Prevention of depression and sleep disturbances in elderly with memory-problems by activation of the biological clock with light--a randomized clinical trial

Photoperiod and metabolic health: evidence, mechanism, and implications

Circadian rhythms are evolutionarily programmed biological rhythms that are primarily entrained by the light cycle. Disruption of circadian rhythms is an important risk factor for several metabolic disorders. Photoperiod is defined as total duration of light exposure in a day. With the extended use of indoor/outdoor light, smartphones, television, computers, and social jetlag people are exposed to excessive artificial light at night increasing their photoperiod. Importantly long photoperiod is not limited to any geographical region, season, age, or socioeconomic group, it is pervasive. Long photoperiod is an established disrupter of the circadian rhythm and can induce a range of chronic health conditions including adiposity, altered hormonal signaling and metabolism, premature ageing, and poor psychological health. This review discusses the impact of exposure to long photoperiod on circadian rhythms, metabolic and mental health, hormonal signaling, and ageing and provides a perspective on possible preventive and therapeutic approaches for this pervasive challenge.

Non-pharmacological interventions for sleep disturbances in people with dementia

BACKGROUND

Sleep disturbances occur frequently in people with dementia with a reported prevalence of up to 40%. Common problems are increased number and duration of awakenings and increased percentage of light sleep. Sleep disturbances are associated with a number of problems for people with dementia, their relatives, and carers. In people with dementia, they may lead to worsening of cognitive symptoms, challenging behaviours such as restlessness or wandering, and further harms, such as accidental falls. Sleep disturbances are also associated with significant carer distress and have been reported as a factor contributing to institutionalisation of people with dementia. As pharmacological approaches have shown unsatisfactory results, there is a need to synthesise the research evidence on non-pharmacological strategies to improve sleep in people with dementia. As interventions are often complex, consisting of more than one active component, and implemented in complex contexts, it may not be easy to identify effective intervention components.

OBJECTIVES

To evaluate the benefits and harms of non-pharmacological interventions on sleep disturbances in people with dementia compared to usual care, no treatment, any other non-pharmacological intervention, or any drug treatment intended to improve sleep, and to describe the components and processes of any complex intervention included.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search was 13 January 2022.

SELECTION CRITERIA

We included individually or cluster-randomised controlled trials in people with dementia comparing non-pharmacological interventions to improve sleep compared to usual care or to other interventions of any type. Eligible studies had to have a sleep-related primary outcome. We included people with a diagnosis of dementia and sleep problems at baseline irrespective of age, type of dementia, severity of cognitive impairment, or setting. Studies reporting results on a mixed sample (e.g. in a nursing home) were only considered for inclusion if at least 80% of participants had dementia.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were 1. objective sleep-related outcomes (e.g. total nocturnal sleep time, consolidated sleep time at night, sleep efficiency, total wake time at night (or time spent awake after sleep onset), number of nocturnal awakenings, sleep onset latency, daytime/night-time sleep ratio, night-time/total sleep ratio over 24 hours) and 2.

ADVERSE EVENTS

Our secondary outcomes were 3. subjective sleep-related outcomes, 4. behavioural and psychological symptoms of dementia, 5. quality of life, 6. functional status, 7. institutionalisation, 8. compliance with the intervention, and 9. attrition rates. We used GRADE to assess the certainty of evidence and chose key outcomes to be included in summary of findings tables.

MAIN RESULTS

We included 19 randomised controlled trials with 1335 participants allocated to treatment or control groups. Fourteen studies were conducted in nursing homes, three included community residents, one included 'inpatients', one included people from a mental health centre, and one included people from district community centres for older people. Fourteen studies were conducted in the US. We also identified nine ongoing studies. All studies applied one or more non-pharmacological intervention aiming to improve physiological sleep in people with dementia and sleep problems. The most frequently examined single intervention was some form of light therapy (six studies), five studies included physical or social activities, three carer interventions, one daytime sleep restriction, one slow-stroke back massage, and one transcranial electrostimulation. Seven studies examined multimodal complex interventions. Risk of bias of included studies was frequently unclear due to incomplete reporting. Therefore, we rated no study at low risk of bias. We are uncertain whether light therapy has any effect on sleep-related outcomes (very low-certainty evidence). Physical activities may slightly increase the total nocturnal sleep time and sleep efficiency, and may reduce the total time awake at night and slightly reduce the number of awakenings at night (low-certainty evidence). Social activities may slightly increase total nocturnal sleep time and sleep efficiency (low-certainty evidence). Carer interventions may modestly increase total nocturnal sleep time, may slightly increase sleep efficiency, and may modestly decrease the total awake time during the night (low-certainty evidence from one study). Multimodal interventions may modestly increase total nocturnal sleep time and may modestly reduce the total wake time at night, but may result in little to no difference in number of awakenings (low-certainty evidence). We are uncertain about the effects of multimodal interventions on sleep efficiency (very low-certainty evidence). We found low-certainty evidence that daytime sleep restrictions, slow-stroke back massage, and transcranial electrostimulation may result in little to no difference in sleep-related outcomes. Only two studies reported information about adverse events, detecting only few such events in the intervention groups.

AUTHORS' CONCLUSIONS

Despite the inclusion of 19 randomised controlled trials, there is a lack of conclusive evidence concerning non-pharmacological interventions for sleep problems in people with dementia. Although neither single nor multimodal interventions consistently improved sleep with sufficient certainty, we found some positive effects on physical and social activities as well as carer interventions. Future studies should use rigorous methods to develop and evaluate the effectiveness of multimodal interventions using current guidelines on the development and evaluation of complex interventions. At present, no single or multimodal intervention can be clearly identified as suitable for widespread implementation.

Early impact on sleep and mental health during the mandatory social isolation of COVID-19 outbreak: an obser vational cross-sectional study carried out in Argentina

Introduction

The mandatory social isolation (MSI) due to the pandemic caused by COVID-19 in the world produced many changes in sleep and different areas of mental health. Objectives: To evaluate the early effects of MSI on sleep, anxiety, and depression in Argentina.

Material and Methods

An anonymous observational cross-sectional web-based study was distributed throughout the country and was completed by 2,594 respondents to analyze demographic information, quality of sleep, REM sleep-related events, depressive, and anxiety symptoms.

