Abstracts

Rationale: Patients with hypothalamic hamartoma (HH) and refractory epilepsy typically demonstrate cognitive impairments, but the nature and level of impairments are quite variable. We wish to determine if these patients improve in their cognitive functioning post neurosurgical resection of their HH, and explore what variables correlate with cognitive outcome. Methods: Thirty-two (32) patients underwent pre- and post-operative neuropsychological testing. The age range of patients was between 3.3 to 39.3 years (mean = 12.2 years, S.D. = 7.0). The average time interval between surgery and post-operative neuropsychological testing was 23.4 months (range between 5.1 and 47.2 months). Tests administered varied on the basis of the patient's age and clinical condition. Results: As a group, measures of overall intelligence showed improvement post surgery with associated improvement in attention and processing speed. Memory scores did not demonstrate consistent improvement or decline (See Table 1). Duration of epilepsy, age at surgery, neurological complications of surgery, and level of neurocognitive functioning prior to surgery were correlated with post-surgical cognitive status (See Table 2). Multiple regression using duration of epilepsy and an estimate of pre-surgical intellectual functioning as the independent variables and change in estimated intellectual functioning as the dependent variable was performed and accounted for 39% of the variance in intellectual functioning [F(2,22)=6.92, p<.01] such that patients with the lowest pre-surgical intellectual functioning and shortest duration of epilepsy showed the greatest improvement in intellectual functioning post-surgery. Conclusions: Despite the great variability in level of cognitive impairment in patients with HH and refractory epilepsy, level of intelligence may show mild to moderate improvements post surgery if no surgical complications occur. The variables that predict cognitive outcome are not fully delineated, but testable individuals with the greatest pre-surgical cognitive impairment and those with the shortest duration of epilepsy (and younger age at surgery) appear to make the greatest gains in intellectual functioning. Findings have clinical implications for surgical decision making (e.g., patient selection and timing of surgery) and providing education to patients and families prior to surgery.