BACKGROUND: The electrophysiological test was mainly achieved by the reaction of nerve fiber to electrical stimulus, usually expressed by the amplitude and latency. Blink reflex and electroneurography (ENOG) are widely applied in facial paralysis, the amplitude would step down, and the latency would prolong when the facial nerve was injured. OBJECTIVE: To compare the value of blink reflex and ENOG in the diagnosis of facial paralysis (Bell’s palsy). DESIGN: A controlled trial. SETTINGS: Affiliated Hospital, Chengdu University of Traditional Chinese Medicine; West China Hospital of Sichuan University; Mianyang Hospital of Traditional Chinese Medicine; Sichuan People’s Hospital. PARTICIPANTS: The patients who had finished the tests of blink reflex (n =207) and ENOG (n =205) were selected from the Affiliated Hospital, Chengdu University of Traditional Chinese Medicine; West China Hospital of Sichuan University; Mianyang Hospital of Traditional Chinese Medicine; Sichuan People’s Hospital from September 2001 to July 2003. After treatment for 4 weeks, the patients finished tests of blink reflex (n =207) and ENOG (n =205) were randomly divided into primary treatment group (n =68, 69), acupuncture group (n =71, 66) and comprehensive treatment group (n =68, 70), respectively. Approval was obtained from the ethic committee of hospital. METHODS: Patients in the primary treatment group and acupuncture group were treated with western medicine, acupuncture and moxibustion alone respectively, and those in the comprehensive treatment group were treated with acupuncture and moxibustion based on western medicine. The whole period of treatment was 4 weeks. The tests of blink reflex and ENOG were carried out using Japanese light and electricity MEB-2200 electromyogram/induced potential instrument for once before and after treatment respectively. The normal value of the latency period of wave R1 was within 13 ms, and the difference was 1-1.2 ms between the left and right sides. MAIN OUTCOME MEASURES: The latency of wave R1 of blink reflect and the latency and wave amplitude of ENOG on the affected and healthy sides before and after treatment were observed. RESULTS: Totally 207 and 205 patients received tests of blink reflex and ENOG, but 17 and 16 cases respectively did not finish the second measurement, finally 190 and 189 cases were involved in the analysis of results. The latencies of wave R1 on the affected side after treatment were significantly longer than those before treatment (t =-6.253, P < 0.01); The latencies of wave R1 on the normal side were in the normal range before and after treatment; The latencies of wave R1 before treatment on the affected side was significantly longer than that on the normal side (t =-5.896, P < 0.01), but there were no significant differences between the affected and normal sides after treatment (P > 0.05). It was indicated that the latencies of wave R1 on the affected side had restored normally, and the blink reflex was improved obviously after treatment. The latency of ENOG on the affected side before treatment was significantly prolonged as compared with that on the normal side (t =2.247, P < 0.01); After treatment, the difference between the affected and normal side became smaller, but remarkable significance still existed (t =10.810, P < 0.01). In spite of the obvious improvement of affected side before and after treatment, there were still significant differences (t =-8.110, P < 0.05). The wave amplitude on the affected side was decreased after treatment, which was not significantly different from that before treatment (P >0.05). CONCLUSION: After treatment of facial paralysis, blink reflect was greatly improved, there was an obvious hysteresis in the latency of ENOG. Therefore, blink reflect was better than ENOG in the early diagnosis, while ENOG was suitable for evaluating the prognosis. The ENOG examination was better than blink reflex at middle and late period.
