Idiopathic photosensitive occipital epilepsy: clinical and electroencephalographic (EEG) features.

Idiopathic photosensitive occipital lobe epilepsy is a reflex, age- and localization-related syndrome. We describe the clinical and electroencephalographic features, therapy, and outcome of 16 children/adolescents with this syndrome. The cohort included 2 sets of siblings and 7 patients with other first- or second-degree relatives with a seizure history. All patients had occipital onset seizures and 15 had secondarily generalized tonic-clonic seizures. Seizure frequency was relatively low in all patients but one. Myoclonic seizures later developed in 2 patients with juvenile myoclonic epilepsy. Eight patients achieved full seizure control with monotherapy, and 5 required a second drug; 3 patients had rare seizures and were not treated with antiepileptics. Seven patients required special education or developmental assistance. This interesting syndrome sheds light on the pathophysiology and genetic etiology of common phenomena such as photosensitivity and headache. Further large prospective studies are required to better define this unique syndrome and its implications.