摘要目的 应用接触性热痛诱发电位(CHEP)研究急性脊髓炎(AM)患者痛觉传导通路中枢段变化特点,探讨CHEP中枢N波检测技术及Aδ纤维脊髓段传导速度在AM中的应用价值,为其电生理诊断提供依据.方法 共选取AM患者20例,应用接触性热痛诱发电位刺激器对AM患者手背正中、上肢前臂掌侧近端1/3处、C7和T12棘突及内踝上方5 cm处皮肤进行热痛刺激(54.5℃),记录其CHEP波形及潜伏期,并计算外周段(手背至上肢前臂近端1/3处)Aδ纤维传导速度及脊髓段传导速度;同时对入选患者进行躯体感觉诱发电位(SEP)检测及感觉神经传导测定,并将其结果与CHEP进行比较.另外本研究同时选取20例体检健康者纳入正常对照组,并将AM组上述检测结果与正常对照组进行对比.结果 于AM组手背正中、内踝上方5 cm处皮肤或C7和T12水平棘突部位给予热痛刺激,发现患者CHEP中枢N波潜伏期[分别为(556.1±26.9)ms,(591.3±29.0) ms,(508.2 ±22.8)ms和(536.3±25.1)ms]均较正常对照组显著延长(P＜0.05),AM组CHEP外周段Aδ纤维传导速度与正常对照组间差异无统计学意义(P＞0.05),脊髓段传导速度[9.6±1.3)m/s]较正常对照组明显减慢(P＜0.05),AM组感觉神经传导速度及感觉神经电位波幅与正常对照组间差异均无统计学意义(P＞0.05),AM组SEP电位N13峰潜伏期[(14.9±1.9)ms]和N9-N13、N13-N20峰间期[分别为(5.2±0.8)ms,(8.6±1.1)ms]均较正常对照组显著延长(P＜0.05).AM组下肢CHEP异常率(85.0％)显著高于上肢异常率(55.0％),AM组CHEP总异常率(90.0％)及下肢CHEP异常率均显著高于SEP异常率(40.0％).结论 AM患者存在痛觉传导通路中枢段受累,CHEP结合MRI或其他电生理检查能更有效辅助诊断AM,有助于AM与运动神经元病及周围神经病间的鉴别诊断,具有重要临床推广价值.

abstractsObjective To study the characteristics of the central part of the nociceptive system in acute myelitis (AM) with contact heat evoked potentials (CHEPs) and to document the potentials in patients with AM.Methods Twenty patients with AM were recruited in this study as an experimental group,and twenty healthy subjects were chosen as a control group.A heat foil was used to elicit pain and CHEPs.Thermal stimuli were applied at 54.5 ℃ at five sites:the dorsum of the hand,the proximal volar surface of the forearm,the skin of the leg 5 cm proximal to the medial malleolus,and at the C7 and T12 acupuncture locations.The latency and waveform of the evoked potentials were recorded.The conduction velocity of the A8 fibers of the peripheral nerves and of the spinal part of the spinothalamic tract were analyzed.The somatosensory evoked potential (SEP) and sensory conduction velocity (SCV) of the limbs were also examined,and the results were compared with the CHEP results.The results were compared between the two groups.Results The N 550 latencies of the CHEP on the dorsum of the hand,the inside of the leg,and at C7 and T12 were prolonged significantly in the patients with AM compared to the healthy controls.There were no significant differences in the nerve conduction velocity of the Aδ fibers and the velocity or amplitude of sensory nerve conduction in the limbs between the groups.The conduction velocities of the spinothalamic tract were significantly reduced in the patients with AM compared to the control group,while the peak latencies of N13 and the interpeak latencies of N9-N13 and N13-N20 in the AM patients were significantly prolonged compared to the healthy persons.In the patients with AM,CHEP abnormality in the lower limbs (17/20,85％) was significantly higher than in the upper limbs,total CHEP abnormality and CHEP abnormality in the lower limbs were significantly greater than SEP abnormality.Conclusion Persons with AM have abnormalities in the central part of the nociceptive system.When used with MRI and other electrophysiological examinations,CHEP may contribute to diagnosing AM.It could be helpful in the differential diagnosis of AM from motor neuron diseases and peripheral nerve lesions.It is of great potential value in clinical practice.