Sleep quality and duration in relation to memory in the elderly: Initial results from the Hellenic Longitudinal Investigation of Aging and Diet

Sleep problems as predictors of cognitive decline in essential tremor: A prospective longitudinal cohort study

BACKGROUND

There is growing evidence that essential tremor (ET) patients are at high risk of cognitive impairment. Predictors of cognitive impairment have not been studied extensively. There is evidence from cross-sectional studies that sleep dysregulation is associated with cognitive dysfunction in ET, but longitudinal studies of the impact of sleep disruption on cognitive change have not been conducted. We investigated the extent to which sleep problems predict cognitive change in patients with ET.

METHODS

ET cases enrolled in a prospective, longitudinal study of cognitive performance. Sleep quality was assessed using the Pittsburg Sleep Quality Index (PSQI). Cognitive abilities across five domains (memory, executive function, attention, language, and visuospatial ability), and a global cognitive score (mean of the domains) were extracted from an extensive neuropsychological assessment. Generalized estimated equations were used to examine the association between baseline sleep problems and cognitive changes over three follow-up assessments each spaced 18 months apart.

RESULTS

The 188 non-demented ET cases had a mean age of 77.7 ± 9.5 years. Longer sleep latency was associated with longitudinal decline in executive function (p = 0.038), and marginally with longitudinal decline in global cognitive performance (p = 0.075). After excluding 29 cases with mild cognitive impairment, results were similar.

CONCLUSION

Cognitively healthy people with ET who have longer sleep latency had greater declines in executive function during prospective follow-up. Early detection of, and possibly intervention for, abnormal sleep latency may protect against certain aspects of cognitive decline in ET patients.

Is poor sleep quality associated with poor neurocognitive outcome in cancer survivors? A systematic review

PURPOSE

Cancer-related neurocognitive impairment and poor sleep are prevalent in cancer survivors and have a negative impact on their quality of life. This systematic review studies the association between sleep disturbance and neurocognitive functioning, as well as the potential positive effects of sleep interventions on neurocognitive functioning in cancer survivors. In addition, we aimed at determining the potential positive effects of sleep interventions on neurocognitive functioning in this population.

METHODS

Following PRISMA guidelines for reporting systematic reviews and meta-analyses, a comprehensive PubMed, Embase, PsycINFO, and CINAHL search was performed. Inclusion criteria were adult cancer survivors, self-reported or objective measures of neurocognitive functioning and sleep quality, or reports on the association between sleep and neurocognitive functioning.

RESULTS

Of the 4,547 records retrieved, 17 studies were retained for this review. Twelve studies were correlational, and five reported on interventions aimed at improving sleep quality. All studies that included self-reported neurocognitive functioning found that poorer sleep was associated with worse neurocognitive functioning. In four out of eight studies, poorer sleep was associated with objective neurocognitive impairment. Three out of five interventional studies showed neurocognitive functioning improved with improved sleep.

CONCLUSIONS

While poor sleep in cancer survivors is associated with self-reported neurocognitive impairment, the association between poor sleep and objective neurocognitive impairment is less evident.

IMPLICATIONS FOR CANCER SURVIVORS

It is important that care providers are aware of the association between sleep and neurocognitive functioning and that improving sleep quality can be a way to decrease neurocognitive impairment in cancer survivors.

Sleep Quality and Cognitive Abilities in the Greek Cohort of Epirus Health Study

Purpose

Sleep is essential to all human body functions as well as brain functions. Inadequate sleep quantity and poor sleep quality have been shown to directly affect cognitive functioning and especially memory. The primary aim of the present study was to investigate the association of sleep quality with cognitive abilities cross-sectionally in a middle-aged Greek population and secondarily to examine this association prospectively in a smaller group of these participants.

Patients and Methods

A total of 2112 healthy adults aged 25-70 years (mean: 46.7±11.5) from the Epirus Health Study cohort were included in the analysis and 312 of them participated in secondary prospective analysis. Sleep quality was measured by the Pittsburgh Sleep Quality Index (PSQI) scale and cognition was assessed in primary cross-sectional analyses with three neuropsychological tests, namely the Verbal Fluency test, the Logical Memory test and the Trail Making test, and in secondary prospective analyses with online versions of Posner cueing task, an emotional recognition task, the Corsi block-tapping task and the Stroop task. Statistical analysis was performed using multivariable linear regression models adjusted for age, sex, education, body mass index and alcohol consumption.

Results

Attention/processing speed was the only cognitive domain associated cross-sectionally with PSQI score. Specifically, participants with better self-reported sleep quality performed faster on the Trail Making Test - Part A (β= 0.272 seconds, 95% CI 0.052, 0.493).

Conclusion

Further studies are needed to clarify the association of sleep quality with cognition, especially in middle-aged people that are still in productive working years.

Gender-and age-specific associations of sleep duration and quality with cognitive impairment in community-dwelling older adults in Anhui Province, China

Objective

To examine associations of sleep duration and quality with cognitive impairment in older adults and the moderating role of gender and age in these associations.

Methods

This community-based cross-sectional study included 4,837 participants aged 60 years and above. Cognitive function was assessed using the Chinese version of the Mini-Mental State Examination (MMSE), and the participants were grouped based on the presence of cognitive impairment. The duration and quality of sleep were assessed using the Pittsburgh Sleep Quality Index (PSQI). Multivariate logistic regression models were used to analyze associations of sleep duration and quality with cognitive impairment. The role of age and gender in these associations have also been explored.

Results

The age (mean ± SD) of the participants was 71.13 ± 5.50 years. Of all older adults, 1,811 (37.44%) were detected as cognitive impairment, and 1755 (36.8%) had poor sleep quality. Among those with cognitive impairment, 51.09% were female. The proportion of the participants with cognitive impairment is significantly higher in those with symptoms of depression (49.73%, 273/549) (χ2 = 41.275, p < 0.001) than in those without depressive symptoms. After adjustment for multiple confounding factors and the crucial covariate (depressive symptoms), the odds ratios (OR) (95% confidence interval [CI]) of cognitive impairment (with 7-7.9 h regarded as the reference group) for individuals with a sleep duration of <6, 6-6.9, 8-8.9, and ≥ 9 h were 1.280 (1.053-1.557), 1.425 (1.175-1.728), 1.294 (1.068-1.566), and 1.360 (1.109-1.668), respectively. Subgroup analysis showed a V-shaped association between night sleep duration and cognitive impairment in males (p ≤ 0.05), and the association was stronger for individuals aged 60-80 years. With regard to sleep quality, the fully adjusted OR (95%CI) of cognitive impairment were 1.263 (1.108-1.440). According to scores of subscales in the PSQI, daytime dysfunction was associated with an increased risk of cognitive impairment (OR: 1.128, 95%CI: 1.055-1.207). Subgroup analysis also revealed a statistically significant correlation between poor sleep quality (including daytime dysfunction) and cognitive impairment in different gender and age groups, with the association being stronger in females (OR: 1.287, 95%CI: 1.080-1.534) and those aged 81-97 years (OR: 2.128, 95%CI: 1.152-3.934). For cognitive impairment, the group aged 81-97 years with daytime dysfunction was associated with a higher odds ratio than other age groups.

Conclusion

The present study showed that inadequate or excessive sleep was associated with cognitive impairment, especially in males, who exhibited a V-shaped association. Cognitive impairment was also associated with poor sleep quality as well as daytime dysfunction, with females and individuals aged 81-97 years exhibiting the strongest association.

