Sleep disturbance in dementia with Lewy bodies and Alzheimer's disease: a multicenter analysis

Impaired sleep is associated with tau deposition on 18F-flortaucipir PET and accelerated cognitive decline, accounting for medications that affect sleep

BACKGROUND

Impaired sleep is commonly associated with Alzheimer's disease (AD), although the underlying mechanisms remain unclear. Furthermore, the moderating effects of sleep-affecting medications, which have been linked to AD pathology, are incompletely characterized. Using data from the Alzheimer's Disease Neuroimaging Initiative, we investigated whether a medical history of impaired sleep, informant-reported nighttime behaviors, and sleep-affecting medications are associated with beta-amyloid and tau deposition on PET and cognitive change, cross-sectionally and longitudinally.

METHODS

We included 964 subjects with 18F-florbetapir PET scans. Measures of sleep impairment and medication use were obtained from medical histories and the Neuropsychiatric Inventory Questionnaire. Multivariate models, adjusted for covariates, were used to assess associations among sleep-related features, beta-amyloid and tau, and cognition. Cortical tau deposition, categorized by Braak stage, was assessed using the standardized uptake value peak alignment (SUVP) method on 18F-flortaucipir PET.

RESULTS

Medical history of sleep impairment was associated with greater baseline tau in the meta-temporal, Braak 1, and Braak 4 regions (p = 0.04, p < 0.001, p = 0.025, respectively). Abnormal nighttime behaviors were also associated with greater baseline tau in the meta-temporal region (p = 0.024), and greater cognitive impairment, cross-sectionally (p = 0.007) and longitudinally (p < 0.001). Impaired sleep was not associated with baseline beta-amyloid (p > 0.05). Short-term use of selective serotonin reuptake inhibitors and benzodiazepines slightly weakened the sleep-tau relationship.

CONCLUSIONS

Sleep impairment was associated with tauopathy and cognitive decline, which could be linked to increased tau secretion from neuronal hyperactivity. Clinically, our results help identify high-risk individuals who could benefit from sleep-related interventions aimed to delay cognitive decline and AD.

Longitudinal Associations Between Mild Behavioral Impairment, Sleep Disturbance, and Progression to Dementia

Background

Clinical guidelines recommend incorporating non-cognitive markers like mild behavioral impairment (MBI) and sleep disturbance (SD) into dementia screening to improve detection.

Objective

We investigated the longitudinal associations between MBI, SD, and incident dementia.

Methods

Participant data were from the National Alzheimer's Coordinating Center in the United States. MBI was derived from the Neuropsychiatric Inventory Questionnaire (NPI-Q) using a published algorithm. SD was determined using the NPI-Q nighttime behaviors item. Cox proportional hazard regressions with time-dependant variables for MBI, SD, and cognitive diagnosis were used to model associations between baseline 1) MBI and incident SD (n = 11,277); 2) SD and incident MBI (n = 10,535); 3) MBI with concurrent SD and incident dementia (n = 13,544); and 4) MBI without concurrent SD and incident dementia (n = 11,921). Models were adjusted for first-visit age, sex, education, cognitive diagnosis, race, and for multiple comparisons using the Benjamini-Hochberg method.

Results

The rate of developing SD was 3.1-fold higher in older adults with MBI at baseline compared to those without MBI (95% CI: 2.8-3.3). The rate of developing MBI was 1.5-fold higher in older adults with baseline SD than those without SD (95% CI: 1.3-1.8). The rate of developing dementia was 2.2-fold greater in older adults with both MBI and SD, as opposed to SD alone (95% CI:1.9-2.6).

Conclusions

There is a bidirectional relationship between MBI and SD. Older adults with SD develop dementia at higher rates when co-occurring with MBI. Future studies should explore the mechanisms underlying these relationships, and dementia screening may be improved by assessing for both MBI and SD.

Association between Sleep and Alzheimer's Disease: A Bibliometric Analysis from 2003 to 2022

INTRODUCTION

Alzheimer's disease (AD) often presents with sleep disorders, which are also an important risk factor for AD, affecting cognitive function to a certain extent. This study aimed to reveal the current global status, present hotspots, and discuss emerging trends of sleep and AD using a bibliometric approach.

METHODS

Research and review articles related to sleep and AD from 2003 to 2022 were extracted from the Web of Science Core Collection. VOSviewer 1.6.18.0, Scimago Graphica, and CiteSpace 6.2.R2 were used to map the productive and highly cited countries, institutions, journals, authors, references, and keywords in the field.

RESULTS

Overall, 4,008 publications were included in this bibliometric analysis. The number of publications and citations showed an increasing trend over the past two decades. The USA and China had the largest and second largest, respectively, number of publications and citations and cooperated with other countries more closely. Ancoli-Israel Sonia published the most papers, and Holtzman David M was co-cited most frequently. The most productive journal was Journal of Alzheimer's Disease, and Neurology was the most frequently cited journal. The risk factors, β-amyloid (Aβ), tau, neuroinflammation, astrocytes, glymphatic system, orexin, functional connectivity, and management have been the main research directions of researchers over the past few years and may be the future trend of valuable research.

CONCLUSION

We identified hotspots and emerging trends including risk factors, Aβ, tau, neuroinflammation, the glymphatic system, orexin, and management, which may help identify new therapeutic targets and improve clinical efficacy of sleep and AD.

An intracerebroventricular injection of AΒ (1-42) modifies temporal profiles of spatial memory performance and oxidative status in the temporal cortex rat

Alzheimer's dementia (AD) is a neurodegenerative disorder that causes memory loss and dementia in older adults. Intracellular accumulation of Aβ causes an imbalance in the oxidative status and cognitive dysfunctions. Besides oxidative stress and loss of memory, Alzheimer's patients show dysfunction of the circadian rhythms. The objective of this work was to evaluate the consequences of an intracerebroventricular injection of Aβ (1-42) on temporal patterns of cognitive performance, as well as on lipid peroxidation, protein oxidation and total antioxidant capacity levels, in the rat temporal cortex. Holtzman male rats from control and Aβ-injected groups were used in this study. We found that MDA, protein carbonyls and total antioxidant capacity levels displayed day-night oscillations in the rat temporal cortex and spatial memory performance also varied rhythmically. An intracerebroventricular injection of Aβ (1-42) modified temporal patterns of cognitive performance as well as daily profiles of parameters of oxidative stress. Thus, elevated levels of Aβ aggregates induces alterations in daily rhythmicity of parameters of oxidative stress and, consequently, would affect cellular clock activity, affecting the spatial memory performance in the AD.

Sleep disturbances in Lewy body dementia: A systematic review

BACKGROUND

Lewy body dementia (LBD) refers to both dementia with Lewy bodies (DLB) and Parkinson's disease with dementia (PDD). Sleep disturbances are common in LBD, and can include poor sleep quality, excessive daytime sleepiness (EDS), and rapid eye movement behaviour disorder (RBD). Despite the high clinical prevalence of sleep disturbances in LBD, they are under-studied relative to other dementias. The aim of the present systematic review was to examine the nature of sleep disturbances in LBD, summarise the effect of treatment studies upon sleep, and highlight specific and necessary directions for future research.

METHODS

Published studies in English were located by searching PubMED and PSYCArticles databases (until 10 June 2022). The search protocol was pre-registered in PROSPERO (CRD42021293490) and performed in accordance with PRISMA guidelines.

RESULTS

Following full-text review, a final total of 70 articles were included. These included 20 studies focussing on subjective sleep, 14 on RBD, 8 on EDS, 7 on objective sleep, and 1 on circadian rhythms. The majority of the 18 treatment studies used pharmacological interventions (n = 12), had an open-label design (n = 8), and were of low-to-moderate quality. Most studies (n = 55) included only patients with DLB. Due to the heterogeneity of the studies, we reported a narrative synthesis without meta-analysis.

CONCLUSIONS

At least one form of sleep disturbance may be present in as many as 90% of people with LBD. Subjectively poor sleep quality, excessive daytime sleepiness, and RBD are more common and severe in LBD relative to other dementias.

Clinical Manifestations of Early-Onset Dementia With Lewy Bodies Compared With Late-Onset Dementia With Lewy Bodies and Early-Onset Alzheimer Disease

Importance

Early-onset dementia, presenting in individuals younger than 65 years, is a diagnosis with significant social and financial implications. The early-onset form of dementia with Lewy bodies (DLB) is poorly understood.

Objective

To investigate clinical features that distinguish early-onset DLB (onset and diagnosis at age <65 years) from late-onset DLB (onset at age ≥65 years) and from early-onset Alzheimer disease (AD) dementia.

