Abstracts

Rationale: Auditory naming (AN) is an ecologically valid method of assessing word-finding deficits in patients with epilepsy. Left temporal lobe epilepsy (LTLE) patients have consistently shown reduced auditory naming as compared to right TLE patients. Furthermore, LTLE patients with mesial temporal sclerosis (MTS) perform worse on visual naming measures than those without MTS. The objective of this study is to add to the knowledge base about AN. In particular, we seek to investigate the relationship between AN performance and degree of temporal lobe abnormality in LTLE patients. Methods: The sample consisted of 46 LTLE patients and 27 control subjects. The subjects with LTLE were further classified as those with normal MRIs (MRI-; n = 20), left mesial temporal sclerosis (LMTS; n = 15), and having undergone a left temporal lobectomy (LTL; n = 11). All subjects were right handed. The control group consisted of patients evaluated in the epilepsy monitoring unit and found to have normal MRIs and video-EEG. There were no significant differences between the four groups with respect to age, gender, education, or WAIS-III FSIQ. The LTL group had a significantly younger age of seizure onset than the other LTLE groups. AN performance was compared between the groups using age and education corrected standard scores. Results: AN performance was significantly different between the four groups as calculated by ANOVA; F(3, 69) = 11.39, p < .001. Follow-up univariate comparisons revealed that the LTL patients scored significantly lower on AN than the other three groups (all p < .01). Furthermore, the LMTS group scored lower on AN than the controls (p < .05) and to a lesser extent, the MRI- group (p = .08). There was no significant difference in AN between the MRI- and control groups. Conclusions: These results confirm the finding of reduced AN ability in persons with LTLE. Moreover, we further established that within this group, AN performance is increasingly impaired in the presence of MTS while even lower scores are obtained following resection of the left temporal lobe. These data provide additional support for the proposal of direct hippocampal involvement in naming.