Sex as a moderator of the sleep and cognition relationship in middle-aged and older adults: A preliminary investigation

OBJECTIVES

Despite known sex differences in the prevalence of sleep disturbance and cognitive impairment, research investigating sex differences in sleep/cognition associations is limited. We examined sex as a moderator of associations between self-reported sleep and objective cognition in middle-aged/older adults.

METHODS

Adults aged 50+ (32 men/31 women, Mage = 63.6 ± 7.7) completed the Pittsburgh Sleep Quality Index (PSQI) and cognitive tasks: Stroop (processing speed, inhibition), Posner (spatial attentional orienting) and Sternberg (working memory). Multiple regressions examined whether PSQI metrics (global score, sleep quality ratings, sleep duration, sleep efficiency) were independently or interactively (with sex) associated with cognition, controlling for age and education.

RESULTS

Sex interacted with sleep quality ratings in its association with endogenous spatial attentional orienting (∆R2 = .10, p = .01). Worse ratings of sleep quality were associated with worse orienting in women (B = 22.73, SE = 9.53, p = .02), not men (p = .24). Sex interacted with sleep efficiency in its associations with processing speed (∆R2 = .06, p = .04). Lower sleep efficiency was associated with slower Stroop control trial performance in women (B = -15.91, SE = 7.57, p = .04), not men (p = .48).

CONCLUSIONS

Preliminary findings suggest middle-aged/older women are more vulnerable to associations between poor sleep quality and low sleep efficiency on spatial attentional orienting and processing speed, respectively. Future studies in larger samples investigating sex-specific prospective sleep and cognition associations are warranted.

Long-term associations between objective sleep quality and quantity and verbal memory performance in normal cognition and mild cognitive impairment

Introduction

Although the link between sleep and memory function is well established, associations between sleep macrostructure and memory function in normal cognition and Mild Cognitive Impairment remain unclear. We aimed to investigate the longitudinal associations of baseline objectively assessed sleep quality and duration, as well as time in bed, with verbal memory capacity over a 7-9 year period. Participants are a well-characterized subsample of 148 persons (mean age at baseline: 72.8 ± 6.7 years) from the Cretan Aging Cohort. Based on comprehensive neuropsychiatric and neuropsychological evaluation at baseline, participants were diagnosed with Mild Cognitive Impairment (MCI; n = 79) or found to be cognitively unimpaired (CNI; n = 69). Sleep quality/quantity was estimated from a 3-day consecutive actigraphy recording, whereas verbal memory capacity was examined using the Rey Auditory Verbal Learning Test (RAVLT) and the Greek Passage Memory Test at baseline and follow-up. Panel models were applied to the data using AMOS including several sociodemographic and clinical covariates.

Results

Sleep efficiency at baseline directly predicted subsequent memory performance in the total group (immediate passage recall: β = 0.266, p = 0.001; immediate word list recall: β = 0.172, p = 0.01; delayed passage retrieval: β = 0.214, p = 0.002) with the effects in Passage Memory reaching significance in both clinical groups. Wake after sleep onset time directly predicted follow-up immediate passage recall in the total sample (β = -0.211, p = 0.001) and in the MCI group (β = -0.235, p = 0.02). In the total sample, longer 24-h sleep duration was associated with reduced memory performance indirectly through increased sleep duration at follow-up (immediate passage recall: β = -0.045, p = 0.01; passage retention index: β = -0.051, p = 0.01; RAVLT-delayed recall: β = -0.048, p = 0.009; RAVLT-retention index:β = -0.066, p = 0.004). Similar indirect effects were found for baseline 24-h time in bed. Indirect effects of sleep duration/time in bed were found predominantly in the MCI group.

Discussion

Findings corroborate and expand previous work suggesting that poor sleep quality and long sleep duration predict worse memory function in elderly. Timely interventions to improve sleep could help prevent or delay age-related memory decline among non-demented elderly.

Earlier chronotype in midlife as a predictor of accelerated brain aging: a population-based longitudinal cohort study

STUDY OBJECTIVES

Evidence suggests that sleep-wake cycle disruption could be an early manifestation of neurodegeneration and might even be a risk factor for developing diseases in healthy adults. We investigated the impact of circadian phase change on structural and functional brain deterioration in a late-adulthood population.

METHODS

We analyzed the data of 1874 participants (mean age 58.6 ± 6.3 years, 50.3% female) from the Korean Genome and Epidemiology Study, who were identified as cognitively unimpaired. The mid-sleep time on free days corrected for sleep debt on workdays (MSFsc) at baseline was adopted as an indicator of the chronotype and used to categorize the participants into three groups. The relationships between the chronotype and longitudinal changes in the gray matter volume (GMV) and cognitive function were investigated (mean interval: 4.2 ± 0.5 years).

RESULTS

The mean MSFsc of the participants was 2:45 am. The earlier MSFsc was linearly associated with smaller right entorhinal GMV (β [SE] = 0.02 [0.01]; p = .001) and lower visual memory function test scores at baseline. Longitudinally, the earlier MSFsc at baseline was only significantly associated with more rapid atrophy in the temporal lobe (β [SE] = 0.18 [0.07]; p = .018) and not with other brain lobes or subregions. Moreover, the earlier MSFsc was associated with more deteriorated verbal learning and visual memory function test scores.

CONCLUSIONS

An earlier chronotype in midlife, measured using a questionnaire, can be a valuable indicator for individuals who should be closely monitored for the development of neurodegenerative disorders.

Computer-Based Cognitive Training vs. Paper-and-Pencil Training for Language and Cognitive Deficits in Greek Patients with Mild Alzheimer's Disease: A Preliminary Study

The purpose of the present study was to explore whether Computer-Based Cognitive Training (C-BCT) versus Paper-Pencil Cognitive Training (P-PCT) is more beneficial in improving cognitive and language deficits in Greek patients living with Alzheimer's disease (pwAD). Twenty pwAD were assigned to two groups: (a) the C-BCT group, receiving a computer-based cognitive training program using the RehaCom software, and (b) the P-PCT group, which received cognitive training using paper and pencil. The cognitive training programs lasted 15 weeks and were administered twice a week for approximately one hour per session. The analyses of each group's baseline versus endpoint performance demonstrated that the P-PCT group improved on delayed memory, verbal fluency, attention, processing speed, executive function, general cognitive ability, and activities of daily living. In contrast, the C-BCT group improved on memory (delayed and working), naming, and processing speed. Comparisons between the two groups (C-BCT vs. P-PCT) revealed that both methods had significant effects on patients' cognition, with the P-PCT method transferring the primary cognitive benefits to real-life activities. Our findings indicate that both methods are beneficial in attenuating cognitive and language deficits in pwAD. The need for large-scale neurobehavioral interventions to further clarify this issue, however, remains a priority.

Mediation Effect of the Coping Strategies on the Relation Between Stress and Sleep Quality

OBJECTIVE

Recently data has been accumulated regarding the role of coping strategies in the relationship between stress and sleep quality. Therefore, we set out to identify the mediating effects of coping strategies between stress and sleep quality.

METHODS

A online-based cross-sectional study was performed using the Perceived Stress Scale-10, the Pittsburgh Sleep Quality Index, and a simplification of the 60-item Coping Orientation to Problems Experienced (Brief COPE) inventory in the nonclinical adult sample. The 24 items of Brief COPE were categorized into four factors (social support, problem solving, avoidance, positive thinking). Then, we used the PROCESS macro to conduct the multiple mediation analysis for the four coping styles as potential mediators in the relationship between stress and sleep quality, and an additional subgroup analysis was examined to identify a gender difference for the mediation effect.

