Poizner H, Clark M A, Merians A S, Macauley B, Gonzalez Rothi L J, Heilman K M
Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ 07102.
Brain. 1995 Feb;118 ( Pt 1):227-42. doi: 10.1093/brain/118.1.227.
Competing models of the basis of limb apraxia were tested through analysis of joint coordination deficits in three apraxic subjects with lesions that included the left parietal lobe. Three-dimensional shoulder, elbow, wrist and hand trajectories were recorded for repetitive 'slicing' gestures made in a series of conditions in which contextual cues were introduced in a graded fashion. The apraxic subjects showed marked deficits in joint coordination across context conditions. Even when actually manipulating a tool and object, the apraxic subjects failed to show proper joint synchronization, failed to apportion their relative joint amplitudes properly, and failed to produce the correct phase relationships among pairs of arm angles. Thus, apraxic subjects not only have deficits in the spatial plan for the movement, but they also have deficits in translating those plans into the details of the angular motions at the joints, even when actually manipulating a tool and object. These data support a model of apraxia in which apraxia can result from either the destruction of visuo-kinaesthetic motor representations of learned movement, stored in posterior association cortex, or from a separation of these representations from premotor or motor areas.
通过分析三名患有包括左顶叶在内的病变的失用症患者的关节协调缺陷，对肢体失用症基础的竞争模型进行了测试。记录了在一系列条件下重复进行“切片”手势时肩部、肘部、腕部和手部的三维轨迹，在这些条件下，情境线索以分级方式引入。失用症患者在不同情境条件下的关节协调表现出明显缺陷。即使在实际操作工具和物体时，失用症患者也无法表现出适当的关节同步，无法正确分配其相对关节幅度，并且无法在成对的手臂角度之间产生正确的相位关系。因此，失用症患者不仅在运动的空间计划方面存在缺陷，而且即使在实际操作工具和物体时，他们在将这些计划转化为关节角度运动的细节方面也存在缺陷。这些数据支持一种失用症模型，即失用症可能源于存储在后部联合皮层中的习得运动的视觉-动觉运动表征的破坏，或者源于这些表征与运动前区或运动区的分离。
