Sharma Nikhil, Simmons Lucy H, Jones P Simon, Day Diana J, Carpenter T Adrian, Pomeroy Valerie M, Warburton Elizabeth A, Baron Jean-Claude
Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
Stroke. 2009 Apr;40(4):1315-24. doi: 10.1161/STROKEAHA.108.525766. Epub 2009 Jan 29.
In recovered subcortical stroke, the pattern of motor network activation during motor execution can appear normal or not, depending on the task. Whether this applies to other aspects of motor function is unknown. We used functional MRI to assess motor imagery (MI), a promising new approach to improve motor function after stroke, and contrasted it to motor execution.
Twenty well-recovered patients with hemiparetic subcortical stroke (14 males; mean age, 66.5 years) and 17 aged-matched control subjects were studied. Extensive behavioral screening excluded 8 patients and 4 control subjects due to impaired MI abilities. Subjects performed MI and motor execution of a paced finger-thumb opposition sequence using a functional MRI paradigm that monitored compliance. Activation within the primary motor cortex (BA4a and 4p), dorsal premotor, and supplementary motor areas was examined.
The pattern of activation during affected-hand motor execution was not different from control subjects. Affected-hand MI activation was also largely similar to control subjects, including involvement of BA4, but with important differences: (1) unlike control subjects and the nonaffected hand, activation in BA4a and dorsal premotor was not lower during MI as compared with motor execution; (2) the hemispheric balance of BA4p activation was significantly less lateralized than control subjects; and (3) ipsilesional BA4p activation positively correlated with motor performance.
In well-recovered subcortical stroke, the motor system, including ipsilesional BA4, is activated during MI despite the lesion. It, however, remains disorganized in proportion to residual motor impairment. Thus, components of movement upstream from execution appear differentially affected after stroke and could be targeted by rehabilitation in more severely affected patients.
在恢复的皮质下卒中患者中，运动执行期间运动网络的激活模式可能正常，也可能因任务而异。这是否适用于运动功能的其他方面尚不清楚。我们使用功能磁共振成像来评估运动想象（MI），这是一种有望改善卒中后运动功能的新方法，并将其与运动执行进行对比。
研究了20例恢复良好的偏瘫皮质下卒中患者（14例男性；平均年龄66.5岁）和17例年龄匹配的对照受试者。广泛的行为筛查排除了8例患者和4例对照受试者，因为他们的运动想象能力受损。受试者使用监测依从性的心算磁共振成像范式进行运动想象和按节奏的拇指对指序列的运动执行。检查初级运动皮层（BA4a和4p）、背侧运动前区和辅助运动区的激活情况。
患侧手运动执行期间的激活模式与对照受试者无差异。患侧手的运动想象激活也与对照受试者大致相似，包括BA4的参与，但存在重要差异：（1）与对照受试者和非患侧手不同，运动想象期间BA4a和背侧运动前区的激活与运动执行相比没有降低；（2）BA4p激活的半球平衡比对照受试者明显更不具有偏侧性；（3）患侧BA4p激活与运动表现呈正相关。
在恢复良好的皮质下卒中患者中，尽管存在病变，但在运动想象期间运动系统（包括患侧BA4）仍被激活。然而，它与残余运动障碍成比例地保持紊乱。因此，执行上游的运动成分在卒中后受到不同程度的影响，对于受影响更严重的患者，康复治疗可以针对这些成分。