RESULTS

As a group, four coping styles mediated significantly the association between perceived stress and poor sleep quality. And avoidance has maintained its significance thought all regression analyses. Finally, this results remained as same in the females.

CONCLUSION

The effect of perceived stress on poor sleep quality was mediated by coping strategies, especially by avoidance. Thus, further research should consider the coping styles of individuals to reduce the influence of stress on sleep quality.

Vascular burden and genetic risk in association with cognitive performance and dementia in a population-based study

BACKGROUND AND PURPOSE

Vascular risk factors may influence cognitive function and thus represent possible targets for preventive approaches against dementia. Yet it remains unknown, if they associate with cognition independently of the individual genetic risk for dementia.

METHODS

In a population-based study of 1172 community-dwelling individuals aged ≥65 years in Greece, we constructed a vascular burden score (VBS; based on presence of hypertension, diabetes, hyperlipidemia, heart disease, and cerebrovascular disease, range 0-5) and a polygenic risk score (PRS) for clinically-diagnosed Alzheimer's disease (AD) based on 23 genetic variants. We then explored in joint models the associations of the PRS for AD and VBS with global cognitive performance, cognitive performance across multiple cognitive domains, and odds of dementia.

RESULTS

The mean age of study participants was 73.9 ± 5.2 years (57.1% females). Both the PRS for AD and VBS were associated with worse global cognitive performance (beta per-SD-increment in PRS: -0.06, 95%CI: -0.10 to -0.02, beta per-point-increment in VBS: -0.05, 95%CI: -0.09 to -0.02), worse performance across individual cognitive domains (memory, executive function, attention, language, visuospatial ability), and higher odds of dementia (OR per-SD increment in PRS: 1.56, 95%CI: 1.17-2.09, OR per-point increment in VBS: 1.38, 95%CI: 1.05-1.81). There was no evidence of an interaction between the two scores. Higher VBS was associated with worse cognitive performance equally across tertiles of the PRS for AD, even among individuals at the highest tertile.

CONCLUSIONS

Both genetic risk and vascular burden are independently and additively associated with worse cognitive performance and higher odds of dementia.

Dietary Inflammatory Index score and prodromal Parkinson's disease incidence: The HELIAD study

AIM

The aim of the present study was to investigate the association of the inflammatory potential of diet with prodromal Parkinson's disease (pPD) probability and incidence among community-dwelling older individuals without clinical features of parkinsonism at baseline.

METHODS

The sample consisted of 1,030 participants 65 years old or older, drawn from a population-based cohort study of older adults in Greece (Hellenic Longitudinal Investigation of Aging and Diet - HELIAD). We calculated pPD probability, according to International Parkinson and Movement Disorder Society research criteria. Dietary Inflammatory Index (DII) was used to measure the dietary inflammatory potential, with higher index score reflecting a more pro-inflammatory diet. Associations of baseline DII with pPD probability cross-sectionally, and with possible/probable pPD incidence (pPD probability ≥30%) during the follow-up period, were examined via general linear models and generalized estimating equations, respectively.

RESULTS

Cross-sectionally, one unit increase of DII score[DII (min, max) = -5.83, 6.01]was associated with 4.9% increased pPD probability [β=0.049, 95%CI (0.025-0.090), p<0.001]. Prospectively, 62 participants developed pPD during 3.1±0.9 (mean±SD) years of follow-up. One unit increase in DII was associated with 20.3% increased risk for developing pPD [RR=1.203, 95%CI (1.070-1.351), p=0.002]. Participants in the highest tertile of DII score were 2.6 times more likely to develop pPD [β=2.594, 95%CI (1.332-5.050), p=0.005], compared to those in the lowest tertile.

CONCLUSION

More pro-inflammatory diet was related with higher pPD probability and pPD incidence (pPD probability ≥30%) in a community-dwelling older adult population. Further studies are needed to confirm these findings.

The "Neural Shift" of Sleep Quality and Cognitive Aging: A Resting-State MEG Study of Transient Neural Dynamics

Sleep quality changes dramatically from young to old age, but its effects on brain dynamics and cognitive functions are not yet fully understood. We tested the hypothesis that a shift in brain networks dynamics relates to sleep quality and cognitive performance across the lifespan. Network dynamics were assessed using Hidden Markov Models (HMMs) in resting-state MEG data from a large cohort of population-based adults (N = 564, aged 18-88). Using multivariate analyses of brain-sleep profiles and brain-cognition profiles, we found an age-related "neural shift," expressed as decreased occurrence of "lower-order" brain networks coupled with increased occurrence of "higher-order" networks. This "neural shift" was associated with both increased sleep dysfunction and decreased fluid intelligence, and this relationship was not explained by age, sex or other covariates. These results establish the link between poor sleep quality, as evident in aging, and a behavior-related shift in neural dynamics.

Association of the Polygenic Risk Score With the Probability of Prodromal Parkinson's Disease in Older Adults

Several studies have investigated the association of the Parkinson’s disease (PD) polygenic risk score (PRS) with several aspects of well-established PD. We sought to evaluate the association of PRS with the prodromal stage of PD. We calculated PRS in a longitudinal sample (n = 1120) of community dwelling individuals ≥ 65 years from the HELIAD (The Hellenic Longitudinal Investigation of Aging and Diet) study in order to evaluate the association of this score with the probability of prodromal PD or any of the established risk and prodromal markers in MDS research criteria, using regression multi-adjusted models. Increases in PRS estimated from GWAS summary statistics’ ninety top SNPS with p < 5 × 10^–8 was associated with increased odds of having probable/possible prodromal PD (i.e., ≥ 30% probability, OR = 1.033, 95%CI: 1.009–1.057 p = 0.006). From the prodromal PD risk markers, significant association was found between PRS and global cognitive deficit exclusively (p = 0.003). To our knowledge, our study is the first population based study investigating the association between PRS scores and prodromal markers of Parkinson’s disease. Our results suggest a strong relationship between the accumulation of many common genetic variants, as measured by PRS, and cognitive deficits.

Sleep Polygenic Risk Score Is Associated with Cognitive Changes over Time

Sleep problems have been associated with cognition, both cross-sectionally and longitudinally. Specific genes have been also associated with both sleep regulation and cognition. In a large group of older non-demented adults, we aimed to (a) validate the association between Sleep Polygenic Risk Score (Sleep PRS) and self-reported sleep duration, and (b) examine the association between Sleep PRS and cognitive changes in a three-year follow-up. Participants were drawn from the Hellenic Longitudinal Investigation of Aging and Diet (HELIAD). A structured, in-person interview, consisting of a medical history report and physical examination, was conducted for each participant during each of the visits (baseline and first follow-up). In total, 1376 participants were included, having all demographic, genetic, and cognitive data, out of which, 688 had at least one follow-up visit. In addition, an extensive neuropsychological assessment examining five cognitive domains (memory, visuo-spatial ability, attention/speed of processing, executive function, and language) was administered. A PRS for sleep duration was created based on previously published, genome-wide association study meta-analysis results. In order to assess the relationship between the Sleep PRS and the rate of cognitive change, we used generalized estimating equations analyses. Age, sex, education, ApolipoproteinE-ε4 genotype status, and specific principal components were used as covariates. On a further analysis, sleep medication was used as a further covariate. Results validated the association between Sleep PRS and self-reported sleep duration (B = 1.173, E-6, p = 0.001). Further, in the longitudinal analyses, significant associations were indicated between increased Sleep PRS and decreased visuo-spatial ability trajectories, in both the unadjusted (B = -1305.220, p = 0.018) and the adjusted for the covariates model (B = -1273.59, p = 0.031). Similarly, after adding sleep medication as a covariate (B = -1372.46, p = 0.019), none of the associations between Sleep PRS and the remaining cognitive domains were significant. PRS indicating longer sleep duration was associated with differential rates of cognitive decline over time in a group of non-demented older adults. Common genetic variants may influence the association between sleep duration and healthy aging/cognitive health.

