Date of Award
2025
Document Type
Open Access Dissertation
Department
Psychology
First Advisor
Christopher Rorden
Abstract
This dissertation investigates the critical role of the cerebellum in speech production, with a focus on chronic post-stroke apraxia of speech (AOS), lesion-related cerebellar degeneration, and age-related changes in cerebellar structure among healthy individuals. While speech deficits have traditionally been attributed to cortical lesions, mounting evidence suggests that the cerebellum contributes significantly to speech-motor planning, execution, and error correction. Using multimodal neuroimaging, lesion-symptom mapping, and standardized speech assessments, this research examines cerebellar gray matter volume (GMV) across three complementary studies.
Aim 1 evaluates the association between cerebellar GMV and AOS severity in individuals with chronic left hemisphere stroke. Findings support that reduced GMV in right cerebellar regions (lobules V, VI, VIII, and Crus I/II) correlates with persistent AOS symptoms, independent of lesion volume and time post-stroke, underscoring the cerebellum’s role in speech-motor coordination.
Aim 2 explores how specific lesion patterns, beyond total lesion volume, predict cerebellar degeneration. Results highlight that damage to cortico-pontine-cerebellar pathways (e.g., internal capsule, superior corona radiata) disproportionately affects contralateral cerebellar regions, supporting diaschisis mechanisms and refining our understanding of remote structural effects.
Aim 3 investigates how domain-specific stroke symptoms, taken from NIHSS sub-scores, are influenced by lesion volume, cerebellar gray matter structure, and regional BrainAge Gap (BAG) in acute stroke groups separated by lesion laterality. By decomposing the NIHSS into grouped symptom domains, this aim evaluates whether regional cerebellar integrity and cortical aging metrics improve prediction of symptom severity beyond lesion size alone. Findings support an informed model of stroke severity that accounts for cerebellar contributions and neurobiological aging, with implications for early rehabilitation and individualized care.
Together, these studies highlight cerebellar involvement in speech-motor control, integrate aging and disease models, and provide biomarkers with clinical relevance. This work advances neuroanatomical theories of speech production and offers new pathways for diagnostic precision, targeted rehabilitation, and prognostic stratification in stroke recovery.
Rights
© 2025, Makayla Joy Gibson
Recommended Citation
Gibson, M. J.(2025). Cerebellar Contributions to Speech and Clinical Outcomes in Stroke: A Multimodal Investigation of Structural Integrity Across Chronic and Acute Cohorts. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/8577