Olfaction and Associations with Long-Term Cognitive Transitions and Short-Term Cognitive Variability




Knight, Jamie

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Olfactory function plays an important role in health and well-being. Deficits have been associated with a greater risk of cognitive decline, dementia, and death, indicating that olfactory ability may be an early marker of cognitive impairment and indicator of brain integrity. In the progression of cognitive impairment related to dementia, intraindividual variability in cognition may precede cognitive decline as an early risk factor, indicating that individuals with more variability in their cognitive performance may have an increased risk of cognitive impairment. Despite a significant amount of literature examining the relationship between olfaction and cognitive decline, to the best of our knowledge, no study has yet examined whether olfaction is associated with the earlier marker of cognitive decline, intraindividual variability in cognition. Project 1. In data drawn from the Rush Memory and Aging Project (N=1501), multistate models were used to estimate the association of olfactory identification with transition patterns through cognitive states including non-impaired cognitive functioning, clinically diagnosed mild cognitive impairment and dementia, and death. Additionally, multinomial regression models were fit to estimate life expectancies for overall and cognitively unimpaired years of life, relative to olfactory identification scores. This dissertation aims to contribute to the current body of literature suggesting potential for the use of olfactory identification as a clinically administered marker for the early detection of cognitive decline and risk of dementia. Project 2. In data collected by our lab (N=65), multilevel models were used to examine whether olfactory identification scores were associated with the magnitude and rate of change of intraindividual variability (IIV) in cognitive functioning. This dissertation aims to address whether olfactory identification is associated with IIV in cognition using self-administered mobile cognitive testing in a 14-day micro-longitudinal study.



olfaction, olfactory, mortality, Alzheimer's, intraindividual variability, cognition, cognitive decline, MCI, dementia