Year of Publication

2017

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Health Sciences

Department

Rehabilitation Sciences

First Advisor

Dr. Gilson J. Capilouto

Second Advisor

Dr. Anne Harrison

Abstract

Stroke is the leading cause of serious, long-term disability and nearly half of older stroke survivors experience moderate to severe disability. A common impairment following stroke is impaired discourse production. Functional outcome studies have proposed that the recovery of discourse abilities is critical to achieving a good quality of life. Communication impairments often persist into the chronic stages of recovery and can cause individuals to withdraw from social situations. Discourse production deficits may not be apparent in basic communication interactions, but become more obvious during complex conversations following non-aphasic brain injury (NABI) or right hemisphere stroke (RHD). The purpose of this three-part dissertation was to examine discourse production deficits following NABI and the current practices of speech-language pathologists in the assessment and treatment of discourse deficits.

The first study examined the macrolinguistic processes of discourse, which included local coherence, global coherence and cohesion, following NABI. Ten individuals with NABI and 10 heathy controls, closely matched for age, gender, and education, provided a narrative recount of an event. Discourse samples were analyzed for local coherence, global coherence, and cohesion. Results indicated that individuals with NABI demonstrated impaired global coherence compared to healthy controls with relatively intact local coherence and cohesion. Although global coherence deficits were identified in the discourse of individuals with NABI, empirical evidence suggests that speech-language pathologists do not routinely assess or treat discourse production deficits.

The second study explored the current practices of speech-language pathologists in the assessment and treatment of individuals with NABI with a specific focus on discourse production deficits using a phenomenological approach. Nine speech-language pathologists participated in semi-structured 1:1 interviews. Results indicated that speech-language pathologists do not routinely assess and treat discourse production deficits due to competing internal values and external or environmental demands. However, speech-language pathologists reported that discourse deficits are present following NABI and are characterized by impaired topic maintenance or global coherence. Participants reported that they were routinely assessing and treating the underlying cognitive process of attention in hopes that it would generalize to improved topic maintenance or global coherence. However, little is known about the relationship between selective attention and global coherence.

The third study examined the maintenance of global coherence across discourse tasks and explored the relationship between selective attention and global coherence. Eleven participants with non-aphasic brain injury secondary to right hemisphere stroke participated in the study. Participants provided discourse samples in response to five discourse tasks in a single-task and dual-task condition. Additionally, participants completed the Stroop test to examine selective attention abilities. Results indicated that mean global coherence scores differed across discourse tasks, and that mean global coherence scores for stories was significantly higher than for simple recount and single picture description tasks. To examine the relationship between selective attention and global coherence, mean global coherence scores in the single-task and dual-task condition were compared. Mean global coherence scores were lower in the dual-task condition for all five discourse tasks. Mean global coherence scores for the complex recount task were significantly lower in the dual-task condition. This suggests that the maintenance of global coherence is influenced by attention abilities. There was no significant correlation between performance on the Stroop task and the maintenance of global coherence for any of the five discourse tasks.

Digital Object Identifier (DOI)

https://doi.org/10.13023/ETD.2017.440

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