Regression in children with epilepsy.

Regression in children with epilepsy may involve loss of cognitive abilities, failure to progress or a slowing of developmental trajectory. A few seizures do not lead to regression. Large numbers of seizures may be associated with regression but the cause is an important cofounder. Individual spike discharges on EEG are associated with transient cognitive impairment and continuous spike discharges with regression. Regression may be global in continuous spike wave in slow sleep (CSWS) or specific (auditory agnosia) in Landau Kleffner syndrome. Regression is mild and transient in Rolandic Epilepsy or profound and permanent in West Syndrome. Epilepsy syndromes grouped under "epileptic encephalopathies" may lead to regression, although proof of this concept is not strong for many syndromes. The absence of cognitive assessment before epilepsy onset, the contribution of the cause and complications of treatment make for difficult methodological problems. The large majority of children with epilepsy do not have regression. There is need for more longitudinal studies of children with epileptic encephalopathies and other epilepsies associated with regression.