Design, Setting, and Participants

This is a retrospective case-control study on patients with pathologically confirmed DLB or AD enrolled in the National Alzheimer's Coordinating Center database from January 2005 to July 2017. The National Alzheimer's Coordinating Center Uniform Data Set comprised deidentified data collected by Alzheimer disease centers in the United States. Of patients fulfilling criteria for all-cause dementia at enrollment (n = 1152), those who at post mortem received a pathological diagnosis of either AD (n = 848) or Lewy body disease (n = 218) were selected. Excluding 52 patients owing to missing data and 12 diagnosed with Parkinson disease dementia, remaining patients were classified by age of symptom onset into early-onset AD, early-onset DLB, and late-onset DLB subgroups. Data were analyzed from June to December 2018 and from November to December 2021.

Exposures

Demographics, cognitive, behavioral, and motor features recorded at first clinic visit and neuropathological characteristics at autopsy were analyzed by disease subgroup.

Main Outcomes and Measures

Concordance between initial etiologic diagnosis of dementia and final pathological diagnosis was assessed, as was time to death.

Results

A total of 542 individuals were categorized as having early-onset AD (n = 363; mean [SD] age, 53.0 [5.8] years; 208 [57.3%] male), early-onset DLB (n = 32; mean [SD] age, 57.9 [3.2] years; 23 [71.9%] male), and late-onset DLB (n = 147; mean [SD] age, 73.5 [5.5] years; 103 [70.1%] male). Early-onset DLB was clinically misdiagnosed in 16 individuals (50%). Features that predicted a diagnosis of early-onset DLB over early-onset AD included visual hallucinations (15 [46.9%] vs 42 [11.6%]), slowness (23 [71.9%] vs 95 [26.2%]), apathy (23 [71.9%] vs 189 [52.1%]), and motor deterioration that preceded cognitive and behavioral symptoms (7 [21.9%] vs 6 [1.7%]). Late-onset DLB had more amnestic features, but this was accounted for by a higher proportion of neocortical neuritic plaques and diffuse plaques (frequent in 79 [53.7%] vs 8 [25%]) than seen in early-onset DLB.

Conclusions and Relevance

This study found that early-onset DLB has clinical features that distinguish it from early-onset AD, whereas features of late-onset DLB are associated with a higher burden of AD copathology.

Sex differences in neuropsychiatric symptoms in Alzheimer's disease dementia: a meta-analysis

Background

Neuropsychiatric symptoms (NPS) are common in individuals with Alzheimer’s disease (AD) dementia, but substantial heterogeneity exists in the manifestation of NPS. Sex differences may explain this clinical variability. We aimed to investigate the sex differences in the prevalence and severity of NPS in AD dementia.

Methods

Literature searches were conducted in Embase, MEDLINE/PubMed, Web of Science Core Collection, Cochrane Central Register of Controlled Trials, PsycINFO, and Google Scholar from inception to February 2021. Study selection, data extraction, and quality assessment were conducted in duplicate. Effect sizes were calculated as odds ratios (OR) for NPS prevalence and Hedges’ g for NPS severity. Data were pooled using random-effects models. Sources of heterogeneity were examined using meta-regression analyses.

Results

Sixty-two studies were eligible representing 21,554 patients (61.2% females). The majority of the included studies had an overall rating of fair quality (71.0%), with ten studies of good quality (16.1%) and eight studies of poor quality (12.9%). There was no sex difference in the presence of any NPS (k = 4, OR = 1.35 [95% confidence interval 0.78, 2.35]) and overall NPS severity (k = 13, g = 0.04 [− 0.04, 0.12]). Regarding specific symptoms, female sex was associated with more prevalent depressive symptoms (k = 20, OR = 1.60 [1.28, 1.98]), psychotic symptoms (general psychosis k = 4, OR = 1.62 [1.12, 2.33]; delusions k = 12, OR = 1.56 [1.28, 1.89]), and aberrant motor behavior (k = 6, OR = 1.47 [1.09, 1.98]). In addition, female sex was related to more severe depressive symptoms (k = 16, g = 0.24 [0.14, 0.34]), delusions (k = 10, g = 0.19 [0.04, 0.34]), and aberrant motor behavior (k = 9, g = 0.17 [0.08, 0.26]), while apathy was more severe among males compared to females (k = 11, g = − 0.10 [− 0.18, − 0.01]). There was no association between sex and the prevalence and severity of agitation, anxiety, disinhibition, eating behavior, euphoria, hallucinations, irritability, and sleep disturbances. Meta-regression analyses revealed no consistent association between the effect sizes across studies and method of NPS assessment and demographic and clinical characteristics.

Discussion

Female sex was associated with a higher prevalence and greater severity of several specific NPS, while male sex was associated with more severe apathy. While more research is needed into factors underlying these sex differences, our findings may guide tailored treatment approaches of NPS in AD dementia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13195-022-00991-z.

Chronic Fragmentation of the Daily Sleep-Wake Rhythm Increases Amyloid-beta Levels and Neuroinflammation in the 3xTg-AD Mouse Model of Alzheimer's Disease

Fragmentation of the daily sleep-wake rhythm with increased nighttime awakenings and more daytime naps is correlated with the risk of development of Alzheimer's disease (AD). To explore whether a causal relationship underlies this correlation, the present study tested the hypothesis that chronic fragmentation of the daily sleep-wake rhythm stimulates brain amyloid-beta (Aβ) levels and neuroinflammation in the 3xTg-AD mouse model of AD. Female 3xTg-AD mice were allowed to sleep undisturbed or were subjected to chronic sleep fragmentation consisting of four daily sessions of enforced wakefulness (one hour each) evenly distributed during the light phase, five days a week for four weeks. Piezoelectric sleep recording revealed that sleep fragmentation altered the daily sleep-wake rhythm to resemble the pattern observed in AD. Levels of amyloid-beta (Aβ₄₀ and Aβ₄₂) determined by ELISA were higher in hippocampal tissue collected from sleep-fragmented mice than from undisturbed controls. In contrast, hippocampal levels of tau and phospho-tau differed minimally between sleep fragmented and undisturbed control mice. Sleep fragmentation also stimulated neuroinflammation as shown by increased expression of markers of microglial activation and proinflammatory cytokines measured by q-RT-PCR analysis of hippocampal samples. No significant effects of sleep fragmentation on Aβ, tau, or neuroinflammation were observed in the cerebral cortex. These studies support the concept that improving sleep consolidation in individuals at risk for AD may be beneficial for slowing the onset or progression of this devastating neurodegenerative disease.

Interactive Associations of Neuropsychiatry Inventory-Questionnaire Assessed Sleep Disturbance and Vascular Risk on Alzheimer's Disease Stage Progression in Clinically Normal Older Adults

Background: To determine whether sleep disturbance (SD) and vascular-risk interact to promote Alzheimer's disease (AD) stage-progression in normal, community-dwelling older adults and evaluate their combined risk beyond that of established AD biomarkers. Methods: Longitudinal data from the National Alzheimer's Coordinating Center Uniform-Dataset. SD data (i.e., SD+ vs. SD-), as characterized by the Neuropsychiatric Inventory-Questionnaire, were derived from 10,600 participants at baseline, with at-least one follow-up visit. A subset (n = 361) had baseline cerebrospinal fluid (CSF) biomarkers and MRI data. The Framingham heart study general cardiovascular disease (FHS-CVD) risk-score was used to quantify vascular risk. Amnestic mild cognitive impairment (aMCI) diagnosis during follow-up characterized AD stage-progression. Logistic mixed-effects models with random intercept and slope examined the interaction of SD and vascular risk on prospective aMCI diagnosis. Results: Of the 10,600 participants, 1,017 (9.6%) reported SD and 6,572 (62%) were female. The overall mean (SD) age was 70.5 (6.5), and follow-up time was 5.1 (2.7) years. SD and the FHS-CVD risk-score were each associated with incident aMCI (aOR: 1.42 and aOR: 2.11, p < 0.01 for both). The interaction of SD and FHS-CVD risk-score with time was significant (aOR: 2.87, p < 0.01), suggesting a synergistic effect. SD and FHS-CVD risk-score estimates remained significantly associated with incident aMCI even after adjusting for CSF (Aβ, T-tau, P-tau) and hippocampal volume (n = 361) (aOR: 2.55, p < 0.01), and approximated risk-estimates of each biomarker in the sample where data was available. Conclusions: Clinical measures of sleep and vascular risk may complement current AD biomarkers in assessing risk of cognitive decline in older adults.

