Late blink reflex changes in lesions of thalamus and internal capsule.

Abstract

A 60-year-old man suddenly suffered from left hemiplegia with sensory loss on the left side of his face, trunk, and extremities. Brain CT disclosed hemorrhage in the right thalamus and internal capsule. Blink reflex with electrical stimulation on the left supraorbital nerve showed normal early response (R1) on the left side but absent late response (R2) on both sides, while stimulation of the right supraorbital nerve showed normal R1 on the right side and normal R2 on both sides. This observation suggests that the impulses of R2 from stimulation of the supraorbital nerve on the affected side may be blocked by contralateral lesions of the thalamus and internal capsule.