title: Evoked electromyography and idiopathic facial paralysis.
abstract: The purpose of this study was to standardize and evaluate the results of evoked electromyography (EEMG) in normal patients and in patients with acute idiopathic facial paralysis. A comparison of the amplitude of response to EEMG from one side of the face to the other in 288 normal patients yielded a great variability in results. The amplitude difference was not greater than 50%, and therefore a difference of less than 50% was considered normal. Test-retest variability of the percentage difference in amplitude in 10 subjects showed a 10% variation in seven patients and up to a 20% variation in the remaining three patients. Fifty patients with acute idiopathic facial paralysis were seen within 14 days of onset. A favorable prognosis was based on an EEMG amplitude of more than 25% of the normal side. With this criterion EEMG was accurate in predicting complete recovery in 36 (92%) of 39 patients. When EEMG was 25% of normal or less, incomplete recovery occurred in 9 (82%) of 11 patients. The response was 0% to 10% in six patients; four had a poor recovery and the remaining two had a fair recovery. The technique, interpretation of results, avoidance of pitfalls, and shortcomings of this test are discussed.
mesh_terms: D004576:Electromyography / Q000295:instrumentation; D005158:Facial Paralysis / Q000503:physiopathology*; D006801:Humans; D011379:Prognosis