The microtubule associated protein tau suppresses the axonal distribution of PDF neuropeptide and mitochondria in circadian clock neurons

Disrupted circadian rhythms is a prominent feature of multiple neurodegenerative diseases. Yet mechanisms linking Tau to rhythmic behavior remain unclear. Here we find that expression of a phosphomimetic human Tau mutant (TauE14) in Drosophila circadian pacemaker neurons disrupts free-running rhythmicity. While cell number and oscillations of the core clock protein PERIOD are unaffected in the small LNv (sLNv) neurons important for free running rhythms, we observe a near complete loss of the major LNv neuropeptide pigment dispersing factor (PDF) in the dorsal axonal projections of the sLNvs. This was accompanied by a ~ 50% reduction in the area of the dorsal terminals and a modest decrease in cell body PDF levels. Expression of wild-type Tau also reduced axonal PDF levels but to a lesser extent than TauE14. TauE14 also induces a complete loss of mitochondria from these sLNv projections. However, mitochondria were increased in sLNv cell bodies in TauE14 flies. These results suggest that TauE14 disrupts axonal transport of neuropeptides and mitochondria in circadian pacemaker neurons, providing a mechanism by which Tau can disrupt circadian behavior prior to cell loss.

Impact of Pharmacotherapy on Insomnia in Patients with Alzheimer's Disease

Insomnia is a pervasive sleep disorder affecting numerous patients across diverse demographical populations and comorbid disease states. Contributing factors are often a complex interaction of biological, psychological, and social components, requiring a multifaceted approach in terms of both diagnosis and management. In the setting of Alzheimer’s disease, insomnia is an even more complicated issue, with a higher overall prevalence than in the general population, greater complexity of contributing etiologies, and differences in diagnosis (at times based on caregiver observation of sleep disruption rather than subjective complaints by the individual with the disorder), and requiring more discretion in terms of treatment, particularly in regard to adverse effect profile concerns. There also is growing evidence of the bidirectional nature of sleep disruption and Alzheimer’s disease, with insomnia potentially contributing to disease progression, making the condition even more paramount to address. The objective of this review was to provide the clinician with an overview of treatment strategies that may have value in the treatment of disturbed sleep in Alzheimer’s disease. Nonpharmacological approaches to treatment should be exhausted foremost; however, pharmacotherapy may be needed in certain clinical scenarios, which can be a challenge for clinicians given the paucity of evidence and guidelines for treatment in the subpopulation of Alzheimer’s disease. Agents such as sedating antidepressants, melatonin, and site-specific γ-aminobutyric acid agonists are often employed based on historical usage but are not necessarily supported by high-quality trials. Newer agents such as dual orexin receptor antagonists have demonstrated some promise but still need further evaluation.

Progression of Clinical Features in Lewy Body Dementia Can Be Detected Over 6 Months

OBJECTIVE

This study aimed to quantify the trajectory and magnitude of change of the key clinical features and corresponding symptom domains of dementia with Lewy bodies (DLB) and Parkinson disease dementia (PDD), including global cognition, parkinsonism, recurrent visual hallucinations, cognitive fluctuations, and sleep disturbance.

METHODS

One hundred sixteen patients with Lewy body dementia (DLB = 72, PDD = 44) underwent assessment at baseline and 3 and 6 months as part of a prospective multicenter randomized controlled trial. Linear mixed models were constructed for core outcome measures using the Mini-Mental State Examination (MMSE), motor section of the Unified Parkinson's Disease Rating Scale (UPDRS-III), Dementia Cognitive Fluctuations Scale (DCFS), and Neuropsychiatric Inventory (NPI).

RESULTS

Within the time frame of our study (6 months), we were able to identify a significant cognitive decline of 1.3 points on the MMSE (p = 0.002) and significant worsening of motor parkinsonism with an increase in UPDRS-III score of 3.2 points (p = 0.018). Fluctuation severity also increased using the DCFS with a 6-month change in score of 1.3 points (p = 0.001). Uniquely, a signal for increased severity of sleep symptoms of 1.2 points (NPI-sleep) was also detectable (p = 0.04). Significant changes in neuropsychiatric symptoms were not detected. There was no difference in rates of change of scores between DLB and PDD.

DISCUSSION

Clinically significant rates of change in core clinical features can be detected and quantified in Lewy body dementia over a relatively short period (6 months) using common clinical instruments and thus may be useful as clinical endpoints for therapeutic trials of disease-modifying and symptomatic agents.

Caregiver self-efficacy and associated factors among caregivers of patients with dementia with Lewy bodies and caregivers of patients with Alzheimer's disease

BACKGROUND

Dementia with Lewy bodies (DLB) is characterized by neuropsychiatric symptoms, which can be distressing to caregivers. However, little is known about their subjective distress in terms of caregiver self-efficacy. Thus, we examined the differences in caregiver self-efficacy and their associated factors between DLB and Alzheimer's disease (AD) caregivers.

METHODS

We conducted a comprehensive questionnaire for DLB and AD caregivers. Caregiver self-efficacy was evaluated using three domains (Self-Efficacy for Obtaining Respite: SE-OR, Self-Efficacy for Responding to Disruptive Patient Behaviours: SE-RDPB, Self-Efficacy for Controlling Upsetting Thoughts about Caregiving: SE-CUT) of the Revised Scale for Caregiving Self-Efficacy (RSCSE). In addition, data on the following features of caregivers were assessed: depression, sleep disturbance, caregiver burden, executive function, loneliness, social support, and distress associated with neuropsychiatric symptoms. The patients were assessed for general cognitive tasks, executive function, and neuropsychiatric symptoms.

RESULTS

Compared with AD caregivers, DLB caregivers experienced a significantly higher burden in terms of not only various clinical factors, but also all three domains of caregiver self-efficacy. Among the caregiver-associated factors, different domains were predictors of self-efficacy in DLB and AD caregivers (distress due to sleep disturbances in DLB patients; distress due to delusions in AD patients). Among the patient-associated factors, different domains were also predictors of self-efficacy in DLB and AD caregivers (sleep disturbances in DLB patients; delusions in AD patients). Among both the caregivers and the patients, executive function was a significant predictor of one RSCSE domain (SE-CUT).

CONCLUSIONS

A reduction in caregiver self-efficacy may contribute to a severe subjective burden among DLB caregivers. Furthermore, two neuropsychiatric symptoms (delusions and sleep disturbances) affected caregiver self-efficacy differently depending on whether care was being provided to a DLB or AD patient. Understanding the association between specific neuropsychiatric symptoms and caregiver self-efficacy may be useful for conducting interventions for DLB patients.

Effectiveness and safety of acupuncture in treating sleep disturbance in dementia patients: A PRISMA-compliant systematic review and limitations of current evidence

BACKGROUND

Dementia is of increasing importance, as it is a major public health problem worldwide. Sleep disturbance is common in dementia patients and may be associated with worse cognitive symptoms or behavioral and psychological symptoms of dementia. Non-pharmacological approaches, such as acupuncture, for treating this clinical condition are gaining importance. This study aimed to comprehensively search and analyze randomized controlled clinical trials (RCTs) of acupuncture in treating sleep disturbance or sleep disorders in dementia patients.

METHODS

A comprehensive search was conducted from 12 electronic databases on December 2, 2020. We included RCTs reporting the effectiveness and safety of acupuncture in treating sleep disorders or disturbance in dementia patients. The methodological quality of the included studies was assessed using the Cochrane Collaboration's risk-of-bias tool.

RESULTS

Five articles with four original RCTs met the inclusion criteria. These studies reported clinical data suggesting that adjuvant acupuncture for hypnotics, and ear acupressure in dementia patients with sleep disorders or sleep disturbance may have clinical benefits in certain sleep-related parameters and total effective rate (TER). Only 1 study reported the safety profile of the intervention, and no acupuncture-related adverse reactions were reported. Some studies compared 2 kinds of acupuncture methods, and found that specific acupuncture methods were superior to conventional acupuncture in improving sleep-related parameters, cognitive function and TER. The methodological quality of the included clinical studies was not high.

CONCLUSIONS

There were limited acupuncture studies on this topic. Given the number of studies included and their sample size, methodological quality, and heterogeneities, clinically relevant conclusions could not be drawn. Further clinical studies are needed in this field considering its urgency and importance.

Evaluation of SAMP8 Mice as a Model for Sleep-Wake and Rhythm Disturbances Associated with Alzheimer's Disease: Impact of Treatment with the Dual Orexin (Hypocretin) Receptor Antagonist Lemborexant

Background:

Many patients with Alzheimer’s disease (AD) display circadian rhythm and sleep-wake disturbances. However, few mouse AD models exhibit these disturbances. Lemborexant, a dual orexin receptor antagonist, is under development for treating circadian rhythm disorders in dementia.

Objective:

Evaluation of senescence-accelerated mouse prone-8 (SAMP8) mice as a model for sleep-wake and rhythm disturbances in AD and the effect of lemborexant by assessing sleep-wake/diurnal rhythm behavior.

Methods:

SAMP8 and control senescence-accelerated mouse resistant-1 (SAMR1) mice received vehicle or lemborexant at light onset; plasma lemborexant and diurnal cerebrospinal fluid (CSF) orexin concentrations were assessed. Sleep-wake behavior and running wheel activity were evaluated.

