Glenn J. Landry

Measuring sleep quality in older adults: a comparison using subjective and objective methods

Sleep quality decreases with aging and thus sleep complaints are prevalent in older adults, particularly for those with cognitive impairment and dementia. For older adults, emerging evidence suggests poor sleep quality increases risk of developing cognitive impairment and dementia. Given the aging population—and the impending economic burden associated with increasing numbers of dementia patients—there is pressing need to improve sleep quality among older adults. As such, research efforts have increased focus on investigating the association between age-related sleep changes and cognitive decline in older adults. Sleep quality is a complex construct to evaluate empirically, and yet the Pittsburg Sleep Quality Index (PSQI) is commonly used in studies as their only measure of sleep quality. Furthermore, the PSQI may not be the best sleep quality measure for older adults, due to its reliance on the cognitive capacity to reflect on the past month. Further study is needed to determine the PSQIs validity among older adults. Thus, the current study examined sleep quality for 78 community dwelling adults 55+ to determine the PSQIs predictive validity for objective sleep quality (as measured by actigraphy). We compared two subjective measures of sleep quality—the PSQI and Consensus Sleep Diary (CSD)—with actigraphy (MotionWatch 8©; camntech). Our results suggest perceived sleep quality is quite different from objective reality, at least for adults 55+. Importantly, we show this difference is unrelated to age, gender, education, or cognitive status (assessed using standard screens). Previous studies have shown the PSQI to be a valuable tool for assessing subjective sleep quality; however, our findings indicate for older adults the PSQI should not be used as a substitute for actigraphy, or vice versa. Hence, we conclude best practice is to include both subjective and objective measures when examining sleep quality in older adults (i.e., the PSQI, CSD, and actigraphy).

Buying time: a rationale for examining the use of circadian rhythm and sleep interventions to delay progression of mild cognitive impairment to Alzheimer's disease.

As of 2010, the worldwide economic impact of dementia was estimated at

Measuring physical activity in older adults: calibrating cut-points for the MotionWatch 8(©).

604 billion USD; and without discovery of a cure or effective interventions to delay disease progression, dementia’s annual global economic impact is expected to surpass

Organisational characteristics associated with shift work practices and potential opportunities for intervention: findings from a Canadian study

1 trillion USD as early as 2030. Alzheimer’s disease (AD) is the leading cause of dementia accounting for over 75% of all cases. Toxic accumulation of amyloid beta (Aβ), either by overproduction or some clearance failure, is thought to be an underlying mechanism of the neuronal cell death characteristic of AD—though this amyloid hypothesis has been increasingly challenged in recent years. A compelling alternative hypothesis points to chronic neuroinflammation as a common root in late-life degenerative diseases including AD. Apolipoprotein-E (APOE) genotype is the strongest genetic risk factor for AD: APOE-ε4 is proinflammatory and individuals with this genotype accumulate more Aβ, are at high risk of developing AD, and almost half of all AD patients have at least one ε4 allele. Recent studies suggest a bidirectional relationship exists between sleep and AD pathology. Sleep may play an important role in Aβ clearance, and getting good quality sleep vs. poor quality sleep might reduce the AD risk associated with neuroinflammation and the ε4 allele. Taken together, these findings are particularly important given the sleep disruptions commonly associated with AD and the increased burden disrupted sleep poses for AD caregivers. The current review aims to: (1) identify individuals at high risk for dementia who may benefit most from sleep interventions; (2) explore the role poor sleep quality plays in exacerbating AD type dementia; (3) examine the science of sleep interventions to date; and (4) provide a road map in pursuit of comprehensive sleep interventions, specifically targeted to promote cognitive function and delay progression of dementia.

Measuring Physical Activity in Older Adults Using MotionWatch 8 Actigraphy: How Many Days are Needed?

Given the world’s aging population, the staggering economic impact of dementia, the lack of effective treatments, and the fact a cure for dementia is likely many years away – there is an urgent need to develop interventions to prevent or at least delay dementia’s progression. Thus, lifestyle approaches to promote healthy aging are an important line of scientific inquiry. Good sleep quality and physical activity (PA) are pillars of healthy aging, and as such, are an increasing focus for intervention studies aimed at promoting health and cognitive function in older adults. However, PA and sleep quality are difficult constructs to evaluate empirically. Wrist-worn actigraphy (WWA) is currently accepted as a valid objective measure of sleep quality. The MotionWatch 8© (MW8) is the latest WWA, replacing the discontinued Actiwatch 4 and Actiwatch 7. In the current study, concurrent measurement of WWA and indirect calorimetry was performed during 10 different activities of daily living for 23 healthy older adults (aged 57–80 years) to determine cut-points for sedentary and moderate-vigorous PA – using receiver operating characteristic curves – with the cut-point for light activity being the boundaries between sedentary and moderate to vigorous PA. In addition, simultaneous multi-unit reliability was determined for the MW8 using inter-class correlations. The current study is the first to validate MW8 activity count cut-points – for sedentary, light, and moderate to vigorous PA – specifically for use with healthy older adults. These cut-points provide important context for better interpretation of MW8 activity counts, and a greater understanding of what these counts mean in terms of PA. Hence, our results validate another level of analysis for researchers using the MW8 in studies aiming to examine PA and sleep quality concurrently in older adults.

