Potenziali evocati visivi nelle epilessie occipitali fotosensibili

Epileptic photosensitivity is usually associated with generalized epileptogenesis, and is included with few exceptions among idiopathic generalized epilepsies. However, in at least 20% of patients, photic-induced seizures are focal, originating from reflex activation of the occipital cortex. Various anomalies in flash (F) and pattern reversal (PR) visual evoked potentials (VEPs) have been described in generalized photosensitive epilepsy. No data are available on VEPs in patients with photosensitive occipital lobe epilepsy (POE). We investigated PR- and F-VEPs in POE and compared them to responses obtained in patients with idiopathic generalized epilepsy with photosensitivity (IGEP) and in controls. Patients with POE had both a significant increase in VEP amplitude and normal latency. Antiepileptic drugs having gabaergic activity reduced VEP amplitude. IGEP patients showed a significant increase in F-VEP amplitude and reduced P100 latency. Our data indicate the presence of hyperexcitability of occipital cortex in POE. Careful study of VEPs prior to and during treatment with gabaergic drugs represents a useful complemental test to EEG in the assessment of photosensitive epilepsies.