Gender-specified mediation of depression between sleep quality and short-term memory in older adults: Study in a semi-closed Island of Xiamen, China

BACKGROUND

Both the quality of sleep and depression impact short-term memory (STM) while they influence each other. However, the underlying mechanisms are not yet clear. Herein, we aimed to explore the mediating effect of depression between sleep quality and STM in older adults and further test the gender differences in this relationship.

METHODS

A cluster sampling survey was carried out among 903 residents that were aged 60+ years in a semi-closed island of Xiamen, China, in 2019. The subjects' sleep quality and depression were measured using the Pittsburgh Sleep Quality Index (PSQI) and the 15-item Geriatric Depression Scale (GDS-15), respectively. The three-item recall test was utilized to measure STM function. Mediation analyses were performed using the structural equation model and bias-corrected bootstrap method. Next, the Wald-test was utilized to determine gender differences in the pathway.

RESULTS

Overall, 355 men and 508 women, with a mean age of 69.55 and 70.97, respectively, had valid data on the main variables. Depression was found to mediate the effect of sleep quality on STM (a*b = -0.076, p < 0.05). Interestingly, while this indirect effect existed in the female group (a_f *b_f  = -0.126, p < 0.05), it did not in the male group (a_m *b_m  = 0.017, p = 0.677). The Wald-test indicated no gender differences in the pathway from sleep quality to depression (p = 0.303). However, the pathway from depression to STM function was found to be significantly stronger for females than males (p = 0.0198).

CONCLUSION

Higher sleep quality was found to be associated with improved STM function. Furthermore, the association was found to be regulate indirectly by lower depressive symptoms for females, but directly for males. Therefore, appropriate psychological interventions may be beneficial to the maintenance of STM for older adults, particularly for women.

Sex, Sleep Duration, and the Association of Cognition: Findings from the China Health and Retirement Longitudinal Study

BACKGROUND

We aimed to examine the association between sleep duration and cognitive impairment among elderly Chinese people.

METHODS

generalized linear modeling was used to analyze the baseline data for adults aged 65 years and over (n = 4785) selected from the 2011 China Health and Retirement Longitudinal Study (CHARLS). The two aspects of cognitive impairment assessed in the study were mental status and memory. Sex-stratified logistic regression models were conducted to identify the effect of sleep duration in the different gender groups.

RESULTS

of all the participants, 49.8% were females and 32.5% aged 75 years and over. Of the participants, 59.7% had short sleep duration (<7 h/day), and 9.0% of them had long sleep duration (>8 h/day). Compared to normal sleep duration, long sleep duration was associated with lower mental status scores (β = -0.43, p = 0.001) and lower memory scores (β = -0.26, p = 0.006). Long sleep duration was associated with lower mental status in both men (β = -0.37, p = 0.033) and women (β = -0.46, p = 0.025), however, only in men was long sleep duration found to be associated with low memory scores (β = -0.26, p = 0.047).

CONCLUSIONS

Our study showed that long sleep duration was significantly associated with poorer mental status and memory scores in elderly Chinese people. Paying greater attention to the effects of sleep patterns on the risk of cognitive decline may yield practical implications for dementia prevention and health promotion, especially among older women with lower educational attainment, living in rural areas, and those who have long sleep duration.

Differences in Subjective Memory Impairment, Depressive Symptoms, Sleep, and Physical Activity in African American and Asian American Elderly

Background: Subjective memory impairment (SMI) is associated with negative health outcomes including mild cognitive impairment and Alzheimer's disease. However, ethnic differences in SMI and disparities in risk factors associated with SMI among minority populations are understudied. The study examined the ethnic differences in SMI, whether SMI was associated with depressive symptoms, sleep, and physical activity (PA), and whether the associations vary across racial/ethnic groups. Methods: Participants included 243 African and Asian Americans (including Chinese, Vietnamese, and Korean Americans) aged 50 or older. Demographic information, SMI, depressive symptoms, daily sleeping hours, and PA levels were assessed. Results: Vietnamese Americans reported the highest SMI score. Depressive symptoms, sleeping hours, and PA levels were significantly associated with SMI. Depressive symptoms were the only significant factor across all ethnic groups. Significant interaction effects were found between ethnicity and health behaviors in predicting SMI. In particular, Vietnamese American participants with greater depressive symptoms and physical inactivity were significantly more likely to experience SMI compared to other ethnic groups Conclusions: Our findings demonstrate ethnic differences in SMI and its association with depressive symptoms, sleep, and PA, which highlight the importance of considering the unique cultural and historical backgrounds across different racial/ethnic groups when examining cognitive functioning in elderly.

Sleep quality, neurocognitive performance, and memory self-appraisal in middle-aged and older adults with memory complaints

OBJECTIVE

Because of inconsistent findings regarding the relationship between sleep quality and cognitive function in people with age-related memory complaints, we examined how self-reports of sleep quality were related to multiple domains of both objective and subjective cognitive function in middle-aged and older adults.

DESIGN

A cross-sectional study involving analysis of baseline data, collected as part of a clinical trial.

MEASUREMENTS

Two hundred and three participants (mean age = 60.4 [6.5] years, 69.0% female) with mild memory complaints were asked to rate their sleep quality using the Pittsburgh Sleep Quality Index (PSQI) and their memory performance using the Memory Functioning Questionnaire (MFQ), which measures self-awareness of memory ability. Neurocognitive performance was evaluated using the Continuous Performance Test (CPT), Trail Making Test, Buschke Selective Reminding Test, and the Brief Visuospatial Test - Revised (BVMT-R).

RESULTS

Total PSQI scores were significantly associated with objective measures of sustained attention (CPT hit reaction time by block and standard error by block) and subjective memory loss (MFQ frequency and seriousness of forgetting). The PSQI components of (poorer) sleep quality and (greater) sleep disturbance were related to (worse) sustained attention scores while increased sleep latency and daytime sleepiness were associated with greater frequency and seriousness of forgetting.

CONCLUSIONS

Sleep quality is related to both objective measures of sustained attention and self-awareness of memory decline. These findings suggest that interventions for improving sleep quality may contribute not only to improving the ability to focus on a particular task but also in reducing memory complaints in middle-aged and older adults.

Association between sleep quality and subjective cognitive decline: evidence from a community health survey

OBJECTIVES

Little is known concerning whether subjective cognitive decline (SCD) is associated with sleep quality. This study aimed to identify the association between self-reported quality of sleep and SCD in a large population of middle-aged and older adults in Korea.

METHODS

We conducted this study based on data collected from the 2018 Korean Community Health Survey. Individuals aged 40 years and older who responded to the Behavioral Risk Factor Surveillance System (BRFSS) and Pittsburgh Sleep Quality Index (PSQI) assessments and did not lack data about multiple covariates were included. A total of 37,712 respondents with SCD and 135,119 those without SCD were included. Sleep quality was estimated using the PSQI, which includes seven self-reported components for sleep health assessment. SCD was assessed using the BRFSS. Logistic regression models adjusted for confounders were used to examine whether each component of the sleep quality index was related to SCD. Additional analysis of the correlation between quantified scores for each component and SCD-related functional limitations as ordinal variables was performed.

