Abstracts

Rationale: It is unclear whether patients with epilepsy show progressive cognitive decline in older adulthood. Executive functioning is a domain that is particularly sensitive to age-related changes, and thus is a logical area to explore in this population. The purpose of this study was to describe the characteristics of a clinical sample of older adult patients with TLE and to examine whether these patients show greater decline in executive functioning over time than would be expected based on age alone. Methods: From a query of available electronic medical records, consecutive patients 55 and older with TLE who had undergone at least two neuropsychological evaluations were selected for analysis. Exclusion criteria included brain tumor, a follow-up period of less than 6 months, and questionable validity (i.e., poor effort, n=1). Tests of executive functioning included Phonemic Fluency, the Wisconsin Card Sorting Test (WCST), Porteus Mazes, and the Working Memory Index (WMI) and Processing Speed Index (PSI) from the Wechsler Adult Intelligence Scales-Third Edition (WAIS-III). Age- and education-based standard or scaled scores were used in data analysis. Impaired performance was defined as a score falling below the 7^th percentile on measures using standard or scaled scores and below the 10^th percentile on WCST Categories Completed and Failure to Maintain Set (FMS). Results: Data was available for 19 patients with TLE. Mean age at initial evaluation was 54.4 (range: 38-71) and 63.7 (range: 55-78) at the second evaluation. Mean time between evaluations was 9.3 years (range: 8 months to 20 years). There was a statistically significant change from Time 1 to Time 2 on Phonemic Fluency (p<.05). Statistical trends were also found on Failure to Maintain Set (p=.065) and WMI (p=.053). On nearly all test measures, however, fewer than 1/3 of patients scored in the impaired range at either Time 1 or Time 2 with one exception. At Time 2, 40% of patients scored in the impaired range on the WCST FMS. Tests on which the greatest percentage of patients declined from intact to impaired performance from Time 1 to Time 2 included PSI, FMS and Mazes. Conclusions: In this sample of patients aged 55 and older with TLE, executive functioning performance was largely within normal limits across a mean 9-year follow-up period. Results suggest that while older adults with epilepsy may show some decline in executive functioning over time, in the population sampled the magnitude of this decline falls largely within the range of age-expected change. Whether changes in executive functioning will be more prevalent in later decades or continue to track along an age-expected trajectory is an area for future research.