Results:

Plasma lemborexant concentrations were similar between strains. The peak/nadir timing of CSF orexin concentrations were approximately opposite between strains. During lights-on, SAMP8 mice showed less non-rapid eye movement (non-REM) and REM sleep than SAMR1 mice. Lemborexant treatment normalized wakefulness/non-REM sleep in SAMP8 mice. During lights-off, lemborexant-treated SAMR1 mice showed increased non-REM sleep; lemborexant-treated SAMP8 mice displayed increased wakefulness. SAMP8 mice showed differences in electroencephalogram architecture versus SAMR1 mice. SAMP8 mice exhibited more running wheel activity during lights-on. Lemborexant treatment reduced activity during lights-on and increased activity in the latter half of lights-off, demonstrating a corrective effect on overall diurnal rhythm. Lemborexant delayed the acrophase of activity in both strains by approximately 1 hour.

Conclusion:

SAMP8 mice display several aspects of sleep-wake and rhythm disturbances in AD, notably mistimed activity. These findings provide some preclinical rationale for evaluating lemborexant in patients with AD who experience sleep-wake and rhythm disturbances.

Cerebrospinal Fluid Hypocretin and Nightmares in Dementia Syndromes

Background/Aims

Hypocretin promotes wakefulness and modulates REM sleep. Alterations in the hypocretin system are increasingly implicated in dementia. We evaluated relationships among hypocretin, dementia biomarkers, and sleep symptoms in elderly participants, most of whom had dementia.

Methods

One-hundred twenty-six adults (mean age 66.2 ± 8.4 years) were recruited from the Emory Cognitive Clinic. Diagnoses were Alzheimer disease (AD; n = 60), frontotemporal dementia (FTD; n = 21), and dementia with Lewy bodies (DLB; n = 20). We also included cognitively normal controls (n = 25). Participants and/or caregivers completed sleep questionnaires and lumbar puncture was performed for cerebrospinal fluid (CSF) assessments.

Results

Except for sleepiness (worst in DLB) and nocturia (worse in DLB and FTD) sleep symptoms did not differ by diagnosis. CSF hypocretin concentrations were available for 87 participants and normal in 70, intermediate in 16, and low in 1. Hypocretin levels did not differ by diagnosis. Hypocretin levels correlated with CSF total τ levels only in men (r = 0.34; p = 0.02). Lower hypocretin levels were related to frequency of nightmares (203.9 ± 29.8 pg/mL in those with frequent nightmares vs. 240.4 ± 46.1 pg/mL in those without; p = 0.05) and vivid dreams (209.1 ± 28.3 vs. 239.5 ± 47.8 pg/mL; p = 0.014). Cholinesterase inhibitor use was not associated with nightmares or vivid dreaming.

Conclusion

Hypocretin levels did not distinguish between dementia syndromes. Disturbing dreams in dementia patients may be related to lower hypocretin concentrations in CSF.

Pharmacotherapies for sleep disturbances in dementia

BACKGROUND

Sleep disturbances, including reduced nocturnal sleep time, sleep fragmentation, nocturnal wandering, and daytime sleepiness are common clinical problems in dementia, and are associated with significant carer distress, increased healthcare costs, and institutionalisation. Although non-drug interventions are recommended as the first-line approach to managing these problems, drug treatment is often sought and used. However, there is significant uncertainty about the efficacy and adverse effects of the various hypnotic drugs in this clinically vulnerable population.

OBJECTIVES

To assess the effects, including common adverse effects, of any drug treatment versus placebo for sleep disorders in people with dementia.

SEARCH METHODS

We searched ALOIS (www.medicine.ox.ac.uk/alois), the Cochrane Dementia and Cognitive Improvement Group's Specialized Register, on 19 February 2020, using the terms: sleep, insomnia, circadian, hypersomnia, parasomnia, somnolence, rest-activity, and sundowning.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared a drug with placebo, and that had the primary aim of improving sleep in people with dementia who had an identified sleep disturbance at baseline.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data on study design, risk of bias, and results. We used the mean difference (MD) or risk ratio (RR) with 95% confidence intervals (CI) as the measures of treatment effect, and where possible, synthesised results using a fixed-effect model. Key outcomes to be included in our summary tables were chosen with the help of a panel of carers. We used GRADE methods to rate the certainty of the evidence.

MAIN RESULTS

We found nine eligible RCTs investigating: melatonin (5 studies, n = 222, five studies, but only two yielded data on our primary sleep outcomes suitable for meta-analysis), the sedative antidepressant trazodone (1 study, n = 30), the melatonin-receptor agonist ramelteon (1 study, n = 74, no peer-reviewed publication), and the orexin antagonists suvorexant and lemborexant (2 studies, n = 323). Participants in the trazodone study and most participants in the melatonin studies had moderate-to-severe dementia due to Alzheimer's disease (AD); those in the ramelteon study and the orexin antagonist studies had mild-to-moderate AD. Participants had a variety of common sleep problems at baseline. Primary sleep outcomes were measured using actigraphy or polysomnography. In one study, melatonin treatment was combined with light therapy. Only four studies systematically assessed adverse effects. Overall, we considered the studies to be at low or unclear risk of bias. We found low-certainty evidence that melatonin doses up to 10 mg may have little or no effect on any major sleep outcome over eight to 10 weeks in people with AD and sleep disturbances. We could synthesise data for two of our primary sleep outcomes: total nocturnal sleep time (TNST) (MD 10.68 minutes, 95% CI -16.22 to 37.59; 2 studies, n = 184), and the ratio of day-time to night-time sleep (MD -0.13, 95% CI -0.29 to 0.03; 2 studies; n = 184). From single studies, we found no evidence of an effect of melatonin on sleep efficiency, time awake after sleep onset, number of night-time awakenings, or mean duration of sleep bouts. There were no serious adverse effects of melatonin reported. We found low-certainty evidence that trazodone 50 mg for two weeks may improve TNST (MD 42.46 minutes, 95% CI 0.9 to 84.0; 1 study, n = 30), and sleep efficiency (MD 8.53%, 95% CI 1.9 to 15.1; 1 study, n = 30) in people with moderate-to-severe AD. The effect on time awake after sleep onset was uncertain due to very serious imprecision (MD -20.41 minutes, 95% CI -60.4 to 19.6; 1 study, n = 30). There may be little or no effect on number of night-time awakenings (MD -3.71, 95% CI -8.2 to 0.8; 1 study, n = 30) or time asleep in the day (MD 5.12 minutes, 95% CI -28.2 to 38.4). There were no serious adverse effects of trazodone reported. The small (n = 74), phase 2 trial investigating ramelteon 8 mg was reported only in summary form on the sponsor's website. We considered the certainty of the evidence to be low. There was no evidence of any important effect of ramelteon on any nocturnal sleep outcomes. There were no serious adverse effects. We found moderate-certainty evidence that an orexin antagonist taken for four weeks by people with mild-to-moderate AD probably increases TNST (MD 28.2 minutes, 95% CI 11.1 to 45.3; 1 study, n = 274) and decreases time awake after sleep onset (MD -15.7 minutes, 95% CI -28.1 to -3.3: 1 study, n = 274) but has little or no effect on number of awakenings (MD 0.0, 95% CI -0.5 to 0.5; 1 study, n = 274). It may be associated with a small increase in sleep efficiency (MD 4.26%, 95% CI 1.26 to 7.26; 2 studies, n = 312), has no clear effect on sleep latency (MD -12.1 minutes, 95% CI -25.9 to 1.7; 1 study, n = 274), and may have little or no effect on the mean duration of sleep bouts (MD -2.42 minutes, 95% CI -5.53 to 0.7; 1 study, n = 38). Adverse events were probably no more common among participants taking orexin antagonists than those taking placebo (RR 1.29, 95% CI 0.83 to 1.99; 2 studies, n = 323).

AUTHORS' CONCLUSIONS

We discovered a distinct lack of evidence to guide decisions about drug treatment of sleep problems in dementia. In particular, we found no RCTs of many widely prescribed drugs, including the benzodiazepine and non-benzodiazepine hypnotics, although there is considerable uncertainty about the balance of benefits and risks for these common treatments. We found no evidence for beneficial effects of melatonin (up to 10 mg) or a melatonin receptor agonist. There was evidence of some beneficial effects on sleep outcomes from trazodone and orexin antagonists and no evidence of harmful effects in these small trials, although larger trials in a broader range of participants are needed to allow more definitive conclusions to be reached. Systematic assessment of adverse effects in future trials is essential.

Sleep Disturbances in MCI and AD: Neuroinflammation as a Possible Mediating Pathway

Mild cognitive impairment (MCI) and Alzheimer’s disease (AD) affect a high proportion of the elderly population with an increasing prevalence. Sleep disturbances are frequent in those with MCI and AD. This review summarizes existing research on sleep disturbances and neuroinflammation in MCI and AD. Although strong evidence supports various pathways linking sleep and AD pathology, the temporal direction of this central relationship is not yet known. Improved understanding of sleep disturbance and neuroinflammation in MCI and AD may aid in the identification of targets for their prevention.