RESULTS

The mean age was 62.7 years in the SCD group and 56.4 years in the control group. In total, 13,777 (28.9%) respondents were male in the SCD group and 62,439 (50.7%) in the control group. The adjusted odds ratios of SCD were 1.25 for very bad sleep quality, 1.26 for long sleep latency, 1.16 for <5 h of sleep duration, 1.08 for <65% habitual sleep efficiency, 2.29 for high sleep disturbance, 1.26 for use of sleep medication ≥3 times a week, and 2.47 for high daytime dysfunction due to sleep problems compared to good sleep conditions. Furthermore, a higher score for each component of the sleep quality index correlated with greater SCD-related functional limitations.

CONCLUSIONS

Our study provides evidence that poor sleep quality is closely related to both SCD and SCD-related functional limitations.

The Relationships between Sleep and Mental and Physical Health of Chinese Elderly: Exploring the Mediating Roles of Diet and Physical Activity

Sleep quality, diet quality, and physical activity are significant factors influencing physical and mental health. However, few studies have explored their underlying mechanisms, especially among the elderly population in East Asia, where people have food culture and lifestyles distinct from those living in Western countries. Therefore, the current study aimed to explore the relationships among sleep quality, diet quality, physical activity, and physical and mental health in a Chinese elderly sample. Sleep quality, diet quality, physical activity, physical health, and mental health were investigated among 313 Chinese elderly (aged 51-92 years, M = 67.90, SD = 7.94). Mediation analysis was used to examine the empirical model based on previous theories and literature. Close positive relationships were observed between all factors investigated (r = 0.22~0.73, p < 0.001). The relationships between sleep quality and physical and mental health were partially mediated by diet quality and physical activity. In clinical interventions, sleep quality, diet quality, and physical activity can be targeted to improve physical and mental health among the older adult populations.

Association between sleep disturbance with motoric cognitive risk syndrome in Chinese older adults

BACKGROUND AND PURPOSE

Sleep disturbance and cognitive impairment are common and related in the elderly population worldwide. The aim of the present study was to explore the association between sleep disturbance and motoric cognitive risk (MCR) syndrome, which is characterized by subjective cognitive complaints and objective slow gait in older individuals without dementia or any mobility disability in the community-dwelling elderly Chinese population.

METHODS

We recruited 940 participants aged ≥65 years from November 2016 to March 2017 in the Ningbo Community Study on Aging (NCSA). Self-reported sleep duration and sleep-quality variables, comprehensive geriatric evaluation, as well as indicators for diagnosing MCR syndrome were evaluated in this cross-sectional study.

RESULTS

Multiple logistic regression analysis showed that a 1-SD increase in night (1.1 h) and 24-h sleep duration (1.3 h) was associated, respectively, with a 21% (95% confidence interval [CI], 1%-47%; p = 0.04) and 30% (95% CI, 3%-64%; p = 0.03) higher odds of having MCR syndrome. Considering sleep duration as a categorical variable, longer night-sleep duration (>8.5 h) was associated with MCR syndrome (OR, 2.03; p = 0.02) compared to shorter night-sleep duration (<8 h). For sleep-quality factors, increasing frequency of trouble falling asleep, waking early or easily, nightmares, and taking sleep drugs were significantly associated with MCR syndrome after adjusting for potential covariables (all p for trend < 0.05), but not for self-perceived sleep quality (p for trend = 0.10).

CONCLUSIONS

Long sleep duration, poor sleep quality, and taking sleep drugs were associated with higher odds of having MCR syndrome in the community-dwelling elderly Chinese population. Further research is needed to explore the underlying mechanisms.

Plasma GSH levels and Alzheimer's disease. A prospective approach.: Results from the HELIAD study

BACKGROUND

Potential links between oxidative stress and the pathophysiology of Alzheimer's disease (AD) have been reported in the existing literature. Biological markers of oxidative stress, such as the reduced form of glutathione (GSH), may have a potential role as predictive biomarkers for AD development. The aim of the present study was to explore the longitudinal associations between plasma GSH and the risk of developing AD or cognitive decline, in a sample of community-dwelling, non-demented older adults.

METHODS

Participants from the Hellenic Longitudinal Investigation of Aging and Diet (HELIAD) were included in the present prospective study. The sample used in the analyses consisted of 391 non-demented individuals over the age of 64 (mean age = 73.85 years; SD = 5.06), with available baseline GSH measurements and longitudinal follow-up. Plasma GSH was treated both as a continuous variable and as tertiles in our analyses. Cox proportional hazards models were used to evaluate the hazard ratio (HR) for AD incidence as a function of baseline plasma GSH. Generalized estimating equations (GEE) models were deployed to explore the associations between baseline plasma GSH and the rate of change of performance scores on individual cognitive domains over time. Models were adjusted for age, years of education and sex. Supplementary exploratory models were also adjusted for mild cognitive impairment (MCI) at baseline, risk for malnutrition, physical activity and adherence to the Mediterranean dietary pattern.

RESULTS

A total of 24 incident AD cases occurred during a mean (SD) of 2.99 (0.92) years of follow-up. Individuals in the highest GSH tertile group (highest baseline plasma GSH values) had a 70.1% lower risk for development of AD, compared to those in the lowest one [HR = 0.299 (0.093-0.959); p = 0.042], and also demonstrated a slower rate of decline of their executive functioning over time (5.2% of a standard deviation less decline in the executive composite score for each additional year of follow-up; p = 0.028). The test for trend was also significant suggesting a potential dose-response relationship.

CONCLUSION

In the present study, higher baseline plasma GSH levels were associated with a decreased risk of developing AD and with a better preservation of executive functioning longitudinally.

Local Sleep and Alzheimer's Disease Pathophysiology

Even prior to the onset of the prodromal stages of Alzheimer's disease (AD), a constellation of sleep disturbances are apparent. A series of epidemiological studies indicate that multiple forms of these sleep disturbances are associated with increased risk for developing mild cognitive impairment (MCI) and AD, even triggering disease onset at an earlier age. Through the combination of causal manipulation studies in humans and rodents, as well as targeted examination of sleep disturbance with respect to AD biomarkers, mechanisms linking sleep disturbance to AD are beginning to emerge. In this review, we explore recent evidence linking local deficits in brain oscillatory function during sleep with local AD pathological burden and circuit-level dysfunction and degeneration. In short, three deficits in the local expression of sleep oscillations have been identified in relation to AD pathophysiology: (1) frequency-specific frontal deficits in slow wave expression during non-rapid eye movement (NREM) sleep, (2) deficits in parietal sleep spindle expression, and (3) deficits in the quality of electroencephalographic (EEG) desynchrony characteristic of REM sleep. These deficits are noteworthy since they differ from that seen in normal aging, indicating the potential presence of an abnormal aging process. How each of these are associated with β-amyloid (Aβ) and tau pathology, as well as neurodegeneration of circuits sensitive to AD pathophysiology, are examined in the present review, with a focus on the role of dysfunction within fronto-hippocampal and subcortical sleep-wake circuits. It is hypothesized that each of these local sleep deficits arise from distinct network-specific dysfunctions driven by regionally-specific accumulation of AD pathologies, as well as their associated neurodegeneration. Overall, the evolution of these local sleep deficits offer unique windows into the circuit-specific progression of distinct AD pathophysiological processes prior to AD onset, as well as their impact on brain function. This includes the potential erosion of sleep-dependent memory mechanisms, which may contribute to memory decline in AD. This review closes with a discussion of the remaining critical knowledge gaps and implications of this work for future mechanistic studies and studies implementing sleep-based treatment interventions.

