Ward N S, Brown M M, Thompson A J, Frackowiak R S J
Wellcome Department of Imaging Neuroscience, Institute of Neurology, University College London, London, UK.
Brain. 2003 Jun;126(Pt 6):1430-48. doi: 10.1093/brain/awg145.
Recovery of motor function after stroke may occur over weeks or months and is often attributed to neuronal reorganization. Functional imaging studies investigating patients who have made a good recovery after stroke have suggested that recruitment of other motor-related networks underlies this recovery. However, patients with less complete recovery have rarely been studied, or else the degree of recovery has not been taken into account. We set out to investigate the relationship between the degree of recovery after stroke and the pattern of recruitment of brain regions during a motor task as measured using functional MRI. We recruited 20 patients who were at least 3 months after their first ever stroke, and 26 right-handed age-matched control subjects. None of our patients had infarcts involving the hand region of the primary motor cortex. All subjects were scanned whilst performing an isometric, dynamic visually paced handgrip task. The degree of functional recovery of each patient was assessed using a battery of outcome measures. Single-patient versus control group analysis revealed that patients with poor recovery were more likely to recruit a number of motor-related brain regions over and above those seen in the control group during the motor task, whereas patients with more complete recovery were more likely to have 'normal' task-related brain activation. Across the whole patient group and across stroke subtypes, we were able to demonstrate a negative correlation between outcome and the degree of task-related activation in regions such as the supplementary motor area, cingulate motor areas, premotor cortex, posterior parietal cortex, and cerebellum. This negative correlation was also seen in parts of both contralateral and ipsilateral primary motor cortex. These results further our understanding of the recovery process by demonstrating for the first time a clear relationship between task-related activation of the motor system and outcome after stroke.
中风后运动功能的恢复可能会持续数周或数月，通常归因于神经元重组。对中风后恢复良好的患者进行的功能成像研究表明，其他与运动相关网络的募集是这种恢复的基础。然而，恢复不太完全的患者很少被研究，或者没有考虑恢复程度。我们着手研究中风后恢复程度与运动任务期间使用功能磁共振成像测量的脑区募集模式之间的关系。我们招募了20名首次中风后至少3个月的患者，以及26名年龄匹配的右利手对照受试者。我们的患者中没有一人梗死累及初级运动皮层的手部区域。所有受试者在进行等长、动态视觉节奏的手握力任务时接受扫描。使用一系列结果测量方法评估每位患者的功能恢复程度。单患者与对照组分析显示，恢复较差的患者在运动任务期间比对照组更有可能募集多个与运动相关的脑区，而恢复更完全的患者更有可能具有“正常”的任务相关脑激活。在整个患者组和不同中风亚型中，我们能够证明在辅助运动区、扣带回运动区、运动前皮层、顶叶后皮层和小脑等区域，结果与任务相关激活程度之间存在负相关。在对侧和同侧初级运动皮层的部分区域也观察到了这种负相关。这些结果首次证明了运动系统的任务相关激活与中风后结果之间的明确关系，进一步加深了我们对恢复过程的理解。
