三叉神经躯体感觉诱发电位评价慢性咀嚼肌疼痛神经功能的初探

目的采用三叉神经躯体感觉诱发电位（trigeminal somatosensory evoked potential，TSEP）检查方法，分析比较慢性咀嚼肌疼痛（masticatory muscle pain，MMP）患者与对照组TSEP各波潜伏期的变化规律，初步探讨慢性MMP患者神经功能变化的机制及TSEP的诊断价值。方法收集慢性MMP患者12例（患者组），以及年龄、性别与患者组匹配的健康人12名（对照组），分别行双侧颏神经和咬肌TSEP检查。归纳全部受试者面部两侧共4个部位的TSEP波形，分析出现率为75％～100％且双侧对称的波形。对测得的波潜伏期进行配对和独立样本t检验。结果获得5个TSEP波（P1、N1、P2、N2和P3）。患者组两侧颏神经TSEP的P1潜伏期缩短，与对照组相比差异有统计学意义（P〈0．05）；其余各波与对照组相比潜伏期延长，左侧P2、N2的差异均有统计学意义（P〈0．05）。咬肌区各波潜伏期的变化不一致。结论慢性MMP患者TSEP波潜伏期的变化有一定规律，初步证明患者中枢和外周神经功能的改变。慢性MMP患者P1潜伏期变短，提示三叉神经节以下外周神经传导活化；P2潜伏期变长提示脑干可能受到抑制。

Evaluation of trigeminal somatosensory evoked potential of patients with chronic masticatory muscle pain

OBJECTIVE: To evaluate trigeminal function of patients with chronic masticatory muscle pain (MMP) using trigeminal somatosensory evoked potential (TSEP) and analyze mechanism of changes compared to the controls. METHODS: Twelve chronic MMP patients and 12 matched controls participated in this study. TSEPs of bilateral masseter regions and inferior alveolar nerves were measured and compared between patient and control groups. The collected waves were concluded and those with appearance rate over 75% - 100% were selected. The latencies of waves were analyzed by use of the paired t test and independent-samples t test. RESULTS: Five stable-appearing waves were obtained and named P1, N1, P2, N2, P3. The latency of P1 was significant reduced in patients (P < 0.05). The latencies of other waves were prolonged, but only P2 and N2 in left were significantly changed (P < 0.05). CONCLUSIONS: TSEP latencies of chronic MMP patients changed in certain regular pattern and TSEP could be used as a parameter to disclose the trigeminal system abnormalities of the patients. The reduced latency of P1 might indicate the increasing conductivity of trigeminal nerves under level of ganglion Gasseri and the prolongation of latency of P2 was possibly related to inhibitory effects of the brain stem.