- An estimated 5.7 million Americans are currently living with the dementia stage of Alzheimer’s disease, impeding health and wellbeing for individuals diagnosed, caregivers, families, and communities across the country (Alzheimer’s Association, 2018). Studying early indicators of age-related cognitive decline and pathological cognitive impairment (e.g., Alzheimer’s disease) is crucial to inform approaches that optimize cognitive health and reduce cognitive decline. Subjective cognitive complaints may be an early indicator of Alzheimer’s disease pathology (Amariglio et al., 2012) and related dementias (Jonker, Geerlings, & Schmand, 2000) that can be detectable prior to significant objective decline. In addition, trial-to-trial fluctuations in response time tasks, known as response time inconsistency (RTI), has emerged as a viable objective indicator of mental noise (Robinson & Tamir, 2005), lapses of attention (West et al., 2002) and processing efficiency (e.g., Eysenck & Calvo, 1992), as well as more durable cognitive decline, cognitive impairment, and central nervous system integrity (e.g., MacDonald & Stawski, 2015) among older adults.
Affective states, both negative and positive experiences of emotion, and relatively enduring personality traits have been associated with cognition in older adulthood (e.g., Brose, Schmiedek, Lövden, & Lindenberger, 2012; Hülür, Hertzog, Pearman, & Gerstorf, 2015) and demonstrated capacity for meaningful within-person fluctuations based on person-environment interactions, age, and measurement approach (e.g., Noftle & Fleeson, 2015; Röcke, Li, & Smith, 2009; Shifren & Hooker, 1995). In the current dissertation we took an IIV approach to elucidate ways in which modifiable negative and positive affective states (NA and PA, respectively), relatively enduring trait neuroticism (e.g., emotionally unstable, worrisome), trait conscientiousness (e.g., dependable, organized), and age were associated with both cognitive complaints (Study One) and RTI (Study Two) to identify within- and between-person factors relevant for optimizing cognitive health in older adulthood. Intensive repeated measurement designs were used in both studies to better align analyses of observed associations among affect and indicators of cognitive health and the underlying dynamic interactions between emotion and cognition processes occurring within persons over time (Phelps, 2006; Nesselroade & Ram, 2004).
In Study One we utilized data from a microlongitudinal 100-day study of 105 community dwelling older adults (Mage=63.19, SD=7.80, Range=52–88) to explore within- and between-person associations between NA, PA, and two cognitive complaints (trouble staying focused and forgot something). For memory-related complaints, those who reported experiencing greater NA-high arousal had increased forgetfulness. Within persons, reporting more NA-high arousal than usual was associated with increased forgetfulness. For attention-related complaints, those who reported experiencing greater NA-low arousal had increased trouble staying focused. Within persons, reporting more NA-low arousal and less PA-high arousal than usual was associated with increased trouble staying focused. Additionally, reporting more PA-low arousal than usual was associated with decreased trouble staying focused among those with higher levels of conscientiousness and the relatively older portion of the sample.
In Study Two we utilized data from a measurement burst study of 116 community dwelling older adults (Mage=80.23, SD=6.30, Range=66–95) to explore within- and between-person associations between NA, PA, and RTI. Within a 14-day time period, participants were assessed on six daily sessions/occasions. This assessment protocol was administered every six months for two years, generating five total bursts of data. RTI was higher on sessions when participants reported more NA-low arousal than usual. Aging-related changes showed a decrease in the magnitude of the association across two years, ultimately resulting in an association between higher NA-low arousal and decreased RTI two years later.
Results from this dissertation may have important implications for personalized approaches to optimize cognitive health trajectories in later life (Hamburg & Collins, 2010; Hill & Payne, 2017). In Study One we offer a means to maximize resource allocation and personalized health efforts by pinpointing for whom and at what moments boosting PA and/or reducing NA can both serve as pathways to benefit daily subjective cognition. In Study Two we suggest efforts toward bolstering cognitive health through NA must consider for whom and at what moments mitigating NA will be maximally beneficial. Finding the most optimal method to improve or promote cognitive health with a limited amount of resources is essential. In this dissertation we elucidated modifiable psychosocial factors as targets for promoting cognitive health, as well as leverage cognitive complaints and RTI as indicators of age-related cognitive decline and pathological cognitive impairment observable early on, when cognitive intervention efforts are most viable (Prince, Bryce, & Ferri, 2011).