Evaluating possible 'next day' impairment in insomnia patients administered an oral medicinal cannabis product by night: a pilot randomized controlled trial

Cannabis and its major constituents, Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD), are being widely used to treat sleep disturbances. However, THC can cause acute cognitive and psychomotor impairment and there are concerns that driving and workplace safety might be compromised the day after evening use. Here, we examined possible 'next day' impairment following evening administration of a typical medicinal cannabis oil in adults with insomnia disorder, compared to matched placebo. This paper describes the secondary outcomes of a larger study investigating the effects of THC/CBD on insomnia disorder. Twenty adults [16 female; mean (SD) age, 46.1 (8.6) y] with physician-diagnosed insomnia who infrequently use cannabis completed two 24 h in-laboratory visits involving acute oral administration of combined 10 mg THC and 200 mg CBD ('THC/CBD') or placebo in a randomised, double-blind, crossover trial design. Outcome measures included 'next day' (≥9 h post-treatment) performance on cognitive and psychomotor function tasks, simulated driving performance, subjective drug effects, and mood. We found no differences in 'next day' performance on 27 out of 28 tests of cognitive and psychomotor function and simulated driving performance relative to placebo. THC/CBD produced a small decrease (-1.4%, p=.016, d=-0.6) in accuracy on the Stroop-Colour Task (easy/congruent) but not the Stroop-Word Task (hard/incongruent). THC/CBD also produced a small increase (+8.6, p=.042, d=0.3) in self-ratings of Sedated at 10 h post-treatment, but with no accompanying changes in subjective ratings of Alert or Sleepy (p's>0.05). In conclusion, we found a lack of notable 'next day' impairment to cognitive and psychomotor function and simulated driving performance following evening use of 10 mg oral THC, in combination with 200 mg CBD, in an insomnia population who infrequently use cannabis.

Different heart rate variability profile during sleep in mid-later life adults with remitted early-onset versus late-onset depression

BACKGROUND

In mid-later life adults, early-onset and late-onset (i.e., onset ≥50 years) depression appear to be underpinned by different pathophysiology yet have not been examined in relation to autonomic function. Sleep provides an opportunity to examine the autonomic nervous system as the physiology changes across the night. Hence, we aimed to explore if autonomic profile is altered in mid-later life adults with remitted early-onset, late-onset and no history of lifetime depression.

METHODS

Participants aged 50-90 years (n = 188) from a specialised clinic underwent a comprehensive clinical assessment and completed an overnight polysomnography study. General Linear Models were used to examine the heart rate variability differences among the three groups for four distinct sleep stages and the wake after sleep onset. All analyses controlled for potential confounders - age, sex, current depressive symptoms and antidepressant usage.

RESULTS

For the wake after sleep onset, mid-later life adults with remitted early-onset depression had reduced standard deviation of Normal to Normal intervals (SDNN; p = .014, d = -0.64) and Shannon Entropy (p = .004, d = -0.46,) than those with no history of lifetime depression. Further, the late-onset group showed a reduction in high-frequency heart rate variability (HFn.u.) during non-rapid eye movement sleep stage 2 (N2; p = .005, d = -0.53) and non-rapid eye movement sleep stage 3 (N3; p = .009, d = -0.55) when compared to those with no lifetime history.

LIMITATIONS

Causality between heart rate variability and depression cannot be derived in this cross-sectional study. Longitudinal studies are needed to examine the effects remitted depressive episodes on autonomic function.

CONCLUSION

The findings suggest differential autonomic profile for remitted early-onset and late-onset mid-later life adults during sleep stages and wake periods. The differences could potentially serve as peripheral biomarkers in conjunction with more disease-specific markers of depression to improve diagnosis and prognosis.

Detection of Δ9 -tetrahydrocannabinol (THC) in oral fluid using two point-of-collection testing devices following oral administration of a THC and cannabidiol containing oil

Point-of-collection testing (POCT) devices are widely used in roadside and workplace drug testing to identify recent cannabis use by measuring the presence of Δ9 -tetrahydrocannabinol (THC) in oral fluid (OF). However, the performance of POCT devices with oral medicinal cannabis products remains poorly described. In a randomised, double-blinded, crossover trial, adults with insomnia disorder (n = 20) received a single (2 mL) oral dose of oil containing 10 mg THC + 200 mg cannabidiol, or placebo, prior to sleep. Participants were tested with the Securetec DrugWipe® 5S (10 ng/mL THC cut-off) and Dräger DrugTest® 5000 (25 ng/mL THC cut-off) POCT devices at baseline (pre-treatment) and then at 0.5, 10, and 18 h post-treatment. An OF sample, taken at each time point, was also analysed using liquid chromatography-tandem mass spectrometry. Large individual variability in OF THC concentrations was observed 0.5 h post-treatment (range: 0-425 ng/mL; mean (SD) 48.7 (107.5) ng/mL). Both the Securetec DrugWipe® 5S and DrugTest® 5000 demonstrated poor sensitivity to THC at 0.5 h post-treatment (25% and 50%, respectively). At 10 and 18 h post-treatment, all participant OF THC concentrations were below screening cut-offs, and all test results were negative. These findings highlight the relatively poor sensitivity of both devices in detecting recent use of an oral medicinal cannabis product. They also suggest a low probability of obtaining a positive THC result the morning after ('one-off') use. Further research is required to establish the probability of obtaining a positive THC result with regular medicinal cannabis use.