Results

The study revealed that 53, 21, 22, 23, and 16% of people surveyed were poor sleepers, had dream-related behaviors, nightmares, depression, and anxiety symptoms, respectively. Multivariate logistic regression showed a positive correlation between anxiety, being a poor sleeper, and having nightmares.

Conclusion

We identified the early effects of MSI on sleep quality, dreaming activity, anxiety, and depression in Argentina during the COVID-19 outbreak. Our findings can be used to formulate sleep and psychological interventions to improve mental health during the pandemic and post-pandemic times.

Smart Wearable Device Users' Behavior Is Essential for Physical Activity Improvement

BACKGROUNDS

This study aimed to explore the effect on physical activity and sedentary behavior of users of wearable devices, and understand the association between physical activity and behavior.

METHODS

This study conducted a three-arm, randomized controlled trial for 12 weeks. Healthy adults without experience of using a wearable device were recruited and were randomly assigned to a control group with a mobile app and two experimental groups with different smart wearable devices. Data were collected through questionnaires.

RESULTS

No significant effect of group, time, or group-by-time interaction among groups for physical activity, sedentary time, or sleep quality was found. Wearing duration significantly positively predicted changes in low-intensity and total physical activity. The number of times the device was checked negatively predicted a change in sedentary time.

CONCLUSIONS

The behavior of wearable device users is an essential factor for successfully increasing physical activity and decreasing sedentary time.

Virtual Reality Therapy for Depression and Mood in Long-Term Care Facilities

Virtual reality (VR) describes a family of technologies which immerse users in sensorily-stimulating virtual environments. Such technologies have increasingly found applications in the treatment of neurological and mental health disorders. Depression, anxiety, and other mood abnormalities are of concern in the growing older population-especially those who reside in long-term care facilities (LTCFs). The transition from the familiar home environment to the foreign LTCF introduces a number of stressors that can precipitate depression. However, recent studies reveal that VR therapy (VRT) can promote positive emotionality and improve cognitive abilities in older people, both at home and in LTCFs. VR thus holds potential in allowing older individuals to gradually adapt to their new environments-thereby mitigating the detrimental effects of place attachment and social exclusion. Nevertheless, while the current psychological literature is promising, the implementation of VR in LTCFs faces many challenges. LTCF residents must gain trust in VR technologies, care providers require training to maximize the positive effects of VRT, and decision makers must evaluate both the opportunities and obstacles in adopting VR. In this review article, we concisely discuss the implications of depression related to place attachment in LTCFs, and explore the potential therapeutic applications of VR.

Comparisons of physical activity and sedentary behavior between owners and non-owners of commercial wearable devices

AIMS

Wearable devices are a new strategy for promoting physical activity in a free-living condition that utilizes self-monitoring, self-awareness, and self-determination. The main purpose of this study was to explore health benefits of commercial wearable devices by comparing physical activity, sedentary time, sleep quality, and other health outcomes between individuals who used and those that did not use commercial wearable devices.

METHODS

The research design was a cross-sectional study using an Internet survey in Taiwan. Self-administered questionnaires included the International Physical Activity Questionnaire-Short Form, Pittsburgh Sleep Quality Index, Health-Promoting Lifestyle Profile, and World Health Organization Quality-of-Life Scale.

RESULTS

In total, 781 participants were recruited, including 50% who were users of wearable devices and 50% non-users in the most recent 3 months. Primary outcomes revealed that wearable device users had significantly higher self-reported walking, moderate physical activity, and total physical activity, and significantly lower sedentary time than non-users. Wearable device users had significantly better sleep quality than non-users.

CONCLUSION

Wearable devices inspire users' motivation, engagement, and interest in physical activity through habit formation. Wearable devices are recommended to increase physical activity and decrease sedentary behavior for promoting good health.

The therapeutic effects and safety of bright light therapy combined with escitalopram oxalate on insomnia in patients with poststroke depression

INTRODUCTION

Bright light therapy (BLT) is known to treat depression and sleep disorders in clinical practice, but its efficacy on poststroke depression (PSD) has not been studied.

OBJECTIVE

To investigate the therapeutic effects and safety of BLT combined with escitalopram oxalate (ESC) on insomnia in patients with PSD.

METHODS

Ischemic stroke patients with depressive symptoms and a score of ≥8 on the Hamilton Depression Scale (HAMD-17) while meeting DSM-IV criteria were diagnosed as having PSD. A total of 112 PSD patients with symptoms of insomnia were randomly assigned to polytherapy (BLT plus ESC) and monotherapy (ESC only) groups. Each regimen continued for 6 weeks. The primary outcomes were a change in scores on the Pittsburgh Sleep Quality Index (PSQI) and a remission rate (PSQI ≤7 at the endpoint). The secondary outcomes included changes in the HAMD-17 and Barthel Index (BI) scores. Adverse effects were assessed by the Adverse Events Scale.

RESULTS

The endpoint assessment included 106 patients (monotherapy, 54; polytherapy, 52). The mean changes in the PSQI scores for the monotherapy and polytherapy groups were 4.85 (1.47) and 5.87 (1.72) (P = 0.001), respectively. Compared to monotherapy, polytherapy improved PSQI remission rate (71.4% vs 50.0%; χ2 = 5.390; P = 0.020), and HAMD-17 score (6.70 [2.12] vs 4.75 [1.98]; P < 0.001). Both treatments improved BI score, with no statistical difference, and were well tolerated, with few significant differences in treatment-associated adverse events.

CONCLUSION

BLT combined with ESC is effective and well tolerated for the treatment of PSD-associated insomnia.

Fiat Lux: The Light Became Therapy. An Overview on the Bright Light Therapy in Alzheimer's Disease Sleep Disorders

BACKGROUND

A system of photosensitive retinal ganglion cells provides 'non-visual' information on the circadian sequences of light to the suprachiasmatic nucleus (SCN), which, as the 'master clock', synchronizes the chronobiological mechanisms of all the biological clocks. Damage to SCN structure alters circadian behavioral and hormonal rhythms and interferes with a regular sleep-wake pattern. Several studies have shown that, in aging and in Alzheimer's disease (AD), circadian rhythms change their synchronization with the environment and behavior loses sync with light.