Non-invasive 40-Hz Light Flicker Ameliorates Alzheimer's-Associated Rhythm Disorder via Regulating Central Circadian Clock in Mice

Alzheimer’s disease (AD) patients often exhibit perturbed circadian rhythm with fragmented sleep before disease onset. This study was designed to evaluate the effect of a 40-Hz light flicker on circadian rhythm in an AD mouse model (APP/PS1). Locomotor rhythms recordings were conducted to examine the circadian clock rhythm in APP/PS1 mice. Molecular biology analyses, including western blot and real-time qPCR assays, were conducted to assess the changes in circadian locomotor output cycles kaput (CLOCK), brain and muscle arnt-like protein-1 (BMAL1), and period 2 (PER2). In addition to determining the direct effect of a 40-Hz light flicker on hypothalamic central clock, whole-cell voltage-clamp electrophysiology was employed to record individual neurons of suprachiasmatic nucleus (SCN) sections. The results reported herein demonstrate that a 40-Hz light flicker relieves circadian rhythm disorders in APP/PS1 mice and returns the expression levels of key players in the central circadian clock, including Clock, Bmal1, and Per2, to baseline. Moreover, the frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) in SCN neurons is significantly lower in APP/PS1 mice than in the control, and the amplitude of sIPSCs is decreased. Exposure to a 40-Hz light flicker significantly increases the sIPSC frequency in SCN neurons of APP/PS1 mice, with little effect on the amplitude. However, the frequency and amplitude of spontaneous excitatory postsynaptic currents (sEPSCs) are both unaffected by a 40-Hz light flicker. The data suggest that a 40-Hz light flicker can ameliorate AD-associated circadian rhythm disorders, presenting a new type of therapeutic treatment for rhythm disorders caused by AD.

Cognitive fluctuations in Lewy body dementia: towards a pathophysiological framework

Fluctuating cognition is a complex and disabling symptom that is seen most frequently in the context of Lewy body dementias encompassing dementia with Lewy bodies and Parkinson’s disease dementia. In fact, since their description over three decades ago, cognitive fluctuations have remained a core diagnostic feature of dementia with Lewy bodies, the second most common dementia in the elderly. In the absence of reliable biomarkers for Lewy body pathology, the inclusion of such patients in therapeutic trials depends on the accurate identification of such core clinical features. Yet despite their diagnostic relevance, cognitive fluctuations remain poorly understood, in part due to the lack of a cohesive clinical and scientific explanation of the phenomenon itself. Motivated by this challenge, the present review examines the history, clinical phenomenology and assessment of cognitive fluctuations in the Lewy body dementias. Based on these data, the key neuropsychological, neurophysiological and neuroimaging correlates of cognitive fluctuations are described and integrated into a novel testable heuristic framework from which new insights may be gained.

Effectiveness of Yi-Zhi-An-Shen granules on cognition and sleep quality in older adults with amnestic mild cognitive impairment: protocol for a randomized, double-blind, placebo-controlled trial

BACKGROUND

Amnestic mild cognitive impairment (aMCI) is a syndrome characterized by significant forgetfulness that does not meet the criteria of dementia. Individuals with aMCI are at greater risk of progressing to dementia. Current studies suggest that good sleep quality is linked with preserved cognition in the elderly, and sleep complaints are common among the elderly with amnesia. Therefore, improving their sleep may be helpful for maintaining and improving their cognitive capacity. According to the theory of traditional Chinese medicine, Yi-Zhi-An-Shen is an herbal compound which may ameliorate forgetfulness and sleep disorders. As growing evidence indicates that the gut microbiome is associated with major mental symptoms, a hypothesis was proposed that Yi-Zhi-An-Shen granules (YZASG) might work by alternating microbial abundance and diversity. In this study, the investigators intend to assess the efficacy of YZASG on global cognition in the elderly suffering from aMCI and evaluate its safety as well as its potential mechanisms via sleep quality, fecal microbial 16S ribosomal DNA and metagenomics analyses, and serum markers.

METHODS/DESIGN

This study is a randomized, double-blind, placebo-controlled clinical trial. A total of 80 patients (aged 60-85 years) will be recruited and allocated randomly to a treatment group and a placebo group in a 1:1 ratio and will then be administered YZASG or isodose placebo three times a day. The intervention course is 16 weeks, with an 18 months follow-up. The primary outcome is the Alzheimer's Disease Assessment Scale-Cognitive Subscale. Secondary outcome measures are the Mini-Mental State Examination, Montreal Cognitive Assessment, Pittsburgh Sleep Quality Index, serum concentrations of immunological factors and inflammatory cytokines, and fecal microbiota. Fecal microbiota will only be collected at the baseline and endpoint of the intervention.

DISCUSSION

The results of this trial will be conducive to assessing the safety and effectiveness on cognition of YZASG in intervening aMCI among the elderly and determining if it takes effect via the improvement of sleep quality, regulation of gut microbiota, and concentration of certain serum markers.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03601000 . Registered on 26 July 2018.

Sleep and Circadian Medicine

Fundamental aspects of neurobiology are time-of-day regulated. Therefore, it is not surprising that neurodegenerative and psychiatric diseases are accompanied by sleep and circadian rhythm disruption. Although the direction of causation remains unclear, abnormal sleep-wake patterns often occur early in disease, exacerbate progression, and are a common primary complaint from patients. Circadian medicine incorporates knowledge of 24-hour biological rhythms to improve treatment. This article highlights how research and technologic advances in circadian biology might translate to improved patient care.

Clinical and video-polysomnographic analysis of rapid eye movement sleep behavior disorder and other sleep disturbances in dementia with Lewy bodies

Objective

The main objective of this study was to study rapid eye movement (REM) sleep behavior disorder (RBD) and other sleep disorders in dementia with Lewy bodies (DLB).

Methods

Consecutive patients with DLB and mild dementia severity were recruited irrespective of sleep complaints. Patients underwent clinical interview, assessment of sleep scales, and video-polysomnography (V-PSG). RBD was diagnosed with V-PSG based on electromyographic and audiovisual analysis.

Results

Thirty-five patients (65.7% men; mean age 77.7 ± 6.1 years) were evaluated. Poor sleep quality (54.3%), hypersomnia (37.1%), snoring (60%), and abnormal nocturnal behaviors (77.1%) were reported. Sleep–wake architecture abnormalities occurred in 75% patients and consisted of occipital slowing on awake electroencephalography (EEG; 34.4%), the absence of sleep spindles and K complexes (12.9%), slow frequency sleep spindles (12.9%), delta activity in REM sleep (19.2%), and REM sleep without atonia (44%). Three patients showed hallucinatory-like behaviors and 10 patients showed abnormal behaviors during arousals mimicking RBD. RBD was diagnosed in 50% of those patients in whom sufficient REM sleep was attained. Of these, 72.7% were not aware of displaying dream-enacting behaviors and in 63.7% RBD preceded the onset of cognitive impairment. For RBD diagnosis, the sensitivity of Mayo Sleep Questionnaire was 50%, specificity was 66.7%, positive predictive value was 83.3%, and negative predictive value was 28%. False-positive RBD cases according to clinical history had hallucinatory-like behaviors, severe obstructive sleep apnea, and prominent periodic limb movements in sleep. Occipital EEG frequency while awake and rate of electromyographic activity in REM sleep were negatively correlated, suggesting a common subcortical origin.

Conclusion

In DLB, RBD and sleep–wake disorders are common, heterogeneous, and complex, challenging their identification without performing V-PSG.

Effects of the dual orexin receptor antagonist DORA-22 on sleep in 5XFAD mice

Introduction

Sleep disruption is a characteristic of Alzheimer's disease (AD) that may exacerbate disease progression. This study tested whether a dual orexin receptor antagonist (DORA) would enhance sleep and attenuate neuropathology, neuroinflammation, and cognitive deficits in an AD-relevant mouse model, 5XFAD.

Methods

Wild-type (C57Bl6/SJL) and 5XFAD mice received chronic treatment with vehicle or DORA-22. Piezoelectric recordings monitored sleep and spatial memory was assessed via spontaneous Y-maze alternations. Aβ plaques, Aβ levels, and neuroinflammatory markers were measured by immunohistochemistry, enzyme-linked immunosorbent assay, and real-time polymerase chain reaction, respectively.

Results

In 5XFAD mice, DORA-22 significantly increased light-phase sleep without reducing Aβ levels, plaque density, or neuroinflammation. Effects of DORA-22 on cognitive deficits could not be determined because the 5XFAD mice did not exhibit deficits.

