Bright light treatment of behavioral and sleep disturbances in patients with Alzheimer's disease

Alzheimer's disease pathophysiology in the Retina

The retina is an emerging CNS target for potential noninvasive diagnosis and tracking of Alzheimer's disease (AD). Studies have identified the pathological hallmarks of AD, including amyloid β-protein (Aβ) deposits and abnormal tau protein isoforms, in the retinas of AD patients and animal models. Moreover, structural and functional vascular abnormalities such as reduced blood flow, vascular Aβ deposition, and blood-retinal barrier damage, along with inflammation and neurodegeneration, have been described in retinas of patients with mild cognitive impairment and AD dementia. Histological, biochemical, and clinical studies have demonstrated that the nature and severity of AD pathologies in the retina and brain correspond. Proteomics analysis revealed a similar pattern of dysregulated proteins and biological pathways in the retina and brain of AD patients, with enhanced inflammatory and neurodegenerative processes, impaired oxidative-phosphorylation, and mitochondrial dysfunction. Notably, investigational imaging technologies can now detect AD-specific amyloid deposits, as well as vasculopathy and neurodegeneration in the retina of living AD patients, suggesting alterations at different disease stages and links to brain pathology. Current and exploratory ophthalmic imaging modalities, such as optical coherence tomography (OCT), OCT-angiography, confocal scanning laser ophthalmoscopy, and hyperspectral imaging, may offer promise in the clinical assessment of AD. However, further research is needed to deepen our understanding of AD's impact on the retina and its progression. To advance this field, future studies require replication in larger and diverse cohorts with confirmed AD biomarkers and standardized retinal imaging techniques. This will validate potential retinal biomarkers for AD, aiding in early screening and monitoring.

Effect of Personalized Blue-Enriched White Light Intervention on Rest-Activity and Light Exposure Rhythms in Mild and Moderate Alzheimer's Disease

OBJECTIVE

We aimed to examine the effectiveness of personalized light intervention using a blue-enriched light-emitting-diodes device on rest-activity rhythm (RAR) and light exposure rhythm (LER) in patients with mild and moderate Alzheimer's disease (AD).

METHODS

AD patients with poor sleep quality and/or insomnia symptoms were assigned into either an experimental group (EG) or control group (CG) in a single-blind design. Personalized light intervention was given at 9-10 h after individual dim light melatonin onset, lasting for 1 h every day for two weeks in the EG (77.36±5.79 years, n=14) and CG (78.10±7.98 years, n=10). Each patient of CG wore blue-attenuating sunglasses during the intervention. Actigraphy recording at home for 5 days was done at baseline (T0), immediate postintervention (T1), and at four weeks after intervention (T2). The variables of RAR and LER were derived using nonparametric analysis.

RESULTS

We found a significant time effect on the intradaily variability (IV) of RAR at T2 with respect to T0 (p=0.039), indicating reduced IV of RAR at four weeks after personalized light intervention regardless of blue-enriched light intervention. There was a time effect on the IV of LER at T1 with respect to T0 (p=0.052), indicating a reduced tendency in the IV of LER immediately after intervention.

CONCLUSION

Our personalized light intervention, regardless of blue-enriched light source, could be useful in alleviating fragmentation of RAR and LER in AD patients.

The Impact of Missing Data and Imputation Methods on the Analysis of 24-Hour Activity Patterns

The purpose of this study is to characterize the impact of the timing and duration of missing actigraphy data on interdaily stability (IS) and intradaily variability (IV) calculation. The performance of three missing data imputation methods (linear interpolation, mean time of day (ToD), and median ToD imputation) for estimating IV and IS was also tested. Week-long actigraphy records with no non-wear or missing timeseries data were masked with zeros or 'Not a Number' (NaN) across a range of timings and durations for single and multiple missing data bouts. IV and IS were calculated for true, masked, and imputed (i.e., linear interpolation, mean ToD and, median ToD imputation) timeseries data and used to generate Bland-Alman plots for each condition. Heatmaps were used to analyze the impact of timings and durations of and between bouts. Simulated missing data produced deviations in IV and IS for longer durations, midday crossings, and during similar timing on consecutive days. Median ToD imputation produced the least deviation among the imputation methods. Median ToD imputation is recommended to recapitulate IV and IS under missing data conditions for less than 24 h.

Circadian rhythms-related disorders in diurnal fat sand rats under modern lifestyle conditions: A review

Modern lifestyle reduces environmental rhythmicity and may lead to circadian desynchrony. We are exposed to poor day-time lighting indoors and excessive night-time artificial light. We use air-conditioning to reduce ambient temperature cycle, and food is regularly available at all times. These disruptions of daily rhythms may lead to type 2 diabetes mellitus (T2DM), obesity, cardiometabolic diseases (CMD), depression and anxiety, all of which impose major public health and economic burden on societies. Therefore, we need appropriate animal models to gain a better understanding of their etiologic mechanisms, prevention, and management.We argue that the fat sand rat (Psammomys obesus), a diurnal animal model, is most suitable for studying the effects of modern-life conditions. Numerous attributes make it an excellent model to study human health disorders including T2DM, CMD, depression and anxiety. Here we review a comprehensive series of studies we and others conducted, utilizing the fat sand rat to study the underlying interactions between biological rhythms and health. Understanding these interactions will help deciphering the biological basis of these diseases, which often occur concurrently. We found that when kept in the laboratory (compared with natural and semi-wild outdoors conditions where they are diurnal), fat sand rats show low amplitude, nocturnal or arrhythmic activity patterns, dampened daily glucose rhythm, glucose intolerance, obesity and decreased survival rates. Short photoperiod acclimation exacerbates these pathologies and further dampens behavioral and molecular daily rhythms, resulting in CMD, T2DM, obesity, adipocyte dysfunction, cataracts, depression and anxiety. Increasing environmental rhythmicity by morning bright light exposure or by access to running wheels strengthens daily rhythms, and results in higher peak-to-trough difference in activity, better rhythmicity in clock genes expression, lower blood glucose and insulin levels, improved glucose tolerance, lower body and heart weight, and lower anxiety and depression. In summary, we have demonstrated that fat sand rats living under the correspondent of “human modern lifestyle” conditions exhibit dampened behavioral and biological rhythms and develop circadian desynchrony, which leads to what we have named “The Circadian Syndrome”. Environmental manipulations that increase rhythmicity result in improvement or prevention of these pathologies. Similar interventions in human subjects could have the same positive results and further research on this should be undertaken.

Circadian Rhythm Sleep-Wake Disorders in Older Adults

The timing, duration, and consolidation of sleep result from the interaction of the circadian timing system with a sleep-wake homeostatic process. When aligned and functioning optimally, this allows for wakefulness throughout the day and a long consolidated sleep episode at night. Changes to either the sleep regulatory process or how they interact can result in an inability to fall asleep at the desired time, difficulty remaining asleep, waking too early, and/or difficulty remaining awake throughout the day. This mismatch between the desired timing of sleep and the ability to fall asleep and remain asleep is a hallmark of a class of sleep disorders called the circadian rhythm sleep-wake disorders. In this updated article, we discuss typical changes in the circadian regulation of sleep with aging; how age influences the prevalence, diagnosis, and treatment of circadian rhythm sleep disorders; and how neurologic diseases in older patient impact circadian rhythms and sleep.

