Orbicularis oculi reflex in brain death.

The early and late components of the orbicularis oculi reflex were absent bilaterally in three patients who fulfilled the clinical and electroencephalographic criteria of brain death. A response to peripheral facial nerve stimulation was obtained in all. These preliminary observations suggest that the study of the orbicularis oculi reflex is a simple, objective, bedside neurophysiological test of brain stem function, complementing the electroencephalogram in the diagnosis of brain death.