Time-Varying Insomnia Symptoms and Incidence of Cognitive Impairment and Dementia among Older US Adults

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.

Factors associated with reduced sleep among spouses and caregivers of older adults with varying levels of cognitive decline

BACKGROUND

Caregivers of persons with cognitive decline (PWCD) are at increased risk of poor sleep quantity and quality. It is unclear whether this is due to factors in the caregiver versus in the PWCD.

METHODS

This secondary data analysis using Aging, Demographics, and Memory Study data from the Health Retirement Study examined factors contributing to reduced sleep/rest among spouses and caregivers of older adults with varying levels of cognitive decline (cognitively normal (CN), cognitive impairment but not dementia (CIND), or dementia).

RESULTS

In our preliminary analysis, among N = 218 spouses (not necessarily caregivers) (mean age (SD) = 73.77 (7.30); 70.64% female) of older adults with varying levels of cognitive decline, regression revealed that frequency of sleep complaints was lowest among spouses with CN partners, second highest with CIND partners, and highest with dementia-partners, X2  = 26.810, P = 0.002.

PRIMARY AIM

among n = 136 caregivers of PWCD (mean age (SD) = 59.27 (13.97); 74.26% female; 22.79% spouses), we analyzed whether caregiver reduced sleep/rest was predicted by PWCD factors (i.e., frequent nighttime waking, dementia severity) and/or caregiver factors (i.e., depression symptoms, caregiver role overload). Regression revealed that caregiver depression symptoms (d = 0.62) and role overload (d = 0.88), but not PWCD factors, were associated with reduced caregiver sleep/rest after adjusting for demographic factors, caregiving frequency, and shared-dwelling status (overall model: X2  = 31.876, P = 0.002). Exploratory analyses revealed that a caregiver was 7.901 times more likely (95% CI: 0.99-63.15) to endorse experiencing reduced sleep/rest if back-up care was not available (P = 0.023).

CONCLUSION

Findings highlight that the frequency of reported sleep problems among spouses increases in a stepwise fashion when partners have dementia versus CIND versus CN. The results also emphasise that caregiver mental health and burden are strongly associated with caregiver sleep disturbances and thus may be targets of intervention for caregiver sleep problems.

Sleep-related predictors of cognition among adults with chronic insomnia and heart failure enrolled in a randomized controlled trial of cognitive behavioral therapy for insomnia

STUDY OBJECTIVES

Cognitive impairment and insomnia are common in chronic heart failure (HF). We examined the effects of cognitive behavioral therapy for insomnia (CBT-I) and the extent to which demographic, clinical, symptom, and functional characteristics predicted cognition among people with chronic HF and insomnia who participated in a randomized controlled trial of CBT-I.

METHODS

Participants with HF were randomized to group-based CBT-I or an attention control (HF self-management education). Outcomes were measured over 1 year. We measured psychomotor vigilance and self-reported cognitive ability (PROMIS Cognitive Abilities Scale), clinical and demographic characteristics, history of sleep apnea, fatigue, pain, insomnia (Insomnia Severity Index), sleepiness (Epworth Sleepiness Scale), Six Minute Walk, EuroQoL Quality of Life, and wrist actigraphy (sleep characteristics and rest-activity rhythms). We used cosinor analysis to compute rest-activity rhythms and general linear models and general estimating equations to test the effects of predictors over 1 year.

RESULTS

The sample included 175 participants (mean age = 63 SD = 12.9 Years; 43% women). There was a statistically significant group-time effect on self-reported cognitive function and increases in the proportion of participants, with < 3 psychomotor vigilance lapses in the CBT-I group. Controlling for group-time effects and baseline cognition, decreased sleepiness, improved rest-activity rhythms, and 6-minute walk distance predicted a composite measure of cognition (psychomotor vigilance lapses and self-reported cognition).

CONCLUSIONS

CBT-I may improve cognition in adults with chronic HF. A future fully powered randomized controlled trial is needed to confirm the extent to which CBT-I improves multiple dimensions of cognition.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Cognitive Behavioral Therapy for Insomnia: A Self-Management Strategy for Chronic Illness in Heart Failure; URL: https://clinicaltrials.gov/ct2/show/NCT02660385; Identifier: NCT02660385.

CITATION

Redeker NS, Conley S, O'Connell M, Geer JH, Yaggi H, Jeon S. Sleep-related predictors of cognition among adults with chronic insomnia and heart failure enrolled in a randomized controlled trial of cognitive behavioral therapy for insomnia. J Clin Sleep Med. 2023;19(6):1073-1081.