Cross-Sectional Relationships of Physical Activity and Sedentary Behavior With Cognitive Function in Older Adults With Probable Mild Cognitive Impairment

Introduction Shift work is a common working arrangement with wide-ranging implications for worker health. Organisational determinants of shift work practices are not well characterised; such information could be used to guide evidence-based research and best practices to mitigate shift works negative effects. This exploratory study aimed to describe and assess organisational-level determinants of shift work practices thought to affect health, across a range of industry sectors. Methods Data on organisational characteristics, shift work scheduling, provision of shift work education materials/training to employees and night-time lighting policies in the workplace were collected during phone interviews with organisations across the Canadian province of British Columbia. Relationships between organisational characteristics and shift work practices were assessed using multivariable logistic regression models. Results The study sample included 88 participating organisations, representing 30 700 shift workers. Long-duration shifts, provision of shift work education materials/training to employees and night-time lighting policies were reported by approximately one-third of participating organisations. Odds of long-duration shifts increased in larger workplaces and by industry. Odds of providing shift work education materials/training increased in larger workplaces, in organisations reporting concern for shift worker health and in organisations without seasonal changes in shift work. Odds of night-time lighting policies in the workplace increased in organisations reporting previous workplace accidents or incidents that occurred during non-daytime hours, site maintenance needs and client service or care needs. Conclusions This study points to organisational determinants of shift work practices that could be useful for targeting research and workplace interventions. Results should be interpreted as preliminary in an emerging body of literature on shift work and health.

Analysis of dynamic, bidirectional associations in older adult physical activity and sleep quality

Evidence suggests sleep and physical activity (PA) are associated with each other and dementia risk. Thus, identifying reliable methods to quantify sleep and PA concurrently in older adults is important. The MotionWatch 8© (MW8) wrist-worn actigraph provides reliable estimates of sleep quality via 14 days of measurement; however, the number of days needed to monitor PA by MW8 for reliable estimates is unknown. Thus, we investigated the number of days of MW8 wear required to assess PA in older adults. Ninety-five adults aged > 55 years wore MW8 for ≥ 14 days. Spearman-Brown analyses indicated the number of monitoring days needed for an ICC = 0.95 was 6-7 days for sedentary activity, 9-10 days for light activity, and 7-8 days for moderate-to-vigorous PA. These results indicate 14 days of MW8 monitoring provides reliable estimates for both sleep and PA. Thus, MW8 is ideal for future investigations requiring concurrent measures of both sleep quality and PA.

Sleep matters: Associations between cognition and objectively measured sleep parameters in older adults with or without mild cognitive impairment

Background Mild cognitive impairment (MCI) represents a transition between normal cognitive aging and dementia and may represent a critical time frame for promoting cognitive health through behavioral strategies. Current evidence suggests that physical activity (PA) and sedentary behavior are important for cognition. However, it is unclear whether there are differences in PA and sedentary behavior between people with probable MCI and people without MCI or whether the relationships of PA and sedentary behavior with cognitive function differ by MCI status. Objective The aims of this study were to examine differences in PA and sedentary behavior between people with probable MCI and people without MCI and whether associations of PA and sedentary behavior with cognitive function differed by MCI status. Design This was a cross‐sectional study. Methods Physical activity and sedentary behavior in adults dwelling in the community (N = 151; at least 55 years old) were measured using a wrist‐worn actigraphy unit. The Montreal Cognitive Assessment was used to categorize participants with probable MCI (scores of <26/30) and participants without MCI (scores of ≥26/30). Cognitive function was indexed using the Alzheimer Disease Assessment Scale‐Cognitive‐Plus (ADAS‐Cog Plus). Physical activity and sedentary behavior were compared based on probable MCI status, and relationships of ADAS‐Cog Plus with PA and sedentary behavior were examined by probable MCI status. Results Participants with probable MCI (n = 82) had lower PA and higher sedentary behavior than participants without MCI (n = 69). Higher PA and lower sedentary behavior were associated with better ADAS‐Cog Plus performance in participants without MCI (&bgr; = −.022 and &bgr; = .012, respectively) but not in participants with probable MCI (&bgr; < .001 for both). Limitations This study was cross‐sectional and therefore could not establish whether conversion to MCI attenuated the relationships of PA and sedentary behavior with cognitive function. The diagnosis of MCI was not confirmed with a physician; therefore, this study could not conclude how many of the participants categorized as having probable MCI would actually have been diagnosed with MCI by a physician. Conclusions Participants with probable MCI were less active and more sedentary. The relationships of these behaviors with cognitive function differed by MCI status; associations were found only in participants without MCI.

