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Dissertation
The Spatial Navigation and Diaschisis Hypothesis: A Premise for Three Feasibility Studies to Screen for Preclinical Alzheimer's Disease
Washington State University
Doctor of Philosophy (PhD), Washington State University
05/2024
DOI:
https://doi.org/10.7273/000006588
Abstract
Background: The core biomarkers of Alzheimer’s disease (AD), amyloid plaques and phosphorylated tau, are not exclusive to AD. They appear secondary to causes such as head injuries, certain foods, and to seal leaky capillaries. While biomarkers are present in cognitively unimpaired (CU) persons who will develop AD dementia (pre-AD), biomarker indicators might contribute to misdiagnosis in persons without the disease (non-AD). Detection may be optimized
with measuring potential changes in cognitive domains informing spatial navigation (SN). These studies aim to determine the feasibility of neuropsychiatric tests for executive function (EF), verbal and visual episodic memory as indicators of preclinical AD and proxy for SN changes.
Methods: A retrospective secondary analysis was performed on neuropsychiatric test data from the National Alzheimer’s Coordinating Center Uniform Data Set Version 3. Pre-AD participant scores were compared to non-AD participants. Three tests were selected for analysis of episodic memory and EF: Craft-21, Benson Complex Figure Test delayed recall (BCFT-DR), and Trail Making Test part-B (TMT-B), respectively. Longitudinal linear mixed modeling is applied and
Cohen’s d for individual timepoints in terms of years remaining as CU (yrs-CU) for pre-AD groups.
Results: The TMT-B results show pre-AD mixed group increased in time for completion by an average of 3.498 seconds per year p <.001, [CI 3.097, 4.294], with scores associated with at-risk driving at 3 yrs-CU for males and 6 yrs-CU females. The Craft-21 test for episodic memory reveal the pre-AD group average score decreased every year by -.510, p < .001, [CI -.757, -.264] while the non-AD increased by .127, p < .001, [CI .101, .153], Cohen’s d = .482 at 4 yrs-CU. The BCFT-DR results expanded our understanding of visual memory and SN as preclinical indicators of AD. The pre-AD group average score decreased annually by -.219, p <.001, [CI (-.251, -.187)] and non-AD group decreased by -.039, p =.001, [CI (-062, -.015)], Cohen's d = .948 at 5 yrs-CU.
Discussion: All tests demonstrated feasibility for preclinical AD detection and proxy for SN. The pre-AD longitudinal cognitive trajectories may allow annual biomarker mapping to establish standardization of biomarker levels for future clinical practice.
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Details
- Title
- The Spatial Navigation and Diaschisis Hypothesis
- Creators
- Jennifer I Nevers
- Contributors
- Lonnie Nelson (Chair)Mary Koithan (Committee Member)Denise Smart (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Nursing, College of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 95
- Identifiers
- 99901122439601842
- Language
- English
- Resource Type
- Dissertation