Distinct Effects of the Hippocampal Transplantation of Neural and Mesenchymal Stem Cells in a Transgenic Model of Alzheimer's Disease

Alzheimer's disease (AD) is a severe disabling condition with no cure currently available, which accounts for 60-70% of all dementia cases worldwide. Therefore, the investigation of possible therapeutic strategies for AD is necessary. To this end, animal models corresponding to the main aspects of AD in humans have been widely used. Similar to AD patients, the double transgenic APPswe/PS1dE9 (APP/PS1) mice show cognitive deficits, hyperlocomotion, amyloid-β (Αβ) plaques in the cortex and hippocampus, and exacerbated inflammatory responses. Recent studies have shown that these neuropathological features could be reversed by stem cell transplantation. However, the effects induced by neural (NSC) and mesenchymal (MSC) stem cells has never been compared in an AD animal model. Therefore, the present study aimed to investigate whether transplantation of NSC or MSC into the hippocampus of APP/PS1 mice reverses AD-induced pathological alterations, evaluated by the locomotor activity (open field test), short- and long-term memory (object recognition) tests, Αβ plaques (6-E10), microglia distribution (Iba-1), M1 (iNOS) and M2 (ARG-1) microglial phenotype frequencies. NSC and MSC engraftment reduced the number of Αβ plaques and produced an increase in M2 microglia polarization in the hippocampus of APP/PS1 mice, suggesting an anti-inflammatory effect of stem cell transplantation. NSC also reversed the hyperlocomotor activity and increased the number of microglia in the hippocampus of APP/PS1 mice. No impairment of short or long-term memory was observed in APP/PS1 mice. Overall, this study highlights the potential beneficial effects of transplanting NSC or MSC for AD treatment.

Clinical outcomes of light therapy in hospitalized patients - A systematic review

Light therapy and the effects on biological function have been known and investigated for decades. Light therapy is used to compensate for the lack of exposure to sunlight, which is thought to be linked to major depressive disorder with seasonal patterns. It is applied as sessions with bright light mimicking natural sunlight. Lack of bright light during daytime is not the only factor to maintain the circadian rhythm, also lack of exposure to bright light at night is important. A new modality called naturalistic light shows promise, mimicking daylight by dynamically changing intensity and wavelengths throughout the day. Evidence of clinical effects, besides bright light effects on depression, is still limited, especially in hospital populations, and present review aims to extract results of the effect of any optical light intervention on hospitalized patients. Through database search, 29 trials were included, of which 8 trials used a variation of naturalistic light. Trials were heterogeneous regarding designs, populations, interventions, methods and outcomes. In 14 out of 17 studies investigating sleep duration, quality and circadian alignment, along with decreased fatigue and improved mood in daytime, light therapy had a significant effect. Circadian rhythm and rhythmicity were affected as well. The effect on mood and cognition was inconsistent across studies. Trials showed more significant outcomes when conducted in non-intensive care units and with duration >5 days. Lux was reported in and compared across 24 studies and did not appear to be correlated to outcome, rather the distribution of wavelengths should be considered when conducting trials in the future. Of the 8 trials investigating naturalistic light, 4 trials had significant outcomes and 3 had adverse outcomes compared to one in the standard light regime. The overall effect of light therapy is beneficial, but evidence for the effect of naturalistic light is still insufficient to be recommended before other modalities. Future research in this area should be conducted in facilities where naturalistic light is installed, with a focus on the spectral distribution.

Mammalian circadian networks mediated by the suprachiasmatic nucleus

The brain has a complex structure composed of hundreds of regions, forming networks to cooperate body functions. Therefore, understanding how various brain regions communicate with each other and with peripheral organs is important to understand human physiology. The suprachiasmatic nucleus (SCN) in the brain is the circadian pacemaker. The SCN receives photic information from the environment and conveys this to other parts of the brain and body to synchronize all circadian clocks. The circadian clock is an endogenous oscillator that generates daily rhythms in metabolism and physiology in almost all cells via a conserved transcriptional-translational negative feedback loop. So, the information flow from the environment to the SCN to other tissues synchronizes locally distributed circadian clocks to maintain homeostasis. Thus, understanding the circadian networks and how they adjust to environmental changes will better understand human physiology. This review will focus on circadian networks mediated by the SCN to understand how the environment, brain, and peripheral tissues form networks for cooperation.

The Effect of Bright Light Treatment on Rest-Activity Rhythms in People with Dementia: A 24-Week Cluster Randomized Controlled Trial

Bright light treatment is an effective way to influence circadian rhythms in healthy adults, but previous research with dementia patients has yielded mixed results. The present study presents a primary outcome of the DEM.LIGHT trial, a 24-week randomized controlled trial conducted at nursing homes in Bergen, Norway, investigating the effects of a bright light intervention. The intervention consisted of ceiling-mounted LED panels providing varying illuminance and correlated color temperature throughout the day, with a peak of 1000 lx, 6000 K between 10 a.m. and 3 p.m. Activity was recorded using actigraphs at baseline and after 8, 16, and 24 weeks. Non-parametric indicators and extended cosine models were used to investigate rest-activity rhythms, and outcomes were analyzed with multi-level regression models. Sixty-one patients with severe dementia (median MMSE = 4) were included. After 16 weeks, the acrophase was advanced from baseline in the intervention group compared to the control group (B = -1.02, 95%; CI = -2.00, -0.05). There was no significant difference between the groups on any other rest-activity measures. When comparing parametric and non-parametric indicators of rest-activity rhythms, 25 out of 35 comparisons were significantly correlated. The present results indicate that ambient bright light treatment did not improve rest-activity rhythms for people with dementia.

Lighting and Alzheimer's Disease and Related Dementias: Spotlight on Sleep and Depression

Alzheimer's disease and related dementias is the collective term for a progressive neurodegenerative disease for which there is presently no cure. This paper focuses on two symptoms of the disease, sleep disturbances and depression, and discusses how light can be used as a non-pharmacological intervention to mitigate their negative effects. Bright days and dark nights are needed for health and well-being, but the present components of the built environment, especially those places where older adults spend most of their days, are too dimly illuminated during the day and too bright at night. To be effective light needs to be correctly specified, implemented, and measured. Yet without the appropriate specification and measurement of the stimulus, researchers will not be able to successfully demonstrate positive results in the field, nor will lighting designers and specifiers have the confidence to implement lighting solutions for promoting better sleep and mood in this population.

Sensory Stimulation for Nursing-Home Residents: Systematic Review and Meta-Analysis of Its Effects on Sleep Quality and Rest-Activity Rhythm in Dementia

INTRODUCTION

Disrupted sleep-wake cycles might be associated with an exacerbation of behavioural disturbances and accelerate disease progression in dementia. The effect of sensory stimulation for improving sleep quality is unclear.

METHODS

A systematic literature search was performed and all studies examining the effects of a sensory stimulation intervention (i.e. bright light, massage, acupuncture, animal-assisted interventions) on rest-activity rhythm (RAR) and/or nocturnal restlessness in nursing-home residents with dementia were included.

RESULTS

Sensory stimulation was shown to improve nocturnal behavioural restlessness as well as sleep duration and continuation, but the effect on the number of awakenings, RAR, and daytime sleep was negligible. Notable was the high heterogeneity between studies regarding treatments and patients' characteristics and sleep parameters.

CONCLUSION

Sleep quality and nocturnal restlessness in nursing-home residents with dementia may benefit from sensory stimulation. An environment with sensory stimulation may prevent or improve sleep disturbances in nursing homes, and thereby contribute to a better quality of life for their patients.

Ambient bright light treatment improved proxy-rated sleep but not sleep measured by actigraphy in nursing home patients with dementia: a placebo-controlled randomised trial

BACKGROUND

Up to 70% of nursing home patients with dementia suffer from sleep problems. Light is the main zeitgeber to the circadian system and thus has a fundamental impact on sleep-wake behaviour. Low indoor light levels in nursing homes have been reported, and in combination with age-related reductions in light sensitivity, insufficient light exposure is likely to contribute to sleep problems in this population. Increasing daytime light exposure using bright light treatment (BLT) may represent a feasible non-pharmacological treatment for sleep problems in nursing home patients with dementia.

