Slide Slam S2 Sandbox Series
Does the connectivity within the right hemisphere predict variability in verbal repetition abilities in post-stroke aphasia?
Ariane Hohl1,2, Diana López-Barroso1,2, María José Torres-Prioris1,2, África Gómez-Pérez1, Lisa Edelkraut1,2, Jessica Aloisi1, Guadalupe Dávila1,2, Marcelo L. Berthier1,2; 1Instituto de Investigacion Biomedica de Malaga - IBIMA, Malaga, Spain, 2Cognitive Neurology and Aphasia Unit, University of Malaga, Malaga, Spain
Language function has traditionally been attributed to the activity of perisylvian areas in the left hemisphere. However, the role of the right hemisphere in language is still an object of debate, with recent studies pointing towards an important impact of this hemisphere in certain tasks and in language recovery in post-stroke aphasia (loss or impairment of language due to brain damage after stroke, [PSA]). Verbal repetition is often affected in acquired (PSA) and degenerative language disorders (primary progressive aphasia, [PPA]) and its functional characterization is relevant since it may directly inform rehabilitation strategies. At brain level, repetition of unknown words and pseudowords has been related to the activity of the arcuate fasciculus (direct and indirect segments) as main dorsal pathways, whereas repetition of known words and sentences has been linked to the ventral system. Investigations regarding verbal repetition and its brain correlates have mainly focused on the left hemisphere, however after brain damage in the language-dominant hemisphere, interindividual variability in verbal repetition abilities is frequent and can be related to the function and structure of the contralateral dorsal and ventral systems. Additionally, studies on verbal repetition in PSA and PPA should correlate the status of function with different stimuli (words, pseudowords, novel and idiomatic phrases, sentences) to explore the underlying mechanisms in a more comprehensive way. This study aims to characterize structural and functional correlates of verbal repetition deficits in the right hemisphere of patients with chronic PSA due to left perisylvian involvement by combining MRI-based T1-weighted imaging, diffusion tensor imaging (DTI), and resting state functional MRI (rs-fMRI).To achieve this, repetition of words, pseudowords and sentences will be evaluated in a sample of 20 persons with chronic PSA (10 women). MRI with T1-weighted imaging, DTI, and rs-fMRI will be acquired in order to perform functional and structural connectivity analyses of the dorsal and ventral streams. DTI will be used to perform tractography analyses of the direct and indirect pathways of the arcuate fasciculus (dorsal pathway), and the ventral pathways (inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, uncinate fasciculus). rs-fMRI will be used to measure functional connectivity strength between the areas connected by the studied dorsal and ventral pathways (i.e., inferior frontal gyrus, angular and supramarginal gyri and posterior middle and superior temporal gyri). Analyses will be performed bilaterally. Data acquisition is currently still ongoing. Results will provide important insights on the role of the non-dominant hemisphere in verbal repetition, allowing to gain a more holistic comprehension of how language is processed in the brain and leading to new information about language recovery in people with PSA that may guide therapeutic interventions.