OBJECTIVE

The current overview aims to examine research studies showing the effect of bright light therapy (BLT) on sleep disorders and sleep-wake patterns in AD.

METHODS

A literature search was conducted, taking into consideration the relevant studies over the last 20 years. Fifteen studies have been thorough: seven followed an environmental-architectural approach and eight followed a treatment devices approach.

RESULTS

Studies agree in considering BLT as a promising non-pharmacological intervention to compensate for circadian rhythm alterations and they support the need for standardized protocols that allow a comparison between multicenter studies.

CONCLUSION

Interestingly, in an attempt to contain the spread of the COVID-19 pandemic, health authorities have forced the population to stay home. Therefore, AD people are not currently able to enjoy exposure to sunlight. It is predictable that they may experience an exacerbation of circadian disturbances and that the BLT can be an effective response to prevent such exacerbation.

Aging Affects the Capacity of Photoperiodic Adaptation Downstream from the Central Molecular Clock

Aging impairs circadian clock function, leading to disrupted sleep-wake patterns and a reduced capability to adapt to changes in environmental light conditions. This makes shift work or the changing of time zones challenging for the elderly and, importantly, is associated with the development of age-related diseases. However, it is unclear what levels of the clock machinery are affected by aging, which is relevant for the development of targeted interventions. We found that naturally aged mice of >24 months had a reduced rhythm amplitude in behavior compared with young controls (3-6 months). Moreover, the old animals had a strongly reduced ability to adapt to short photoperiods. Recording PER2::LUC protein expression in the suprachiasmatic nucleus revealed no impairment of the rhythms in PER2 protein under the 3 different photoperiods tested (LD: 8:16, 12:12, and 16:8). Thus, we observed a discrepancy between the behavioral phenotype and the molecular clock, and we conclude that the aging-related deficits emerge downstream of the core molecular clock. Since it is known that aging affects several intracellular and membrane components of the central clock cells, it is likely that an impairment of the interaction between the molecular clock and these components is contributing to the deficits in photoperiod adaptation.

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.

Light therapy for preventing seasonal affective disorder

BACKGROUND

Seasonal affective disorder (SAD) is a seasonal pattern of recurrent major depressive episodes that most commonly occurs during autumn or winter and remits in spring. The prevalence of SAD ranges from 1.5% to 9%, depending on latitude. The predictable seasonal aspect of SAD provides a promising opportunity for prevention. This review - one of four reviews on efficacy and safety of interventions to prevent SAD - focuses on light therapy as a preventive intervention. Light therapy is a non-pharmacological treatment that exposes people to artificial light. Mode of delivery and form of light vary.

OBJECTIVES

To assess the efficacy and safety of light therapy (in comparison with no treatment, other types of light therapy, second-generation antidepressants, melatonin, agomelatine, psychological therapies, lifestyle interventions and negative ion generators) in preventing SAD and improving patient-centred outcomes among adults with a history of SAD.

SEARCH METHODS

We searched Ovid MEDLINE (1950- ), Embase (1974- ), PsycINFO (1967- ) and the Cochrane Central Register of Controlled Trials (CENTRAL) to 19 June 2018. An earlier search of these databases was conducted via the Cochrane Common Mental Disorders Controlled Trial Register (CCMD-CTR) (all years to 11 August 2015). Furthermore, we searched the Cumulative Index to Nursing and Allied Health Literature, Web of Science, the Cochrane Library, the Allied and Complementary Medicine Database and international trial registers (to 19 June 2018). We also conducted a grey literature search and handsearched the reference lists of included studies and pertinent review articles.

SELECTION CRITERIA

For efficacy, we included randomised controlled trials (RCTs) on adults with a history of winter-type SAD who were free of symptoms at the beginning of the study. For adverse events, we also intended to include non-randomised studies. We intended to include studies that compared any type of light therapy (e.g. bright white light, administered by visors or light boxes, infrared light, dawn stimulation) versus no treatment/placebo, second-generation antidepressants, psychological therapies, melatonin, agomelatine, lifestyle changes, negative ion generators or another of the aforementioned light therapies. We also planned to include studies that looked at light therapy in combination with any comparator intervention.

DATA COLLECTION AND ANALYSIS

Two review authors screened abstracts and full-text publications, independently abstracted data and assessed risk of bias of included studies.

MAIN RESULTS

We identified 3745 citations after de-duplication of search results. We excluded 3619 records during title and abstract review. We assessed 126 full-text papers for inclusion in the review, but only one study providing data from 46 people met our eligibility criteria. The included RCT had methodological limitations. We rated it as having high risk of performance and detection bias because of lack of blinding, and as having high risk of attrition bias because study authors did not report reasons for dropouts and did not integrate data from dropouts into the analysis.The included RCT compared preventive use of bright white light (2500 lux via visors), infrared light (0.18 lux via visors) and no light treatment. Overall, white light and infrared light therapy reduced the incidence of SAD numerically compared with no light therapy. In all, 43% (6/14) of participants in the bright light group developed SAD, as well as 33% (5/15) in the infrared light group and 67% (6/9) in the non-treatment group. Bright light therapy reduced the risk of SAD incidence by 36%; however, the 95% confidence interval (CI) was very broad and included both possible effect sizes in favour of bright light therapy and those in favour of no light therapy (risk ratio (RR) 0.64, 95% CI 0.30 to 1.38; 23 participants, very low-quality evidence). Infrared light reduced the risk of SAD by 50% compared with no light therapy, but the CI was also too broad to allow precise estimations of effect size (RR 0.50, 95% CI 0.21 to 1.17; 24 participants, very low-quality evidence). Comparison of both forms of preventive light therapy versus each other yielded similar rates of incidence of depressive episodes in both groups (RR 1.29, 95% CI 0.50 to 3.28; 29 participants, very low-quality evidence). Reasons for downgrading evidence quality included high risk of bias of the included study, imprecision and other limitations, such as self-rating of outcomes, lack of checking of compliance throughout the study duration and insufficient reporting of participant characteristics.Investigators provided no information on adverse events. We could find no studies that compared light therapy versus other interventions of interest such as second-generation antidepressants, psychological therapies, melatonin or agomelatine.