METHODS

The present study reports on sleep outcomes, which are the primary outcomes of the DEM.LIGHT trial (Therapy Light Rooms for Nursing Home Patients with Dementia- Designing Diurnal Conditions for Improved Sleep, Mood and Behavioural Problems), a 24-week cluster-randomised placebo-controlled trial including 8 nursing home units and 69 resident patients. The intervention comprised ambient light of 1000 lx and 6000 K from 10:00 to 15:00, with gradually increasing and decreasing light levels prior to and following this interval, using ceiling mounted light-fixtures and light emitting diode technology. The placebo condition had continuous standard light levels (150-300 lx, ~ 3000 K). Sleep was assessed at baseline and follow-up at week 8, 16, and 24, using the proxy-rated Sleep Disorder Inventory (SDI) and actigraphy (Actiwatch II, Philips Respironics). Mixed linear models were used to evaluate intervention effects, adjusting for relevant covariates such as age, gender, number of drugs, severity of dementia, eye disease, and estimated light exposure.

RESULTS

Sleep as measured by the SDI was significantly improved in the intervention group compared to the control group from baseline to week 16 (B = - 0.06, 95% CI -0.11 - -0.01, p < .05) and from baseline to week 24 (B = - 0.05, 95% CI -0.10 - -0.01, p < .05). There was no effect according to the SDI at week 8 and no significant effects in terms of actigraphically measured sleep.

CONCLUSIONS

Proxy-rated sleep improved among nursing home patients with dementia following 16 and 24 weeks of BLT. These improvements were not corroborated by actigraphy recordings.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03357328 . Registered 29 November 2017 - Retrospectively registered.

Positive effect of timed blue-enriched white light on sleep and cognition in patients with mild and moderate Alzheimer's disease

Conflicting results have been reported regarding the effectiveness of light treatment (LT) in patients with Alzheimer's disease (AD). We investigated the effectiveness of blue-enriched white LT on sleep, cognition, mood and behavior in patients with mild and moderate AD. The treatment group (n = 14) sat about 60 cm away from a small (136 × 73 × 16 mm) LED light box for 1 h each morning for 2 weeks. The control group (n = 11) wore dark, blue-attenuating sunglasses during the 1 h exposures. The morning light started 9-10 h after each individual's dim light melatonin onset (DLMO). Assessments were done at baseline (T0), immediate post-treatment (T1), and 4 weeks after the end of the 2 weeks of LT (T2). Sleep was measured by actigraphy. Blue-enriched LT had a significantly better effect on the Pittsburgh Sleep Quality Index at T2 compared to blue-attenuated LT, and a trend of better effectiveness on total sleep time at T2. There was a significant increase in Mini-Mental State Examination score at T2 after blue-enriched LT than that at T0. Our findings suggest that morning blue-enriched LT has a benefit in improving sleep and cognitive function in AD patients.

Behavioural effects of light intervention in people with Korsakoff Syndrome: A pilot study

Korsakoff Syndrome (KS) is commonly associated with behavioural symptoms such as agitation, apathy, and disinhibition. People with KS often reside in long-term care facilities, which reduces their exposure to natural light. Little is known regarding positive effects of light intervention in KS. Our objective was to evaluate the influence of a dawn simulation therapy on behavioural symptoms in KS. 38 patients residing in a 24-hour care facility were exposed for 6 weeks to a dawn simulation system in their bedrooms, which gradually increased from 0 lux to 290 lux. Behavioural symptoms were measured over 9 weeks. Weeks 1-3 consisted of the baseline phase and weeks 3-9 consisted of the light intervention phase. Our study showed that total severity of neuropsychiatric symptoms was less prominent during light intervention. More specifically, a decrease on the apathy, disinhibition, behaviour at night and appetite and eating behaviour subscales was found during the light intervention phase compared to the baseline phase. Additionally, a significant effect was found on decreasing emotional distress for caregivers. Results suggest that light intervention therapy has a positive effect on reducing behavioural symptoms in KS as well as the levels of stress experienced by the patients' caregivers.

The history of light therapy in hospital physiotherapy and medicine with emphasis on Australia: Evolution into novel areas of practice

Objective: The objective of this narrative review was to investigate the history of light therapy in hospital settings, with reference to physiotherapy and particularly in an Australian context.Types of articles and search method:a review of available literature was conducted on PubMed, Medline and Google Scholar using keywords light therapy, photobiomodulation, physiotherapy, low-level laser, heliotherapy. Physiotherapy textbooks from Sydney University Library were searched. Historical records were accessed from the San Hospital library. Interviews were conducted with the San Hospital Chief Librarian and a retired former Head Physiotherapist from Royal Prince Alfred Hospital.Summary: Historically, light treatment has been used in both medical and physiotherapy practice. From its roots in ancient Egypt, India, and Greece, through to medieval times, the modern renaissance in 'light as therapy ' was begun by Florence Nightingale who, in the 1850s, advocated the use of clean air and an abundance of sunlight to restore health. Modern light therapy (phototherapy) had a marked uptake in use in medicine in Scandinavia, America, and Australia from 1903, following the pioneering work of Niels Finsen in the late 19th century, which culminated in Dr Finsen receiving the Nobel Prize for Medicine for the treatment of tuberculosis scarring with ultraviolet (UV) light, and treatment of smallpox scarring with red light. Treatment with light, especially UVB light, has been widely applied by physiotherapists in hospitals for dermatological conditions since the 1950s, particularly in Australia, Scandinavia, USA, England and Canada. In parallel, light treatment in hospitals for hyperbilirubinemia was used for neonatal jaundice. Since the 1980s light was also used in the medical specialties of ophthalmology, dermatology, and cardiology. In more recent years in physiotherapy, light was mostly used as an adjunct to the management of orthopedic/rheumatological conditions. Since the 1990s, there has been global use of light, in the form of photobiomodulation for the management of lymphedema, including in supportive cancer care. Photobiomodulation in the form of low-level laser has been used by physiotherapists and pain doctors since the 1990s in the management of chronic pain. The use of light as therapy is exemplified by its use in the San Hospital in Sydney, where light therapy was introduced in 1903 (after Dr. John Harvey Kellogg visited Niels Finsen in Denmark) and is practiced by nurses, physiotherapists and doctors until the present day. The use of light has expanded into new and exciting practices including supportive cancer care, and treatment of depression, oral mucositis, retinopathy of prematurity, and cardiac surgery complications. Light is also being used in the treatment of neurological diseases, such as Parkinson's disease, traumatic brain injury, and multiple sclerosis. The innovative uses of light in physiotherapy treatment would not be possible without the previous experience of successful application of light treatment.Conclusion: Light therapy has had a long tradition in medicine and physiotherapy. Although it has fallen somewhat out of favour over the past decades, there has been a renewed interest using modern techniques in recent times. There has been continuous use of light as a therapy in hospitals in Australia, most particularly the San Hospital in Sydney where it has been in use for almost 120 years.

