Abstract
Human blink reflexes elicited by optic, trigeminal, acoustic and spinal nerve stimuli were investigated electrophysiologically by recording the EMG of orbicularis oculi muscles and the following results were obtained.
1. Either a weak tap on the glabella or percutaneous electrical stimulation of the supraorbital nerve evoked reflex responses of the orbicularis oculi muscles bilaterally. The early response had a latency of 8-12msec elicited ipsilateral to the stimulus and the late response had a latency of 30-40msec elicited bilaterally.
2. Auditory stimuli to an ear by pure tone bursts evoked blink reflexes with no distinct components bilaterally. The latency of this reflex response was about 30msec on both sides.
3. Optic stimuli to an eye with a flash light evoked blink reflexes on both sides. The latency of this reflex response was 42-50msec on both sides.
4. Percutaneous electrical stimulation of the radial nerve evoked blink reflexes with a mean latency of 55msec on both sides. This reflex response was elicited in 30% of the subjects in our series.
These results indicate that blink reflexes can be elicited by stimulation of various afferent nerves and may be helpful in pinpointing the site of intracranial lesions which involve these reflex pathways.