AUTHORS' CONCLUSIONS

Evidence on light therapy as preventive treatment for people with a history of SAD is limited. Methodological limitations and the small sample size of the only available study have precluded review author conclusions on effects of light therapy for SAD. Given that comparative evidence for light therapy versus other preventive options is limited, the decision for or against initiating preventive treatment of SAD and the treatment selected should be strongly based on patient preferences.

Investigating daily fatigue scores during two-week offshore day shifts

OBJECTIVES

This study examined daily scores of fatigue and circadian rhythm markers over two-week offshore day shift periods.

METHODS

A prospective cohort study among N = 60 offshore day-shift workers working two-week offshore shifts was conducted. Offshore day shifts lasted from 07:00 - 19:00 h. Fatigue was measured objectively with pre- and post-shift scores of the 3-minute psychomotor vigilance tasks (PVT-B) parameters (reaction times, number of lapses, errors and false starts) and subjectively with pre- and post-shift Karolinska Sleepiness Scale (KSS) ratings. Evening saliva samples were collected on offshore days 2,7 and 13 to measure circadian rhythm markers such as dim-light melatonin onset times and cortisol. Generalized and linear mixed model analyses were used to examine daily fatigue scores over time.

RESULTS

Complete data from N = 42 offshore day shift workers was analyzed. Daily parameters of objective fatigue, PVT-B scores (reaction times, average number of lapses, errors and false starts), remained stable over the course of the two-week offshore day shifts. Daily subjective post-shift fatigue scores significantly increased over the course of the two-week offshore shifts. Each day offshore was associated with an increased post-shift subjective fatigue score of 0.06 points (95%CI: .03 - .09 p < .001). No significant statistical differences in subjective pre-shift fatigue scores were found. Neither a circadian rhythm phase shift of melatonin nor an effect on the pattern and levels of evening cortisol was found.

CONCLUSION

Daily parameters of objective fatigue scores remained stable over the course of the two-week offshore day shifts. Daily subjective post-shift fatigue scores significantly increased over the course of the two-week offshore shifts. No significant changes in circadian rhythm markers were found. Increased post-shift fatigue scores, especially during the last days of an offshore shift, should be considered and managed in (offshore) fatigue risk management programs and fatigue risk prediction models.

Examinations of the methods used to power supply of different light sources and their effect on bioelectrical brain activity

OBJECTIVE

The article represents the preliminary study, with the aim of the experiment being to examine whether different types of light sources used commonly in building interiors combined with various color temperature have an effect on EEG activity. The effect of frequency pulsation and color temperature on brain activity in EEG examinations in the beta 2 band was assumed.

MATERIAL/PARTICIPANTS

Twenty healthy men aged 19-25 years participated in the experiment.

METHODS

The research stand was lit by: LED diodes with color temperatures of 3000K, 4200K, 6500K, with the power supplied using the pulse width modulation (PWM) method with the current frequency of 122Hz, linear fluorescent tubes (3000K, 6500K), with the power supplied with the frequency of 50Hz and 52kHz from the electromagnetic and electronic ballasts, and the conventional light bulb, with the power supplied directly from the mains electricity, used as a reference light. System Flex 30 apparatus with TrueScan software was used to record the EEG signal. The examination used two factors (speed and accuracy) of the Kraepelin's work curve to describe changes in work performance for various types of lighting.

RESULTS

The results demonstrate that the use of different types of emission of light and color temperature of the light have an effect on bioelectrical brain activity and work performance.

CONCLUSIONS

The highest activity of brain waves concerns the beta band in the frequency range of 21-22Hz, regardless of the type of the light source (LED, fluorescent tube). The methods used to supply power and color temperature of fluorescent tubes do not significantly affect bioelectrical brain activity during "work", but previous lighting with fluorescent tubes during work has an essential effect on bioelectrical brain activity during rest. Regardless of the color temperature, LED lighting with PWM power supply leads to the highest bioelectrical activity (mainly in the range of 21-22Hz) in the brain during work and rest, which might suggests the usefulness of this method of supplying power for everyday work. Incandescent light does not affect the bioelectrical brain activity during work and rest.

The genetics of circadian rhythms, sleep and health

Circadian rhythms are 24-h rhythms in physiology and behaviour generated by molecular clocks, which serve to coordinate internal time with the external world. The circadian system is a master regulator of nearly all physiology and its disruption has major consequences on health. Sleep and circadian rhythm disruption (SCRD) is a ubiquitous feature in today's 24/7 society, and studies on shift-workers have shown that SCRD can lead not only to cognitive impairment, but also metabolic syndrome and psychiatric illness including depression (1,2). Mouse models of clock mutants recapitulate these deficits, implicating mechanistic and causal links between SCRD and disease pathophysiology (3-5). Importantly, treating clock disruption reverses and attenuates these adverse health states in animal models (6,7), thus establishing the circadian system as a novel therapeutic target. Significantly, circadian and clock-controlled gene mutations have recently been identified by Genome-Wide Association Studies (GWAS) in the aetiology of sleep, mental health and metabolic disorders. This review will focus upon the genetics of circadian rhythms in sleep and health.

Efficacy of light therapy on nonseasonal depression among elderly adults: a systematic review and meta-analysis

OBJECTIVE

The aim of this study was to examine the effectiveness of light therapy in the treatment of geriatric depression.

METHODS

A systematic review and meta-analysis were carried out. Data sources for the literature search were PubMed, Cochrane Collaboration's Central Register of Controlled Clinical Trials, Cochrane Systematic Reviews, and ClinicalTrials.gov. Controlled trials of light therapy on older patients with nonseasonal depression and depression rating scales were eligible. Studies were pooled using a random-effect model for comparisons with light therapy. We used effect size (ES), which expresses changes in depression severity, in each selected meta-analysis to calculate the standardized mean difference on the basis of Hedges' adjusted g; positive values indicated that the depression severity improved after light therapy. All results were presented with 95% CIs. Statistical heterogeneity was explored through visual inspection of funnel plots and the I2 statistic. Moderators of effects were explored using meta-regression.

