Traversa R, Cicinelli P, Bassi A, Rossini P M, Bernardi G
IRCCS S Lucia, Universitá Tor Vergata, Rome, Italy.
Stroke. 1997 Jan;28(1):110-7. doi: 10.1161/01.str.28.1.110.
Focal transcranial magnetic stimulation (TCS) is used for noninvasive and painless mapping of the somatotopical organization of the motor cortex. TCS mapping of motor cortical output to the abductor digiti minimi (ADM) muscle was followed up in monohemispheric stroke patients by evaluating motor evoked potentials (MEPs). This approach allowed noninvasive investigation of the functional reorganization of hand motor areas.
Motor maps were constructed for 15 subacute stroke patients about 2 months from the ictus by recording MEPs from the ADM muscle via focal TCS in the affected hemisphere (AH) and unaffected hemisphere (UH) at the beginning of (T1) and after 8 to 10 weeks of neurorehabilitation (T2). Barthel Index and Canadian Neurological Scale scores were evaluated as well. An age-sex matched group of 15 healthy control subjects was enrolled to establish normative data.
MEP excitability threshold was significantly higher in the AH of stroke patients than in normal subjects and in the UH (P < .001); excitability threshold was not significantly different between normal subjects and UH. In the AH, MEPs were significantly (P < .001) delayed in latency both in T1 and T2, with a significant decrease of the extenuation of motor output area to the ADM muscle (P < .05) in T1 versus control group and UH. This area was significantly enlarged (P < .05) in T2. Amplitude of MEPs from the AH, both at rest and during voluntary contraction, was significantly lower than normal in T1 (P < .001); it increased in T2 (P < .01) during relaxation but was still smaller than normal during contraction (P < .001). In combination with these findings, an improvement of Barthel Index and Canadian Neurological Scale scores (P < .001) was observed between T1 and T2 (P < .001). Central conduction time was prolonged in stroke patients both in T1 and T2. Changes in the shape of motor maps in the AH during follow-up in T2 were either isolated (therefore increasing the interhemispheric asymmetry) or also were "mirrored" on the UH.
Our neurophysiological data are consistent with the presence of a rearrangement of the motor cortical output area and correlate well with an improvement of motor performances. These findings confirm the existence in adults of a "plasticity" in the central nervous system that is still operating between 2 and 4 months from the acute ictal episode. The observed neurophysiological modifications are significantly correlated with clinical improvement of disability and clinical scores.
局灶性经颅磁刺激（TCS）用于对运动皮层的躯体感觉组织进行无创且无痛的映射。通过评估运动诱发电位（MEP），对单半球卒中患者运动皮层至小指展肌（ADM）的输出进行TCS映射随访。这种方法允许对手部运动区的功能重组进行无创研究。
对15例亚急性卒中患者进行运动图谱构建，这些患者在发病后约2个月，在神经康复开始时（T1）以及8至10周后（T2），通过局灶性TCS在患侧半球（AH）和未患侧半球（UH）记录ADM肌肉的MEP。同时评估巴氏指数和加拿大神经功能量表评分。纳入15名年龄和性别匹配的健康对照者以建立正常数据。
卒中患者AH侧的MEP兴奋性阈值显著高于正常受试者和UH侧（P <.001）；正常受试者和UH侧之间的兴奋性阈值无显著差异。在AH侧，T1和T2时MEP潜伏期均显著延迟（P <.001），与对照组和UH侧相比，T1时ADM肌肉运动输出区的衰减显著降低（P <.05）。T2时该区域显著扩大（P <.05）。AH侧在静息和自主收缩时MEP的波幅在T1时均显著低于正常（P <.001）；T2时放松时波幅增加（P <.01），但收缩时仍小于正常（P <.001）。结合这些发现，观察到T1和T2之间巴氏指数和加拿大神经功能量表评分有所改善（P <.001）。卒中患者在T1和T2时中枢传导时间均延长。T2随访期间AH侧运动图谱形状的变化要么是孤立的（因此增加了半球间不对称性），要么也在UH侧“镜像”出现。
我们的神经生理学数据与运动皮层输出区的重新排列一致，并且与运动表现的改善密切相关。这些发现证实了在成人中枢神经系统中存在“可塑性”，在急性发作后2至4个月内仍在起作用。观察到的神经生理学改变与残疾的临床改善和临床评分显著相关。
