Early diagnosis in Bell's palsy. A nerve conduction study.

In 100 consecutive patients affected by idiopathic facial palsy the final degree of recovery was found to be inversely related to the distal latency time (DLT) measured within 72 hours of the onset of the disease. Incomplete recovery occurred in 77% of patients in whom the DLT was prolonged more than 10.0 msec, while complete recovery was found in 92% of cases in whom the DLT was less than 6.0 msec. This inexpensive test is easily and quickly performed and does not depend on the subjective responses or the cooperation of the patients. It may fill the gap between the onset of the palsy and the period in which other electrodiagnostic tests can be usefully employed.