经颅磁刺激运动诱发电位在肌萎缩侧索硬化中的应用

目的：探讨经颅磁刺激运动诱发电位（TMS—MEP）在肌萎缩侧索硬化（ALS）患者上运动神经元损害评价中的作用。方法：对符合E1 Escorial诊断标准的20例ALS患者（ALS组）和15名健康对照者（健康对照组）进行双小指展肌、胫前肌TMS-MEP测定。运动诱发电位（MEP）中枢性损害的判断标准为中枢运动传导时间（CMCT）延长、安静状态双侧皮层刺激MEP未引出或易化状态至少一侧皮层刺激MEP未引出；CMCT侧间差增大为可疑异常。对两组患者的MEP中枢异常进行比较。结果：ALS患者小指展肌易化状态、安静状态CMCT、胫前肌易化状态CMCT与对照组比较显著延长。ALS患者TMS—MEP中枢性损害的出现率为60％，主要表现为CMCT延长和MEP引不出，分别占50％（10／20）和50％（10／20），如将CMCT侧间差增大者计入，则总异常率提高到75％。按诊断级别分组后，临床确诊、拟诊和可能的ALS患者的MEP中枢性损害出现率分别为87．5％、71．4％和60．0％，单纯CMCT侧间差增大而无其他异常，仅见于拟诊或可能的ALS患者。结论：对于拟诊或可能的ALS，MEP中枢性异常可以帮助确立上运动神经元受累。单纯CMCT侧间差增大可能发生于早期患者，有助于发现轻度或亚临床上运动神经元病损。

Diagnostic value of transcranial magnetic stimulation motor evoked potentials in amyotrophic lateral sclerosis

Objective： To investigate the （TMS-MEP） in amyotrophic lateral sclerosis neuron （UMN） lesion in patients with ALS changes of transcranial magnetic stimulation motor evoked potential （ALS） and assess the value of TMS-MEP in diagnosis of upper motor Methods： Twenty cases of ALS patients （ALS group）, and 15 healthy controls （control group） were enrolled in the study. TMS-MEP measurements were performed on bilateral abductor digiti minimi （ADM） and tibialis anterior （TA） muscles of all the subjects. We made the judgement of central nervous system （CNS） pattern abnormality basing on MEP if either of the following criteria was met： central motor conduction time （CMCT） increased, responses to cortical stimulation were absent on both sides in the resting muscles or one side in the active muscles. Increased interside differences in CMCT were considered suspected abnormalities. Results： In ALS group, facilitated CMCT, resting CMCT in the ADM muscles and facilitated CMCT in the TA muscles were significantly higher than those in controls （P 〈 0. 05）. TMS-MEP showed CNS pattern abnor- malities in 60% of ALS patients, manifesting as prolonged CMCT （50% , 10/20） and absent MEP （50%, 10/ 20）. If increased interside differences in CMCT were included into the judgement, the overall abnormality rate raised to 75%. The rates of CNS pattern abnormalities in clinically definite, clinically probable and clinically possible ALS subgroups were 87.5%, 71.4% and 60% respectively. And patients with pure increased interside differences in CMCT but without other abnormalities were found in the latter two subgroups. Conclusion： The presence of MEP indicated CNS pattern abnormalities will help to demonstrate UMN involvement in clinically probable- laboratory-supported ALS or possible ALS. Pure increased interside differences in CMCT may be more common in patients in early stages, and could contribute to the detection of slight or subclinical UMN lesions.