Electronic Thesis and Dissertation Repository

Thesis Format



Master of Science


Health and Rehabilitation Sciences


Orange, J.B.


Analyses of elicited spoken discourse can identify mild cognitive impairment (MCI) and Alzheimer’s dementia (AD). Topic management, one feature of discourse defined as acts that maintain or terminate an established topic, can be measured via global coherence measures. Little is known, however, about whether analyses of topic management can distinguish spoken discourse performances of persons living with MCI (PLwMCI) vs. persons living with AD (PLwAD). The current study investigated whether there are differences in topic management in the spoken discourse performances of PLwMCI vs. PLwAD. Analyses were conducted on 120 transcripts of spoken sequenced story picture descriptions of PLwMCI (n=83) and PLwAD (n=37). Diagnostic group performances were analyzed using average global coherence ratings. No significant group differences were found. Average global coherence ratings were not a predictor of diagnostic group membership. Findings highlight the need for further investigation of topic management in PLwMCI and PLwAD.

Summary for Lay Audience

Mild cognitive impairment (MCI) is a condition that represents the stage between healthy aging and dementia. MCI can indicate that an individual is at greater risk of developing dementia. Dementia is a syndrome that impairs memory and thinking abilities. Alzheimer’s dementia (AD) is the most common type of dementia. Persons living with MCI (PLwMCI) and persons living with AD (PLwAD) typically experience a declining ability to use language and communicate. For the purposes of this thesis, discourse is the production of spoken language and can be elicited using a picture stimulus. Language impairments in PLwMCI and PLwAD can be studied and analyzed using a spoken discourse sample. Discourse in PLwMCI and PLwAD is characterized by few words, limited ideas, frequent repetitions, and difficulty maintaining topic; often with PLwAD showing greater problems than PLwMCI. However, it is unknown whether the spoken discourse performance of PLwMCI vs. PLwAD can be distinguished based on topic management. Global coherence is a measure of how closely related an individual’s spoken discourse performance is to the general topic at hand. This thesis examined the global coherence of spoken discourse samples in PLwMCI and PLwAD. Spoken discourse data from the Ontario Neurodegenerative Disease Research Initiative (ONDRI) were used in this analysis. These discourse samples involved participants using a sequence of six pictures to tell a story. The differences and relationships between participant groups were investigated. Findings show that group differences were not found. Thus, global coherence was not able to predict diagnostic group, and diagnostic group was not able to predict an average global coherence score. This thesis proposes various suggestions for why the findings contrast the available literature and highlights the need for continued research in this area.