Department of Neurology, University of Würzburg, Würzburg, Germany.
J Neurol Neurosurg Psychiatry. 2011 May;82(5):578-83. doi: 10.1136/jnnp.2010.219964. Epub 2010 Oct 27.
In patients with multiple sclerosis (MS), motor tasks are associated with increased activation of ipsilateral motor cortical areas. The authors examined the role of two ipsilateral motor areas during performance of a simple motor task in MS patients in relation to their motor impairment and CNS injury.
Single pulses of transcranial magnetic stimulation (TMS) were used to interfere transiently with neuronal processing in the contralateral (M1(CONTRA)) or ipsilateral (M1(IPSI)) primary motor cortex or ipsilateral dorsal premotor cortex (PMd(IPSI)) during a simple reaction time (RT) task in 26 right-handed patients with moderately severe stable MS and matched healthy controls. Subjects responded to an auditorily presented Go signal as quickly as possible by performing isometric right-thumb abductions. TMS was applied 100 ms after the Go signal. Motor impairment was evaluated by hand function tests. CNS injury was assessed by magnetic resonance spectroscopy (normalised N-acetyl-aspartate spectra, NAA/Cr), by the total cerebral T2-weighted MRI hyperintense lesion load, and by corticomuscular latency (CML) to the abductor pollicis brevis muscle.
TMS applied to M1(CONTRA) slowed RT in patients and controls. In contrast, stimulation of M1(IPSI) or PMd(IPSI) increased RT only in MS patients. In patients, the relative RT changes following TMS over M1(IPSI) or PMd(IPSI) did not correlate with any of the motor function tests or with NAA/Cr or total cerebral lesion load. However, RT changes following TMS over M1(IPSI) correlated inversely with CML.
Recruitment of ipsilateral motor areas may be a functionally relevant, yet limited adaptive response to chronic brain injury in MS patients.
在多发性硬化症（MS）患者中，运动任务与对侧运动皮质区域的活动增加有关。作者研究了在执行简单运动任务时，MS 患者双侧运动区的作用与其运动障碍和中枢神经系统损伤的关系。
在 26 名右利手、中度稳定 MS 患者和匹配的健康对照组中，在简单反应时间（RT）任务期间，使用经颅磁刺激（TMS）单次脉冲暂时干扰对侧（M1（CONTRA））或同侧（M1（IPSI））初级运动皮质或同侧背侧运动前皮质（PMd（IPSI））的神经元处理。受试者通过尽可能快地进行右侧拇指外展来对听觉呈现的 Go 信号做出反应。TMS 在 Go 信号后 100 毫秒施加。运动障碍通过手部功能测试进行评估。中枢神经系统损伤通过磁共振波谱（正常化 N-乙酰天冬氨酸谱，NAA/Cr）、总脑 T2 加权 MRI 高信号病变负荷以及对拇短展肌的皮质运动潜伏期（CML）进行评估。
TMS 施加于 M1（CONTRA）会使患者和对照组的 RT 变慢。相比之下，刺激 M1（IPSI）或 PMd（IPSI）仅增加 MS 患者的 RT。在患者中，TMS 对 M1（IPSI）或 PMd（IPSI）的相对 RT 变化与任何运动功能测试或 NAA/Cr 或总脑病变负荷均无相关性。然而，TMS 对 M1（IPSI）的 RT 变化与 CML 呈负相关。
同侧运动区的募集可能是 MS 患者慢性脑损伤的一种具有功能相关性但有限的适应性反应。