Discussion

These findings suggest that DORAs may improve sleep in AD patients. Further investigations should optimize the dose and duration of DORA-22 treatment and explore additional AD-relevant animal models and cognitive tests.

Orexins as Novel Therapeutic Targets in Inflammatory and Neurodegenerative Diseases

Orexins [orexin-A (OXA) and orexin-B (OXB)] are two isoforms of neuropeptides produced by the hypothalamus. The main biological actions of orexins, focused on the central nervous system, are to control the sleep/wake process, appetite and feeding, energy homeostasis, drug addiction, and cognitive processes. These effects are mediated by two G protein-coupled receptor (GPCR) subtypes named OX1R and OX2R. In accordance with the synergic and dynamic relationship between the nervous and immune systems, orexins also have neuroprotective and immuno-regulatory (i.e., anti-inflammatory) properties. The present review gathers recent data demonstrating that orexins may have a therapeutic potential in several pathologies with an immune component including multiple sclerosis, Alzheimer's disease, narcolepsy, obesity, intestinal bowel diseases, septic shock, and cancers.

Sleep physiology and disorders in aging and dementia

Sleep problems occur commonly in normal and pathologic aging. Older adults typically have more difficulty falling asleep and remaining asleep, report more daytime napping, and have an increased prevalence of primary sleep disorders such as insomnia, parasomnias, sleep apnea, and sleep-related movement disorders. Medical and psychiatric disorders as well as medications used to treat them also contribute to sleep disturbances in aging. Patients with mild cognitive impairment and dementia have more severe sleep problems, and disturbed sleep and sleep disorders contribute to earlier onset and more rapid progression of neurodegenerative disorders. Approaches to diagnosing and treating sleep disorders in the elderly are discussed.

Sleep Disturbance and the Risk of Cognitive Decline or Clinical Conversion in the ADNI Cohort

BACKGROUND

We investigated the relationship between sleep disturbance and cognitive decline or clinical conversion in individuals with normal cognition (CN), as well as those with mild cognitive impairment (MCI) and dementia due to Alzheimer disease (AD-dementia).

METHODS

Secondary analysis of 1,629 adults between 48 and 91 years of age with up to 24 months of follow-up from the ADNI (Alzheimer's Disease Neuroimaging Initiative), a longitudinal cohort study.

RESULTS

Sleep disturbance was not associated with decline in memory, executive function, or global cognition. The presence of sleep disturbance did not significantly increase the risk of diagnostic conversion in CN, early MCI, or late MCI participants.

CONCLUSION

This study investigated the effect of sleep disturbance on cognitive decline using several outcomes and does not support the hypothesis that sleep disturbance predicts subsequent cognitive decline.

Daytime sleepiness in dementia with Lewy bodies is associated with neuronal depletion of the nucleus basalis of Meynert

INTRODUCTION

Excessive daytime sleepiness is a commonly reported clinical feature of dementia with Lewy bodies (DLB) that can occur early in the disease. Cholinergic depletion is known to be severe in DLB, even when dementia severity is mild. The nucleus basalis of Meynert serves as a primary source of cortical acetylcholine, and has a role in facilitating cortical activation and arousal. We sought to determine whether daytime sleepiness at the initial evaluation of patients with DLB was associated with neuronal loss in the nucleus basalis of Meynert.

METHODS

Autopsy-confirmed patients who met clinical criteria for probable DLB at their initial evaluation and who were administered the informant-completed Epworth Sleepiness Scale were included in the study (n = 40). Each patient had a dementia at baseline (80% with mild severity) and two or more features of parkinsonism, visual hallucinations, fluctuations, or probable REM sleep behavior disorder. Quantitative digital pathology of the nucleus basalis of Meynert was performed in the DLB group and in 20 non-DLB autopsy controls.

RESULTS

DLB had greater neuronal depletion in the nucleus basalis of Meynert (p < 0.0001) than pathologic controls. Sleepiness was present in 58% of the DLB group and those with daytime sleepiness had significantly lower neuron counts in the nucleus basalis of Meynert than their non-sleepy counterparts (p = 0.001). Regression modeling revealed that sleepiness was a stronger predictor of neuronal loss in the nucleus basalis of Meynert than visual hallucinations, fluctuations or dementia severity (p = 0.003).

CONCLUSIONS

Excessive daytime sleepiness in early DLB is indicative of a more profound loss of basal forebrain cholinergic integrity.

Bright light therapy for sleep disturbance in dementia is most effective for mild to moderate Alzheimer's type dementia: a case series

BACKGROUND

Sleep problems in people with dementia are common and place a high burden on caregivers. Although hypnotic agents are often used to treat sleep disturbances, their use is associated with a considerable number of high-risk side-effects such as daytime sleepiness, amnesia, and an increased frequency of falling. The administration of bright light therapy (BLT) in the morning was a non-pharmacological remedy that was expected to treat sleep disorders in patients with dementia by entraining the circadian rhythm to ameliorate disturbances to the normal sleep-wake cycle. However, there are some unsolved issues related to the application of BLT, including the types of dementia for which it is effective and its efficacy in the different stages of cognitive decline and dementia. Furthermore, a protocol for effective BLT has not yet been proposed.

METHODS

In this study, we explored the efficacy of BLT in the treatment of 17 participants, including those with Alzheimer's type dementia (AD) (n = 8), vascular dementia (n = 4), and dementia with Lewy bodies (n = 5). Patients sat in front of the light box for 1 h/day from 0900 to 1000. The patients underwent treatment every day for 2 weeks.

RESULTS

BLT led to the improvement of sleep disturbance in four participants, all of whom were AD patients. The four AD patients showed a shorter duration of illness and/or had mild to moderate AD.

CONCLUSION

BLT could be an effective strategy for treating dementia patients, depending on their type and grade of their dementia. To confirm this hypothesis, it would be necessary to study a larger number of cases. Non-pharmacological therapies for sleep disorders should be emphasized as a safe form of treatment for patients with dementia.

Sleep in older adults and in subjects with dementia

The neuronal structures for the regulation of sleep and wakefulness are located in the brain. This complex network is vulnerable to numerous factors, most importantly neurodegenerative diseases and drugs. The macrostructure and microstructure of sleep change with age. These changes are more pronounced in subjects with dementia. Sleep disorders in subjects with dementia may be independent of dementia or caused by dementia. Furthermore, epidemiological studies reveal that sleep disorders per se may induce dementia by reduction of cerebral clearance of beta-amyloids. The population attributable risk (PAR) of sleep disturbances to the incidence of dementia is estimated to be about 15%; therefore, management of sleep disturbances in older adults and subjects with dementia gives the opportunity of an impact on incidence and course of dementia. Sleep history should be taken from each individual and obvious sleep disturbances, especially sleep apnea, should be managed according to current guidelines. Future studies that concern the incidence and the management of dementia must take into account sleep and sleep disturbances.

Efficacy, Safety, and Tolerability of Armodafinil Therapy for Hypersomnia Associated with Dementia with Lewy Bodies: A Pilot Study

BACKGROUND/AIMS

Hypersomnia is common in dementia with Lewy bodies (DLB). We assessed the efficacy, safety, and tolerability of armodafinil for hypersomnia associated with DLB.

METHODS

We performed a 12-week pilot trial of armodafinil therapy (125-250 mg orally daily) in DLB outpatients with hypersomnia. The patients underwent neurologic examinations, a neuropsychological battery, laboratory testing, electrocardiography, and polysomnography. Efficacy was assessed at 2, 4, 8, and 12 weeks. Safety assessment included laboratory examinations, QTc interval, and heart rate. Tolerability was assessed by analysis of adverse events. Data were analyzed using the last-observation-carried-forward method.

RESULTS

Of 20 participants, 17 completed the protocol. The median age was 72 years, most of the participants were men (80%), and most had spouses as caregivers. The Epworth Sleepiness Scale (p < 0.001), Maintenance of Wakefulness Test (p = 0.003), and Clinical Global Impression of Change (p < 0.001) scores improved at week 12. The Neuropsychiatric Inventory total score (p = 0.003), visual hallucinations (p = 0.003), and agitation (p = 0.02) improved at week 4. Caregiver overall quality of life improved at week 12 (p = 0.004). No adverse events occurred.

CONCLUSION

These pilot data suggest improvements in hypersomnia and wakefulness and reasonable safety and tolerability of armodafinil therapy in hypersomnolent patients with DLB. Our findings inform the use of pharmacologic strategies for managing hypersomnolence in these patients.

