Abstracts

RATIONALE: Previous studies have shown that long standing refractory epileptic seizures usually interfere with intellectual functioning in children but not in adults. Because studies have been performed separately in children and adults, it is difficult to decide whether the children may initially have had a more serious epilepsy or a more progressive course of the disease than the adults. Our aim was to study changes in intelligence over time in children and adults with refractory seizures, taking severity and course of the disease into consideration.
METHODS: Seventeen paediatric and 17 adult patients with refractory epileptic seizures were tested twice with the age-appropriate version of the Wechsler Intelligence Scales. Mean test-retest interval was 4.8 years. All patients had been referred to our epilepsy center to obtain an optimal drug treatment. The groups were compared with respect to several epilepsy-related variables including etiology, age at seizure onset, laterality of the epileptogenic region, seizure frequency, seizure severity, EEG pathology, and changes in the latter three variables during the test-retest period.
RESULTS: Children had an earlier onset of seizures than adults, which was controlled for statistically. Adults had a longer duration of the epilepsy than children and more complex partial seizures at both test occasions. There were no further significant differences between the groups with regard to seizure-related variables at the first assessment or changes in these variables during the test-retest period. The children had significantly higher IQ scores than the adults at Test 1, but not at Test 2. Children showed a significant decline and adults a significant increase in Performance and Full Scale IQ scores during the test-retest interval.
CONCLUSIONS: Our results confirm previous findings that children with refractory seizures seem to be at considerable risk for intellectual decline despite optimal drug treatment, while intellectual functioning in adults usually is not adversely affected by recurrent seizures. The results further show that these differences between children and adults may not be due to more serious seizures in children or different courses of the disease. We applied a developmental model to explain the different effects of seizures on intelligence in children and adults.
Support: The work was supported by a grant from the National Center for Epilepsy[ssquote]s research fund.