PERIPHERAL FACIAL PALSY BEFORE AND AFTER ACUPUNCTURE TREATMENT

Wang Kemo, Yao Shimin

(Research Laboratory of Physiology, Xi'an Medical College)

Luo Guoli, Ren Yalan

{First Hospital, Xi'an Medical College)

This study was carried out in 42 cases of peripheral facial palsy (28 males and 14 females). The needling EMG of frontalis and the orbicularis oris including its stimulus threshold, the maximum amplitude and the latency of evoked response were observed in using of the DISA 1500 EMG system. The standard for evaluating the effect and the physiological function of the facial muscles were based on EMG of patients at the healthy side. The main points were Qianzheng and Yifeng, the accessory points were Yangbai and Taiyang. The results of the EMG examination were as follows: The motor unit action potential amplitudes ranged from 50 to 600 mv and durations from 4 to 8 msec when the frontalis and the orbicularis oris at the healthy side of the subjects contracted slightly. On their forced contraction the amplitudes ranged from 100 to 1500 mv, the motor unit potentials shown in interference pattern. The Thresholds of the orbicularis oris evoked response in the healthy side was less than 4 mA in most cases. The maximum amplitudes of response varied from 600 to 1500 mv, but reached as high as 2500 mv in some cases. The latencies ranged from 2.4 to 3.8 msec and less than 3.4 msec in most cases. Different degree of abnormalities were found by the EMG at the impaired side. There were neither residual motor unit action potentials nor evoked responses in severe cases. The EMG of patients who had responded to needling treatment showed improvement but the degree of improvement was not prominent, compared with the healthy side. The orbicularis oris still had fibrillation potential in one of 21 cases (4.8%) in the recovery group. The durations on slight contraction were longer than those of the healthy side in 6 cases (28.6%). The amplitudes on forced contraction were lower than those of the healthy side in 15 cases (71.2%). The latencies of the evoked response were prolonged in seven cases (33.4%). The results showed that the physiological functions of the facial muscles were not fully returned to normal after clinical recovery. We compared the electric response and EMG of the facial muscles in the impaired side with the therapeutic effect after treatment. It was found that there was a slight or moderate abnormality in the EMG and the therapeutic effect was satisfactory. Six cases did not respond to the electric stimulus, small and sparse motor unit action potentials were seen in 5 of 6 cases. The other one had no action potential and no therapeutic effect either. Out of the above 5 cases, one responded to the therapy better and four showed improvement. Thus, the electric response only proved a rough estimation of prognosis. The presence of residual motor unit action potential in the EMG examination of the paralytic facial muscles will help in giving an accurate judgment of prognosis.