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Repetitive Transcranial Magnetic Stimulation Targeting the Right Anterior Temporal Lobe to Improve Lexicosemantic Impairments in People with Post-stroke Aphasia
Poster Session C, Saturday, September 13, 11:00 am - 12:30 pm, Field House
Sophie Arheix-Parras1, Sidney Crouse1, Sophia Moore1, Rutvik H. Desai1,2; 1Department of psychology, University of South Carolina, 2Institute for Mind and Brain, College of Arts and Sciences, Columbia,
Repetitive Transcranial Magnetic Stimulation (rTMS) is a non-invasive brain stimulation that can enhance aphasia recovery. Most rTMS studies in post-stroke aphasia target the right Inferior Frontal Gyrus using inhibitory stimulation. However, this approach does not account for the variability in clinical profiles, lesion sizes and sites among individuals with post-stroke aphasia. Some authors have highlighted the limitations of this approach, given the complexity of language processes and paths for aphasia recovery. Persons with post-stroke aphasia (PWA) may experience difficulties such as anomia or produce semantic errors due to lexicosemantic impairments. Lexicosemantic processes involve a large brain network that includes the Anterior Temporal Lobe. Although the exact role of the ATL in lexicosemantic processes is still debated, we propose that it is a promising target for rTMS in PWA. Our aim is to target the ATL in PWA suffering from lexicosemantic impairments to improve language processes. We hypothesize that stimulating the ATL with rTMS will engage the connected network through intra- and inter-hemispheric connectivity, including the ventral semantic stream. In a multiple baseline Single-Case Experimental Design (SCED), we aim to include three PWA with lexicosemantic impairments. Each participant will perform five linguistic tasks (a Picture Naming task, an Auditory Naming task, a Word-Picture Matching task, a Lexical Decision task and a Semantic Decision task) five times a week for one or two weeks, to establish baseline scores for each participant. The baseline length will be pseudorandomized across participants following SCED guidelines. Then, each participant will receive continuous inhibitory Theta Burst Stimulation targeting the right ATL, five times a week for two weeks. After each rTMS session, participants will perform all linguistic tasks. A follow-up measurement will be taken one month after the end of the study. The study is still ongoing, with P1 having completed all sessions, P2 having received all rTMS sessions, and P3 currently being recruited. After stimulation, P1 showed significant improvement in the Picture Naming task with an increase in accuracy (Tau=0.674, p=0.001, SETau=0.240), in the Auditory Naming task with an increase in accuracy (Tau=0.466, p=0.025, SETau=0.287) and a decrease in reaction time (Tau=-0.480, p=0.031, SETau=0.310). We also observed a decrease in reaction time for the Semantic Decision task (Tau=-0.494, p=0.014, SETau=0.282). For P2, initial results showed an improvement in Semantic Decision in terms of accuracy (Tau=0.535, p=0.023, SETau=0.309) and reaction time (Tau=-0.690, p=0.003, SETau=0.264), as well as a decrease in Picture Word Matching reaction time (Tau=-0.662, p=0.004 (SETau=0.274). This study aligns with previous findings about the role of ATL in lexicosemantic processes. By stimulating the ATL, we suggest that rTMS impacts ventral pathways by affecting areas linked to the ATL, inducing a specific improvement in lexical retrieval processes. This study also highlights the possibility of choosing the cortical target for rTMS based on the clinical profile of the participant, making it more accessible to clinicians. Incorporating rTMS into clinical practice could be based on a combination of literature data (selection of the cortical target and stimulation parameters) and practitioner expertise (contraindications and side effects management).
Topic Areas: Speech-Language Treatment, Disorders: Acquired