Poster E51, Thursday, August 22, 2019, 3:45 – 5:30 pm, Restaurant Hall
Anterior temporal lobe regions critical for picture naming: Voxel-based lesion-symptom mapping in patients undergoing left temporal lobe resections
Sara B. Pillay1, Jia-Qing Tong1, William L. Gross1, Wade M. Mueller1, Manoj Raghavan1, Sara J. Swanson1, Lisa L. Conant1, Linda Allen1, Christopher T. Anderson1, Chad Carlson1, Leonardo Fernandino1, Colin J. Humphries1, Lisa Schwartz1, Robyn M. Busch2, Mark Lowe2, John T. Langfitt3, Madalina Trivarus3, Daniel L. Drane4, David W. Loring4, Monica Jacobs5, Victoria Morgan5, Jerzy P. Szaflarski6, Leonardo Bonilha7, Jeffery R. Binder1;1Medical College of Wisconsin, 2Cleveland Clinic, 3University of Rochester, 4Emory University, 5Vanderbilt University, 6University of Alabama at Birmingham, 7Medical University of South Carolina, 8for the FMRI in Anterior Temporal Epilepsy Surgery (FATES) study
Both picture naming (PN) and auditory description naming (ADN) are used during pre-surgical cortical stimulation mapping to identify regions critical for naming. Lateral anterior temporal lobe (ATL) stimulation (<4cm from temporal pole) typically impairs ADN more often than PN, yet paradoxically ATL resection mainly impairs PN. We sought to clarify the ATL regions critical for PN using VLSM in a series of left temporal lobe epilepsy patients. Major advantages of this approach over lesion correlation in stroke patients include the fact that pre-lesion performance level and language dominance are known, and surgical lesions in this region more often include ventral temporal areas that may be especially critical for PN. Participants were 32 patients with left language dominance confirmed by either fMRI or Wada testing who underwent partial left temporal lobe resection for drug-resistant temporal lobe epilepsy. They completed pre- and 6-month postoperative neuropsychological testing. Surgical lesions were mapped manually using high-resolution postoperative MRI, then mapped to a common template using nonlinear morphing of non-lesioned structures. Lesions varied widely in location and extent, including standard ATL resections with variable caudal extension and STG sparing, focal lateral or ventral resections, selective temporal pole removals, and selective hippocampal ablations. VLSM analyses identified the lesion correlates of pre- to post-surgery change scores on PN (Boston Naming Test) and on an ADN task, first with no controls, and then adding performance change scores on the ADN and PN task, respectively, as covariates to highlight differences in the critical areas associated with these tasks. The resulting maps were thresholded at voxel-wise p < .005 and cluster-corrected at FWE p < .05, as determined by randomization testing. Post-operative percent change on the PN and ADN measures were significantly correlated with one another, p < .001. Patients experienced greater declines on PN (mean percent change = 17.4%) than ADN (mean percent change = 7.9%), p < .001. Post-operative declines on PN were associated with resections in a focal region centered on the left anterior fusiform gyrus, including adjacent collateral sulcus, perirhinal cortex, and inferior temporal gyrus, but completely sparing the hippocampus and temporal pole. Inclusion of ADN as a control restricted the region associated with PN decline to a smaller area situated primarily in the anterior fusiform gyrus. Regions associated with ADN decline partly overlapped those associated with PN decline but were less extensive. No regions were correlated with ADN decline independent of PN decline. ATL regions critically necessary for picture naming are located in the anterior-ventral part of the ATL, centered in the anterior fusiform gyrus. PN decline was not associated with resection of the hippocampus or the temporal pole. Damage in the anterior fusiform gyrus is more strongly correlated with PN decline than with ADN decline. We hypothesize that this region is critical for mapping between visual perceptual and abstract conceptual representations. Resection of this “basal temporal language area” at the anterior end of the ventral visual object recognition pathway is likely the main cause of post-operative naming decline in patients undergoing left temporal lobe surgery.
Themes: Language Production, Disorders: Acquired
Method: Behavioral