Benecke R, Rothwell J C, Dick J P, Day B L, Marsden C D
Brain. 1987 Apr;110 ( Pt 2):361-79. doi: 10.1093/brain/110.2.361.
The following sequences of two single movements were examined in 10 patients with Parkinson's disease and compared with the performance of 9 normal subjects of similar age. Isometric opposition of thumb and fingers to a force of 30 N ('squeeze'), followed by isotonic elbow flexion ('flex') through 15 degrees with the same arm. 'Squeeze' with the left hand followed by 'flex' with the right elbow. Isotonic opposition of thumb and fingers ('cut') through 90 degrees followed by isotonic 'flex' with the same arm. Isotonic elbow 'flex' followed by isometric 'squeeze' with the same arm. All movements were self-paced. Subjects were given instructions to move as rapidly as possible and to start the second movement immediately after the end of the first. Patients were slower than normal when each single movement was performed separately. There was a further decrease in speed when two movements were executed sequentially. This was due to an increase in movement duration of each of the component movements, especially the second, and to an increase in the pause between the first and second movements. In both normals and patients, there was no correlation between the times taken to perform the first and second movements of any of the four sequences that were studied. Because of this we suggest that the two components of the sequence remained under the control of two separate motor programs. When performing the sequential tasks, normal subjects automatically chose an interval between the onsets of the two separate movements of about 230 ms, even in tasks in which the duration of the first movement was less than 200 ms. If normal subjects were instructed to begin the second movement with an interonset interval of less than 200 ms, the speed of the second movement was much slower. Patients with Parkinson's disease automatically chose a much longer interonset interval of 400-500 ms. In addition, they exhibited difficulty in switching from the first to the second movement in the sequence. We suggest that the problems exhibited by patients with Parkinson's disease when they try to perform two rapid sequential movements can be seen as a deficit in the capacity to switch from one motor program to another within an overall motor plan.
对10例帕金森病患者进行了以下两个单动作序列的检查，并与9名年龄相仿的正常受试者的表现进行了比较。拇指和手指以30牛的力进行等长对抗（“挤压”），随后同一只手臂进行15度的等张肘关节屈曲（“屈曲”）。左手“挤压”，随后右肘关节“屈曲”。拇指和手指进行90度的等张对抗（“切割”），随后同一只手臂进行等张“屈曲”。等张肘关节“屈曲”，随后同一只手臂进行等长“挤压”。所有动作均为自定节奏。受试者被要求尽可能快速地移动，并在第一个动作结束后立即开始第二个动作。当分别执行每个单动作时，患者比正常人慢。当依次执行两个动作时，速度进一步下降。这是由于每个组成动作的持续时间增加，尤其是第二个动作，以及第一个和第二个动作之间的停顿增加。在正常人和患者中，所研究的四个序列中任何一个序列的第一个和第二个动作的执行时间之间均无相关性。因此，我们认为序列的两个组成部分仍受两个独立运动程序的控制。在执行连续任务时，正常受试者会自动在两个独立动作的起始之间选择约230毫秒的间隔，即使在第一个动作持续时间小于200毫秒的任务中也是如此。如果要求正常受试者以小于200毫秒的起始间隔开始第二个动作，第二个动作的速度会慢得多。帕金森病患者会自动选择400 - 500毫秒的长得多的起始间隔。此外，他们在序列中从第一个动作切换到第二个动作时表现出困难。我们认为，帕金森病患者在尝试执行两个快速连续动作时表现出的问题可被视为在整体运动计划内从一个运动程序切换到另一个运动程序的能力缺陷。