Detection of Insomnia and Its Relationship with Cognitive Impairment, Depression, and Quality of Life in Older Community-Dwelling Mexicans

Sleep disturbances are one of the most frequent health problems in old age, among which insomnia stands out. It is characterized by difficulty falling asleep, staying asleep, frequent awakenings, or waking up too early and not having restful sleep, which may be a risk factor for cognitive impairment and depression, affecting functionality and quality of life. Insomnia is a very complex multifactorial problem that requires a multi- and interdisciplinary approach. However, it is frequently not diagnosed in older community-dwelling people, increasing the risk of psychological, cognitive, and quality of life alterations. The aim was to detect insomnia and its relationship with cognitive impairment, depression, and quality of life in older community-dwelling Mexicans. An analytical cross-sectional study was carried out in 107 older adults from Mexico City. The following screening instruments were applied: Athens Insomnia Scale, Mini-Mental State Examination, Geriatric Depression Scale, WHO Quality of Life Questionnaire WHOQoL-Bref, Pittsburgh Sleep Quality Inventory. The frequency of insomnia detected was 57% and its relationship with cognitive impairment, depression, and low quality of life was 31% (OR = 2.5, 95% CI, 1.1-6.6. p < 0.05), 41% (OR = 7.3, 95% CI, 2.3-22.9, p < 0.001), and 59% (OR = 2.5, 95% CI, 1.1-5.4, p < 0.05), respectively. Our findings suggest that insomnia is a frequent clinical disorder that is not diagnosed and a significant risk factor for cognitive decline, depression, and poor quality of life.

Sleep Disorders in Mild Cognitive Impairment

We have an increasingly aging population and, therefore, cognitive impairment and dementia are becoming more common. Similarly, sleep disorders are also more common among the older population. There is a bidirectional relationship between mild cognitive impairment and sleep disorders. Additionally, both of these issues are underdiagnosed. By identifying and treating sleep disturbances early, we may delay the onset of dementia. Sleep helps in clearing metabolites like amyloid-beta (A-beta) lipoprotein. Clearance leads to decreased fatigue and proper functioning of the brain. A-beta lipoprotein and tau aggregates lead to neurodegeneration. Slow-wave sleep that decreases with aging is important for memory consolidation. In the initial stages of Alzheimer's disease, A-beta lipoprotein and tau deposits were linked to lower slow-wave activity in non-rapid eye movement sleep. Improvement in sleep decreases oxidative stress which in turn leads to decreased A-beta lipoprotein accumulation.

Patterns of sleep disturbances across stages of cognitive decline

OBJECTIVES

The purpose of this study was to investigate insomnia symptoms and excessive sleep/sluggishness across stages of cognitive decline (cognitively normal [CN], Cognitively Impairment, Not Demented [CIND], dementia) in a large, racially/ethnically diverse sample of older adults (70+) in the US. We also examined whether sleep disturbances at baseline predicted conversion to CIND or dementia at follow-up.

METHODS

In this secondary analysis of the Aging, Demographics, and Memory Study (ADAMS) supplement of the Health Retirement Study, we analyzed patterns of informant-reported insomnia and excessive sleep symptoms among three groups of older adults (n = 846): CN, CIND, and dementia.

RESULTS

CIND adults were significantly more likely to have informant-reported insomnia symptoms than those in the CN group (p = 0.013). This was driven by a significant race/ethnicity-by-insomnia interaction with diagnostic status (p = 0.029), such that CIND Black and Hispanic older adults had increased insomnia symptom rates compared to CN, whereas White adults had similar insomnia symptoms across diagnostic status. Across all racial/ethnic groups, the prevalence of excessive sleep symptoms increased stepwise from CN to CIND to dementia (p < 0.001). Overall, insomnia symptoms at baseline predicted conversion from CN to CIND (p < 0.001, OR = 0.288; 95% CI: 0.143-0.580) at 4-year (approximate) follow-up; there was no relationship between baseline insomnia or excessive sleep/sluggishness symptoms and conversion from CIND to dementia.

DISCUSSION/CONCLUSION

This study provides evidence for the increased risk of insomnia symptoms among Hispanic and Black older adults with CIND, and indicates that insomnia symptoms may be associated with increased risk for development of cognitive impairment.

Hospital-diagnosed sleep disorders and incident dementia: a nationwide observational cohort study

BACKGROUND AND PURPOSE

Several smaller, community-based studies have suggested a link between sleep disorders and dementia with a focus on sleep as a modifiable risk factor for dementia. Studies on neurodegenerative diseases are prone to reverse causation, and few studies have examined the association with long follow-up time. Our aim was to explore the possible association between sleep disorders and late-onset dementia in an entire population.

METHODS

In a nationwide cohort with 40-year follow-up, associations between hospital-based sleep disorder diagnoses and late-onset dementia were assessed. Incidence rate ratios (IRR) were calculated using Poisson regression.

