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DTI-based structural connectivity of picture naming scores in chronic post-stroke aphasia

Poster C42 in Poster Session C, Friday, October 7, 10:15 am - 12:00 pm EDT, Millennium Hall

Samaneh Nemati¹, Chris Rorden², Roger Newman-Norlund², Leonardo Bonilha, Julius Fridriksson¹; ¹University of South Carolina, Department of Communication Sciences and Disorders, ²University of South Carolina, Department of Psychology, ³Emory University, Department of Neurology

Impairment in various features of speech production is a complicated phenomenon yet a widely occurring symptom among individuals with post-stroke aphasia. To date, aphasia researchers have primarily used either a single-case or small group designs to investigate associations between brain damage and language deficits. In this paper, we explore the relationship between structural connectivity (SC) in the brain and picture naming scores in a relatively large sample of persons with left hemisphere post-stroke. Ninety-three participants with chronic stroke (36 Broca’s, 20 Anomia, 17 Conduction, 5 Global, 4 Wernicke’s, 2 Transcortical Motor, and 9 no aphasia) were recruited and assessed using the Western Aphasia Battery, Revised (WAB-R) and neuroimaging data. We analyzed structural connectome measures of a left hemisphere neural network to detect brain networks supporting language outcomes from the Philadelphia Naming Task (PNT). An updated version of NiiStat (https://github.com/neurolabusc/NiiStat) was applied to explore the brain-language relationship using General Linear Model (GLM). Our analyses revealed that several regions primarily included in the dual-stream model of language processing are correlated with the task assessing picture naming abilities. Specifically, we found that increased white matter connectivity within the dorsal stream and between areas in the ventral and dorsal streams was associated with higher correct responses on the picture naming task (GLM z-scores between 3.93 to 4.81). In particular, connections between inferior frontal gyrus and superior temporal gyrus, inferior frontal gyrus and precentral gyrus, superior frontal gyrus and middle temporal gyrus, inferior frontal gyrus and supramarginal gyrus showed significantly positive correlation with number of correct responses on the PNT test. This means that the stronger the structural connection between these brain regions is, the better participants of this study performed on the PNT test. It is clear that different features of speech production are processed by a network of regions distributed across the brain, and disruption in any of these regions could result in impaired language performance. The current research shows that higher score on the picture naming task is correlated with higher synchrony in the dual-stream network of language. Discussion will focus on the role of structural brain connections in supporting object naming, and the extent that structural connections/disconnection can be useful in predicting language outcomes in aphasia.

Topic Areas: Language Production, Computational Approaches