Aim: To determine the value of the blink reflex as a predictor of outcome of idiopathic peripheral partial facial paresis.
Method: The study included 30 patients suffering from acute idiopathic peripheral facioparesis and 30 age- and sex-matched healthy controls. Patients with symptomatic disease were excluded on the basis of neuroradiologic and laboratory findings. We stimulated the supraorbital foramen and recorded the evoked response from both orbiculares oculi muscles. We measured the ipsilateral early phasic component (R1) and bilateral late tonic component (ipsilateral R2 and contralateral R2) immediately, and a week and 6 months after the first test.
Results: In the acute phase of idiopathic peripheral partial facioparesis, the blink reflex showed slightly prolonged latencies and greatly reduced amplitudes of both R1 and R2 and the normal latencies and amplitudes of R2. All subjects showed clinical symptoms and typical electromyographic (EMG) changes, whereas 24 had blink reflex abnormalities. One week after the onset, all patients were still symptomatic and showed EMG changes, but blink reflex abnormalities remained in only 11 patients. Six months after the onset, 21 patients became asymptomatic and showed no EMG changes, 7 had no clinical symptoms but showed chronic neurogenic EMG changes, whereas 2 showed both clinical symptoms and EMG changes. Blink reflex abnormalities were observed in 6 patients. The amplitudes of R1 immediately and one week after the onset were the best predictors of residual motor deficit.
Conclusion: Blink reflex is a useful tool for follow-up and recovery prognosis in patients with partial idiopathic facioparesis, especially in the early recovery phase.