Cognitive outcomes following epilepsy in infancy: A longitudinal community-based study

Objective: Onset of epilepsy before 2 years of age is associated with poor cognitive outcome; however, the natural course of the range of epilepsies that occur at this age is unknown. The aim of this prospective community-based study was to investigate the neuropsychological development of infants with newly diagnosed epilepsy longitudinally and to identify the clinical factors that predict long-term impairment.

Methods: Sixty-six infants <24 months of age were enrolled in the baseline phase of this study; 40 were seen again at 1-year follow-up and 40 at 3-year follow-up. Children underwent a neurological and neuropsychological assessment at each time point.

Results: More than 55% of children demonstrated impaired cognitive functioning at each assessment, with a similar percentage showing impaired memory and attention at 3-year follow-up. Cognitive scores obtained at each time point were correlated. More than 20 seizures/seizure clusters prior to assessment and an abnormal neurologic examination predicted poor cognitive functioning at baseline, whereas continuing seizures and baseline cognitive score predicted 3-year intelligence quotient (IQ)/cognitive score.

Significance: These findings demonstrate the following: (1) infants who are performing poorly at baseline continue to display impaired development at follow-up, (2) these children are delayed across a range of neuropsychological functions, and (3) a high number of seizures close to initial diagnosis and continuing seizures at follow-up independently predict cognitive impairment. These findings help to identify those infants with new-onset epilepsy who are most at risk for poor developmental outcome and suggest that multimodal interventions should be instituted early in the course of the disorder to improve outcomes.