An experimental study of motor evoked potentials of the diaphragm elicited by transcranial electric stimulation / 中华物理医学与康复杂志

ABSTRACT

Objective To study the characteristics of the transcranial electric stimulation(TES)-elicited motor evoked potentials(MEP)recorded from different points of the diaphragm,and to determine the optimal record- ing site in the diaphragm.Methods One EEG electrode was placed subcutaneously in the midline of the skull as stimulation electrode and another EEG electrode was inserted into hard palate submucously as cathode in 30 male rats.And single square wave electrical pulse was used for stimulation.The stimulation intensity was 15 mA,the du- ration of the pulse was 0.2 ms,and the stimulating interval was 200 ms.The concentric needle electrode were insert- ed into the following eight sitesthe medial,intermediate,lateral crura of the diaphragm,the junction of the posterior axilla line and the inferior border of the eleventh rib,the junction of the anterior axilla line and the inferior border of the ninth rib,the junction of the intermediate line of the clavicle and the inferior border of the eighth rib,the junction of the para-sternal line and the inferior border of the seventh rib,the pars sternalis.The MEP was recorded from each point,respectively.The optimal sites of the diaphragm MEP were found and recorded.Results The MEPs were re- corded from each of the 8 sites of the diaphragm in all the rats after TES.There was no statistically significant differ- ence among the latencies of every site.But the amplitude varied from 6.08?0.46 mV in maximum along the inferior border of the ninth rib at the anterior line of the axilla to the minimum of O.91?0.03 mV at the pars sternalis. Conclusion It is safer to insert the needle along the inferior border of the ninth rib at the anterior line of the axilla, because there was certain distant from the folding part of the pleura and the amplitude of the recorded wave at this point is maximal.