Association Between Sleep Duration and Cognitive Decline

Importance

An association between sleep duration and the trajectory of cognitive decline has not been conclusively demonstrated.

Objective

To investigate the association between sleep duration and cognitive decline by a pooled analysis of 2 nationally representative aging cohorts.

Design, Setting, and Participants

A pooled cohort study using data from waves 4 to 8 (2008-2009 to 2016-2017) in the English Longitudinal Study of Ageing and waves 1 to 3 (2011 to 2015) in the China Health and Retirement Longitudinal Study in a population-based setting. Participants were 2 randomly enrolled cohorts comprising 28 756 individuals living in England who were 50 years or older and those living in China who were 45 years or older.

Exposure

Self-reported sleep duration per night according to face-to-face interviews.

Main Outcomes and Measures

Global cognitive z scores were calculated according to immediate and delayed recall test, an animal fluency test, the serial sevens test, an intersecting pentagon copying test, and a date orientation test.

Results

Data were analyzed from 20 065 participants, including 9254 from the English Longitudinal Study of Ageing (mean [SD] age, 64.6 [9.8] years; 55.9% [5174 of 9254] women; median follow-up duration, 8 [interquartile range, 6-8] years) and 10 811 from the China Health and Retirement Longitudinal Study (mean [SD] age, 57.8 [9.0] years; 50.2% [5425 of 10 811] men; median follow-up duration, 4 [interquartile range, 4-4] years). During 100 000 person-years of follow-up, global cognitive z scores in individuals with 4 hours or less (pooled β = -0.022; 95% CI, -0.035 to -0.009 SD per year; P = .001) and 10 hours or more (pooled β = -0.033; 95% CI, -0.054 to -0.011 SD per year; P = .003) of sleep per night declined faster than in the reference group (7 hours per night) after adjusting for a number of covariates. An inverted U-shaped association between sleep duration and global cognitive decline was also observed.

Conclusions and Relevance

In this pooled cohort study, an inverted U-shaped association between sleep duration and global cognitive decline was found, indicating that cognitive function should be monitored in individuals with insufficient (≤4 hours per night) or excessive (≥10 hours per night) sleep duration. Future studies are needed to examine the mechanisms of the association between sleep duration and cognitive decline.

Assessing functional status using the IADL-extended scale: results from the HELIAD study

OBJECTIVES

Instrumental activities of daily living (IADL) have been operationalized as exhibiting a greater level of complexity than basic ADL. In the same way, incorporating more advanced ADLs may increase the sensitivity of functional measures to identify cognitive changes that may precede IADL impairment. Towards this direction, the IADL-extended scale (IADL-x) consists of four IADL tasks and five advanced ADLs (leisure time activities).

DESIGN

Retrospective, cross-sectional study.

SETTING

Athens and Larissa, Greece.

PARTICIPANTS

1,864 community-dwelling men and women aged over 64.

MEASUREMENTS

We employed both the IADL-x and IADL scales to assess functional status among all the participants. Diagnoses were assigned dividing the population of our study into three groups: cognitively normal (CN), mild cognitive impairment (MCI) and dementia patients. Neuropsychological evaluation was stratified in five cognitive domains: memory, language, attention-speed, executive functioning and visuospatial perception. Z scores for each cognitive domain as well as a composite z score were constructed. Models were controlled for age, sex, education and depression.

RESULTS

In both IADL-x and IADL scales dementia patients reported the most functional difficulties and CN participants the fewest, with MCI placed in between. When we restricted the analyses to the CN population, lower IADL-x score was associated with worse cognitive performance. This association was not observed when using the original IADL scale.

CONCLUSION

There is strong evidence that the endorsement of more advanced IADLs in functional scales may be useful in detecting cognitive differences within the normal spectrum.

Sleep and the aging brain. A multifaceted approach

In the current review we provide a theoretical background on studies examining the association between sleep and brain function. We focus on the association between sleep and cognitive performance, cognitive changes over time and incident dementia as well. We then present some data on the link between sleep and subjective cognitive complaints, in participants without any objective clinical cognitive decline. We conclude with investigating the association between sleep and brain biomarkers, by highlighting the importance of specific genes and specific brain regions' morphometry. The role of sleep is vital in maintaining a healthy aging brain, and multiple factors should be taken under account when investigating this association.

Construction and validation of a sleep hygiene booklet for the elderly

OBJECTIVE

to construct and validate an educational booklet for the elderly, with guidelines on sleep hygiene.

METHOD

a methodological research with booklet construction; validation by 22 judges and evaluation by 22 elderly people. The content was extracted from the guidelines of the Brazilian Sleep Association and the elderly health manual of the Human Rights Office. The item with Content Validity Index (CVI) greater than 0.8 or whose concordance ratio verified with the Binomial Test was valid and statistically equal to or greater than 80%.

RESULTS

the booklet presented 14 guidelines for the elderly about sleep hygiene distributed over 25 pages. All items were evaluated as relevant. The CVI had an average of 0.95 by the judges and 0.95 by the elderly.

CONCLUSION

the booklet was constructed and validated as to its content and appearance. It can be used by health professionals in the various services with the elderly.

Later-life sleep, cognition, and neuroimaging research: an update for 2020

This review summarizes recent studies of sleep and brain health in later life, focusing on cognitive and magnetic resonance imaging (MRI)-derived outcomes. The majority of older people report sleep problems, and over one-third have sleep-disordered breathing (SDB). The research described herein builds on work demonstrating that abnormal sleep duration, sleep fragmentation, and SDB are associated with memory impairment and executive dysfunction. Self-reported short sleep is linked with greater cortical thinning and lower white matter integrity, and objectively measured fragmentation and SDB are tied to gray matter atrophy and altered connectivity. Results suggest that brain changes mediate previously identified sleep-cognition associations. Additional clinical trials are needed to determine whether treating insomnia or SDB benefits cognition in this population.

Pesticide exposure and cognitive function: Results from the Hellenic Longitudinal Investigation of Aging and Diet (HELIAD)

BACKGROUND

Results from studies to date, regarding the role of chronic pesticide exposure on cognitive function remain contradictory.

OBJECTIVE

To investigate the relationship between self-reported pesticide exposure and cognitive function.

METHODS

Data from a population-based cohort study of older adults (HEllenic Longitudinal Investigation of Aging and Diet) in Greece was used. Pesticide exposure classification was based on 1) living in areas that were being sprayed; 2) application of spray insecticides/pesticides in their gardens; and 3) occupational application of sprays. Associations between z-scores of cognitive performance and self-reported pesticide exposure were examined with linear regression analyses. Adjusted models were applied, for all analyses.

RESULTS

Non-demented individuals who reported that they had been living in areas near sprayed fields, had poorer neuropsychological performance, compared to those who had never lived in such areas. Sub-analyses revealed poorer performance in language, executive and visual-spatial functioning, and attention. These associations remained after a sensitivity analysis excluding subjects with mild cognitive impairment.

CONCLUSION

Self-reported exposure to pesticides was negatively associated with cognitive performance.

Dietary Patterns, Physical Activity, Sleep, and Risk for Dementia and Cognitive Decline

PURPOSE OF REVIEW

Diet, physical activity, and sleep are three major modifiable lifestyle factors. This selective review examines the evidence for strong and reliable associations between these three lifestyle factors and risk of dementia and cognitive decline, in an effort to assist clinicians with providing more informed answers to the common questions they face from patients.

