Desiato Maria Teresa, Bernardi Giorgio, Hagi H Abdikarim, Boffa Laura, Caramia Maria D
Clinica Neurologica, Dipartimento di Neuroscienze, Università Tor Vergata, Ospedale S. Eugenio, Piazzale Umanesimo, 10, 00144 Rome, Italy.
Clin Neurophysiol. 2002 Jan;113(1):132-40. doi: 10.1016/s1388-2457(01)00724-6.
In amyotrophic lateral sclerosis (ALS), transcranial magnetic stimulation (TMS) detects remarkable abnormalities of central motor circuits: cortical excitability threshold, silent period (SP) duration and intra-cortical inhibition. TMS directed to cranio-facial musculature was performed in ALS patients in order: (1) to document the neurophysiological involvement of motor central and peripheral cranial pathways by evaluating changes of threshold and SP; (2) to discover a possible correlation between the clinical picture and abnormal excitability properties.
Motor evoked potentials (MEPs) were recorded from masseter, genioglossus and orbicularis oris muscles of both sides in 25 ALS patients and 25 controls, in response to TMS delivered over the face M1 area and the vertex.
TMS gave rise to two orders of responses: bilateral MEPs during contraction represented the central responses, and motor action potentials (MAPs) during rest represented the peripheral responses. MEPs were followed by SPs, which increased linearly with increasing TMS intensity (r=0.8). At least one of the analyzed parameters was abnormal in all patients: central abnormalities (increased active threshold, delayed MEPs, reduced SP) were found in 96% of patients, alone or combined with abnormalities of the MAPs (reduced area and/or prolonged latency). The reduction of SP was linearly related to the Norris score (r=0.95).
Our study shows that TMS is able to detect the involvement of multiple cranial muscles in ALS. This finding offers often pre-clinical information about the disease picture. Therefore, it can be employed as a valuable means for early diagnosis.
在肌萎缩侧索硬化症（ALS）中，经颅磁刺激（TMS）可检测到中枢运动回路的显著异常：皮质兴奋性阈值、静息期（SP）持续时间和皮质内抑制。对ALS患者进行针对颅面部肌肉组织的TMS，目的如下：（1）通过评估阈值和SP的变化来记录运动中枢和外周颅神经通路的神经生理学受累情况；（2）发现临床表现与异常兴奋性特征之间可能存在的相关性。
在25例ALS患者和25例对照者中，记录双侧咬肌、颏舌肌和口轮匝肌在经面部M1区和头顶给予TMS刺激时的运动诱发电位（MEP）。
TMS引发了两种反应：收缩时的双侧MEP代表中枢反应，静息时的运动动作电位（MAP）代表外周反应。MEP之后是SP，其随TMS强度增加呈线性增加（r = 0.8）。所有患者中至少有一项分析参数异常：96%的患者存在中枢异常（激活阈值增加、MEP延迟、SP缩短），单独出现或与MAP异常（面积减小和/或潜伏期延长）合并出现。SP缩短与诺里斯评分呈线性相关（r = 0.95）。
我们的研究表明，TMS能够检测到ALS中多块颅肌的受累情况。这一发现常常提供有关疾病情况的临床前信息。因此，它可作为早期诊断的一种有价值的手段。
