Examining Chronic Post-Stroke Aphasia Recovery Using Non-Invasive Brain Stimulation and Neuroimaging

Low, Trevor A

Examining Chronic Post-Stroke Aphasia Recovery Using Non-Invasive Brain Stimulation and Neuroimaging

dc.contributor.advisor	Dukelow, Sean
dc.contributor.author	Low, Trevor A
dc.contributor.committeemember	Goodyear, Bradley
dc.contributor.committeemember	Kirton, Adam
dc.date.accessioned	2024-06-27T16:57:17Z
dc.date.available	2024-06-27T16:57:17Z
dc.date.issued	2024-06-24
dc.description.abstract	Aphasia, an impairment in language processing, affects approximately one-third of stroke survivors immediately after stroke and up to 50% will have long-term impairments. Rehabilitation of aphasia at the chronic phase is possible, though outcomes are variable and often minimal. Novel therapeutic approaches and an increased understanding of the neurobiology supporting recovery are needed. Chapter Two assessed the safety and feasibility of combining repetitive transcranial magnetic stimulation (rTMS) with high-intensity Multi-Modality Aphasia Therapy (M-MAT) in chronic post-stroke aphasia (n=20). This novel combination therapy was determined to be feasible and safe in chronic post-stroke aphasia. On the basis of all participants benefiting from M-MAT regardless of rTMS allocation, we used resting-state fMRI (Chapter Three) and diffusion-weighted MRI (Chapter Four) to examine functional and structural connectivity associated with changes in speech production. In individuals that made positive, significant changes in naming, pre-treatment functional and structural connectivity of left hemisphere temporal and parietal language regions were associated with greater treatment-related improvement in naming. Additionally, naming improvements were associated with decreases in functional connectivity of bilateral posterior temporoparietal regions with frontoparietal, sensorimotor and visual networks at post-treatment. In Chapter Five, we conducted a randomized controlled trial investigating the efficacy of rTMS plus M-MAT on aphasia severity in a larger cohort of chronic stroke participants (n=43). Delivery of rTMS combined with M-MAT resulted in significant supplemental improvements in aphasia severity compared to sham plus M-MAT at follow-up. This demonstrates that rTMS is a promising adjuvant therapy for M-MAT in chronic stroke. Chapter Six investigated the neural basis of adjuvant rTMS effects using overt naming fMRI. Participants who received rTMS with M-MAT demonstrated dynamic functional reorganization over time, resulting in increased recruitment of left hemisphere perisylvian and temporoparietal regions at 15 weeks compared to sham. These data demonstrate potential mechanisms for the behavioural improvements observed following rTMS plus M-MAT. This thesis provides evidence to support the efficacy of rTMS plus M-MAT for improving chronic post-stroke aphasia. In addition, this thesis advances our understanding of the structural and functional brain architecture that supports aphasia recovery. These behavioural and neuroimaging results are important for the advancement of post-stroke aphasia rehabilitation.
dc.identifier.citation	Low, T. A. (2024). Examining chronic post-stroke aphasia recovery using non-invasive brain stimulation and neuroimaging (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.
dc.identifier.uri	https://hdl.handle.net/1880/119036
dc.language.iso	en
dc.publisher.faculty	Cumming School of Medicine
dc.publisher.institution	University of Calgary
dc.rights	University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subject	Aphasia
dc.subject	Stroke rehabilitation
dc.subject	Transcranial magnetic stimulation
dc.subject	Speech language therapy
dc.subject	Magnetic resonance imaging
dc.subject.classification	Neuroscience
dc.subject.classification	Rehabilitation and Therapy
dc.subject.classification	Speech Pathology
dc.title	Examining Chronic Post-Stroke Aphasia Recovery Using Non-Invasive Brain Stimulation and Neuroimaging
dc.type	doctoral thesis
thesis.degree.discipline	Medicine – Neuroscience
thesis.degree.grantor	University of Calgary
thesis.degree.name	Doctor of Philosophy (PhD)
ucalgary.thesis.accesssetbystudent	I require a thesis withhold – I need to delay the release of my thesis due to a patent application, and other reasons outlined in the link above. I have/will need to submit a thesis withhold application.