Butters, Meryl A.

Abstract Introduction Comparing sleep and rest-activity rhythms (RARs) across the spectrum of cognitive aging can reveal novel risk factors and potential mechanisms underlying dementia disorders. However, our current understanding is restricted by differences in sleep measurement, limited longitudinal data, and heterogeneous cognitive aging processes. We aimed to determine (1) which sleep/RAR features exhibit meaningful changes within three distinct cognitive pathways; and (2) which sleep/RAR features differ between cognitive aging pathways prior to and after the onset of mild cognitive impairment (MCI) and/or dementia. Methods Longitudinal self-reported sleep and actigraphy data were obtained from 1,449 participants in the Rush Memory and Aging Project (mean age= 81.2±7.1 years, 75.2% female, 5.2% Black, 94.8% White). We applied flexible cubic spline models to quantify differences in the levels and trajectories of sleep amount (self-reported duration; actigraphy rest interval length and alpha), regularity (actigraphy interdaily stability, intradaily variability, and midpoint standard deviation), and timing (self-reported midpoint; actigraphy midpoint and acrophase) within and between three cognitive aging pathways over 12 years: Normal Cognitive Aging (‘Normal’), Progression to MCI (‘Stable MCI’), and Progression to Dementia (‘Dementia’). Models were adjusted for key sociodemographic and health variables. Results Sleep amount was lowest in the Dementia pathway prior to MCI or dementia, but increased with age, most rapidly following dementia. The greatest effect was observed in self-reported duration (standardized mean change, d[95%CI]=0.912 [0.47, 1.36]. Regularity declined across all pathways, most rapidly after cognitive diagnoses, with the largest increases in intradaily variability occurring among the Stable MCI (d=0.97 [0.70, 1.23]) and Dementia paths (d=1.11 [0.84, 1.38). Shifts toward earlier sleep timing were observed in actigraphy measures across all three pathways (-0.54≤d≤-0.31). Conclusion Shorter sleep amount in cognitively healthy older adults may be a risk factor or prodromal indicator of dementia, while longer sleep amounts and decreasing regularity following dementia may reflect neurodegeneration. Advances in sleep timing may be less useful as a clinical indicator of future cognitive impairment or decline. Differences between self-reported and actigraphy-measured sleep/RAR outcomes may reflect distinct underlying mechanisms, warranting further research. Support (if any) NIH: T32HL082610, RF1AG056331, R01AG052488, R01AG071638, RF1AG070436, R01AG17917

AbstractINTRODUCTIONComparing sleep and rest–activity rhythms across different cognitive aging pathways can identify novel risk factors and potential mechanisms. However, our current understanding is restricted by differences in sleep measurement, limited longitudinal data, and heterogeneous cognitive aging processes.METHODSWe applied cubic splines to longitudinal self‐reported sleep and actigraphy data from 1449 participants in the Rush Memory and Aging Project and quantified differences in the levels and trajectories of sleep amount, regularity, and timing within and between three cognitive aging pathways: normal, stable mild cognitive impairment, dementia.RESULTSSleep amount was lowest in the dementia pathway prior to cognitive impairment but increased with age, most rapidly after dementia. Regularity declined across all pathways, most rapidly after cognitive diagnoses. Timing advanced across all pathways.DISCUSSIONShorter sleep amount in cognitively healthy older adults may be a risk factor or prodromal indicator of dementia, while longer sleep amounts and decreasing regularity may reflect neurodegeneration.Highlights We quantified longitudinal changes in sleep across three cognitive‐aging pathways. We incorporated both subjective and objective measures of sleep health. Self‐report duration increased noticeably from before to after cognitive diagnosis. Sleep irregularity increased most prominently after cognitive diagnosis. Advances in sleep timing occurred in both normal and pathological aging.

Background: Cognitive impairment (CI) is a key feature of late life depression (LLD), but the contribution of underlying neurodegenerative pathology remains unclear. Objective: To evaluate cognitive dysfunction in LLD relative to a sample of nondepressed (ND) older adults with matched levels of memory impairment and amyloid-β (Aβ) burden. Methods: Participants included 120 LLD and 240 ND older adults matched on age, education, sex, Mini-Mental State Exam, mild cognitive impairment diagnosis, and PET Aβ burden. Results: LLD showed higher rates of impairment relative to ND with 54.6% of the LLD sample demonstrating impairment in at least one cognitive domain compared to 42.9% of controls ( H = 7.13, p = 0.008). LLD had poorer performance and higher rates of impairment on Rey Auditory Verbal Learning Test learning and memory compared to controls. In the overall sample, Aβ positivity was associated with worse performance on Logical Memory I ( p = 0.044), Logical Memory II ( p = 0.011), and Trail Making Test –B ( p = 0.032), and APOE ɛ4 genotype was associated with worse performance on Logical Memory I ( p = 0.022); these relationships did not differ between LLD and ND. Conclusion: LLD showed higher rates of CI driven by focal deficits in verbal learning and memory. Alzheimer’s disease (AD) biomarkers were associated with worse performance on timed set-shifting and story learning and memory, and these relationships were not impacted by depression status. These findings suggest that AD may account for a portion of previously reported multi-domain CI in LLD and highlight the potential for AD to confound studies of cognition in LLD.

AbstractBackgroundThe Cognitive and Emotional Health Project (CEHP) seeks to identify the demographic, social, and biological determinants of cognitive and emotional health in the older adult. As part of the CEHP, a critical evaluation study committee was formed to assess the state of epidemiological research on demographic, social, and biological determinants of cognitive and emotional health.MethodsCriteria for inclusion in the survey were large cohort studies, longitudinal in design, participants predominantly 65 years or older, with measurements of both cognition and emotion, and information on a wide variety of demographic, psychosocial, and biological factors. North American and European studies, which met these criteria, were selected for the review. Outcome measures included cognition, cognitive decline, and cognitive function. For emotion, symptoms included depression and anxiety, positive and negative affect, subjective well being, mastery, and resilience.ResultsNinety‐six papers were identified that addressed cognitive and emotional outcomes. A large variety of risk factors were consistently identified with cognitive outcomes, particularly those previously associated with increased risk of cardiovascular disease. There was considerable overlap between risk factors for cognitive and emotional outcomes.ConclusionThis review identifies a large number of lifestyle and health behaviors that alter the risk for maintenance of cognitive and emotional health. Large longitudinal cohort studies are a unique source to explore factors associated with cognitive and emotional health. Secondary analyses of these studies should be encouraged as should the development of standardized questionnaires to measure cognitive and emotional health. Future research in this field should study cognitive and emotional health simultaneously.