Abstracts

Rationale: Visual object naming is the most frequently used task in cortical stimulation mapping for the identification of essential language cortex. However, inclusion of auditory description (“auditory naming”) reveals a topographical pattern in which stimulation in anterior temporal cortex tends to disrupt auditory naming but not visual naming, whereas stimulation in the posterior perisylvian region tends to disrupt both visual and auditory naming (i.e., “dual” visual-auditory naming sites). Moreover, auditory naming sites appear to be essential, as resection of these sites is associated with significant postoperative naming decline. The basal temporal region, which is a common resection area, has been shown to contain stimulation identified language sites; however, it is not clear whether basal temporal stimulation would disrupt auditory naming, or if a topographical pattern similar to that found in lateral temporal cortex would be found in this area.We investigated the presence and topographical pattern of auditory and visual naming sites in the basal temporal region of left TLE patients. We hypothesized that, similar to lateral temporal findings, auditory naming sites in the basal temporal region would be located anterior to dual, visual-auditory naming sites. Methods: Participants were 25 left, dominant, TLE patients who underwent basal temporal stimulation language mapping with both auditory and visual naming tested at each site (16 women, mean age: 30.2, SD: 11.7; mean years of education: 13.7, SD: 3.8; mean IQ: 96.35, SD: 13.2). A mean of 8.8 (SD: 5.26) basal temporal sites were tested per patient (range of 1-22). Anterior was defined as  < 5cm from the temporal pole, posterior was defined as ≥ 5cm from the temporal pole. Fischer’s exact test was used to test the topographical distribution of auditory and visual naming sites. Results: Thirteen patients were found to have at least one positive naming site in the basal temporal region. Of the 23 total naming sites found, 4 were auditory naming sites and 19 were dual, visual-auditory naming sites. In the anterior basal temporal area, 4/11 naming sites detected were auditory naming only sites, while in the posterior basal temporal lobe, all 12 naming sites found were dual visual-auditory sites (P = 0.037). Conclusions: As hypothesized, and consistent with lateral temporal patterns, these preliminary results suggest that auditory naming sites are located anterior to dual, visual-auditory naming sites in the basal temporal region. As resection of lateral temporal auditory naming sites is associated with postoperative decline, it would be important to determine whether similar declines would occur following resection of these sites in the basal temporal region.  Funding: NIH grant R01 NS35140 (MJH)