Abstracts

Rationale: International League Against Epilepsy recently proposed two idiopathic occipital lobe epilepsy syndromes according to different predominant epileptic manifestation: early onset (Panayiotopolous type) and late onset (Gastaut type). We attempted to evaluate the validity of this classification by analyzing electroclinical features of patients with suspected idiopathic occipital lobe epilepsy. Methods: Forty five patients enrolled from 2002 to 2007 were diagnosed as having idiopathic occipital lobe epilepsy at Seoul National University Children’s Hospital. Clinical data including initial ictal semiology, age onset, seizure frequency, electroencephalographic characteristics, and treatment response were analyzed retrospectively. Patients were subdivided into three groups according to ictal manifestations or seizure types at diagnosis; versive seizures and/or ictal vomiting as group I, ictal visual symptoms as II, the other seizure types as III. Two epilepsy syndromes were matched to these groups and were re-evaluated through their clinical courses. Results: The average seizure onset of 45 patients (29 males, 16 females) was 5.3 years (2.5 - 13.4 years) and the average follow-up period from seizure onset was 3.5 years (1.1 - 10.3 years). Thirty one patients were classified as group I, 5 patients as group II, and 9 patients as group III. Compared to group II, group I showed the younger average seizure onset (5.1 years vs 7.3 years), more frequent nocturnal and prolonged (>10 min) seizures (55% vs 20%, 32% vs 20%), less frequent seizures during the initial 6 months period from seizure onset (75% vs 40%, percent of patients with less than 5 seizures), less frequent association of headache (22% vs 60%). All patients of group II were classified as late onset Gastaut type. However, only 19 patients of group I were classified as early onset Panayiotopolous type. Among remained 12 patients in group I, 10 patients showed other type of seizures with mixed semiology , and 2 patients showed typical ictal visual symptoms in Gastaut type after 1.1 and 6.2 years from the seizure onset. Ten patients out of 19 patients with early onset Panayiotopolous type experienced persistent seizures more than 1 year from the seizure onset. Conclusions: Gastaut type is a rare but well-defined subtype of idiopathic occipital lobe epilepsy in childhood. However, Panayiotopolous type seemed to be less distinctive. Conclusively, idiopathic occipital lobe epilepsy in children showed diverse clinical spectrum and clinical validity of classification into two epilepsy syndromes needs more verification.