RESULTS

We identified eight trials involving 395 participants that met the inclusion criteria. Light therapy was significantly more effective than comparative treatments, including placebo or dim light, with an ES of 0.422 (95% CI: 0.174-0.709, P=0.001). In addition, six of the eight trials used bright (white) light, resulting in significantly reduced severity of geriatric depression (N=273, ES: 0.460, 95% CI: 0.085-0.836, P=0.016). Furthermore, pale blue light therapy reduced the severity of geriatric depression (N=89, ES: 0.464, 95% CI: 0.046-0.882, P=0.030).

CONCLUSION

Our results highlighted the significant efficacy of light therapy in the treatment of geriatric depression. Additional well-designed, controlled studies are necessary to adopt standard parameters, adequate group sizes, and randomized assignment to evaluate more thoroughly the efficacy of light therapy for treating geriatric depression.

Crossing the Boundaries of Our Current Healthcare System by Integrating Ultra-Weak Photon Emissions with Metabolomics

The current healthcare system is hampered by a reductionist approach in which diagnostics and interventions focus on a specific target, resulting in medicines that center on generic, static phenomena while excluding inherent dynamic nature of biological processes, let alone psychosocial parameters. In this essay, we present some limitations of the current healthcare system and introduce the novel and potential approach of combining ultra-weak photon emission (UPE) with metabolomics technology in order to provide a dynamic readout of higher organizational systems. We argue that the combination of metabolomics and UPE can bring a new, broader, view of health state and can potentially help to shift healthcare toward more personalized approach that improves patient well-being.

Bright light therapy in pregnant women with major depressive disorder: study protocol for a randomized, double-blind, controlled clinical trial

BACKGROUND

Depression during pregnancy is a common and high impact disease. Generally, 5-10 % of pregnant women suffer from depression. Children who have been exposed to maternal depression during pregnancy have a higher risk of adverse birth outcomes and more often show cognitive, emotional and behavioural problems. Therefore, early detection and treatment of antepartum depression is necessary. Both psychotherapy and antidepressant medication, first choice treatments in a non-pregnant population, have limitations in treating depression during pregnancy. Therefore, it is urgent and relevant to investigate alternative treatments for antepartum depression. Bright light therapy (BLT) is a promising treatment for pregnant women with depressive disorder, for it combines direct availability, sufficient efficacy, low costs and high safety, taking the safety for the unborn child into account as well.

METHODS

In this study, 150 pregnant women (12-18 weeks pregnant) with a DSM-V diagnosis of depressive disorder will be randomly allocated in a 1:1 ratio to one of the two treatment arms: treatment with BLT (9.000 lux) or treatment with dim red light therapy (100 lux). Both groups will be treated for 6 weeks at home on a daily basis for 30 min, within 30 min of habitual wake-up time. Follow-up will take place after 6 weeks of therapy, 3 and 10 weeks after end of therapy, at birth and 2, 6 and 18 months postpartum. Primary outcome will be the average change in depressive symptoms between the two groups, as measured by the Structured Interview Guide for the Hamilton Depression Scale - Seasonal Affective Disorder version and the Edinburg Postnatal Depression Scale. Changes in rating scale scores of these questionnaires over time will be analysed using generalized linear mixed models. Secondary outcomes will be the changes in maternal cortisol and melatonin levels, in maternal sleep quality and gestational age, birth weight, infant behaviour, infant cortisol exposure and infant cortisol stress response.

DISCUSSION

If BLT reduces depressive symptoms in pregnant women, it will provide a safe, cheap, non-pharmacological and efficacious alternative treatment for psychotherapy and antidepressant medication in treating antepartum depression, without any expected adverse reactions for the unborn child.

TRIAL REGISTRATION

Netherlands Trial Register NTR5476 . Registered 5 November 2015.

A double-blind randomized controlled trial to assess the effect of bright light therapy on depression in patients with Parkinson's disease

BACKGROUND

A disturbed circadian rhythm seems to be a causal factor in the occurrence of depressive disorders in patients with Parkinson's disease (PD). The circadian rhythm can be restored with light. Therefore, Bright Light Therapy (BLT) might be a new treatment option for depression in PD patients.

METHODS/DESIGN

In this double-blind controlled trial, 84 subjects with idiopathic PD are randomized to either BLT or a control light condition. The BLT condition emits white light with an intensity of 10,000 Lux, while the control device emits dim white light of 200 Lux, which is presumed to be too low to influence the circadian rhythm. Subjects receive 30 min of home treatment twice daily for three months. Timing of treatment is based on the individual chronotype. After finishing treatment, subjects enter a follow-up period of six months. The primary outcome of the study is the severity of depressive symptoms, as measured with the Hamilton Depression Rating Scale. Secondary outcomes are alternative depression measures, objective and subjective sleep measures, and salivary melatonin and cortisol concentrations. For exploratory purposes, we also assess the effects on motor symptoms, global cognitive function, comorbid psychiatric disorders, quality of life and caregiver burden. Data will be analyzed using a linear mixed models analysis.

DISCUSSION

Performing a placebo-controlled trial on the effects of BLT in PD patients is challenging, as the appearance of the light may provide clues on the treatment condition. Moreover, fixed treatment times lead to an improved sleep-wake rhythm, which also influences the circadian system. With our study design, we do not compare BLT to placebo treatment, i.e. an ineffective control treatment. Rather, we compare structuring of the sleep-wake cycle in both conditions with additional BLT in the experimental condition, and additional dim light in the control condition. Participants are not informed about the exact details of the two light devices and the expected therapeutic effect, and expectancies are rated prior to the start of treatment. Ideally, the design of a future study on BLT should include two extra treatment arms where BLT and control light are administered at random times.

TRIAL REGISTRATION

This trial was registered on ClinicalTrials.gov on May 17th 2012 (ClinicalTrials.gov Identifier: NCT01604876 ).

Effect of a Family-Oriented Communication Skills Training Program on Depression, Anxiety, and Stress in Older Adults: A Randomized Clinical Trial

BACKGROUND

Older adults face several physical and psychological problems such as hearing loss, vision loss, and memory loss, which diminish the quality of their communication. Poor communication in turn affects their psychological wellbeing and induces substantial depression, anxiety, and stress. The family has an important role in the mental health of older adults.

