Visual Evoked Potentials in Photosensitive Epilepsy

Photosensitive epilepsy is a condition that affects I in 3000 of the population. Themost common ages of onset of photosensitive epilepsy ranges from 7 to 19 years. Various abnormalities in flash and pattern reversal visual evoked potentials have been described in photosensitive epilepsy. Hyperexcitability in visual system may accountfor photosensitivity. We studied PR- VEPs in 32 patients with photoparoxysmal response. Pattern reversal VEPs were within normal limits for latency and amplitude. Twenty four patients were seizure free for approximately 1 year but showed photoparoxysmalresponses in the EEG. The normality of the PR-VEPs recorded in the absence of epileptiform activity may support the integrity of the visual system. Five cases with clinical seizures were on VPA therapy.