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Language Network Reorganization Following Anterior Temporal Lobe rTMS in Post-Stroke Aphasia: Neuroimaging Protocol of the ATLAS Trial
Poster Session B, Wednesday, September 30, 4:30 - 6:30 pm, Wangari Maathai
This poster is part of the Sandbox Series.
Sophie Arheix-Parras1, Sophia R. Moore, Chris Rorden, Leonardo Bonilha, Rutvik H. Desai; 1Department of Psychology, University of South Carolina, Columbia, (SC), USA, 2Department of Neurology, School of Medicine Columbia, Columbia, SC, USA, 3Institute for Mind and Brain, University of South Carolina, Columbia, (SC), USA
Introduction. Post-stroke aphasia is a major public health concern, as it affects quality of life and community integration. Repetitive Transcranial Magnetic Stimulation (rTMS) can improve language recovery with the majority of rTMS studies using inhibitory stimulation targeting the right Inferior Frontal Gyrus (IFG) or facilitatory stimulation targeting the left IFG, following the theory of interhemispheric imbalance. However, the exact neural mechanisms underlying its effects remain poorly understood. The Anterior Temporal Lobe (ATL) serves as a semantic hub in the hub-and-spoke model, while other theories highlight its lexical sensitivity. Preliminary evidence suggests that inhibitory rTMS targeting the right ATL improves picture naming in post-stroke participants with lexicosemantic impairments. Since rTMS modulates not only the targeted area but also connected networks via inter- and intrahemispheric connectivity, neuroimaging can help understand how ATL stimulation reorganizes language network in post-stroke participants. Furthermore, lesion localization and structural disconnections may explain variability in rTMS response. We hypothesize that in people with post-stroke aphasia (a) both right ATL inhibition and left ATL facilitation will increase activation in the ventral lexicosemantic stream, (b) each stimulation type will induce distinct patterns of hemispheric reorganization, and (c) preserved structural connectivity between the left ATL and posterior temporal lobe will predict rTMS efficacy. Methods. The ATLAS trial is a single-blinded sham-controlled randomized clinical trial recruiting 45 participants with chronic mild-to-moderate aphasia with lexicosemantic impairments following a single left hemispheric stroke. Participants are randomized into three groups: (1) inhibitory continuous Theta Burst Stimulation (cTBS) targeting the right ATL; (2) facilitatory intermittent Theta Burst Stimulation (iTBS) targeting the left ATL; (3) sham stimulation. All groups receive 10 rTMS sessions over two weeks, each immediately followed by 30 minutes of Semantic Feature Analysis therapy. Neuroimaging data will be acquired at baseline (S1) and immediately post-intervention (S2) using a Siemens 3T scanner. Each session includes a structural T1 and FLAIR, 10 minutes of resting-state fMRI, and two task-based fMRI paradigms: a Picture Naming Task (80 pictures contrasted with 40 scrambled images) and a Semantic Matching Task in which participants judge whether word pairs are semantically related, contrasted with false-font string pairs. Structural sequences will be used for lesion symptom mapping to assess how lesion location and white matter disconnections predict language improvement following rTMS. Resting-state fMRI will capture changes in interhemispheric connectivity. Task-based fMRI will assess intervention related changes in ATL activation and left ventral stream connectivity. Results. Data collection began in May 2026 (n=2). Results are not yet available. Rationale, design, and preliminary neuroimaging data will be presented at the conference. Discussion. The neuroimaging component of the ATLAS trial will characterize the neural mechanisms of ATL stimulation in post-stroke aphasia. Comparing resting-state and task-based fMRI across groups will aim to explain whether right hemispheric inhibition and left hemisphere facilitation produce distinct or convergent pattern of language network reorganization, following the theory of interhemispheric imbalance. Lesion symptom mapping will aim to identify predictors of rTMS response.
Topic Areas: Speech-Language Treatment, Disorders: Acquired