OBJECTIVES

This study aimed to investigate the effect of a family-oriented communication skills training program on depression, anxiety, and stress in older adults.

PATIENTS AND METHODS

For this randomized controlled clinical trial, we enrolled 64 older adults from two healthcare centers affiliated to the Isfahan University of Medical Sciences. The subjects were randomly allocated to an experimental group (n = 32) and a control group (n = 32). In the experimental group, older adults along with their primary caregiver participated in six sessions of communication skill education. The control group participated in two training sessions on nutrition and exercise. All participants answered the DASS21 questionnaire three times-at the start of the study, at the end of the sixth week, and a month after the last educational session of the experimental group. Data were analyzed using chi-square, Fisher's exact and t tests and by repeated measures analysis of variance (ANOVA).

RESULTS

In the experimental group, the mean depression score significantly reduced from 10.56 ± 3.34 before intervention to 7.46 ± 2.80 and 6.30 ± 2.75 after intervention and at follow-up, respectively; the mean anxiety score significantly reduced from 8.46 ± 1.88 before intervention to 5.83 ± 1.93 and 5.80 ± 2.12 after intervention and at follow-up, respectively; and the mean stress score significantly decreased from 11.40 ± 4.53 before intervention to 8.90 ± 3.81 and 8.43 ± 3.31 after intervention and at follow-up, respectively (P < 0.05 for all three domains). In contrast, the control group did not show any significant change in the mean depression, anxiety, and stress scores.

CONCLUSIONS

Family-oriented education on communication skills could reduce depression, anxiety, and stress in the elderly. Therefore, such programs should be adopted as a non-pharmacological and cost-effective method for reducing depression, anxiety, and stress in older adults.

Study of Sedative-Hypnotic Effects of Aloe vera L. Aqueous Extract through Behavioral Evaluations and EEG Recording in Rats

In this study, we investigated the sedative and hypnotic effects of the aqueous extract of Aloe vera on rats. In order to evaluate the overall hypnotic effects of the Aloe vera extract, open field and loss of righting reflex tests were primarily used. The sedative and hypnotic effects of the extract were then confirmed by detection of remarkable raise in the total sleeping time through analysis of electroencephalographic (EEG) recordings of animals. Analysis of the EEG recordings showed that there is concomitant change in Rapid Eye Movement (REM) and None Rapid Eye Movement (NREM) sleep in parallel with the prolonged total sleeping time. Results of the current research show that the extract has sedative-hypnotic effects on both functional and electrical activities of the brain.

Investigation of sedative and hypnotic effects of Amygdalus communis L. extract: behavioral assessments and EEG studies on rat

Amygdalus communis L. (almond) has been traditionally used as a natural medicine in the treatment of various diseases. The present research studied the sedative and hypnotic effects of the aqueous fraction of seeds of almond in rats. In order to investigate these effects, a combination of behavioral methods (open field test and loss of righting reflex test) as well as quantitative and analytic methods (EEG and EMG) were applied. The results of the open field test showed that a dose of 400 mg/kg of the almond extract significantly inhibited the locomotion activity of rats compared to normal. The results also illustrated that the almond extract affected pentobarbital-induced sleep through increasing the number of fallings asleep and prolongation of sleeping time. Analysis of EEG recordings of the animals which had received the same dose of the almond extract as the open field test demonstrated marked changes in the animals' sleep architecture. Significant prolongation of total sleeping time as well as significant increase in NREM sleep were the main observed changes compared to the normal condition. These results suggest that the aqueous extract of almond has significant sedative and hypnotic effects, which may support its therapeutic use for insomnia.

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.

The circadian system in Alzheimer's disease: disturbances, mechanisms, and opportunities

Alzheimer's disease (AD) is a devastating neurodegenerative condition associated with severe cognitive and behavioral impairments. Circadian rhythms are recurring cycles that display periods of approximately 24 hours and are driven by an endogenous circadian timekeeping system centered on the suprachiasmatic nucleus of the hypothalamus. We review the compelling evidence that circadian rhythms are significantly disturbed in AD and that such disturbance is of significant clinical importance in terms of behavioral symptoms. We also detail findings from neuropathological studies of brain areas associated with the circadian system in postmortem studies, the use of animal models of AD in the investigation of circadian processes, and the evidence that chronotherapeutic approaches aimed at bolstering weakened circadian rhythms in AD produce beneficial outcomes. We argue that further investigation in such areas is warranted and highlight areas for future research that might prove fruitful in ultimately providing new treatment options for this most serious and intractable of conditions.

Tryptophan-enriched cereal intake improves nocturnal sleep, melatonin, serotonin, and total antioxidant capacity levels and mood in elderly humans

Melatonin and serotonin rhythms, which exhibit a close association with the endogenous circadian component of sleep, are attenuated with increasing age. This decrease seems to be linked to sleep alterations in the elderly. Chrononutrition is a field of chronobiology that establishes the principle of consuming foodstuffs at times of the day when they are more useful for health, improving, therefore, biorhythms and physical performance. Our aim was to analyze whether the consumption of cereals enriched with tryptophan, the precursor of both serotonin and melatonin, may help in the reconsolidation of the sleep/wake cycle and counteract depression and anxiety in 35 middle-aged/elderly (aged 55-75 year) volunteers in a simple blind assay. Data were collected for 3 weeks according to the following schedule: The control week participants consumed standard cereals (22.5 mg tryptophan in 30 g cereals per dose) at breakfast and dinner; for the treatment week, cereals enriched with a higher dose of tryptophan (60 mg tryptophan in 30 g cereals per dose) were eaten at both breakfast and dinner; the posttreatment week volunteers consumed their usual diet. Each participant wore a wrist actimeter that logged activity during the whole experiment. Urine was collected to analyze melatonin and serotonin urinary metabolites and to measure total antioxidant capacity. The consumption of cereals containing the higher dose in tryptophan increased sleep efficiency, actual sleep time, immobile time, and decreased total nocturnal activity, sleep fragmentation index, and sleep latency. Urinary 6-sulfatoxymelatonin, 5-hydroxyindoleacetic acid levels, and urinary total antioxidant capacity also increased respectively after tryptophan-enriched cereal ingestion as well as improving anxiety and depression symptoms. Cereals enriched with tryptophan may be useful as a chrononutrition tool for alterations in the sleep/wake cycle due to age.

