Quantitative evaluation of facial hypersthesia with electrically elicited blink reflex

Electrically elicited blink reflex was serially carried out in 12 stroke patients with hemi-facial hypesthesia. AU patients were not associated with facial motor paralysis. Of the 12 patients, one had cerebral sensory cortex lesion, 6 thalamic lesions, and 5 brainstem lesions. Stimulation on the affected side of the face elicited diminished R2 EMG activity or area in all 12 patients, regardless of pathoanatomcal lesions. R2 was delayed in 9 patients. Three patients with thalamic lesions had only attenuation of R2 area without latency delay. In contrast, stimulation on the normal side of the face evoked normal R2 area and latency bilaterally in 10 of the 12 patients. The other two patients with midbrain lesions disclosed delayed R2 latency bilaterally. A smaller R2 response indicated more complete sensory loss. In the context of clinical improvement, R2 area was getting bigger and its latency was shorter. The blink reflex provides a means of quantitating facial sensation.