Abstracts

Rationale:
Word-finding or “naming” difficulty is a well-established finding in “young” adults with left (language dominant) temporal lobe epilepsy (TLE). Accordingly, naming impairment, determined via visual or auditory naming tests, can assist in lateralizing and localizing the region of seizure onset. Unlike these reliable younger adult findings, our preliminary results in older adults ( >age 55) have not shown naming impairment in left TLE (LTLE), diminishing our ability to use naming performance to assist in lateralization of the epileptogenic region in older TLE patients. However, despite similar overall naming performance on auditory and visual naming tasks, clinical observations suggest that the nature of immediate incorrect responses (which are not considered errors if followed by a correct response within 20 seconds) differ between LTLE and RTLE patients. We aimed to determine whether the frequency and type of immediate naming errors might differentiate older adults with LTLE versus RTLE.
Method:
Participants were 28 LTLE and 16 RTLE patients, ages 55-87. Demographic data were as follows: mean (SD): LTLE: Age: 68.2 (8.4), Education: 15.2 (2.7), FSIQ: 107.7 (15.7); RTLE: Age: 62.5 (6.3), Education: 15.6 (3.1), FSIQ: 106.6 (19.0). All participants were administered the 36-item older adult ANT and VNT. Naming errors were defined as: Coordinate (“lemon” for “banana”), Remote (“ruler” for “thermometer”), Associated (“fire” for “chimney”), Phonemic (“pigwin” for “penguin”), Superordinate (“animal” for “tiger”), Parts (“stove” for “kitchen”), Circumlocutions (“mask on your eyes” for “goggles”) and Unrelated (“lipstick” for “gloves”). Independent t-tests assessed demographic differences and Mann-Whitney non-parametric tests evaluated group differences in frequency of errors and error types.
Results:
There were no group differences in FSIQ (p = .84) or education (p = .74), although LTLE patients were older than RTLE patients (p = .02). Groups did not differ in number of immediate naming errors for Auditory Naming (LTLE M= 1.89, SD= 2.17; RTLE M= 1.75, SD= 3.38; p = .14) or Visual Naming (LTLE M= 1.43, SD= 2.03; RTLE M= 0.69, SD= 0.60, p = .13). For both Auditory and Visual Naming, LTLE and RTLE patients did not differ in phonemic, remote, associated, superordinate, parts, circumlocutions or unrelated errors (all p > 0.05). Although coordinate errors were the most common error type for both groups, on Visual Naming, LTLE patients (M= 1.11, SD= 1.40) produced significantly more coordinate errors than RTLE patients (M= 0.44, SD= 0.63), p = 0.045.
Conclusion:
As reported previously, older adults with LTLE and RTLE exhibited similar naming performance by standard measures. However, analysis of error types revealed group differences on visual naming, characterized by significantly more coordinate errors by LTLE patients. These preliminary results suggest that analysis of error type in older adults with TLE might assist in lateralizing dysfunction associated with the epileptogenic region.
Funding:
:Supported by NIH grant R01 NS 083876