Triple stimulation technique: normative value of Chinese adults / 中华神经科杂志

ABSTRACT

Objective To validate the technique and to establish the reference values of triple stimulation technique(TST)in healthy Chinese adults.Methods One hundred healthy subjects were recruited to undergo TST from April 2010 to February 2011 in both abductor digiti minimi.The TST combines transcranial magnetic stimulation(TMS)of the motor cortex with peripheral collision studies.Three stimuli were given,leading to two collisions.A first magnetic stimulus was applied to the scalp overlying the motor cortex.After a delay,an electric stimulus was applied over the ulnar nerve at the wrist.The delay was chosen so that the action potentials descending from the cortex collided with the antidromic action potentials evoked at the wrist,with the collision site at the wrist and above.After another delay,another electrical stimulus was applied to Erb' s point.This delay was chosen so that ascending antidromic action potentials evoked by wrist stimulation collided at or distal to Erb' s point.At the same time,TST test curves were recorded.The TST test curve was compared with a TST control curve in which the first stimulus was applied to Erb' s point and the other two stimulus sites were the same as the test curve.Control stimuli were thus applied successively to Erb' s point,the wrist,Erb' s point.TST quantifies the number of conducting central motor neurons(expressed by the TST amplitude ratio).The values were compared among genders,age groups,arm length and sides respectively.Results The TST amplitude ratio(TSTteat/TSTcontrol)was 85.0％ ± 6.7％.There were no difference among genders,age groups,arm length and sides respectively.The TST amplitude ratio were 85.0％ ± 2.6％ and 85.0％ ± 8.7％,respectively in subjects with arm length 61-70 cm and 71-80 cm.Conclusion TST could be examined precisely and the normative value could be got.