The effects of refractory epilepsy on intellectual functioning in children and adults. A longitudinal study

The aim of this study was to compare the long-term consequences of refractory epileptic seizures for intellectual functioning in pediatric and adult patients, taking the severity of the epilepsy into consideration. Thirty-four patients, 17 children (mean age 10.2 years) and 17 adults (mean age 24.4 years) were tested twice with the age-appropriate version of Wechsler's Intelligence Scales. The mean test-retest interval in the two groups was 3.5 and 6.0 years, respectively. There were no statistically significant differences between the groups with respect to severity of the epilepsy at Test 1, as indicated by retrospective assessments of seizure severity, interictal EEG pathology, and number of antiepileptic drugs received per patient. Assessments of changes in these variables during the test-retest interval did not indicate different courses of the disease in the two groups. Despite these similarities, a statistically significant difference was found between the children and the adults regarding changes in intellectual functioning. In the children, there was a decline in mean intelligence quotient (IQ) scores during the test-retest interval, while the IQ scores increased in the adult group. It is concluded that recurrent seizures may represent a considerable risk for intellectual decline in children, while intellectual functioning seem to be less vulnerable in adults with early onset of epilepsy.