Effects of resveratrol on daily rhythms of locomotor activity and body temperature in young and aged grey mouse lemurs

In several species, resveratrol, a polyphenolic compound, activates sirtuin proteins implicated in the regulation of energy balance and biological clock processes. To demonstrate the effect of resveratrol on clock function in an aged primate, young and aged mouse lemurs (Microcebus murinus) were studied over a 4-week dietary supplementation with resveratrol. Spontaneous locomotor activity and daily variations in body temperature were continuously recorded. Reduction in locomotor activity onset and changes in body temperature rhythm in resveratrol-supplemented aged animals suggest an improved synchronisation on the light-dark cycle. Resveratrol could be a good candidate to restore the circadian rhythms in the elderly.

Adaptation to experimental jet-lag in R6/2 mice despite circadian dysrhythmia

The R6/2 transgenic mouse model of Huntington's disease (HD) shows a disintegration of circadian rhythms that can be delayed by pharmacological and non-pharmacological means. Since the molecular machinery underlying the circadian clocks is intact, albeit progressively dysfunctional, we wondered if light phase shifts could modulate the deterioration in daily rhythms in R6/2 mice. Mice were subjected to four x 4 hour advances in light onset. R6/2 mice adapted to phase advances, although angles of entrainment increased with age. A second cohort was subjected to a jet-lag paradigm (6 hour delay or advance in light onset, then reversal after 2 weeks). R6/2 mice adapted to the original shift, but could not adjust accurately to the reversal. Interestingly, phase shifts ameliorated the circadian rhythm breakdown seen in R6/2 mice under normal LD conditions. Our previous finding that the circadian period (tau) of 16 week old R6/2 mice shortens to approximately 23 hours may explain how they adapt to phase advances and maintain regular circadian rhythms. We tested this using a 23 hour period light/dark cycle. R6/2 mice entrained to this cycle, but onsets of activity continued to advance, and circadian rhythms still disintegrated. Therefore, the beneficial effects of phase-shifting are not due solely to the light cycle being closer to the tau of the mice. Our data show that R6/2 mice can adapt to changes in the LD schedule, even beyond the age when their circadian rhythms would normally disintegrate. Nevertheless, they show abnormal responses to changes in light cycles. These might be caused by a shortened tau, impaired photic re-synchronization, impaired light detection and/or reduced masking by evening light. If similar abnormalities are present in HD patients, they may suffer exaggerated jet-lag. Since the underlying molecular clock mechanism remains intact, light may be a useful treatment for circadian dysfunction in HD.

Severe impairment of circadian rhythm in Alzheimer's disease

Circadian rhythmicity was repeatedly determined in a patient with Alzheimer's disease by measuring his core temperature with a rectal thermistor and motor activity by an ambulatory activity monitor. The first recording, performed 9 years after he was diagnosed with Alzheimer's disease, showed well organized 24 hr circadian rhythm of core body temperature. The second recording, made four months later, showed very poor fit of core body temperature to 24 hour rhythm, but excellent fit with 36 hour rhythm. The third recording, made two months later, showed again good fit of core body temperature with 24 hour cycle. The last recording, which was performed 5 months later, showed almost complete disappearance of circadian rhythm of body temperature. These changes probably reflect gradual lengthening of the circadian cycle that at one point became extremely lengthened before returning to the 24 hr cycle.

Bright light therapy as an adjunctive treatment with risperidone in patients with delirium: a randomized, open, parallel group study

OBJECTIVE

The purpose of this study was to determine the effect of adjuvant light therapy with antipsychotic treatment in patients with delirium.

METHODS

Thirty-six patients were referred to the consulting psychiatry division of our hospital for a disturbance in consciousness. The patients were randomized to risperidone (n=16) or risperidone with light therapy (n=20). They were evaluated on Day 0 (baseline) and on Days 1 to 5 with the Delirium Rating Scale (DRS) and the Memorial Delirium Assessment Scale (MDAS). Sleep parameters were measured using a sleep log.

RESULTS

Mean DRS and MDAS scores decreased significantly over time in both treatment groups. Risperidone with light therapy group showed a significantly greater decrease in the DRS score than the risperidone-only group (F=2.87, P=.025), but the MDAS score was not significantly different between the two groups. There was a significant improvement in total sleep time (F=2.07, P=.037) and sleep efficiency (F=2.79, P=.029) in the risperidone with light therapy group than in the risperidone-only group.

CONCLUSIONS

Our results indicate that risperidone with light therapy may be a helpful adjuvant treatment for patients with delirium. Adequately powered studies with a head-to-head comparison design are mandatory to confirm our findings.

Neuropsychiatric symptoms in Alzheimer's disease

Neuropsychiatric symptoms (NPS) are core features of Alzheimer's disease and related dementias. Once thought to emerge primarily in people with late-stage disease, these symptoms are currently known to manifest commonly in very early disease and in prodromal phases, such as mild cognitive impairment. Despite decades of research, reliable treatments for dementia-associated NPS have not been found, and those that are in widespread use present notable risks for people using these medications. An Alzheimer's Association Research Roundtable was convened in the spring of 2010 to review what is known about NPS in Alzheimer's disease, to discuss classification and underlying neuropathogenesis and vulnerabilities, and to formulate recommendations for new approaches to tailored therapeutics.

Neuropsychiatric symptoms in Alzheimer's disease

Neuropsychiatric symptoms (NPS) are core features of Alzheimer's disease and related dementias. Once thought to emerge primarily in people with late-stage disease, these symptoms are currently known to manifest commonly in very early disease and in prodromal phases, such as mild cognitive impairment. Despite decades of research, reliable treatments for dementia-associated NPS have not been found, and those that are in widespread use present notable risks for people using these medications. An Alzheimer's Association Research Roundtable was convened in the spring of 2010 to review what is known about NPS in Alzheimer's disease, to discuss classification and underlying neuropathogenesis and vulnerabilities, and to formulate recommendations for new approaches to tailored therapeutics.

