Clinical and EEG features of epilepsy in children and adolescents in Down syndrome.

Epilepsy is rarely considered as a major component of Down syndrome. We evaluated the prevalence of epileptic seizures in 252 (97 girls and 155 boys) children and adolescents with Down syndrome evaluated at Department of Pediatric Neurology between 1994 and 2007. Results showed that 15 (6%) patients had epileptic seizures: 8 partial seizures; 1 infantile spasms, 1 Lennox-Gastaut syndrome, and 5 generalized tonic-clonic seizures. Electroencephalography was performed on all patients with Down syndrome. Focal changes, spikes, generalized slowing, and hypsarrhythmia were recorded. The electroencephalography was found to be abnormal in Down syndrome with epilepsy in 100%. Almost 60% of patients with Down syndrome and epilepsy had seizures, but 40% of the patients were seizures-free. Quantitative electroencephalography analysis revealed significant differences between children with Down syndrome and the control groups in the alpha, delta, and beta rhythms. Our findings are in accordance with other reports.