Buying time: a proof-of-concept randomized controlled trial to improve sleep quality and cognitive function among older adults with mild cognitive impairment

Sleep quality and physical activity (PA) appear to be interrelated; thus, by promoting one behaviour, it may be possible to improve the other in older adults. Examination of the within‐person day‐to‐day variation in PA and sleep quality could potentially elucidate the directionality of the association of these behaviours. We measured sleep quality (i.e. fragmentation, efficiency, duration and latency) and moderate‐to‐vigorous PA using the MotionWatch8© over 14 consecutive days and nights in community‐dwelling adults (n = 152; age range 53–101 years). Multilevel modelling estimated within‐subject autoregressive and cross‐lagged effects and between‐subject associations between PA and sleep quality. On days when individuals engaged in a high amount of PA on one day (relative to their averages), they were more likely to engage in a high amount of PA on the next day (estimate, 0.19; 95% CI, 0.14, 0.24). Nights in which individuals had a long sleep latency were followed by nights in which they also had a long sleep latency (estimate, 0.09; 95% CI, 0.03, 0.14). In contrast, nights in which individuals slept for a long period of time were followed by nights in which they slept relatively less than their averages (estimate, −0.09; 95% CI, −0.13, −0.04). When individuals engaged in a large amount of PA during the day, they tended to sleep longer that following night (estimate, 0.01; 95% CI, 0.001, 0.02). All other associations between PA and sleep quality were not significant. Increasing PA therefore might increase sleep duration in older adults.

EXAMINING RELATIONSHIPS OF PHYSICAL ACTIVITY AND SEDENTARY BEHAVIOUR WITH COGNITIVE FUNCTION AMONG OLDER ADULTS WITH MILD COGNITIVE IMPAIRMENT: A CROSS-SECTIONAL STUDY

Background: Large epidemiological studies have shown a relationship between moderate caffeine and alcohol consumption and reduced rates of cognitive decline and dementia in older adults, using broad measures of global cognition and clinical decline. In this study, we investigated the relationship betweenmultiple domains of cognitive functioning (memory, executive function, and processing speed) and habitual caffeine and alcohol intake in a well-characterized cross-sectional sample of clinically normal older adults. Methods: Our sample included 282 clinically normal (CDR1⁄40) older adults (59% women, aged 65-90 (mean1⁄4 73.7), mean education 1⁄4 15.8 years) participating in the Harvard Aging Brain Study. Approximate daily consumption of any caffeinated and alcoholic beverages was measured by self-report. Composites for Memory, Executive Function, and Processing Speed were computed. Correlations were obtained between the caffeine and alcohol consumption variables, cognitive composite scores, and demographics of age, sex, and estimated Verbal IQ (VIQ). Three backward elimination regressions were run to predict each cognitive factor score, with either caffeine or alcohol intake and relevant potential confounding demographic variables of age, sex, and VIQ included as predictors. Results: Greater caffeine consumption was associated with better Memory performance controlling for age, sex, and VIQ (Beta1⁄40.12, p1⁄40.02). This relationship persisted when moderate caffeine intake (2-5 cups/day) was substituted as a binary category for overall caffeine intake (Beta1⁄40.13, p1⁄40.02). There was no significant relationship between caffeine consumption and executive function or processing speed factor scores. No association was found between alcohol consumption and any of the cognitive factor scores. Conclusions: In clinically normal older adults, better memory is associated with greater caffeine consumption. This may be related to the stimulatory effects of caffeine and provides cross-sectional support for positive longitudinal findings. Although previous epidemiological data suggest that alcohol may have long-term neuroprotective effects, our findings do not support any cross-sectional benefit or deleterious effects on cognition. Future work to corroborate current findings with longitudinal studies will be important.