Childhood absence epilepsy and electroencephalographic focal abnormalities with or without clinical manifestations

Abstract

Introduction: Evidence of focal electrocortical discharges, with or without evident partial seizures in patients with childhood absence epilepsies (CAE) is rare, but possible. The aim of this study was to establish the frequency of focal electroencephalographic discharges with or without clinical evidence in children with CAE and to explore the clinical course in patients with two types of epileptic seizures: simple absences and partial seizures. Patients and methods: During a 10-year period (1998-2008) we treated and followed-up 66 patients (35 girls and 31 boy), from 1.8 to 13 years of age (median age 6.7 years) with typical absences. Average duration of clinical follow-up was five years. Results: In 11/66 (16, 7%) children with CAE focal EEG discharges revealed changes identical to those in benign partial epilepsies (BPE). Five of 11 patients also manifested partial seizures indicative of Panayiotopoulos syndrome (PS) (4 children), or benign partial epilepsy with occipital paroxysms – of the Gastaut type (1 patient). The age of children at the time of the first partial seizure was 1.7 - 11 years. In three children BPE attacks proceeded, and in two they began simultaneously or after the beginning of the absences. In all patients absence seizure control was achieved inside six weeks to 11 months. Focal EEG discharges disappeared in 7/11 patients, in four they are still present, but without relapse of partial seizures. Conclusion: Although the relationship between partial and generalized seizures in the same patient can be coincidental, the possibility of genetic linkage cannot be excluded and further investigation is needed. Detailed analysis of clinical and electroencephalographic features, the results of treatment and establishment of long-term prognosis in patients with focal electroencephalographic changes with or without clinically evident partial seizures characteristic for BPE and generalized changes characteristic for CAE, could lead us to the definition of the specific form of CAE.