RECENT FINDINGS

Certain aspects of nutrition can decrease risk for dementia. Physical activity has also been associated with delayed or slower age-related cognitive decline. In addition, emerging evidence links sleep dysfunction and dementia, with amyloid deposition being a possible mediator. Data from further clinical trials are needed before more definitive conclusions can be drawn regarding the efficacy of these lifestyle interventions for lowering the risk of incident dementia and cognitive decline. Nevertheless, it is reasonable to make recommendations to our patients to adopt certain dietary changes and to engage in regular physical activity to improve cardiovascular risk factors for dementia. It is also reasonable to include questions on sleep during cognitive evaluations of the elderly, given the common co-occurrence of sleep dysfunction and cognitive impairment in the elderly population.

Motor function and the probability of prodromal Parkinson's disease in older adults

BACKGROUND

Identification and characterization of Parkinson's disease (PD) in its prodromal stage is crucial.

OBJECTIVE

The objective of this study was to investigate the association between motor function and the probability of prodromal PD in a community-dwelling older population.

METHODS

We used data from a population-based cohort of older adults (HELIAD study). Subjective motor function was evaluated with a 12-item motor symptoms questionnaire and objective motor function indirectly with a physical activity questionnaire and two gait speed tests. The probability of prodromal PD was calculated according to the Movement Disorder Society research criteria for n = 1731 without PD. Regression multiadjusted models were used to investigate the associations between each motor measure and prodromal PD probability.

RESULTS

For each unit increase in motor symptoms score and for each kcal/kg/day lower energy expenditure (corresponding to 20 minutes of light walking/day for a 75-kg man) there was a 27% and 3% higher probability for prodromal PD, respectively (P < 0.001). Having at least one subjective motor symptom increased the odds of having possible/probable prodromal PD (n = 49; P < 0.05). Including subjective and indirect motor variables in the same model showed that both (symptoms and physical activity) contributed significantly to the model (P < 0.01). Excluding subthreshold parkinsonism from the calculation showed that gait speed less than 0.8 m/s was also associated with a higher prodromal PD probability score (P < 0.001).

CONCLUSIONS

Subjective motor symptoms as well as simple objective motor measures of physical activity or gait speed are associated with a higher probability of prodromal PD in older adults. These data may serve to enable the early identification of prodromal PD cohorts, particularly if they are confirmed in longitudinal studies. © 2019 International Parkinson and Movement Disorder Society.

Visuospatial functioning is associated with sleep disturbance and hallucinations in nondemented patients with Parkinson's disease

Introduction: Cognitive impairment is a common symptom of Parkinson's disease (PD) associated with reduced quality of life and a more severe disease state. Previous research has shown an association between visuospatial dysfunction and worse disease course; however, it is not clear whether this is separable from executive dysfunction and/or dementia. This study sought to determine whether distinct cognitive factors could be measured in a large PD cohort, and if those factors were differentially associated with other PD-related features, specifically to provide insight into visuospatial dysfunction. Methods: Non-demented participants with PD from the Pacific Udall Center were enrolled (n = 197). Co-participants (n = 104) completed questionnaires when available. Principal components factor analysis (PCFA) was utilized to group the neuropsychological test scores into independent factors by considering those with big factor loading (≥.40). Linear and logistic regression analyses were performed to examine the relationship between the cognitive factors identified in the PCFA and other clinical features of PD. Results: Six factors were extracted from the PCFA: 1) executive/processing speed, 2) visual learning & memory/visuospatial, 3) auditory working memory, 4) contextual verbal memory, 5) semantic learning & memory, and 6) visuospatial. Motor severity (p = 0.001), mood (p < 0.001), and performance on activities of daily living scores (informant: p < 0.001, patient: p = 0.009) were primarily associated with frontal and executive factors. General sleep disturbance (p < 0.006) and hallucinations (p = 0.002) were primarily associated with visuospatial functioning and visual learning/memory. Conclusions: Motor symptoms, mood, and performance on activities of daily living were primarily associated with frontal/executive factors. Sleep disturbance and hallucinations were associated with visuospatial functioning and visual learning/memory only, over and above executive functioning and regardless of cognitive disease severity. These findings support that visuospatial function in PD may indicate a more severe disease course, and that symptom management should be guided accordingly.

Prevalence and determinants of subjective cognitive decline in a representative Greek elderly population

OBJECTIVES

We studied the prevalence of subjective cognitive decline (SCD) and its determinants in a sample of 1456 cognitively normal Greek adults ≥65 years old.

METHODS/DESIGN

Subjects were evaluated by a multidisciplinary team on their neurological, medical, neuropsychological, and lifestyle profile to reach consensus diagnoses. We investigated various types of SCD, including single-question, general memory decline, specific subjective memory decline based on a list of questions and three types of subjective naming, orientation, and calculation decline.

RESULTS

In a single general question about memory decline, 28.0% responded positively. The percentage of our sample that reported at least one complaint related to subjective memory decline was 76.6%. Naming difficulties were also fairly common (26.0%), while specific deficits in orientation (5.4%) and calculations/currency handling (2.6%) were rare. The majority (84.2%) of the population reported subjective deficits in at least one cognitive domain. Genetic predisposition to dementia increased the odds for general memory decline by more than 1.7 times. For each one-unit reduction in the neuropsychological composite score (a mean of memory, executive, language, visuospatial, and attention-speed composite scores), the odds for decline in orientation increased by 40.3%. Depression/anxiety and increased cerebrovascular risk were risk factors for almost all SCD types.

CONCLUSIONS

SCD regarding memory is more frequent than non-memory decline in the cognitively normal Greek elderly population. Genetic predisposition to dementia, lower cognitive performance, affective symptoms, and increased cerebrovascular risk are associated with prevalent SCD. Further prospective research is needed to improve understanding of the evolution of SCD over time.

Does poor sleep impair cognition during aging? Longitudinal associations between changes in sleep duration and cognitive performance among older Mexican adults

Alterations in sleep patterns are common among older adults; further, short and long sleep durations have been linked with impaired cognitive performance in older individuals. Yet most research examining these relationships has been cross-sectional, limited to high-income nations, and has failed to consider how changes in sleep duration may impact cognitive decline. The present longitudinal study uses nationally-representative data to test whether changes in sleep length among "healthy" baseline sleepers are associated with reduced cognitive function in older Mexican adults (>50 years old) at follow-up. Data were drawn from the first and second waves of the World Health Organization's Study on global AGEing and adult health. Self-report data captured sleep duration over two nights, and five cognitive tests (immediate and delayed verbal recall, forward and backward digit span, and verbal fluency) were used to measure various cognitive domains and create a composite z-score of cognitive performance. Linear regressions were performed to assess associations between sleep length changes and cognitive decline, controlling for relevant lifestyle and health factors. Increased sleep durations at follow-up among individuals who reported intermediate sleep durations (6-9 h/night) at baseline were significantly associated with greater rates of decline in overall cognitive function. Longer sleepers also trended toward greater rates of decline for attention/working memory and executive function. This study suggests that long sleep durations are a risk factor for certain types of impaired cognition among older adults living in a middle-income country. These findings are clinically important given the growing rates of dementia and aging populations globally.

Higher probability of prodromal Parkinson disease is related to lower cognitive performance

OBJECTIVE

Given the limited information on cognitive function before Parkinson disease (PD) clinical onset in the general population, we sought to assess prodromal PD (pPD) probability and relate it to detailed cognitive performance in a community cohort.

