All ETDs from UAB

Advisory Committee Chair

Virginia Wadley Bradley

Advisory Committee Members

Karlene Ball

Michael Crowe

Georg Deutsch

Richard Kennedy

Document Type

Dissertation

Date of Award

2020

Degree Name by School

Doctor of Philosophy (PhD) College of Arts and Sciences

Abstract

Performance of instrumental activities of daily living (IADLs) can become compromised in older adults with mild cognitive impairment (MCI). Poor self-awareness of deficits, also known as anosognosia, occurs in a substantial minority of those with MCI and varies in extent depending on the domain examined. This dissertation attempts to explain the inter- and intra-patient variability in anosognosia by examining (1) differences in objective IADL performance and self-awareness of functional difficulties between those with amnestic single- (-ASD) and multi-domain (-AMD) MCI, and by examining (2) the neuropsychological and (3) neuroanatomical correlates of anosognosia for IADLs in older adults across a broad continuum of cognitive impairment. Participants (n=103; age range=54-88) with MCI and mild probable dementia were recruited from hospital-based neurology and geriatrics clinics and administered neuropsychological tests and structural brain MRI along with subjective and performance-based assessments of six IADLs: financial management, driving, telephone use, nutrition evaluation, grocery shopping, and medication management. For each IADL, participants were classified as having anosognosia when there was objective impairment but no subjective complaints. Depending on the IADL, 13-39% of the sample had objective impairment, and individuals with MCI-AMD performed significantly worse on objective measures of financial management, driving, and nutrition evaluation compared to those with MCI-ASD. Of the participants with objective impairment, 65-93% lacked insight into their deficits. Individuals with MCI-AMD were significantly more likely than those with MCI-ASD to overestimate performance on Driving and Telephone Use domains. In the full sample, measures of global cognition, executive function, visual attention, and verbal memory predicted classification of anosognosia, and these relationships varied across IADLs. Anosognosia was also related to reduced volume in the bilateral medial prefrontal cortex, middle and posterior cingulate cortex, right insular cortex, and cerebellum. In conclusion, underlying cognitive mechanisms of anosognosia may be contingent on the domain assessed, explaining both inter- and intra-patient variability in self-awareness of functional deficits. Regardless, cortical midline and cerebellar structures may be related self-referential processing. When possible, clinicians should obtain objective measures in combination with detailed informant reports of functional abilities in order to evaluate capacity to independently engage in various daily activities.

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