Effects of acupuncture on Bell’s palsy patients in the acute stage based on the surface electromyography

To investigate the effects of acupuncture on the muscle strength and fatigue levels of facial muscles of the patients with Bell’s facial paralysis in the acute stage, using surface electromyography.

Sixty patients diagnosed with acute Bell’s facial paralysis were randomly assigned to an observation group (30 cases) and a control group (30 cases). In the observation group, the routine acupuncture was applied to Quanliao (SI18), Yangbai (GB14), Yifeng (TE17), Jiache (ST6) and Dicang (ST4) on the affected side and Hegu (LI4) on the healthy side. The needles were retained for 30 min, and acupuncture was delivered once every two days. In the control group, prednisone acetate combined with methylcobalamin tablets were administered orally. The interventions lasted till to the 28th day of illness in the two groups. At the baseline and after treatment, the root mean square amplitude (RMS) ratio and the median frequency (MF) of the frontal muscle, zygomatic muscle and orbicularis oculi muscle and the changes in the scores of H-B scale and Sunnybrook facial nerve function were observed in the two groups. The correlation was analyzed between the indicators detected by surface electromyography and the scale score, the clinical effect was compared and recovery time survival analysis was performed.

The RMS ratio and MF of the facial muscles (frontal, zygomatic, and orbicularis oculi muscles) were increased in both groups compared with pretreatment (P<0.01, P<0.05), and RMS ratio in the observation group was higher than that of the control group after treatment (P<0.05). After intervention, the H-B scale score and Sunnybrook score were improved in both groups compared with those pretreatment (P<0.01), and the scores in the observation groups were superior to the control group (P<0.01). Survival analysis of curative time showed that the curative time in the observation group was shorter than that of the control group (P<0.05). After interventions, the cured and markedly effective rate of the observation group was 93.33% (28/30), which was higher than that (76.67%, 23/30) of the control group (P<0.05). Correlation analysis revealed that the H-B and Sunnybrook scores were negatively correlated with the RMS ratios of the frontal, zygomatic and orbicularis oculi muscles at the baseline and after treatment (P<0.01); and the correlation was not presented with MF.

The intervention with acupuncture in the acute stage of Bell’s palsy markedly increases the muscle strength of facial muscles, relieves muscular fatigue and shortens the curative time. The correlation analysis between the scale score and RMS ratios indicates that RMS ratios can be taken as one of the objective indicators in clinical assessment of the severity of facial paralysis.