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The role of facial nerve conduction studies and electromyography in predicting the outcome of Bell's palsy
Author(s) -
Yamout B. I.,
Zaytoun G.,
Nuweihed I.
Publication year - 1997
Publication title -
european journal of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 124
eISSN - 1468-1331
pISSN - 1351-5101
DOI - 10.1111/j.1468-1331.1997.tb00360.x
Subject(s) - electromyography , medicine , palsy , compound muscle action potential , denervation , facial nerve , facial muscles , nerve conduction velocity , nerve conduction study , bell's palsy , facial electromyography , anesthesia , electrophysiology , physical medicine and rehabilitation , cardiology , surgery , anatomy , nerve conduction , pathology , alternative medicine
Many electrophysiological tests have been used to determine prognosis and extent of recovery in Bell's palsy but the reliability and sensitivity of the different parameters used is still controversial. We performed bilateral percutaneous facial nerve conduction studies, and volitional needle electromyography on 23 patients within 10–14 days post onset of their Bell's palsy. The following parameters were assessed: denervation and recruitment of the frontalis and orbicularis oris muscles, latency of the compound muscle action potential (CMAP), and CMAP amplitude ratio. The patients were re‐examined 6 months later and their recovery graded according to the House‐Brackman classification. The CMAP amplitude ratio and the recruitment scores of the frontalis and orbicularis oris muscles were the only parameters to reliably predict outcome ( p = 0.016, 0.007 and 0.036, respectively). All patients with a CMAP amplitude ratio above 10% had a complete recovery. Since Bell's palsy is probably caused by herpes simplex virus, the active disease process is completed within 10–14 days; therefore, facial nerve conduction studies and electromyography at that time are appropriate to predict prognosis.