Calautti Cinzia, Naccarato Marcello, Jones Peter S, Sharma Nikhil, Day Diana D, Carpenter Adrian T, Bullmore Edward T, Warburton Elizabeth A, Baron Jean-Claude
University of Cambridge, Department of Clinical Neurosciences, Addenbrooke's Hospital Box 83 Cambridge CB2 2QQ, UK.
Neuroimage. 2007 Jan 1;34(1):322-31. doi: 10.1016/j.neuroimage.2006.08.026. Epub 2006 Oct 10.
Functional imaging during movement of the hand affected by a stroke has shown excess activation of the contralesional motor network, implying less physiological hemisphere activation balance. Although this may be adaptive, the relationship between the severity of motor deficit and the hemisphere activation balance for the four major cortical motor areas has not been systematically studied. We prospectively studied 19 right-handed patients with first-ever stroke (age range 61+/-10 years) in the stable phase of recovery (>3 months after onset), using auditory-paced index-thumb (IT) tapping of the affected hand at 1.25 Hz as the fMRI paradigm. The hemisphere activation balance for the primary motor (M1), primary somatosensory (S1), supplementary motor (SMA) and dorsal premotor (PMd) areas was measured by a modified weighted laterality index (wLI), and correlations with motor performance (assessed by the affected/unaffected ratio of maximum IT taps in 15 s, termed IT-R) were computed. There were statistically significant negative correlations between IT-R and the wLI for M1 and S1, such that the more the hemispheric balance shifted contralesionally, the worse the performance. Furthermore, worse performance was related to a greater amount of contralesional, but not ipsilesional, activation. No significant correlation between IT-R and the wLI was obtained for the SMA and PMd, which functionally have stronger bilateral organization. These findings suggest that the degree of recovery of fine finger motion after stroke is determined by the extent to which activation balance in the primary sensory motor areas--where most corticospinal fibers originate--departs from normality. This observation may have implications for therapy.
对中风后受影响手部运动进行的功能成像显示，对侧运动网络过度激活，这意味着生理上的半球激活平衡降低。尽管这可能具有适应性，但运动功能缺损的严重程度与四个主要皮质运动区的半球激活平衡之间的关系尚未得到系统研究。我们前瞻性地研究了19例首次发生中风的右利手患者（年龄范围为61±10岁），这些患者处于恢复稳定期（发病后>3个月），使用受影响手部以1.25 Hz的频率进行听觉驱动的示指-拇指（IT）敲击作为功能磁共振成像（fMRI）范式。通过改良的加权偏侧性指数（wLI）测量初级运动区（M1）、初级体感区（S1）、辅助运动区（SMA）和背侧运动前区（PMd）的半球激活平衡，并计算其与运动表现（通过15秒内最大IT敲击次数的患侧/健侧比值评估，称为IT-R）的相关性。IT-R与M1和S1的wLI之间存在统计学上的显著负相关，即半球平衡向对侧转移得越多，表现越差。此外，表现越差与对侧而非同侧的激活量越大有关。对于功能上具有更强双侧组织的SMA和PMd，未获得IT-R与wLI之间的显著相关性。这些发现表明，中风后精细手指运动的恢复程度取决于大多数皮质脊髓纤维起源的初级感觉运动区的激活平衡偏离正常的程度。这一观察结果可能对治疗具有启示意义。
