left inferior parietal lesions has been widely interpreted as evidence of damage or impaired access to representations of tool-use, but most research has investigated pantomime of tool actions, not handling of actual tools. An alternative account is that inferior parietal damage does not affect tool-use representations but impairs cognitive processing about postural and hand-tool spatial relationships which is necessary for planning and controlling any complex action. Four apraxic patients and 10 age-matched controls were asked to reach rapidly for tools or abstract objects of similar dimensions. Under conditions of time pressure and divided attention, the patients frequently failed to invert the hand to grasp inverted tools by the handle, whereas ability to invert the hand to avoid a barrier and grasp abstract objects was largely unimpaired. Frequency of errors in tool grasping correlated with severity of apraxia. When inverted tools were correctly grasped, rotation of the wrist occurred later during the reaching movement than when inverting the hand to grasp an abstract object. These data are consistent with the theory of degraded access to tool-use representations in apraxia, but this theory cannot account for co-occurring deficits in imitating or matching meaningless hand or body postures.
左顶下叶损伤后的失用症被广泛解释为工具使用的代表受损或受损的证据，但大多数研究都调查了工具动作的模仿，而不是实际工具的处理。另一种解释是，顶下叶损伤不会影响工具使用的表示，但会损害规划和控制任何复杂动作所需的关于姿势和手工具空间关系的认知处理。四名失用症患者和 10 名年龄匹配的对照组被要求快速伸手取工具或类似尺寸的抽象物体。在时间压力和注意力分散的情况下，患者经常无法将手反转以通过手柄抓住倒置的工具，而反转手以避开障碍物并抓住抽象物体的能力则基本不受影响。工具抓握错误的频率与失用症的严重程度相关。当正确抓住倒置工具时，手腕的旋转发生在伸手运动中比反转手以抓住抽象物体时更晚。这些数据与失用症中工具使用表示的访问受损理论一致，但该理论无法解释同时出现的模仿或匹配无意义的手或身体姿势的缺陷。