Alterations of Clock Gene RNA Expression in Brain Regions of a Triple Transgenic Model of Alzheimer's Disease

A disruption to circadian rhythmicity and the sleep/wake cycle constitutes a major feature of Alzheimer's disease (AD). The maintenance of circadian rhythmicity is regulated by endogenous clock genes and a number of external Zeitgebers, including light. This study investigated the light induced changes in the expression of clock genes in a triple transgenic model of AD (3×Tg-AD) and their wild type littermates (Non-Tg). Changes in gene expression were evaluated in four brain areas¾suprachiasmatic nucleus (SCN), hippocampus, frontal cortex and brainstem¾of 6- and 18-month-old Non-Tg and 3×Tg-AD mice after 12 h exposure to light or darkness. Light exposure exerted significant effects on clock gene expression in the SCN, the site of the major circadian pacemaker. These patterns of expression were disrupted in 3×Tg-AD and in 18-month-old compared with 6-month-old Non-Tg mice. In other brain areas, age rather than genotype affected gene expression; the effect of genotype was observed on hippocampal Sirt1 expression, while it modified the expression of genes regulating the negative feedback loop as well as Rorα, Csnk1ɛ and Sirt1 in the brainstem. In conclusion, during the early development of AD, there is a disruption to the normal expression of genes regulating circadian function after exposure to light, particularly in the SCN but also in extra-hypothalamic brain areas supporting circadian regulation, suggesting a severe impairment of functioning of the clock gene pathway. Even though this study did not demonstrate a direct association between these alterations in clock gene expression among brain areas with the cognitive impairments and chrono-disruption that characterize the early onset of AD, our novel results encourage further investigation aimed at testing this hypothesis.

Pharmacotherapies for sleep disturbances in dementia

BACKGROUND

Sleep disturbances, including reduced nocturnal sleep time, sleep fragmentation, nocturnal wandering, and daytime sleepiness are common clinical problems in dementia, and are associated with significant caregiver distress, increased healthcare costs, and institutionalisation. Drug treatment is often sought to alleviate these problems, but there is significant uncertainty about the efficacy and adverse effects of the various hypnotic drugs in this vulnerable population.

OBJECTIVES

To assess the effects, including common adverse effects, of any drug treatment versus placebo for sleep disorders in people with dementia, through identification and analysis of all relevant randomised controlled trials (RCTs).

SEARCH METHODS

We searched ALOIS (www.medicine.ox.ac.uk/alois), the Cochrane Dementia and Cognitive Improvement Group's Specialized Register, in March 2013 and again in March 2016, using the terms: sleep, insomnia, circadian, hypersomnia, parasomnia, somnolence, rest-activity, sundowning.

SELECTION CRITERIA

We included RCTs that compared a drug with placebo, and that had the primary aim of improving sleep in people with dementia who had an identified sleep disturbance at baseline. Trials could also include non-pharmacological interventions, as long as both drug and placebo groups had the same exposure to them.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data on study design, risk of bias, and results from the included study reports. We obtained additional information from study authors where necessary. We used the mean difference as the measure of treatment effect, and where possible, synthesized results using a fixed-effect model.

MAIN RESULTS

We found six RCTs eligible for inclusion for three drugs: melatonin (222 participants, four studies, but only two yielded data on our primary sleep outcomes suitable for meta-analysis), trazodone (30 participants, one study), and ramelteon (74 participants, one study, no peer-reviewed publication, limited information available).The participants in the trazodone study and almost all participants in the melatonin studies had moderate-to-severe dementia due to Alzheimer's disease (AD); those in the ramelteon study had mild-to-moderate AD. Participants had a variety of common sleep problems at baseline. All primary sleep outcomes were measured using actigraphy. In one study of melatonin, drug treatment was combined with morning bright light therapy. Only two studies made a systematic assessment of adverse effects. Overall, the evidence was at low risk of bias, although there were areas of incomplete reporting, some problems with participant attrition, related largely to poor tolerance of actigraphy and technical difficulties, and a high risk of selective reporting in one trial that contributed very few participants. The risk of bias in the ramelteon study was unclear due to incomplete reporting.We found no evidence that melatonin, at doses up to 10 mg, improved any major sleep outcome over 8 to 10 weeks in patients with AD who were identified as having a sleep disturbance. We were able to synthesize data for two of our primary sleep outcomes: total nocturnal sleep time (mean difference (MD) 10.68 minutes, 95% CI -16.22 to 37.59; N = 184; two studies), and the ratio of daytime sleep to night-time sleep (MD -0.13, 95% CI -0.29 to 0.03; N = 184; two studies). From single studies, we found no difference between melatonin and placebo groups for sleep efficiency, time awake after sleep onset, or number of night-time awakenings. From two studies, we found no effect of melatonin on cognition or performance of activities of daily living (ADL). No serious adverse effects of melatonin were reported in the included studies. We considered this evidence to be of low quality.There was low-quality evidence that trazodone 50 mg given at night for two weeks improved total nocturnal sleep time (MD 42.46 minutes, 95% CI 0.9 to 84.0; N = 30; one study), and sleep efficiency (MD 8.53%, 95% CI 1.9 to 15.1; N = 30; one study) in patients with moderate-to-severe AD, but it did not affect the amount of time spent awake after sleep onset (MD -20.41, 95% CI -60.4 to 19.6; N = 30; one study), or the number of nocturnal awakenings (MD -3.71, 95% CI -8.2 to 0.8; N = 30; one study). No effect was seen on daytime sleep, cognition, or ADL. No serious adverse effects of trazodone were reported.Results from a phase 2 trial investigating ramelteon 8 mg administered at night were available in summary form in a sponsor's synopsis. Because the data were from a single, small study and reporting was incomplete, we considered this evidence to be of low quality in general terms. Ramelteon had no effect on total nocturnal sleep time at one week (primary outcome) or eight weeks (end of treatment) in patients with mild-to-moderate AD. The synopsis reported few significant differences from placebo for any sleep, behavioural, or cognitive outcomes; none were likely to be of clinical significance. There were no serious adverse effects from ramelteon.

AUTHORS' CONCLUSIONS

We discovered a distinct lack of evidence to help guide drug treatment of sleep problems in dementia. In particular, we found no RCTs of many drugs that are widely prescribed for sleep problems in dementia, including the benzodiazepine and non-benzodiazepine hypnotics, although there is considerable uncertainty about the balance of benefits and risks associated with these common treatments. From the studies we identified for this review, we found no evidence that melatonin (up to 10mg) helped sleep problems in patients with moderate to severe dementia due to AD. There was some evidence to support the use of a low dose (50 mg) of trazodone, although a larger trial is needed to allow a more definitive conclusion to be reached on the balance of risks and benefits. There was no evidence of any effect of ramelteon on sleep in patients with mild to moderate dementia due to AD. This is an area with a high need for pragmatic trials, particularly of those drugs that are in common clinical use for sleep problems in dementia. Systematic assessment of adverse effects is essential.

Sleep in Alzheimer's Disease - Beyond Amyloid

Sleep disorders are prevalent in Alzheimer's disease (AD) and a major cause of institutionalization. Like AD pathology, sleep abnormalities can appear years before cognitive decline and may be predictive of dementia. A bidirectional relationship between sleep and amyloid β (Aβ) has been well established with disturbed sleep and increased wakefulness leading to increased Aβ production and decreased Aβ clearance; whereas Aβ deposition is associated with increased wakefulness and sleep disturbances. Aβ fluctuates with the sleep-wake cycle and is higher during wakefulness and lower during sleep. This fluctuation is lost with Aβ deposition, likely due to its sequestration into amyloid plaques. As such, Aβ is believed to play a significant role in the development of sleep disturbances in the preclinical and clinical phases of AD. In addition to Aβ, the influence of tau AD pathology is likely important to the sleep disturbances observed in AD. Abnormal tau is the earliest observable AD-like pathology in the brain with abnormal tau phosphorylation in many sleep regulating regions such as the locus coeruleus, dorsal raphe, tuberomammillary nucleus, parabrachial nucleus, and basal forebrain prior to the appearance of amyloid or cortical tau pathology. Furthermore, human tau mouse models exhibit AD-like sleep disturbances and sleep changes are common in other tauopathies including frontotemporal dementia and progressive supranuclear palsy. Together these observations suggest that tau pathology can induce sleep disturbances and may play a large role in the sleep disruption seen in AD. To elucidate the relationship between sleep and AD it will be necessary to not only understand the role of amyloid but also tau and how these two pathologies, together with comorbid pathology such as alpha-synuclein, interact and affect sleep regulation in the brain.

Depressive symptoms are associated with daytime sleepiness and subjective sleep quality in dementia with Lewy bodies

OBJECTIVE

Sleep problems and depression are common symptoms in dementia with Lewy bodies (DLB), where patients typically experience subjectively poor sleep quality, fatigue and excessive daytime sleepiness. However, whilst sleep disturbances have been linked to depression, this relationship has not received much attention in DLB. The present cross-sectional study addresses this by examining whether depressive symptoms are specifically associated with subjective sleep quality and daytime sleepiness in DLB, and by examining other contributory factors.

