Trigeminal Sometic Evoked Potentials Elicited by Tainful Electric Dental Stimulation

本实验观察了不同刺激频率（1、0.5、0.5T/sec）下躯体诱发电位SEP的变化，用模拟疼痛量表和刺激强度评价主观疼痛感，以及小剂量地西泮（0.01、0.02、0.05mg/Kg，iv）、二氟尼柳（DFS）250 mg，在电刺激牙痛后50 ~ 500 msec的SEP中，所有受试者均检测到5种成分（N70，P100，N155，P260，N350）。峰-峰振幅随刺激频率的降低而增加，尤其是N155-P260（P<0.01）。在不同的刺激强度之间没有观察到峰值潜伏期的显著变化。P155-P260和N70-P100的波幅随刺激强度的增加而增加（P<0.001）。N65-P100与主观疼痛评分和刺激强度相关。N155-P260与主观疼痛评分显著相关，实验组患者的潜伏期峰值明显减慢，尤其是P260小剂量地西泮后N65-P100波幅轻度升高，二氟尼柳后1h N155-P260波幅降低（p<0.005）。在一氧化二氮浓度和SEP振幅之间进行比较时，在N155-P260处观察到最显著的振幅降低。与室内空气相比，吸入15%和3% N2 O2后SEP波幅逐渐降低，尤以3% N2 O2组降低最为显著（P<0.001）。30%N2O使SEP各成分均显著延迟，15%N2O使N70、P100和N150的早期成分显著增加，并有使其他成分增加的趋势，提示SEP可作为判断主观疼痛的一个有用指标。

The present experiment observed the somatic evoked potentials SEPs changes between different stimulus rates (1,0.5,0.5 T/sec), subjective painfulness evaluated by analogue pain scale and stimulus intensities, the effect of low doses diazepam injection (0.01, 0.02, 0.05mg/Kg, iv), diflunisal DFS 250mg p.o., and the changes in nitrous oxide anesthesia (room air, 100% 02,15% N20,30% N20,15% N20,100% 02), elicited by electric dental painful stimulation.In SEPs between 50 msec to 500 msec following stimuli, five components were detected in all subjects(N70, P100, N155, P260,N350). Peak-to peak amplitudes increased as stimulus rate was decreased, especially N155-P260(P<0.01). No significantly changes in peak latencies were observed across different stimulus intencities. Peak-to-peak amplitude increased systematically with increased stimuli, especially N155-P260 and N70-P100(P<0.001). N65-P100 correlated with both subjective pain score and stimulus intencities. N155-P260 significantly correlated with subjective pain score.The experiment group's peak latencies were slowed, especially P260(P<0.05), and N65-P100 amplitude was slightly increased after low doses diazepam injection.One hour after taking diflunisal, amplitude of N155-P260 were decreased(p<0.005).Upon comparison between nitrous oxide concentrations and the amplitude of SEPs, the most significant amplitude decrease was observed at N155-P260. As compared with the room air, graded reductions in the amplitude of SEPs were noted at pre-15% and 3/% nitrous oxid, particularly in the latter where the reduction was statistically significant (P<0.001). 30% nitrous oxide significantly delayed all elements of SEPs, while 15% nitrous caused significant increased in the early components of N70, P100 and N150, and tended to increase other components.The results as described above suggested the possibility of SEPs as a useful index for determination of subjective painfulness.