Melatonin and its analogs in insomnia and depression

Benzodiazepine sedative-hypnotic drugs are widely used for the treatment of insomnia. Nevertheless, their adverse effects, such as next-day hangover, dependence and impairment of memory, make them unsuitable for long-term treatment. Melatonin has been used for improving sleep in patients with insomnia mainly because it does not cause hangover or show any addictive potential. However, there is a lack of consistency on its therapeutic value (partly because of its short half-life and the small quantities of melatonin employed). Thus, attention has been focused either on the development of more potent melatonin analogs with prolonged effects or on the design of slow release melatonin preparations. The MT(1) and MT(2) melatonergic receptor ramelteon was effective in increasing total sleep time and sleep efficiency, as well as in reducing sleep latency, in insomnia patients. The melatonergic antidepressant agomelatine, displaying potent MT(1) and MT(2) melatonergic agonism and relatively weak serotonin 5HT(2C) receptor antagonism, was found effective in the treatment of depressed patients. However, long-term safety studies are lacking for both melatonin agonists, particularly considering the pharmacological activity of their metabolites. In view of the higher binding affinities, longest half-life and relative higher potencies of the different melatonin agonists, studies using 2 or 3mg/day of melatonin are probably unsuitable to give appropriate comparison of the effects of the natural compound. Hence, clinical trials employing melatonin doses in the range of 50-100mg/day are warranted before the relative merits of the melatonin analogs versus melatonin can be settled.

Effectiveness of Physio Acoustic Sound (PAS) therapy in demented nursing home residents with nocturnal restlessness: study protocol for a randomized controlled trial

Background

Many older people with neuropsychiatric disorders such as Alzheimer's disease and frontotemporal dementia suffer from sleeping problems and often show nocturnal restlessness. Professionals and informal carers face considerable problems in solving these problems. Attempts to diminish these problems with medication in a safe and responsible manner have proven hardly effective or not effective at all. Therefore, nowadays the focus lies more on non-pharmacological solutions, for example by influencing environmental factors. There are indications that treatment with low-frequency acoustic vibrations, that is Physio Acoustic Sound (PAS) therapy, has a positive effect on sleeping problems. Therefore we study the effectiveness of PAS therapy in demented patients with nocturnal restlessness.

Methods

In a randomized clinical trial, 66 nursing home patients will be divided into two groups: an intervention group and a control group. For both groups nocturnal restlessness will be measured with actiwatches during a period of six weeks. In addition, a sleep diary will be filled in.

For the intervention group the baseline will be assessed, in the first two weeks, reflecting the existing situation regarding nocturnal restlessness. In the next two weeks, this group will sleep on a bed identical to their own, but with a mattress containing an in-built PAS device. As soon as the patient is lying in bed, the computer programme inducing the vibrations will be switched on for the duration of 30 min. In the last two weeks, the wash-out period, the measurements of the intervention group are continued, without the PAS intervention.

During the total study period, other relevant data of all the implied patients will be recorded systematically and continuously, for example patient characteristics (data from patient files), the type and seriousness of the dementia, occurrence of neuropsychiatric symptoms during the research period, and the occurrence of intermittent co-morbidity.

Discussion

If PAS therapy turns out to be effective, it can be of added value to the treatment of nocturnal restlessness in demented patients. Non-pharmacological PAS therapy is not only safe and patient-friendly, but it can also be widely used in a simple and relatively inexpensive way, both in institutions such as nursing homes and residential homes for the elderly, and at home. Ultimately, this may lead to a decrease in the frequent and still common use of psychotropic drugs. In addition, care needs of demented patients also may decrease as well as the number of preventable admissions to care institutions.

Trial registration

Netherlands Trial Register (NTR): NTR3242

The circadian clock and pathology of the ageing brain

Ageing leads to a functional deterioration of many brain systems, including the circadian clock--an internal time-keeping system that generates ∼24-hour rhythms in physiology and behaviour. Numerous clinical studies have established a direct correlation between abnormal circadian clock functions and the severity of neurodegenerative and sleep disorders. Latest data from experiments in model organisms, gene expression studies and clinical trials imply that dysfunctions of the circadian clock contribute to ageing and age-associated pathologies, thereby suggesting a functional link between the circadian clock and age-associated decline of brain functions. Potential molecular mechanisms underlying this link include the circadian control of physiological processes such as brain metabolism, reactive oxygen species homeostasis, hormone secretion, autophagy and stem cell proliferation.

CLOCK Genes and Circadian Rhythmicity in Alzheimer Disease

Disturbed circadian rhythms with sleep problems and disrupted diurnal activity are often seen in patients suffering from Alzheimer disease (AD). Both endogenous CLOCK genes and external Zeitgeber are responsible for the maintenance of circadian rhythmicity in humans. Therefore, modifications of the internal CLOCK system and its interactions with exogenous factors might constitute the neurobiological basis for clinically observed disruptions in rhythmicity, which often have grave consequences for the quality of life of patients and their caregivers. Presently, more and more data are emerging demonstrating how alterations of the CLOCK gene system might contribute to the pathophysiology of AD and other forms of dementia. At the same time, the impact of neuropsychiatric medication on CLOCK gene expression is under investigation.

Sleep-wake changes and cognition in neurodegenerative disease

With the increasing aging population, neurodegenerative disorders will become more common in clinical practice. These disorders involve multiple pathophysiological mechanisms that differentially affect cognition, mood, and physical functions. Possibly due to the involvement of common underlying neurobiological circuits, sleep and/or circadian (sleep-wake) changes are also common in this disease group. Of significance, sleep-wake changes are often a prodromal feature and are predictive of cognitive decline, psychiatric symptoms, quality of life, need for institutional care, and caregiver burden. Unfortunately, in neurodegenerative disease, few studies have included detailed polysomnography or neuropsychological assessments although some data indicate that sleep and neurocognitive features are related. Further studies are also required to address the effects of pharmacological and nonpharmacological treatments on cognitive functioning. Such research will hopefully lead to targeted early intervention approaches for cognitive decline in older people.