Abstracts

Rationale: Research on cognitive functioning in older adults with epilepsy is limited. This group may be more likely to show cognitive deficits than younger adults due to cognitive effects of normal aging and increased medical comorbidities. Further, they may be at higher risk for cognitive changes following epilepsy surgery than their younger counterparts. This study examined differences between older and younger adults in preoperative memory abilities and memory changes after temporal lobectomy. Methods: Patients aged 25-35 and 55-73 were compared on age-corrected Wechsler Memory Scale-III Index scores before and 6 months after temporal lobectomy. The older group was comprised of 21 patients (12 left, 9 right), and the 21 patients in the younger sample were chosen to match the older group on demographic and seizure variables. To reduce effects of group differences in seizure onset and duration, these variables were dichotomized and groups were matched in frequency of patients within each of the four cells. Despite this attempt, younger and older patients differed in seizure onset (14.1 and 26.7 years, respectively) and duration (17.7 and 31.8 years, respectively). Low power precluded inferential statistical analysis; thus, analyses were based on analysis of effect sizes and individual patient scores. Results: Older adults performed more poorly than the younger adults on visual memory measures before surgery (small to moderate effect sizes), although indices were generally in the low average range. There were no group differences in the low average to average presurgical auditory memory scores. After surgery, the older adults performed similarly to younger adults on both visual and auditory memory measures. Older adults did not demonstrate greater memory declines than younger adults and, in fact, appeared to mildly improve relative to their younger cohort on the visual immediate memory index. The two age groups demonstrated similar pre to postoperative changes on auditory memory measures. Conclusions: Results suggest that on preoperative testing, older patients may experience reduced visual memory, but similar auditory memory, compared with a younger cohort. However, older adults are not expected to experience greater postoperative memory decline. These results should be considered preliminary prior to replication. Limitations of this study include the small sample size, group differences in seizure onset and duration, and possible bias of an “overly healthy” older adult group, as less healthy older adults may have been precluded from surgery. Nevertheless, these results represent one of the few investigations regarding memory performance before and after surgery in older adults.