The Sleep Side of Aging and Alzheimer's Disease

As we age, sleep patterns undergo significant modifications in micro and macrostructure, worsening cognition and quality of life. These are associated with remarkable brain changes, like deterioration in synaptic plasticity, gray and white matter, and significant modifications in hormone levels. Sleep alterations are also a core component of mild cognitive impairment (MCI) and Alzheimer's Disease (AD). AD night time is characterized by a gradual decrease in slow-wave activity and a substantial reduction of REM sleep. Sleep abnormalities can accelerate AD pathophysiology, promoting the accumulation of amyloid-β (Aβ) and phosphorylated tau. Thus, interventions that target sleep disturbances in elderly people and MCI patients have been suggested as a possible strategy to prevent or decelerate conversion to dementia. Although cognitive-behavioral therapy and pharmacological medications are still first-line treatments, despite being scarcely effective, new interventions have been proposed, such as sensory stimulation and Noninvasive Brain Stimulation (NiBS). The present review outlines the current state of the art of the relationship between sleep modifications in healthy aging and the neurobiological mechanisms underlying age-related changes. Furthermore, we provide a critical analysis showing how sleep abnormalities influence the prognosis of AD pathology by intensifying Aβ and tau protein accumulation. We discuss potential therapeutic strategies to target sleep disruptions and conclude that there is an urgent need for testing new therapeutic sleep interventions.

Application of light therapy in older adults with cognitive impairment: A systematic review

This systematic review aims to assess the efficacy of light therapy on behavioural and psychological symptoms of dementia (BPSD), cognition, functional status, and quality of life in older adults with cognitive impairment; and secondarily, to identify the optimal characteristics of light therapy to establish an adequate protocol for its clinical application. We searched Web of Science and Medline databases through December 2019, resulting in 36 included articles: 3 evaluated the effects on BPSD, 25 on sleep, 12 on agitation, 10 on mood, 4 on neuropsychiatric symptoms, 4 on cognition, 2 on quality of life and 2 on functional status. Literature has shown potential evidence for positive effects of light therapy on managing sleep, behavioural and mood disturbances in people with cognitive impairment, but a limited effect on cognition, quality of life and functional status. This review provides guidelines for intervention protocols with light therapy in older people with cognitive impairment.

Light interventions and sleep, circadian, behavioral, and psychological disturbances in dementia: A systematic review of methods and outcomes

Dementia is a devastating disease with a global impact, and there is an urgent need for effective interventions to alleviate the accompanying disturbances in behavior, mood, sleep, and circadian rhythms. Bright light treatment (BLT) is a promising non-pharmacological intervention; however, studies have yielded conflicting results. This systematic review provides a comprehensive overview of the effect of BLT in dementia, with a specific focus on how study characteristics might have affected the available results. The included studies were small and comprised time-limited interventions and follow-ups. Light values, adherence to treatment, and time of year were not consistently reported. Varying designs, methods, and population characteristics such as age, gender, dementia diagnosis, circadian phase, and baseline symptoms may have moderated the outcomes and affected review results. The use of crossover designs and too high illumination as placebo lights might have nullified positive effects of BLT. Because some studies had negative outcomes after ambient BLT with high amounts of short wavelengths, more modest light levels should be further investigated. Employing rigorous designs and detailed reporting of intervention characteristics, i.e., the illumination, correlated color temperature, timing, and duration of light utilized, are of utmost importance to establish the optimal treatment approach in this population. Systematic review registration number: PROSPERO CRD42017051004.

Treatment of delirium with phototherapy: a case report

A case is described where phototherapy rapidly restored sleep-wake disturbances and concurrent symptoms of delirium in a patient who did not respond to conventional treatment with haloperidol. In this case, the delirious state may have been caused by a change in metabolism as a result of sepsis. Exposition of the patient to 8,000 Lux during 1.5 h for 5 consecutive days was sufficient to suppress all delirious symptoms and to normalize sleep. This result may encourage the setup of systematic studies towards the extent of desynchronization between various rhythmic cycles in delirium and towards the value of phototherapy for the restoration of normal circadian rhythmicity.

An Actigraphy-Based Validation Study of the Sleep Disorder Inventory in the Nursing Home

Background: Disrupted sleep is common among nursing home patients with dementia and is associated with increased agitation, depression, and cognitive impairment. Detecting and treating sleep problems in this population are therefore of great importance, albeit challenging. Systematic observation and objective recordings of sleep are time-consuming and resource intensive and self-report is often unreliable. Commonly used proxy-rated scales contain few sleep items, which affects the reliability of the raters' reports. The present study aimed to adapt the proxy-rated Sleep Disorder Inventory (SDI) to a nursing home context and validate it against actigraphy. Methods: Cross-sectional study of 69 nursing home patients, 68% women, mean age 83.5 (SD 7.1). Sleep was assessed with the SDI, completed by nursing home staff, and with actigraphy (Actiwatch II, Philips Respironics). The SDI evaluates the frequency, severity, and distress of seven sleep-related behaviors. Internal consistency of the SDI was evaluated by Cronbach's alpha. Spearman correlations were used to evaluate the convergent validity between actigraphy and the SDI. Test performance was assessed by calculating the sensitivity, specificity, and predictive values, and by ROC curve analyses. The Youden's Index was used to determine the most appropriate cut-off against objectively measured sleep disturbance defined as <6 h nocturnal total sleep time (TST) during 8 h nocturnal bed rest (corresponding to SE <75%). Results: The SDI had high internal consistency and convergent validity. Three SDI summary scores correlated moderately and significantly with actigraphically measured TST and wake-after-sleep-onset. A cut-off score of five or more on the SDI summed product score (sum of the products of the frequency and severity of each item) yielded the best sensitivity, specificity, predictive values, and Youden's Index. Conclusion: We suggest a clinical cut-off for the presence of disturbed sleep in institutionalized dementia patients to be a SDI summed product score of five or more. The results suggest that the SDI can be clinically useful for the identification of disrupted sleep when administered by daytime staff in a nursing home context. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT03357328.

Therapy for Insomnia and Circadian Rhythm Disorder in Alzheimer Disease

PURPOSE OF THE REVIEW

There is strong evidence for a bidirectional association between sleep disorders and Alzheimer's disease (AD). In particular, insomnia may be a potentially modifiable risk factor for AD. The present review summarizes recent advances in treatment of sleep disorders in AD.

RECENT FINDINGS

Some studies investigated the efficacy and safety of hypnotic agents as ramelteon and mirtazapine to treat sleep disorders in AD but no significant therapeutic effects have been observed. Benzodiazepines are the most frequently used medication for treatment of insomnia but they may cause significant side effects in old subjects. Suvorexant, an orexin receptor antagonist, showed a positive effect on AD insomnia. Recent report suggests an association between trazodone use and delayed cognitive decline in AD. With respect to circadian rhythm disorders, non-pharmacological treatments, especially bright light therapy, could be useful and safe options for treatment in AD. Some pharmacological and non-pharmacological treatments might have benefits in AD patients with sleep disturbances, but further well-designed controlled trials are needed.

An exploratory investigation of the effect of naturalistic light on fatigue and subjective sleep quality in stroke patients admitted for rehabilitation: A randomized controlled trial

BACKGROUND

Daylight entrains the central circadian pacemaker to the 24-hour day and is crucial for optimal alertness and sleep-quality. Rehabilitation patients tend to lack exposure to sufficient natural light.

OBJECTIVE

Installed diurnal naturalistic light may reduce the known disrupted sleep quality and fatigue seen in post stroke patients.

METHODS

Stroke patients were randomized to either an intervention rehabilitation unit (IU) equipped with naturalistic lighting (artificial sunlight spectrum) or to a control rehabilitation unit (CU) with standard indoor lighting. At inclusion and discharge, fatigue and subjective sleep quality were measured.

RESULTS

Ninety stroke patients were included between May 2014, and June 2015. At discharge, patients from the IU experienced less fatigue than the CU patients, based on the Multidimensional Fatigue Inventory questionnaire general (IU, n = 28; CU, n = 30; diff - 20.6%, 95% confidence interval (CI) [- 35.0%; - 3.0%]; P = 0.025) and the Rested Statement (IU, n = 28; CU, n = 30; diff + 41.6%, 95% CI [+4.6%; +91.8%]; P =  0.025). No differences were detected between groups in sleepiness or subjective sleep quality by the Pittsburgh Sleep Quality Index.

