[Orbicularis oculi reflexes and evoked response of orbicularis oris muscle in Bell's palsy. A prognostic study...

In 84 patients with idiopathic, clinically complete Bell's palsy the electrically induced blink reflexes with their two components (OOR I and II) were electromyographically recorded on both sides using skin electrodes. In 67 of these patients the evoked responses of the orbicularis oris muscle were also studied. The latencies and amplitudes were measured and related to the clinical outcome of the facial paralysis. The patients were divided into two groups, one with good recovery of the palsy (46 patients), the other with significant residual paresis and/or strong associated movements of the facial musculature (38 patients). In the group with good recovery the following results were obtained: 1. the OOR I remained elicitable or reappeated during the first 12 days after the onset of palsy; 2. the OOR II began to rise during the first 10 days of palsy; 3. the amplitude of the orbicularis oris response did not decrease to below 10%. In the group with poor recovery: 1. both components of the OOR were absent or diminished to below 4% for more than 12 days after the onset of palsy; 2. the latency difference of the OOR I exceeded 8 msec; 3. the amplitude of the orbicularis oris responses decreased to below 10%. Using these criteria it appears to be possible in about 85% of patients to make a prognosis between the 3rd to 5th and the 10th to 12th day after the onset of Bell's palsy.