Clinical correlations of occipital epileptiform discharges in children.

Abstract

To determine the frequency of different causes of occipital epileptiform discharges (OEDs) in children and to analyze the EEG features that help predict epilepsy type and prognosis. We identified children with OEDs in the absence of other focal discharges using an EEG database at our center; the presence of generalized spike-wave discharges (GSW) or slowing was not an exclusion criterion. Diagnosis, neurologic status, seizure semiology, and seizure remission status were recorded. Of 90 patients with OEDs, 50 (56%) had symptomatic seizures (18 with cerebral palsy, 11 with cerebral dysgenesis, 8 with genetic abnormalities); 31 (34%) had idiopathic seizures, including 6 with benign childhood epilepsy with occipital paroxysms (BCEOP), 8 (9%) had no seizures; and 1 (1%) had febrile seizures. Only two reported ictal visual symptoms. Eighty-seven percent with background slowing had symptomatic seizures, and 87% with normal backgrounds had idiopathic seizures (p < 0.001). Of 72 children with seizures and adequate follow-up, 28 of 45 (62%) with a normal background experienced seizure remission compared with 10 of 27 (37%) with background slowing (p = 0.04). Twenty of 81 patients with epilepsy had GSW. Twelve (60%) of the 20 GSW-positive patients had idiopathic epilepsy compared with 19 of 61 (31%) without GSW (p = 0.02). Most epilepsy in referred children with OEDs is symptomatic; syndromes such as BCEOP are rare. Visual ictal symptoms are rare. The presence of GSW or a normal background rhythm correlates with idiopathic seizures and a better prognosis.