Researchers at the Epilepsy Center and Department of Psychiatry at Lurie Children’s Hospital of Chicago examined the association of cognitive scores and age at onset of epilepsy, pharmacoresistance, and interaction between the two in a prospective community-based study of 198 children, aged <8 years, with new-onset epilepsy. The range of epilepsy syndromes reflected those seen in this age group. The average age at the first unprovoked seizure was 3.7 years. Full-scale IQ (FSIQ) assessed with the WISC for Children (WISC-III) after 8-9 years follow-up (mean IQ 94.2) was not correlated with age at onset. In 38 (19.2%) patients meeting the study criteria, pharmacoresistance was associated with an 11.4-point lower FSIQ (p=0.002) and similar decrements in each WISC-III domain. Pharmacoresistance lessened with increasing age. IQ was strongly correlated with age at onset in the pharmacoresistant group (p<0.0001) but not in the non-pharmacoresistant group (p=0.61). Impairment of cognitive function associated with uncontrolled seizures is most severe in infancy and lessens with increasing age at onset. The findings emphasize the need for early aggressive treatment and control of seizures in infants and young children. 
COMMENT. This study corroborates the clinical and laboratory evidence pointing to an injurious effect of seizures and epileptic encephalopathy on cognition, especially in the young. In a previous analysis of very young patients in this cohort (seizure onset 0-3 years), Vineland Adaptive Behavior Scale (VABS) scores declined over the first 3 years in patients with pharmacoresistant seizures but stayed constant in those with well-controlled seizures . The effect of seizures on the developing brain appears to be potentially more injurious than that of sedative anticonvulsants.