METHODS

In a population-based cohort of 1,629 dementia-free and PD-free participants ≥65 years of age in Greece, we assessed probability of pPD according to the International Parkinson and Movement Disorder Society's criteria. Clinical cognitive diagnoses (cognitively unimpaired, mild cognitive impairment [MCI], dementia) considering neuropsychological testing and functional status were assigned in consensus conferences. Cognitive performance in 5 cognitive domains was assessed by a detailed neuropsychological battery and summarized in the form of z scores. We investigated associations between pPD probability (and its individual constituents) and cognitive outcomes.

RESULTS

The median probability of pPD was 1.81% (0.2%-96.7%). Participants with MCI had higher probability of pPD compared to those with normal cognition (p < 0.001). Higher probability of pPD was related to lower performance in all cognitive domains (memory, language, executive, attention, and visuospatial function) (p < 0.001). Lower cognitive performance was further associated with certain nonmotor markers of pPD, such as daytime somnolence, depression, urinary dysfunction, constipation, and subthreshold parkinsonism (p < 0.001).

CONCLUSIONS

Higher probability of pPD was associated with lower cognitive performance in all domains and higher probability of MCI. This may reflect a widespread pathologic process although future studies are warranted to infer causality. These results suggest to clinicians that they should assess cognition early, and to researchers that they should further look into the possible mechanisms that may underlie this observation.

Mild cognitive impairment: associations with sleep disturbance, apolipoprotein e4, and sleep medications

OBJECTIVE

Mild cognitive impairment (MCI) is associated with increased memory problems although the ability to complete daily life activities remains relatively intact. This study examined: (1) if sleep disturbance increased the hazard of MCI; (2) if APOE e4 carriers with sleep disturbance experience an increased risk of MCI; and, (3) if prescription sleep medications provide a protective effect against MCI. We hypothesized that sleep disturbance increases the hazard of MCI, this relationship is stronger among APOE e4 carriers reporting a sleep disturbance. Furthermore, we hypothesized that sleep medications decrease the hazard of MCI.

METHODS

To determine whether sleep medication mediates the risk of developing MCI for individuals with sleep disturbance and/or APOE e4, we analyzed the National Alzheimer's Coordinating Center Uniform Data Set. We selected participants with normal cognition at baseline (n = 6798), and conduced survival analyses.

RESULTS

Our main findings indicated that the hazard of MCI was significantly associated with sleep disturbance. The hazard remained among those who did not use sleep medication. Trazodone and zolpidem users did not have a significant hazard of MCI, but the significant hazard remained for those who did not use these medications. APOE e4 carriers had a significantly higher hazard of MCI. Among e4 carriers who used trazodone or zolpidem, there was not a statistically significant risk of MCI.

CONCLUSION

This study demonstrated the potential utilization of trazodone and zolpidem in the treatment of sleep disturbance while potentially mitigating the risk of MCI. While trazodone and zolpidem have been shown to positively impact sleep disturbance in individuals with normal cognition, further research should explore these findings given that these medications are potentially inappropriate for older adults.

Mediterranean diet adherence is related to reduced probability of prodromal Parkinson's disease

BACKGROUND

The International Parkinson and Movement Disorder Society recently introduced a methodology for probability score calculation for prodromal PD.

OBJECTIVES

To assess the probability of prodromal PD in an older population and investigate its possible association with Mediterranean diet adherence.

METHODS

Data from a population-based cohort study of older adults (HEllenic Longitudinal Investigation of Aging and Diet) in Greece were used. Probability of prodromal PD was calculated according to International Parkinson and Movement Disorder Society research criteria. A detailed food frequency questionnaire was used to evaluate dietary intake and calculate Mediterranean diet adherence score, ranging from 0 to 55, with higher scores indicating higher adherence.

RESULTS

Median probability of prodromal PD was 1.9%, ranging from 0.2 to 96.7% in 1,731 PD-free individuals aged ≥ 65 (41% male). Lower probability for prodromal PD (P < 0.001) in the higher Mediterranean diet adherence groups was noted, driven mostly by nonmotor markers of prodromal PD, depression, constipation, urinary dysfunction, and daytime somnolence. Each unit increase in Mediterranean diet score was associated with a 2% decreased probability for prodromal PD (P < 0.001). Compared to participants in the lowest quartile of Mediterranean diet adherence, those in the highest quartile were associated with a ∼21% lower probability for prodromal PD.

CONCLUSIONS

Adherence to the Mediterranean diet is associated with lower probability of prodromal PD in older people. Further studies are needed to elucidate the potential causality of this association, potential relation of the Mediterranean diet to delayed onset or lower incidence of PD, as well as the underlying neurobiological mechanisms. © 2018 International Parkinson and Movement Disorder Society.

Sleep and subjective cognitive decline in cognitively healthy elderly: Results from two cohorts

Subjective cognitive decline may reflect a dementia prodrome or modifiable risk factor such as sleep disturbance. What is the association between sleep and subjective cognitive decline? Cross-sectional design, from two studies of older adults: the WHICAP in the USA and the HELIAD in Greece. A total of 1,576 WHICAP and 1,456 HELIAD participants, without mild cognitive impairment, dementia or severe depression/anxiety, were included. Participants were mostly women, with 12 (WHICAP) and 8 (HELIAD) mean years of education. Sleep problems were estimated using the Sleep Scale from the Medical Outcomes Study. Subjective cognitive decline was assessed using a structured complaint questionnaire that queries for subjective memory and other cognitive symptoms. Multinomial or logistic regression models were used to examine whether sleep problems were associated with complaints about general cognition, memory, naming, orientation and calculations. Age, sex, education, sleep medication, use of medications affecting cognition, co-morbidities, depression and anxiety were used as co-variates. Objective cognition was also estimated by summarizing neuropsychological performance into composite z-scores. Sleep problems were associated with two or more complaints: WHICAP: β = 1.93 (95% confidence interval: 1.59-2.34), p ≤ .0001; HELIAD: β = 1.48 (95% confidence interval: 1.20-1.83), p ≤ .0001. Sleep problems were associated with complaints in all the cognitive subcategories, except orientation for the WHICAP. The associations were noted regardless of objective cognition. At any given level of objective cognition, sleep disturbance is accompanied by subjective cognitive impairment. The replicability in two ethnically, genetically and culturally different cohorts adds validity to our results. The results have implications for the correlates, and potential aetiology of subjective cognitive decline, which should be considered in the assessment and treatment of older adults with cognitive complaints.

Dataset on the associations between sleep quality/duration and cognitive performance in cognitively healthy older adults

In the present data, we provide the details of the cross-sectional study examining the associations between sleep quality/sleep duration and cognitive performance. Data are from the Hellenic Longitudinal Investigation of Aging and Diet (HELIAD). A total of 1484 older adults (65 y.o. or older) took part in the study. Sleep measurements were drawn from the sleep scale of the Medical Outcomes Study (MOS). Cognition was used as a z-score drawn by different tests. The domains examined were: executive function, visuo-spatial ability, language, attention- speed of processing, as well as the composite z-score of all the cognitive domains (including memory). Linear regression models were conducted to investigate the associations between sleep quality and cognition, and sleep duration and cognition as well. We also conducted linear regression analyses for the associations between sleep quality/duration and cognitive domains/composite cognitive score based on the status of the Apolipoprotein E-ε4 (ApoE-ε4) genotype. Analyses were performed excluding both the demented and the Mild Cognitive Impairment (MCI) participants. Adjustments conducted for multiple covariates. For further analyses and enhanced discussion, see original article: "Sleep quality and duration in relation to memory in the elderly: initial results from the Hellenic Longitudinal Investigation of Aging and Diet" by Tsapanou et al. [1].