Tamburin Stefano, Fiaschi Antonio, Andreoli Annalisa, Forgione Antonio, Manganotti Paolo, Zanette Giampietro
Section of Neurological Rehabilitation, Department of Neurological Sciences and Vision, University of Verona, Verona, Italy.
Clin Neurophysiol. 2003 Apr;114(4):643-51. doi: 10.1016/s1388-2457(03)00002-6.
To examine the sensorimotor interactions in cerebellar patients.
We investigated the effects of electrical stimulation of the second (D2) and fifth (D5) fingers on the amplitude of motor evoked potentials (MEPs) in response to transcranial magnetic stimulation and transcranial electrical stimulation (TES) in the relaxed right abductor digiti minimi muscles of 7 patients with cerebellar syndromes and of 14 age-matched controls. The digital stimulation was set at 3 times the sensory threshold and preceded brain stimulation at interstimulus intervals (ISIs) ranging from 10 to 100 ms.
D5 stimulation produced significant MEP inhibition in normal subjects at ISIs of 20-50 ms, while D2 stimulation resulted in a non-significant inhibitory trend with the same intervals. In contrast, digital stimulation had no effect on MEP amplitude in cerebellar patients. A significant difference was found between patients and controls at ISIs of 20-50 ms with D5 stimulation. The difference in amplitude of MEPs conditioned by D5 and D2 stimulation was statistically significant between patients and controls at ISIs of 30 and 50 ms. TES conditioning induced MEP inhibition only at ISIs <40 ms.
Digital stimulation would appear to modulate motor system excitability less effectively in cerebellar patients. MEP inhibition by cutaneous afferences is reduced in response to stimulation of contiguous, as well as non-contiguous fingers. The difference between the conditioning effects of the two fingers is also decreased, and therefore the somatotopic distribution of cutaneomotor inhibition is absent in patients. These abnormalities may contribute to the genesis of cerebellar motor symptoms and their time course suggests involvement of subcortical and cortical sites.
研究小脑病变患者的感觉运动交互作用。
我们调查了对7例小脑综合征患者及14例年龄匹配的对照者右侧放松的小指展肌进行经颅磁刺激和经颅电刺激（TES）时，电刺激第二指（D2）和第五指（D5）对运动诱发电位（MEP）幅度的影响。数字刺激设定为感觉阈值的3倍，并在10至100毫秒的刺激间隔（ISI）下先于脑刺激进行。
在20 - 50毫秒的ISI时，D5刺激在正常受试者中产生了显著的MEP抑制，而D2刺激在相同间隔下导致了不显著的抑制趋势。相比之下，数字刺激对小脑病变患者的MEP幅度没有影响。在20 - 50毫秒的ISI下，D5刺激时患者与对照者之间存在显著差异。在30和50毫秒的ISI时，患者与对照者之间由D5和D2刺激调节的MEP幅度差异具有统计学意义。TES调节仅在ISI <40毫秒时诱导MEP抑制。
在小脑病变患者中，数字刺激似乎对运动系统兴奋性的调节效果较差。对相邻以及不相邻手指的刺激反应中，皮肤传入引起的MEP抑制减弱。两指调节效应之间的差异也减小，因此患者不存在皮肤运动抑制的躯体定位分布。这些异常可能导致小脑运动症状的发生，其时间进程提示皮层下和皮层部位受累。