CONCLUSIONS

Fatigue was significantly reduced in rehabilitation patients exposed to naturalistic lighting during admission.

Actigraphy for Assessing Light Effects on Sleep and Circadian Activity Rhythm in Alzheimer's Dementia: A Narrative Review

Background:

Alzheimer's Disease (AD) is often accompanied by severe sleep problems and circadian rhythm disturbances which may to some extent be attributed to a dysfunction in the biological clock. The 24-h light/dark cycle is the strongest Zeitgeber for the biological clock. People with AD, however, often live in environments with inappropriate photic Zeitgebers. Timed bright light exposure may help to consolidate sleep- and circadian rest/activity rhythm problems in AD, and may be a low-risk alternative to pharmacological treatment.

Objective & Method:

In the present review, experts from several research disciplines summarized the results of twenty-seven light intervention studies which used wrist actigraphy to measure sleep and circadian activity in AD patients.

Results:

Taken together, the findings remain inconclusive with regard to beneficial light effects. However, the considered studies varied substantially with respect to the utilized light intervention, study design, and usage of actigraphy. The paper provides a comprehensive critical discussion of these issues.

Conclusion:

Fusing knowledge across complementary research disciplines has the potential to critically advance our understanding of the biological input of light on health and may contribute to architectural lighting designs in hospitals, as well as our homes and work environments.

Therapeutic implications of circadian clocks in neurodegenerative diseases

Circadian clocks, endogenous oscillators generating daily biological rhythms, have important roles in the nervous system to control diverse cellular processes-not only in the suprachiasmatic nucleus (SCN), where the master clocks reside to synchronize all circadian clocks in the body but also in other non-SCN areas. Accumulating evidence has shown relationships between circadian abnormalities (e.g., sleep disturbances and abnormal rest-activity rhythms) and disease progressions in various neurodegenerative diseases, including Alzheimer's (AD) and Parkinson's (PD) disease. Although circadian abnormalities were frequently considered as consequences of disease onsets, recent studies suggest altered circadian clocks as risk factors to develop neurodegenerative diseases via altered production or clearance rates of toxic metabolites like amyloid β. In this review, we will summarize circadian clock-related pathologies in the most common neurodegenerative diseases in the central nervous system, AD and PD. Then, we will introduce the current clinical trials to rescue circadian abnormalities in AD and PD patients. Finally, a discussion about how to improve targeting circadian clocks to increase treatment efficiencies and specificities will be followed. This discussion will provide insight into circadian clocks as potential therapeutic targets to attenuate onsets and progressions of neurodegenerative diseases.

Irregular Sleep-Wake Rhythm Disorder

This article focuses on irregular sleep-wake rhythm disorder (ISWRD) and its associations with several other comorbidities. Irregular sleep-wake rhythm disorder is a circadian disorder characterized by a lack of a clear sleep-wake pattern. The disorder has yet to be fully understood from pathophysiologic perspective. Treatments are available, but there is a need for development of novel interventions. The goal of this article is to focus on multiple aspects of ISWRD.

Effects of a dawn-dusk simulation on circadian rest-activity cycles, sleep, mood and well-being in dementia patients

Light is the most powerful "zeitgeber" signal to synchronize circadian sleep-wake cycles. In dementia, these rhythms are often fragmented - probably due to loss of neuronal function of the suprachiasmatic nuclei (the biological "master clock" in the brain) and/or weakness of external zeitgebers. We investigated the effects of a prototype dawn-dusk simulator (DDS) on circadian rest-activity cycles, sleep, mood and well-being in a balanced crossover design during fall and winter in 20 institutionalized patients with dementia (86 ± 6 y, 17 f). All participants had one baseline week followed by exposure to individually timed DDS over their beds for 7-8 weeks. They spent 8 weeks without DDS as a control. Mood, self-reliant daily activity, social behavior, agitation, and quality of life were assessed by standardized questionnaires and visual analogue scales, regularly rated by trained caregivers. Circadian and sleep characteristics of their rest-activity cycles were analyzed by actimetry over 17 weeks. DDS exposure led to significantly better mood in the morning hours after waking. The effects were most pronounced in the second 4 weeks with DDS, indicating that positive effects emerged gradually. Differences in circadian rest-activity cycles and sleep were mainly age-dependent. We found statistically significant correlations between measures of higher quality of life and better mood, greater alertness and circadian rhythm stability. We conclude that continuous, long-term application of dawn-dusk simulation at the sleep-wake transitions appears to increase external zeitgeber strength in institutionalized patients with dementia. The DDS may provide an effective, non-invasive tool to improve mood and ameliorate patients' quality of life.

Non-pharmacological treatments for sleep disturbance in mild cognitive impairment and dementia: A systematic review and meta-analysis

No disease-modifying treatments for dementia are available. Sleep disturbance is strongly associated with cognitive impairment. Non-pharmacological treatments targeting sleep may offer an alternative therapeutic approach. We searched PubMed, CINAHL, EMBASE and the Cochrane library for non-pharmacological treatments for sleep disturbance in mild cognitive impairment (MCI) and dementia, published in English from October 1965 to 2018, including all designs, excluding studies of drug therapies. In all, 53 papers representing 48 studies were included. Participant age ranged from 67.3 to 89.4 years. Most studies (79%) had small samples (<50 participants, range 1-173) and were conducted in long-term/residential care (62%). The majority (85%) recruited participants with moderate-severe dementia; mean MMSE scores ranged from 0 to 28.3/30. Four studies examined MCI. Light therapy delivered over 1-10 weeks was the most studied stand-alone intervention (n = 27), and the majority (81.5%) of these studies found improvements on objective or subjective sleep measures, though the evidence was inconclusive with significant clinical and methodological heterogeneity. Seven multi-modal intervention studies were identified, all incorporating light exposure, and six of these reported improved sleep. Other interventions included electrotherapy stimulation (n = 4), physical exercises/activities (n = 4), acupressure/acupuncture (n = 3) and mindfulness/cognitive behavioural therapy (n = 3). Those examining MCI utilised different mono-modal approaches. A meta-analysis of data from randomised controlled trials showed a statistically significant (mean difference = 3.44, 95% CI: 0.89-5.99, I²=0%; p = 0.008) improvement in sleep efficiency between interventions and controls, favouring the pooled interventions (bright light, multi-domain and other therapies). No other significant differences in sleep or non-sleep outcomes were found. While evidence is available for non-pharmacological sleep interventions, particularly multi-domain approaches, studies were diverse and had small samples. More research examining multi-modal interventions, community-dwellers and those with MCI is required.

Effects of Light Treatment on Sleep, Cognition, Mood, and Behavior in Alzheimer's Disease: A Systematic Review

BACKGROUND

Bright light treatment is a therapeutic intervention mainly used to treat sleep and circadian disturbances in Alzheimer's disease (AD) patients. Recently, a handful of studies also focused on the effect on cognition and behavior. Conflicting findings are reported in the literature, and no definite conclusions have been drawn about its specific therapeutic effect.

SUMMARY

The aim of this review is to provide a critical evaluation of available evidence in this field, highlighting the specific characteristics of effective bright light treatment. Eligible studies were required to assess at least one of the following outcome measures: sleep, cognition, mood, and/or behavior (e.g., depression, agitation). A total of 32 articles were included in this systematic review and identified as research intervention studies about light treatment in AD. The quality of the papers was evaluated based on the US Preventive Service Task Force guidelines. Key Messages: Overall, the current literature suggests that the effects of light treatment in AD patients are mixed and may be influenced by several factors, but with a general trend toward a positive effect. Bright light seems to be a promising intervention treatment without significant adverse effects; therefore, further well-designed randomized controlled trials are needed taking into account the highlighted recommendations.