RESULTS

The cohort consisted of 1,491,276 people. Those with any sleep disorder had a 17% higher risk of dementia (IRR 1.17, 95% confidence interval [CI] 1.11-1.24) compared to people with no sleep disorder, adjusted for age, sex, calendar year, highest attained educational level at age 50, and somatic and psychiatric comorbidity. The risk of dementia was significantly increased 0-5 years after sleep disorder diagnosis (IRR 1.35, 95% CI 1.25-1.47), whilst the association after 5 years or more was non-significant (1.05, 95% CI 0.97-1.13).

CONCLUSIONS

Our findings show an increased short-term risk of dementia following a hospital-based sleep disorder diagnosis, whilst weaker evidence of a long-term risk was found. This could potentially point towards sleep disorders as an early symptom of dementia. Further research is needed to distinguish sleep disorders as an early symptom of dementia, a risk factor, or both.

Fatigue performance in patients with chronic insomnia

Insomnia is associated with fatigue and poor driving performance, thus increasing the risk of traffic accidents. This study aimed to evaluate the effect of fatigue on driving in patients with chronic insomnia in a free-flow traffic scenario and car-following scenario, and to investigate the relationships between driving performance, cognitive function, and insomnia. The Trail Making Test (TMT), Stroop Color and Word Test (SCWT), Symbol Digit Modalities Test (SDMT), and Digit Span Test (DST) of 15 participants with mild-to-moderate chronic insomnia and 16 healthy participants were assessed. During the fatigue driving task, drivers completed simulated driving tasks under free-flow traffic and car-following scenarios. The mean speed (MS), mean acceleration (MA), mean lateral position (MLP), and standard deviation of lateral position (SDLP) were measured to assess driving performance. During fatigued tasks, the MA and MLP in the free-driving scenario were higher than those in the car-following scenario (P < 0.01), the SDLP was higher in the insomnia group than in the healthy group (P = 0.02), and the interaction effect was significantly different for MLP between the groups (P = 0.03). MS was negatively correlated with TMT score, SDMT score, and DST score, and positively correlated with time to complete TMT, errors in SCWT, and time to complete SCWT. SDLP was negatively correlated with DST score and positively correlated with time to complete SCWT. Furthermore, the insomnia group had poorer lateral vehicle control ability than the healthy group. The insomnia group had a more impaired driving performance in the free-driving scenario than in the car-following scenario. Drivers with impaired cognitive function exhibited impaired driving performance.

Sleep and Cognition: A Narrative Review Focused on Older Adults

Little is known regarding sleep's association with the traditional developmental course of late-life cognitive functioning. As the number of older adults increases worldwide, an enhanced understanding of age-related changes in sleep and cognition is necessary to slow decline and promote optimal aging. This review synthesizes the extant literature on sleep and cognitive function in healthy older adults, older adults with insomnia, and older adults with sleep apnea, incorporating information on the potential promising effects of treating poor sleep on cognitive outcomes in older adults. Unifying theories of the sleep-cognition association, possible mechanisms of action, and important unanswered questions are identified.

The role of depression and anxiety in the relationship between poor sleep quality and subjective cognitive decline in Chinese elderly: Exploring parallel, serial, and moderated mediation

BACKGROUND

Poor sleep quality exacerbates subjective cognitive decline (SCD). Mental health may play an important role in the relationship, but the potential underlying mechanisms remain unknown.

METHODS

A cross-sectional study was conducted on older adult residents in Guangdong province, south China from November 2020 to March 2021. A total of 717 adults aged 60 years and over were recruited for a face-to-face investigation on a range of socio-demographic factors, lifestyle behaviors, sleep quality, SCD, depressive and anxiety symptoms. Parallel, serial and moderated mediation models were used to examine whether depression and anxiety mediated in the poor sleep quality-SCD linkage.

RESULTS

Both direct and indirect effects of poor sleep quality on SCD symptoms were found. Anxiety and depressive symptoms mediated the relationship between poor sleep quality and SCD symptoms(β_Anxiety = 0.123, 95%CI: 0.079 to 0.173; β_Depression=0.274, 95%CI: 0.200 to 0.348), respectively. Serial mediation analyses indicated that depressive and anxiety symptoms co-play a serial mediating role in the association of poor sleep quality and SCD symptoms (β_a=0.052, 95% CI: 0.026 to 0.084; β_b=0.077, 95% CI: 0.033 to 0.128). Moderated mediation model revealed that the mediation of depressive symptoms on the relationship between poor sleep quality and SCD symptoms was moderated by anxiety symptoms(β=0.318, 95% CI: 0.164 to 0.472).

LIMITATIONS

The study is the cross-sectional design, which limits the causal inference ability.

CONCLUSIONS

These findings provided new insights into possible avenues for prevention and intervention on SCD through sleep-based treatments with a multi-faceted approach on psychiatric disorders.