Chroni Elisabeth, Lekka Nicoletta P, Tsoussis Ioannis, Nikolakopoulou Anastasia, Paschalis Christos, Beratis Stavroula
Department of Neurology, University Hospital of Patras, Greece.
J Clin Neurophysiol. 2002 Jun;19(3):240-4. doi: 10.1097/00004691-200206000-00007.
Under normal conditions, motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation increase in amplitude if the subject exercises the examined muscle immediately before recording. The authors examined the effect of nonfatiguing exercise on the amplitude of MEPs on 42 psychiatric, medicated inpatients (14 with depression, 14 with schizophrenia, and 14 with mania) compared with 14 healthy control subjects. For each subject, a total of 50 baseline and 50 postexercise MEPs were recorded. The mean (+/- standard deviation) postexercise MEP facilitation, expressed as a percentage of mean baseline values, was significantly lower (p </= 0.02) in all three patient groups (148 +/- 91% in the depressed, 107 +/- 43% in the schizophrenic, and 143 +/- 63% in the manic patients) compared with the control subjects (268 +/- 223%). There was no clear evidence that psychotropic medication could be fully responsible for the modified MEP response to exercise, but the degree to which they were responsible is impossible to assess. These findings indicate that the reduced postexercise MEP facilitation is not related to any particular psychiatric illness, but rather that it represents a suppressed reaction of cortical excitability shared by patients with either depression, mania, or schizophrenia. The authors propose that, despite the lack of specificity, the study of postexercise MEP alterations could be useful in the neurophysiologic evaluation of motor cortex excitability in some psychiatric illnesses, except in those patients who may have diminished somatosensory input associated with voluntary muscle contraction resulting in decreased cortical excitability.
在正常情况下，如果受试者在记录运动诱发电位（MEP）之前立即对所检查的肌肉进行锻炼，经颅磁刺激所诱发的MEP波幅会增加。作者研究了非疲劳性运动对42名接受药物治疗的精神科住院患者（14名抑郁症患者、14名精神分裂症患者和14名躁狂症患者）MEP波幅的影响，并与14名健康对照者进行比较。对每名受试者，共记录50次基线MEP和50次运动后MEP。以平均基线值的百分比表示的运动后MEP易化均值（±标准差），在所有三个患者组中均显著低于对照组（p≤0.02）（抑郁症患者为148±91%，精神分裂症患者为107±43%，躁狂症患者为143±63%），而对照组为268±223%。没有明确证据表明精神药物能完全解释MEP对运动反应的改变，但它们所起作用的程度无法评估。这些发现表明，运动后MEP易化降低与任何特定精神疾病无关，而是代表抑郁症、躁狂症或精神分裂症患者共有的皮质兴奋性抑制反应。作者提出，尽管缺乏特异性，但运动后MEP改变的研究可能有助于某些精神疾病运动皮质兴奋性的神经生理学评估，除了那些可能因与随意肌肉收缩相关的体感输入减少而导致皮质兴奋性降低的患者。