The Effect of Light on Sleep and Sleep-Related Physiological Factors Among Patients in Healthcare Facilities: A Systematic Review

OBJECTIVES

Lighting is one of the environmental factors which can improve patient sleep in healthcare environments. Due to the high degree of variation in study designs and results on this topic, the implications have been difficult to interpret. This review consolidates studies on the impact of bright light exposure on sleep to identify lighting conditions that can be applied and researched in future healthcare environments.

METHODS

We searched for peer-reviewed articles on the impact of light on sleep or sleep-related outcomes in healthcare settings. We provided detailed analysis of the direct links between light and sleep, and a more cursory analysis of links between light and sleep-related factors, from 34 articles which met our inclusion criteria.

RESULTS

The current state of the literature includes evidence on how various durations and intensities of morning, midday, and evening bright light exposure, as well as whole-day light exposure interventions can improve specific aspects of sleep. Lighting interventions differed in all attributes (illuminance levels, exposure time, exposure duration, and spectral qualities) but showed promising results in improving patients' sleep.

CONCLUSIONS

Short-term bright light exposure in the morning, up to 2 hr of moderate (3,000-10,000 lux) morning exposures, up to 4 hr of moderate evening exposure, and whole-day exposures to lower illuminance levels (<3,000 lux) can improve patient sleep outcomes. Based on new findings on the mechanism through which light impacts sleep, future studies should be more specific about the spectral qualities of light sources.

Sleepless in the hospital: A systematic review of non-pharmacological sleep interventions

OBJECTIVE

Poor sleep is highly prevalent in inpatient medical settings and has been associated with attenuated healing and worsened outcomes following hospitalization. Although nonpharmacological interventions are preferred, little is known about the best way to intervene in hospital settings.

METHOD

A systematic review of published literature examining nonpharmacological sleep interventions among inpatients in Embase, PsycINFO and PubMed in accordance with PRISMA guidelines.

RESULTS

Forty-three of the 1529 originally identified manuscripts met inclusion criteria, encompassing 2713 hospitalized participants from 18 countries comprised of psychiatric and older adult patients living in hospital settings. Main outcomes were subjective and objective measures of sleep duration, quality, and insomnia.

CONCLUSIONS

Overall, the review was unable to recommend any specific intervention due to the current state of the literature. The majority of included research was limited in quality due to lack of controls, lack of blinding, and reliance on self-reported outcomes. However, the literature suggests melatonin and CBT-I likely have the most promise to improve sleep in inpatient medical settings. Additionally, environmental modifications, including designated quiet time and ear plugs/eye masks, could be easily adopted in the care environment and may support sleep improvement. More rigorous research in nonpharmacological sleep interventions for hospitalized individuals is required to inform clinical recommendations.

Impact of the design of the built environment on people with dementia: an evidence-based review

OBJECTIVE

In this review the impact of the design of the built environment on people with dementia in long-term care settings is systematically analyzed and summarized. Architects and designers will be provided with credible evidence on which they can confidently base their design decisions. Researchers will be able to determine which environmental aspects have been well investigated and where there are gaps in the current state of the research.

BACKGROUND

A great number of studies have established a relationship between the design of the physical environment of long-term care settings and outcomes of people with dementia. However, the methods employed are heterogeneous and the results are often conflicting. Consequently, the process of integrating the best evidence available into architectural designs may be hindered.

METHODS

A systematic literature search was conducted reviewing studies that meet certain inclusion criteria. Using an evidence-based approach, the methodical quality of the studies was rated.

RESULTS

One hundred sixty-nine studies were found. They were thematically summarized into four main categories: basic design decisions, environmental attributes, ambience, and environmental information. The effectiveness of the interventions on the behavior, cognition, function, well being, social abilities, orientation, and care outcomes on people with dementia was illustrated by matrices.

CONCLUSIONS

Results of this review indicate that, with the exception of cognition, specific design interventions are beneficial to the outcomes of people with dementia. Overall, the field of environmental design for people with dementia is well researched in many aspects and only few gaps in knowledge were identified.

Medical hypothesis: Light at night is a factor worth considering in critical care units

Exposure to light at night is not an innocuous consequence of modernization. There are compelling data linking long-term exposure to occupational and environmental light at night with serious health conditions, including heart disease, obesity, diabetes, and cancer. However, far less is known about the physiological and behavioral effects of acute exposure to light at night. Among healthy volunteers, acute night-time light exposure increases systolic blood pressure and inflammatory markers in the blood, and impairs glucose regulation. Whether critically ill patients in a hospital setting experience the same physiological shifts in response to evening light exposure is not known. This paper reviews the available data on light at night effects on health and wellbeing, and argues that the data are sufficiently compelling to warrant studies of how lighting in intensive care units may be influencing patient recovery.

Night-time activity forecast by season and weather in a longitudinal design - natural light effects on three years' rest-activity cycles in nursing home residents with dementia

Backround: Night-time agitation is a frequent symptom of dementia. It often causes nursing home admission and has been linked to circadian rhythm disturbances. A positive influence of light interventions on night-time agitation was shown in several studies. The aim of our study was to investigate whether there is a long-term association between regional weather data (as indicator for daylight availability) and 24-hour variations of motor activity.

METHODS

Motor activity of 20 elderly nursing home residents living with dementia was analyzed using recordings of continuously worn wrist activity monitors over a three-year period. The average recording duration was 479 ± 206 days per participant (mean ± SD). Regional cloud amount and day length data from the local weather station (latitude: 52°56'N) were included in the analysis to investigate their effects on several activity variables.

RESULTS

Nocturnal rest, here defined as the five consecutive hours with the least motor activity during 24 hours (L5), was the most predictable activity variable per participant. There was a significant interaction of night-time activity with day length and cloud amount (F 1,1174 = 4.39; p = 0.036). Night-time activity was higher on cloudy short days than on clear short days (p = 0.007), and it was also higher on cloudy short days than on cloudy long days (p = 0.032).

CONCLUSIONS

The need for sufficient zeitgeber (time cue) strength during winter time, especially when days are short and skies are cloudy, is crucial for elderly people living with dementia. Activity forecast by season and weather might be a valuable approach to anticipate adequately complementary use of electrical light and thereby foster lower night-time activity.

Light, sleep and circadian rhythms in older adults with Alzheimer's disease and related dementias

Alzheimer's disease and related dementias (ADRD) can cause sleep and behavioral problems that are problematic for ADRD patients and their family caregivers. Light therapy has shown promise as a nonpharmacological treatment, and preliminary studies demonstrate that timed light exposure can consolidate and improve nighttime sleep efficiency, increase daytime wakefulness and reduce evening agitation without the adverse effects of pharmacological solutions. Compliance with light treatment and the accurate measurement of light exposures during treatment, however, have presented barriers for the adoption of light therapy for ADRD. Recent research showing that the circadian system is maximally sensitive to short-wavelength light opens the way for the potential application of lower, more-targeted light intensities to maximize compliance and individualize light dose/timing in therapeutic settings.

