Date of Award

Summer 2023

Document Type

Open Access Thesis


Public Health

First Advisor

Roozbeh Behroozmand


Speech production is a complex and highly organized process comprised of various sensory and perceptual components. Post-stroke aphasia can impair speech production abilities by interrupting individuals’ ability to detect and correct speech errors and produce their targeted behavior. Contemporary models of speech production aim to understand the relationship between sensory systems and the human ability to produce perceptually accurate speech. This study seeks to understand the relationship between visual feedback and vocal compensation abilities in individuals with post-stroke aphasia to determine the effectiveness of incorporating visual feedback into therapeutic expressive language intervention. It was hypothesized that that the multi-sensory experimental condition will improve vocal control ability in both experimental groups as indexed by smaller compensation magnitude of (i.e., more stabilized) responses in the presence of artificial pitch-shift perturbations. It was also hypothesized that the post-stroke aphasia group would benefit more from the audiovisual feedback experimental condition and would produce a more stable vocal output via suppressing vocal compensation responses to external pitch-shift stimuli compared with control participants. The results revealed that there are no significant effects of visual feedback on improved stabilization of vocal pitch or suppression of external altered auditory feedback stimuli on control participants. However, this experiment revealed a significant effect on the aphasia group for the downward shift in the AV Sham condition, indicating that visual feedback may benefit individuals with post-stroke aphasia. The results of this present study add to current literature to inform professionals in the field of communication sciences and disorders about the impact of multi-sensory feedback on speech productions. Additionally, the results revealed through this research uncover potential benefits of involving visual feedback into therapeutic expressive language intervention for individuals with post-stroke aphasia.


© 2023, Marissa Rylee Olson