METHODS

DLB patients (n = 32) completed the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS) and the 15-item Geriatric Depression Scale (GDS-15). Motor and cognitive functioning was also assessed. Pearson correlations were used to assess the relationship between GDS-15, ESS and PSQI scores.

RESULTS

GDS-15 scores were positively associated with both ESS (r = 0.51, p < 0.01) and PSQI (r = 0.59, p < 0.001) scores.

CONCLUSIONS

Subjective poor sleep and daytime sleepiness were associated with depressive symptoms in DLB. Given the cross-sectional nature of the present study, the directionality of this relationship cannot be determined, although this association did not appear to be mediated by sleep quality or daytime sleepiness. Nevertheless, these findings have clinical relevance; daytime sleepiness or poor sleep quality might indicate depression in DLB, and subsequent work should examine whether the treatment of depression can reduce excessive daytime sleepiness and improve sleep quality in DLB patients. Alternatively, more rigorous screening for sleep problems in DLB might assist the treatment of depression. © 2015 The Authors. International Journal of Geriatric Psychiatry published by John Wiley & Sons, Ltd.

Sleep, Cognition and Dementia

The older patient population is growing rapidly around the world and in the USA. Almost half of seniors over age 65 who live at home are dissatisfied with their sleep, and nearly two-thirds of those residing in nursing home facilities suffer from sleep disorders. Chronic and pervasive sleep complaints and disturbances are frequently associated with excessive daytime sleepiness and may result in impaired cognition, diminished intellect, poor memory, confusion, and psychomotor retardation all of which may be misinterpreted as dementia. The key sleep disorders impacting patients with dementia include insomnia, hypersomnolence, circadian rhythm misalignment, sleep disordered breathing, motor disturbances of sleep such as periodic leg movement disorder of sleep and restless leg syndrome, and parasomnias, mostly in the form of rapid eye movement (REM) sleep behavior disorder (RBD). RBD is a pre-clinical marker for a class of neurodegenerative diseases, the "synucleinopathies", and requires formal polysomnographic evaluation. Untreated sleep disorders may exacerbate cognitive and behavioral symptoms in patients with dementia and are a source of considerable stress for bed partners and family members. When left untreated, sleep disturbances may also increase the risk of injury at night, compromise health-related quality of life, and precipitate and accelerate social and economic burdens for caregivers.

Higher Frequency and Complexity of Sleep Disturbances in Dementia with Lewy Bodies as Compared to Alzheimer's Disease

BACKGROUND

Sleep disturbances (SDs) are common in patients with all forms of dementia. However, most studies focus on Alzheimer's disease (AD) and less is known about the prevalence and characteristics of SD in dementia with Lewy bodies (DLB).

OBJECTIVE

The aims of this cross-sectional study were: (1) to examine the frequency of SD in DLB versus AD; (2) to compare patients with and without SD with regard to relevant clinical variables, and (3) to investigate the associations between SD and medication use.

METHODS

Patients with a first-time diagnosis of probable or possible DLB or AD were selected from the Dementia Study of Western Norway and recruited from clinics for old age psychiatry from 2010 until the end of 2013.

RESULTS

In all, 123 (55.7%) subjects with dementia suffered from at least one SD. Insomnia was present in 77 (34.8%), and 34 (20.7%) patients had probable REM-sleep behaviour disorder (RBD). All SDs were also significantly more frequent in patients with DLB than in AD, and DLB patients also more often had several co-occurring SDs. The presence of any SD was associated with more neuropsychiatric symptoms, higher morbidity, more parkinsonian symptoms and excessive daytime sleepiness. Antiparkinsonian medication was used more often in RBD, restless leg syndrome (RLS) and periodic limb movements, and benzodiazepines were also common in RLS.

CONCLUSIONS

Sleep problems are more common in DLB patients compared to AD, and are associated with more clinical impairment. DLB patients frequently have several sleep problems occurring simultaneously, which suggests a need for screening and accurate assessment of sleep in DLB.

Sleep-disordered breathing in dementia with Lewy bodies

Dementia with Lewy bodies (DLB) is the second most common form of dementia, and it is very frequently associated with changes in sleep patterns. To date, the literature has focused mainly on REM sleep behavior as the most prominent sleep disorder in DLB while little is known about the prevalence and the impact of sleep-disordered breathing (SDB) in DLB. Clinicians should be aware that the clinical diagnosis of SDB in DLB is difficult to establish and that the risk of overlooking SDB in patients with DLB is substantial. Polysomnographic sleep investigations may therefore be advisable in patients with DLB in order to objectify their sleep respiratory patterns. The available literature data on this topic, which are very limited and based on small case series, indicate that SDB occurs in 34.8 to 60% of patients with DLB. SDB can be hypothesized to coexist with other sleep-related disorders in an interactive loop: SDB alters sleep continuity, which can in turn facilitate nocturnal and daytime vigilance-dependent phenomena. There is an absolute need for prospective, preferably multi-center, controlled trials to establish whether, and to what extent, SDB might affect neuropsychological performances in patients with DLB and whether its treatment can improve residual daytime functioning in these patients.

Sleep Quality and Risk of Dementia Among Older Male Veterans

OBJECTIVE

To determine whether a diagnosis of sleep disturbance is associated with dementia in older veterans.

METHODS

For this retrospective cohort study, we obtained medical record data from the Department of Veterans Affairs National Patient Care Database for 200,000 randomly selected veterans aged 55 years and older. Prevalent cases of dementia from the baseline period (2000-2003) were excluded, leaving an analytic sample of 179,738 male veterans. Follow-up took place from 2004 to 2011. The primary outcome was all-cause dementia, ascertained using International Classification of Disease, Ninth Revision codes. Sleep disturbance, the primary predictor, was also ascertained using these codes.

RESULTS

After adjusting for potential confounders, those with sleep disturbance had a 27% increased risk of dementia (hazard ratio: 1.27; 95% confidence interval: 1.20-1.34).

CONCLUSION

Sleep disturbance was associated with increased risk of dementia among a large cohort of older, primarily male veterans.

Increased fragmentation of sleep-wake cycles in the 5XFAD mouse model of Alzheimer's disease

Sleep perturbations including fragmented sleep with frequent night-time awakenings and daytime naps are common in patients with Alzheimer's disease (AD), and these daily disruptions are a major factor for institutionalization. The objective of this study was to investigate if sleep-wake patterns are altered in 5XFAD mice, a well-characterized double transgenic mouse model of AD which exhibits an early onset of robust AD pathology and memory deficits. These mice have five distinct human mutations in two genes, the amyloid precursor protein (APP) and Presenilin1 (PS1) engineered into two transgenes driven by a neuron-specific promoter (Thy1), and thus develop severe amyloid deposition by 4 months of age. Age-matched (4-6.5 months old) male and female 5XFAD mice were monitored and compared to wild-type littermate controls for multiple sleep traits using a non-invasive, high throughput, automated piezoelectric system which detects breathing and gross body movements to characterize sleep and wake. Sleep-wake patterns were recorded continuously under baseline conditions (undisturbed) for 3 days and after sleep deprivation of 4h, which in mice produces a significant sleep debt and challenge to sleep homeostasis. Under baseline conditions, 5XFAD mice exhibited shorter bout lengths (14% lower values for males and 26% for females) as compared to controls (p<0.001). In females, the 5XFAD mice also showed 12% less total sleep than WT (p<0.01). Bout length reductions were greater during the night (the active phase for mice) than during the day, which does not model the human condition of disrupted sleep at night (the inactive period). However, the overall decrease in bout length suggests increased fragmentation and disruption in sleep consolidation that may be relevant to human sleep. The 5XFAD mice may serve as a useful model for testing therapeutic strategies to improve sleep consolidation in AD patients.

Sleep in persons with frontotemporal dementia and their family caregivers

BACKGROUND

Dementia is associated with disruptions in sleep and sleep quality for patients and their family caregivers. Little is known about the impact of frontotemporal dementia (FTD) on sleep.

OBJECTIVE

The purpose of this study was to characterize sleep in patients with FTD and their family caregivers.

METHODS

Twenty-two patient-caregiver dyads were enrolled: Thirteen behavioral variant FTD (bvFTD) and nine semantic dementia (SD). Sleep and sleep quality data were collected for 2 weeks using diaries and Actiwatches.

RESULTS

Patients with bvFTD and SD spent more time in bed at night compared to their caregivers. Nighttime behaviors were reported more frequently by caregivers for the bvFTD patients and strongly correlated with caregiver distress. Actigraphy data showed normal sleep efficiency and timing of the nighttime sleep period for both patients and their caregivers. Caregivers of patients with bvFTD reported poorer sleep quality compared to the SD caregivers. A greater number of bvFTD caregivers compared to SD reported negative aspects of sleep quality for themselves and used sleep medications more frequently.

CONCLUSION

The clinical manifestations of bvFTD appear to be associated with different and more distressing impacts on the caregiver sleep quality than SD.