Sundowning in Dementia: Clinical Relevance, Pathophysiological Determinants, and Therapeutic Approaches

Sundowning means the emergence or worsening of neuropsychiatric symptoms (NPS) in the late afternoon or early evening. This syndrome has been recognized since a long time in the field of dementing illnesses and is well known among most of health-care providers involved in the assistance of people with dementia. Indeed, it represents a common manifestation among persons with dementia and is associated with several adverse outcomes (such as institutionalization, faster cognitive worsening, and greater caregiver burden). Its occurrence and phenotypic characteristics may be influenced by diverse neurobiological, psychosocial, and environmental determinants. Moreover, it may pose diagnostic challenges in relation to other common causes of behavioral disruptions. Beside these considerations, this phenomenon has so far drawn limited clinical and scientific interest compared to other specific NPS occurring in dementias, as indicated by the lack of commonly agreed definitions, specific screening/assessment tools, and robust estimates on its prevalence. Accordingly, no randomized controlled trial specifically investigating the effectiveness of pharmacological and non-pharmacological strategies in managing this condition among demented patients has been yet conducted. In the present narrative review, we present and discuss available evidence concerning sundowning occurring in people with dementia. A special focus is given to its definitions, pathophysiological determinants, and clinical relevance, as well as to the clinical and therapeutic approaches required for its management in the daily practice.

Effect of light therapy upon disturbed behaviors in Alzheimer patients

Alzheimer's disease (AD) causes sleep and behavioral disturbares which may be related to abnormalities of circadian rhythms caused by damage of the suprachiasmatic nucleis. Exposure to bright light may compensate for this danlage by improving synchronization, timing and amplijude of circadian rhythms. Three case studies, presented in this paper, demonstrate the beneficial effect of light therapy on sleep and one of the cases also suggests that light therapy may be effective in the treatment of agitated behavior. The clinical observations also suggest a need for increased level of lighting in long term care facilites.

Need-driven dementia-compromised behavior: An alternative view of disruptive behavior

The disruptive behavior of persons with dementia is a problem of considerable clinical interest and growing scientific concern. This paper offers a view of these behaviors as expressions of unmet needs or goals and provides a comprehensive conceptual framework to guide further research and clinical practice. Empiricalfindings and clinical impressions related to wandering, vocalizations and aggression to support and illustrate the framework are presented

Bright light therapy for demented nursing home patients with behavioral disturbance

The objective of this study was to examine the effects of morning bright light on behavioral disturbances in dementia using a repeated measures ABA design. We hypothesized that morning bright light in demented patients reduces the agitation rating and directly observed disruptive behavior, but increases observed positive behavior.

The study was done in a special care unit of a long term care facility, with 16 demented residents ages 60 to 89, 13 female and three male. Morning bright light (Day-Light Box 10000, produced by DayLight Technologies, Inc, providing 10,000 lux) was administered Monday to Friday during the treatment week. The Global Deterioration Scale rating at baseline, followed by baseline, treatment and post-treatment ratings in the Cohen-Mansfield Agitation Inventory (CMAI) and Environment-Behavior Interaction Code (EBIC) were used as measurements

Compared to baseline, the mean total Cohen-Mansfield score decreased more during the phototherapy week than during the post-treatment week (p < 0.05 on one-tailed paired t-test). Regardless of phototherapy, Cohen-Mansfield scores decreased significantly in summer versus fall-spring (p < .005). Although the direct behavioral measures [EBIC] showed no statistically significant change compared to baseline, there was a pattern of greater mean increase in positive behaviors (p = .08) during phototherapy than in the post-treatment week, and a mean decrease of total disruptive behaviors most pronounced in the post-treatment week (p = .05).

Bright light therapy has modest efficacy in reducing agitation, with possible concurrent improvement in positive behaviors. Disruptive behaviors may also become less frequent during phototherapy with evidence of even greater delayed optimal effect. Further research should focus on subgroups of patients demonstrating a particularly robust response, enhance power through a larger sample, provide for longer light exposure, and control for seasonal variables.

Treatment of Sleep Disorders in Dementia

OPINION STATEMENT

Sleep and circadian disorders occur frequently in all types of dementia. Due to the multifactorial nature of sleep problems in dementia, we propose a structured approach to the evaluation and treatment of these patients. Primary sleep disorders such as obstructive sleep apnea should be treated first. Comorbid conditions and medications that impact sleep should be optimally managed to minimize negative effects on sleep. Patients and caregivers should maintain good sleep hygiene, and social and physical activity should be encouraged during the daytime. Given the generally benign nature of bright light therapy and melatonin, these treatments should be tried first. Pharmacological treatments should be added cautiously, due to the risk of cognitive side effects, sedation, and falls in the demented and older population. Regardless of treatment modality, it is essential to follow patients with dementia and sleep disorders closely, with serial monitoring of individual response to treatment.

Clinical Practice Guideline for the Treatment of Intrinsic Circadian Rhythm Sleep-Wake Disorders: Advanced Sleep-Wake Phase Disorder (ASWPD), Delayed Sleep-Wake Phase Disorder (DSWPD), Non-24-Hour Sleep-Wake Rhythm Disorder (N24SWD), and Irregular Sleep-Wake Rhythm Disorder (ISWRD). An Update for 2015: An American Academy of Sleep Medicine Clinical Practice Guideline

A systematic literature review and meta-analyses (where appropriate) were performed and the GRADE approach was used to update the previous American Academy of Sleep Medicine Practice Parameters on the treatment of intrinsic circadian rhythm sleep-wake disorders. Available data allowed for positive endorsement (at a second-tier degree of confidence) of strategically timed melatonin (for the treatment of DSWPD, blind adults with N24SWD, and children/ adolescents with ISWRD and comorbid neurological disorders), and light therapy with or without accompanying behavioral interventions (adults with ASWPD, children/adolescents with DSWPD, and elderly with dementia). Recommendations against the use of melatonin and discrete sleep-promoting medications are provided for demented elderly patients, at a second- and first-tier degree of confidence, respectively. No recommendations were provided for remaining treatments/ populations, due to either insufficient or absent data. Areas where further research is needed are discussed.

Suprachiasmatic neuron numbers and rest-activity circadian rhythms in older humans

The suprachiasmatic nucleus (SCN) of the hypothalamus, the master mammalian circadian pacemaker, synchronizes endogenous rhythms with the external day-night cycle. Older humans, particularly those with Alzheimer disease (AD), often have difficulty maintaining normal circadian rhythms compared to younger adults, but the basis of this change is unknown. We report that the circadian rhythm amplitude of motor activity in both AD subjects and age-matched controls is correlated with the number of vasoactive intestinal peptide-expressing SCN neurons. AD was additionally associated with delayed circadian phase compared to cognitively healthy subjects, suggesting distinct pathologies and strategies for treating aging- and AD-related circadian disturbances.

Methodological challenges in studies of bright light therapy to treat sleep disorders in nursing home residents with dementia

AIM

Numerous studies have explored the effectiveness of bright light therapy as a treatment of sleep disorders in nursing home and long-stay geriatric hospital residents, most of whom have dementia. A recent Cochrane Collaboration meta-analysis of 10 selected studies concluded that there was insufficient evidence to assess its therapeutic efficacy as most available studies had methodological problems. We sought to remedy this situation by developing proposals to guide research methods in future studies.

METHODS

Based on the literature and our own clinical and research experience, we developed a series of proposals relating to study design, participant selection, light delivery modalities and outcome measures that we believe will maximize the chances of identifying a bright light treatment effect. We then checked adherence to these proposals in all relevant published experimental studies.

RESULTS

Of the 18 studies published in the last two decades that met our selection criteria, only half the studies had selected participants with a sleep disorder. Eleven studies excluded people with severe vision loss; seven included a clinical rating of sleep, and five measured baseline lighting levels. Most checked psychoactive medication prescriptions but few reported changes in prescriptions over the course of the study. Most also checked treatment adherence and included some control for differences in amount of social contact.

