Abstracts

Rationale: Word finding or “naming” difficulty is a well-established finding in adults with left (dominant) TLE and has traditionally been assessed solely by visual object naming (VN). More recent work using auditory description naming (AN) has shown that while both AN and VN are below expectation in left TLE (LTLE), AN tends to be more severely and more reliably impaired in this group. This work, and our understanding of naming in TLE is based, primarily, on relatively young adults. However, the incidence and prevalence of epilepsy has become highest in the elderly, and it is important to consider that aging likely introduces additional concerns overlaid upon existent, epilepsy-related naming difficulty. Having recently developed AN and VN tests for older adults (age 55+), we aimed to characterize AN and VN performance in older adults with TLE. We hypothesized that, similar to younger adults with TLE, older right TLE (RTLE) patients would perform comparably to age-matched healthy controls, whereas, older LTLE patients would perform more poorly than both controls and RTLE patients, on both tasks. We also anticipated that similar to younger adults with LTLE, older adults with LTLE would exhibit poorer AN than VN performance. Methods: Participants were 28 LTLE (18 women) and 18 RTLE (8 women) older adult patients. Demographic data were as follows (mean (SD): LTLE: Age: 67.5 years (8.3); Education: 15.2 years (2.6); Age of epilepsy onset: 46.4 years (23. 4); FSIQ: 106.6 (16.1) and RTLE: Age 62.9 years (6.9); Education: 15.1 years (3.2); Age of epilepsy onset: 42.0 (23.2), FSIQ: 101.7 (19.6)). VN and AN tests consist of 36 items each. Test scores were converted to z-scores based on an age-stratified normative data from 397 healthy adults, ages 56-95. Naming was assessed using both accuracy and time-based measures: Number correct within 20 seconds (i.e., untimed), Number correct in < 2 seconds (i.e., automatic retrieval), Tip-of-the-tongues (“TOT”= items named in 2-20 seconds or after 20 seconds following a phonemic cue) and a summary score combining two of these scores (Correct in < 2 seconds – TOTs). Multivariate ANOVA assessed potential demographic and naming performance differences between LTLE and RTLE patients. Results: LTLE and RTLE patients were comparable in onset age (P = .55) and education (P = .85); however, LTLE patients were older than RTLE patients (P = .04); therefore, Age served as a covariate in analyses comparing LTLE and RTLE naming performance. At odds with our hypothesis, and inconsistent with naming results in younger TLE patients, LTLE and RTLE patients performed comparably on AN and VN tasks, with mean scores falling within 0.5 SD from the mean of healthy controls (AN: all P > .70, VN: all P > .60). Conclusions: Despite concerns of additive effects of aging and naming impairment frequently observed in younger adults with LTLE, our sample of older adults with LTLE performed comparably to both RTLE and age-matched healthy controls. Although encouraging, we question whether intact naming was related to the late epilepsy onset. Although we were unable to explore this possibility due to an insufficient number of early onset patients in our sample, future work is underway to test this hypothesis. Funding: R01NS083976 (MJH); Tris Pharma, Inc. did not fund or contribute to this research.