blink reflex
An electrophysiological test of trigeminal and facial nerve function using electrical stimulation.
Full Definition
The blink reflex is an electrophysiological test that evaluates the trigeminal and facial nerve pathways by electrically stimulating the supraorbital nerve while recording responses from the orbicularis oculi muscle. The test produces characteristic R1 and R2 responses: R1 is an early ipsilateral response reflecting the direct brainstem reflex arc, while R2 is a bilateral late response involving polysynaptic brainstem pathways. The blink reflex is valuable for assessing facial nerve lesions, trigeminal nerve dysfunction, and brainstem pathology. Abnormalities in latency, amplitude, or morphology can help localize lesions within the trigeminal-facial reflex pathway.
Usage
Usage note: Distinguish from natural corneal reflex testing.
In Context
- "The blink reflex showed absent R1 and delayed R2 responses on the affected side, consistent with facial nerve neuropathy." — Facial nerve study report
- "Bilateral blink reflex abnormalities suggested a pontine lesion affecting the central reflex pathways." — Brainstem evaluation