CONCLUSIONS

Evidence for the effectiveness of bright white light treatment in people residing in nursing homes is equivocal. We anticipate that the quality of this evidence will be improved if researchers refine their study methods and adopt a more uniform approach.

Tailored lighting intervention improves measures of sleep, depression, and agitation in persons with Alzheimer's disease and related dementia living in long-term care facilities

Background

Light therapy has shown great promise as a nonpharmacological method to improve symptoms associated with Alzheimer’s disease and related dementias (ADRD), with preliminary studies demonstrating that appropriately timed light exposure can improve nighttime sleep efficiency, reduce nocturnal wandering, and alleviate evening agitation. Since the human circadian system is maximally sensitive to short-wavelength (blue) light, lower, more targeted lighting interventions for therapeutic purposes, can be used.

Methods

The present study investigated the effectiveness of a tailored lighting intervention for individuals with ADRD living in nursing homes. Low-level “bluish-white” lighting designed to deliver high circadian stimulation during the daytime was installed in 14 nursing home resident rooms for a period of 4 weeks. Light–dark and rest–activity patterns were collected using a Daysimeter. Sleep time and sleep efficiency measures were obtained using the rest–activity data. Measures of sleep quality, depression, and agitation were collected using standardized questionnaires, at baseline, at the end of the 4-week lighting intervention, and 4 weeks after the lighting intervention was removed.

Results

The lighting intervention significantly (P<0.05) decreased global sleep scores from the Pittsburgh Sleep Quality Index, and increased total sleep time and sleep efficiency. The lighting intervention also increased phasor magnitude, a measure of the 24-hour resonance between light–dark and rest–activity patterns, suggesting an increase in circadian entrainment. The lighting intervention significantly (P<0.05) reduced depression scores from the Cornell Scale for Depression in Dementia and agitation scores from the Cohen–Mansfield Agitation Inventory.

Conclusion

A lighting intervention, tailored to increase daytime circadian stimulation, can be used to increase sleep quality and improve behavior in patients with ADRD. The present field study, while promising for application, should be replicated using a larger sample size and perhaps using longer treatment duration.

Synchronizing an aging brain: can entraining circadian clocks by food slow Alzheimer's disease?

Alzheimer's disease (AD) is a global epidemic. Unfortunately, we are still without effective treatments or a cure for this disease, which is having devastating consequences for patients, their families, and societies around the world. Until effective treatments are developed, promoting overall health may hold potential for delaying the onset or preventing neurodegenerative diseases such as AD. In particular, chronobiological concepts may provide a useful framework for identifying the earliest signs of age-related disease as well as inexpensive and noninvasive methods for promoting health. It is well reported that AD is associated with disrupted circadian functioning to a greater extent than normal aging. However, it is unclear if the central circadian clock (i.e., the suprachiasmatic nucleus) is dysfunctioning, or whether the synchrony between the central and peripheral clocks that control behavior and metabolic processes are becoming uncoupled. Desynchrony of rhythms can negatively affect health, increasing morbidity and mortality in both animal models and humans. If the uncoupling of rhythms is contributing to AD progression or exacerbating symptoms, then it may be possible to draw from the food-entrainment literature to identify mechanisms for re-synchronizing rhythms to improve overall health and reduce the severity of symptoms. The following review will briefly summarize the circadian system, its potential role in AD, and propose using a feeding-related neuropeptide, such as ghrelin, to synchronize uncoupled rhythms. Synchronizing rhythms may be an inexpensive way to promote healthy aging and delay the onset of neurodegenerative disease such as AD.

Light therapy for improving cognition, activities of daily living, sleep, challenging behaviour, and psychiatric disturbances in dementia

BACKGROUND

Rest-activity and sleep-wake cycles are controlled by the endogenous circadian rhythm generated by the suprachiasmatic nuclei (SCN) of the hypothalamus. Degenerative changes in the SCN appear to be a biological basis for circadian disturbances in people with dementia, and might be reversed by stimulation of the SCN by light.

OBJECTIVES

The review examines the effectiveness of light therapy in improving cognition, activities of daily living (ADLs), sleep, challenging behaviour, and psychiatric symptoms associated with dementia.

SEARCH METHODS

ALOIS, the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group (CDCIG), The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL and LILACS were searched on 20 January 2014 using the terms: "bright light*", "light box*", "light visor*", "dawn-dusk*", phototherapy, "photo therapy", "light therapy" "light treatment", light* . The CDCIG Specialized Register contains records from all major healthcare databases (The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, LILACS) as well as from many trials databases and grey literature sources.

SELECTION CRITERIA

All relevant, randomized controlled trials were included in which light therapy, at any intensity and duration, was compared with a control group for the effect of improving cognition, ADLs, sleep, challenging behaviour, and psychiatric symptoms associated with dementia (as well as institutionalization rates or cost of care). Included were people with dementia of any type and degree of severity.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the retrieved articles for relevance, and four review authors independently assessed the selected studies for risk of bias and extracted the data. Statistically significant differences in outcomes between the treatment and control groups at the end of treatment and follow-up were examined. Each study was summarized using a measure of effect (for example mean difference).

MAIN RESULTS

Eleven trials (13 articles) met the inclusion criteria. However, three of the studies could not be included in the analyses either because the reported data could not be used in the meta-analysis or we were unable to retrieve the required data from the authors.This updated review found no effect of light therapy on cognitive function, sleep, challenging behaviour (for example agitation), or psychiatric symptoms associated with dementia. Reduction in the development of ADL limitations was reported in one study, at three of five time points, and light therapy was found to have an effect after six weeks and two years but not after one year.

AUTHORS' CONCLUSIONS

There is insufficient evidence to justify the use of bright light therapy in dementia. Further research should concentrate on replicating the suggested effect on ADLs, and establishing the biological mechanism for how light therapy improves these important outcomes.

Noninvasive fractal biomarker of clock neurotransmitter disturbance in humans with dementia

Human motor activity has a robust, intrinsic fractal structure with similar patterns from minutes to hours. The fractal activity patterns appear to be physiologically important because the patterns persist under different environmental conditions but are significantly altered/reduced with aging and Alzheimer's disease (AD). Here, we report that dementia patients, known to have disrupted circadian rhythmicity, also have disrupted fractal activity patterns and that the disruption is more pronounced in patients with more amyloid plaques (a marker of AD severity). Moreover, the degree of fractal activity disruption is strongly associated with vasopressinergic and neurotensinergic neurons (two major circadian neurotransmitters) in postmortem suprachiasmatic nucleus (SCN), and can better predict changes of the two neurotransmitters than traditional circadian measures. These findings suggest that the SCN impacts human activity regulation at multiple time scales and that disrupted fractal activity may serve as a non-invasive biomarker of SCN neurodegeneration in dementia.

Light therapy and Alzheimer's disease and related dementia: past, present, and future

Sleep disturbances are common in persons with Alzheimer's disease or related dementia (ADRD), resulting in a negative impact on the daytime function of the affected person and on the wellbeing of caregivers. The sleep/wake pattern is directly driven by the timing signals generated by a circadian pacemaker, which may or may not be perfectly functioning in those with ADRD. A 24-hour light/dark pattern incident on the retina is the most efficacious stimulus for entraining the circadian system to the solar day. In fact, a carefully orchestrated light/dark pattern has been shown in several controlled studies of older populations, with and without ADRD, to be a powerful non-pharmacological tool to improve sleep efficiency and consolidation. Discussed here are research results from studies looking at the effectiveness of light therapy in improving sleep, depression, and agitation in older adults with ADRD. A 24-hour lighting scheme to increase circadian entrainment, improve visibility, and reduce the risk of falls in those with ADRD is proposed, and future research needs are discussed.