THE ROLE OF FACIAL-NERVE CONDUCTION STUDIES AND ELECTROMYOGRAPHY IN PREDICTING THE OUTCOME OF BELLS-PALSY

Many electrophysiological tests have been used Po determine prognosis and extent of recovery in Bed's palsy but the reliability and sensitiv ity of the different parameters used is still controversial. We perfor med bilateral percutaneous Facial nerve conduction studies, and voliti onal needle electromyography on 23 patients within 10-14 days past ons et of their Bell's palsy The following parameters were assessed: dener vation and recruitment of tile frontalis and orbicularis oris muscles, latency of the compound muscle action potential (CMAP), and CMAP ampl itude ratio, The patients were re-examined 6 months later and their re covery graded according: to the House-Brackman classification. The CMA P amplitude ratio and the recruitment scares of the frontalis and orbi cularis oris muscles were the only parameters to reliably predict outc ome (p = 0.016, 0.007 and 0.036, respectively). All patients with a CM AP amplitude ratio above 10% had a complete recovery. Since Bell's pal sy is probably caused by herpes simplex virus, the active disease proc ess is completed within 10-14 days; therefore, Facial nerve conduction studies and electromyography at that time are appropriate to predict prognosis.