Abstracts

Rationale: Previous research has shown that left anterior temporal lobectomy (LATL) patients show poorer preoperative naming abilities and greater postoperative naming decline than right ATL (RATL) patients. The majority of these studies have used visual common-noun naming paradigms. Recently, studies have shown that auditory naming paradigms are more sensitive for detecting left temporal lobe dysfunction, mapping language during electrical stimulation, and predicting naming outcome; however, again, most of these studies have only used common-noun stimuli. In this study, pre- and postoperative naming was examined in LATL and RATL patients using an auditory semantic category-specific naming paradigm. Methods: 33 right and 34 left consecutive ATL patients who underwent preoperative fMRI language mapping using an auditory category-specific naming paradigm were included. Of this group, 13 right and 11 left ATL patients completed the identical naming test outside the scanner approximately 3 months postoperatively. The naming test consisted of 128 auditory definitions equally distributed across 4 semantic categories (common/proper noun x living/non-living). Patients were given two seconds to name the object, person, or place being referred to in the definition (e.g., “what a king wears on his head?”), and one point was given for each correct response. Response accuracy for each semantic category and pre- to postoperative change scores were calculated where possible. Results: Preoperatively, a significant group difference (p < .05) was found between the L and RATL groups in overall naming abilities collapsed across semantic categories. This group difference was largely driven by the proper-noun category, with the LATL group naming significantly fewer proper-noun living (67% correct, p < .05) and non-living (65% correct, p < .05) items than the RATL group (80% & 75% correct, respectively). There were no group differences in common-noun naming. Postoperatively, the LATL group showed significant decline in their ability to name both proper-noun living (26 % decline, p < .05) and non-living categories (11% decline, p = .055) but not common nouns, whereas the RATL group showed no decline in any semantic category with proper noun naming actually improving. Conclusions: LATL patients were poorer at naming proper-noun stimuli preoperatively and experienced greater postoperative proper-noun naming decline than RATL patients. L- and RATL patients did not significantly differ in their auditory common noun naming abilities either pre- or postoperatively. This is the first study to demonstrate category-specific semantic deficits using an auditory naming paradigm in LATL patients and further highlights the role of the left anterior temporal lobe in proper-noun naming.