经颅磁刺激运动诱发电位阈值与年龄及皮层功能水平的关系

目的研究年龄在经颅磁刺激(transcranialmagneticstimulation,TMS)运动诱发电位(motorevokedpotentials,MEPs)中,两侧生理刺激阈值的不同。方法76例健康者,右利手63例,依年龄不同分为3组:青年组22例(19～39岁);中年组20例(40～59岁);老年组21例(60～82岁)。左利手13例,为青年组健康者(19～39岁)。应用8字形磁刺激器分别刺激左右侧运动皮层,记录对应拇短展肌(abductorpollicisbrevismuscle,APBM)运动诱发电位,测定其在静息和随意收缩时刺激阈值的变化。结果右利手青年组和中年组,右侧APBM运动诱发电位的皮层刺激阈值明显低于左侧APBM(P<0.01);而老年组双侧刺激阈值无明显区别;左利手青年组,左侧APBM运动诱发电位的皮层刺激阈值明显低于右侧。结论推测TMS运动诱发电位双侧皮层刺激阈值在各年龄组的不对称变化主要与运动皮层的功能水平有关。

The study in aged - dependent physiological threshold with the motor evoked potentials of transcranial magnetic stimulation

Aim To study the the effect of age on the physiological threshold asymmetry for the motor ev oked potentials(MEPs )by transcranial magnetic stimulation(TMS ).Methods Among 76healthy subjects ,63right-hand subjects were divided in to three groups:22in young group(aged19-39)including 13left-hand subjects,20in middle-aged group(aged 40-59)and 21in old group(aged 60-82).The MEPs thresholds of APBM were measured during voluntary contraction among 3groups respectively.ResultsFor the right-hand subjects,the MEPs thresholds of the right APBM in youn g and middle-age groups were signific antly lower than those of the left APB M,which were reversed for the left-han d subjects.But the thresholds were n ot different between both sides in old g roup.Conclusion The asymmetries of the MEPs thresholds were mainly related with the cortical functional level.