Visual Evoked Potentials in Hemiplegic Strokes by Pattern Reversal and Flash Stimulation

J Korean Assoc EMG Electrodiagn Med 2005;7(2):122-127.
Published online May 10, 2005.

Abstract

Objectives: This study was designed to evaluate the clinical utility of flash visual evoked potential (VEP) and pattern reversal VEP in patients with post-stroke hemiplegia. Methods: We studied 13 patients with post-stroke hemiplegia and 17 volunteers without visual problem. The pattern reversal and flash stimulation VEP studies were performed and N75, P100 and N145 latencies by pattern reversal stimulation and N1, P1, N2, P2, N3 latencies by flash stimulation were measured. Results: The P100 latency of pattern reversal VEP of ipsilateral and contralateral stimulation of the lesion site in hemiplegic patients was significantly longer than that of P100 latency in control group. The mean P2 and N3 latencies on ipsilateral and contralateral stimulation in hemiplegia patient were significantly longer than those of P2 and N3 latencies in control group. There were significant positive correlations between P100 latency and N2, P2 latency in control group, and between P100 latency and N2, P2, N3 latency in hemiplegic patients group. Conclusions: Our results suggest that there was significant correlation between P100 latency of pattern reversal stimulation and N2 and P2 latencies of flash stimulation. In performing the VEP, flash stimulation could be used for the patient with difficulty in performing pattern reversal stimulation.

Key Words: Pattern reversal evoked potential, Flash evoked potential, Stroke