Prognosis in Bell's palsy.

This is a concluding report of a study in which only patients with Bell's palsy initially seen within ten days of onset are included. The purposes are to observe the natural course of the disorder and to illustrate electromyographic EMG) criteria by which early forecast of recovery is possible. Appraisals of facila muscle strength, nerve stimulation responses and electromyographic needle electrode examinations correlated with the time required for recovery and the relative degree of recovery of patients with Bell's palsy. Three categories of recovery are evident. Of 90 patients, 79% recovered completely within two months (class I), 7% recovered adequately within two to six months (class II) and 14% required longer than six months (class III). Using clinical and electromyographic methods it should be possible to forecast recovery within three days after onset in order to preselect patients in need of any proposed curative treatment program designed to salvage the facial nerve. For prognosis in patients without clinically detectable facial muscle function, the data suggest that they be evaluated on a daily basis from onset until day 4 (past 72 hours). Finding that residual motor unit potentials are sustained in four to five muscles during that period strongly indicates a favorable outcome. Finding activity in two to three muscles could be less favorable and finding zero to one muscle with activity is clearly unfavorable. During this period of time there is a tendency for progressive loss of EMG activity in the facial muscles, both in patients with favorable and with less favorable outcomes.