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Poster B39, Thursday, August 16, 3:05 – 4:50 pm, Room 2000AB

Predictive Neural Correlates of Action Naming and Recovery in Chronic Stroke Patients

Lynsey M Keator1, Shannon M Sheppard1, Kevin Kim1, Sadhvi Saxena1, Amy Wright1, Rajani Sebastian1, Argye E Hillis1,2,3;1Department of Neurology, Johns Hopkins University School of Medicine, 2Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, 3Department of Cognitive Science, Krieger School of Arts and Sciences, Johns Hopkins University

Introduction: Anomia is a common consequence following neurological damage and affects both object and verb naming (Hillis & Caramazza, 1995; Hillis et al., 2006; Thompson et al., 2012; Tranel et al., 2001; Zingeser & Berndt, 1990). Previous studies have identified neural correlates critical to action naming; however, few have examined these impairments longitudinally or considered acute lesions for prognosis. Brodmann area 37 (inferior temporal gyrus, fusiform gyrus) (Ardila, Bernal, Rosselli, 2015) is commonly associated with involvement across domains of visual recognition (perception) and semantic language function. We tested the hypothesis that behavioral impairments specific to action naming and semantic processing were associated with left hemisphere lesion volume and location and that these acutely identified areas are predictive of impairments at the chronic stage; greater damage results in compromised action naming and semantic processing. Methods: In this study, we recruited, consented, and assessed participants with unilateral left hemisphere ischemic strokes within 48 hours of stroke and then assessed the same group chronically (6-12 months post stroke). The cohort included 14 participants (6 women) aged 28-87 years (M=55.85; SD= 12.52). The Hopkins Action Naming Assessment, short form (HANA; Breining, et al., 2015a) and Pyramids and Palm Trees Test, short form (PPTT; Breining et al., 2015b) were administered to assess naming abilities specific to verbs and amodal semantic processing, respectively. All participants received an acute MRI scan, including diffusion weighted-imaging (DWI). Areas of acute ischemia were traced on DWI scans. We normalized DWI images and lesion tracings and calculated proportion of damaged tissue in each of the parcels of the Brodmann atlas (82 areas) for each participant. The analysis regressed lesion volume and relied on permutation thresholding (5000 permutations; p<0.05). Only regions where at least two participants had damage were included. Scores from the HANA and PPTT at acute and chronic time points were associated with acute lesions to calculate percent of voxels damaged. Results: At the acute time point, participants achieved a mean score of 21 (SD= 9.72) on the HANA and mean score of 13.78 (SD=.42) on the PPTT. Acutely, impaired action naming and semantic processing were associated with Brodmann area 37 (Z= 2.07, Z=1.69). Nine patients showed improvement at the chronic time point in the HANA with a mean score of 24 (SD= 7.72) and all fourteen participants scored 14 (equivalent to 100% accuracy) in the PPTT. Longitudinally, participants’ HANA scores were associated with Brodmann areas 30 (Z=2.63) and 37 (Z=3.10). Conclusions/Summary: The results of the lesion mapping analysis indicate the importance of Brodmann area 37 in action naming at the acute stage, and also after cortical reorganization of language functioning preceding the chronic stage of recovery. We found acute lesions are indicative of recovery patterns; those with acute damage to Brodmann area 37 demonstrated poorer outcomes in action naming at the chronic stage, even when there were no chronic semantic processing deficits. Localization of acute lesions and lesion mapping are imperative considerations when considering recovery, therapy outcomes, and prognosis.

Topic Area: Language Disorders