Department of Physical Medicine and Rehabilitation, Faculty of Medicine, University Jean Monnet, Saint-Etienne, France.
Cortex. 2012 Jun;48(6):746-57. doi: 10.1016/j.cortex.2011.02.003. Epub 2011 Feb 12.
Amputees who have a phantom limb often report the ability to move this phantom voluntarily. In the literature, phantom limb movements are generally considered to reflect motor imagery rather than motor execution. The aim of this study was to investigate whether amputees distinguish between executing a movement of the phantom limb and imagining moving the missing limb. We examined the capacity of 19 upper-limb amputees to execute and imagine movements of both their phantom and intact limbs. Their behaviour was compared with that of 18 age-matched normal controls. A global questionnaire-based assessment of imagery ability and timed tests showed that amputees can indeed distinguish between motor execution and motor imagery with the phantom limb, and that the former is associated with activity in stump muscles while the latter is not. Amputation reduced the speed of voluntary movements with the phantom limb but did not change the speed of imagined movements, suggesting that the absence of the limb specifically affects the ability to voluntarily move the phantom but does not change the ability to imagine moving the missing limb. These results suggest that under some conditions, for example amputation, the predicted sensory consequences of a motor command are sufficient to evoke the sensation of voluntary movement. They also suggest that the distinction between imagined and executed movements should be taken into consideration when designing research protocols to investigate the analgesic effects of sensorimotor feedback.
有幻肢的截肢者常常报告说能够自主地移动这个幻肢。在文献中，幻肢运动通常被认为反映了运动意象，而不是运动执行。本研究旨在调查截肢者是否能区分执行幻肢运动和想象缺失肢体的运动。我们检查了 19 名上肢截肢者执行和想象他们的幻肢和健全肢体运动的能力。他们的行为与 18 名年龄匹配的正常对照组进行了比较。一项基于全局问卷的意象能力评估和定时测试表明，截肢者确实可以区分幻肢的运动执行和运动意象，前者与残肢肌肉的活动有关，而后者则没有。截肢减少了幻肢的自愿运动速度，但没有改变想象运动的速度，这表明肢体的缺失特别影响了自愿移动幻肢的能力，而不改变想象缺失肢体的能力。这些结果表明，在某些情况下，例如截肢，运动指令的预测感觉后果足以引起自愿运动的感觉。它们还表明，在设计研究方案以研究感觉运动反馈的镇痛效果时，应考虑到想象和执行运动之间的区别。