A systematic review on adherence to continuous positive airway pressure (CPAP) treatment for obstructive sleep apnoea (OSA) in individuals with mild cognitive impairment and Alzheimer's disease dementia

Obstructive sleep apnoea (OSA) is highly prevalent in mild cognitive impairment (MCI) and Alzheimer's disease (AD). The gold standard treatment for OSA is continuous positive airway pressure (CPAP). Long-term, well-powered efficacy trials are required to understand whether CPAP could slow cognitive decline in individuals with MCI/AD, but its tolerability in this group remains uncertain. The present review investigates CPAP adherence among individuals with OSA and MCI/AD. Electronic searches were performed on 8 databases. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Six independent studies and four secondary analyses included 278 unique participants (mean age = 72.1 years). In five of the retained studies, around half of participants (45% N = 85 MCI, 56% N = 22 AD) were adherent to CPAP, where ≥4 h use per night was considered adherent. Three of the retained studies also reported average CPAP use to range between 3.2 and 6.3 h/night. CPAP adherence in individuals with MCI and AD is low, albeit similar to the general elderly population. Reporting adherence in future studies as both average duration as well as using a binary cut-off would improve our understanding of the optimum CPAP use in dementia clinical trials and care.

REducing Sleep Apnoea for the PrEvention of Dementia (REShAPED): Protocol for a multi-site feasibility randomised controlled trial

There is accumulating evidence that has linked OSA with increased risk of cognitive decline and dementia. Here we present the protocol for an Australian, multi-site randomised controlled, parallel open-label trial which will evaluate the feasibility for a full-scale trial investigating the effects of treating OSA on cognitive decline in older adults at risk of dementia within memory clinic settings. We will randomise 180 older adults to either the treatment intervention group or control group for 2 years. Inclusion criteria include: 50-85 years; mild-severe OSA (defined average ODI ≥ 10 with 3% oxygen desaturation determined by wrist oximetry over two nights); and subjective cognitive complaints or mild cognitive impairment. The treatment intervention arm aims to achieve an optimal treatment response based on reducing hypoxic burden with either CPAP, mandibular advancement splint, positional therapy, or oxygen therapy. Furthermore, participants will receive up to 8 sessions which involve motivational interviewing, collaborative goal setting, and behavioural sleep management. The control arm will not receive OSA treatment as part of this trial, however there will be no OSA treatment restrictions, and any treatment will be documented. Primary outcomes are 1) acceptability based upon willingness of participants to be randomised; 2) alleviating hypoxic burden by reducing OSA severity; 3) tolerability of the trial burden based upon collection of outcomes over the 2-year follow-up. Secondary outcomes include safety and cognitive function. Outcomes will be collected at 0, 6 and 24-months. This feasibility study aims to will provide the basis for a larger longer-term trial of dementia prevention.

Sleep Deficiency and Cardiometabolic Disease

Epidemiologic studies have demonstrated that short sleep duration is associated with an increased risk of cardio-metabolic health outcomes including cardiovascular disease mortality, coronary heart disease, type 2 diabetes mellitus, hypertension, and metabolic syndrome. Experimental sleep restriction studies have sought to explain these findings. This review describes the main evidence of these associations and possible mechanisms explaining them. Whether sleep extension reverses these now widely acknowledged adverse health effects and the feasibility of implementing such strategies on a public health level is discussed.

Cannabinol (CBN; 30 and 300 mg) effects on sleep and next-day function in insomnia disorder ('CUPID' study): protocol for a randomised, double-blind, placebo-controlled, cross-over, three-arm, proof-of-concept trial

OBJECTIVE

Insomnia is the most prevalent sleep disorder, with few effective pharmacotherapies. Anecdotal reports and recent preclinical research suggest that cannabinol (CBN), a constituent of Cannabis sativa derived from delta-9-tetrahydrocannabinol, could be an effective treatment. Despite this, the isolated effects of CBN on sleep have yet to be systematically studied in humans.

METHODS

The present protocol paper describes a randomised, double-blind, placebo-controlled, single-dose, three-arm, cross-over, proof-of-concept study which investigates the effects of CBN on sleep and next-day function in 20 participants with clinician-diagnosed insomnia disorder and an Insomnia Severity Index Score ≥15. Participants receive a single fixed oral liquid dose of 30 mg CBN, 300 mg CBN and matched placebo, in random order on three treatment nights; each separated by a 2-week wash-out period. Participants undergo overnight sleep assessment using in-laboratory polysomnography and next-day neurobehavioural function tests. The primary outcome is wake after sleep onset minutes. Secondary outcomes include changes to traditional sleep staging, sleep-onset latency and absolute spectral power during non-rapid eye movement (NREM) sleep. Tertiary outcomes include changes to sleep spindles during NREM sleep, arousal indices, absolute spectral power during REM sleep and subjective sleep quality. Safety-related and exploratory outcomes include changes to next-day simulated driving performance, subjective mood and drug effects, postural sway, alertness and reaction time, overnight memory consolidation, pre and post-sleep subjective and objective sleepiness; and plasma, urinary, and salivary cannabinoid concentrations. The study will provide novel preliminary data on CBN efficacy and safety in insomnia disorder, which will inform larger clinical trials.

ETHICS AND DISSEMINATION

Human Research Ethics Committee approval has been granted by Bellberry (2021-08-907). Study findings will be disseminated in a peer-reviewed journal and at academic conferences.

TRIAL REGISTRATION NUMBER

NCT05344170.

Does daily energy and macronutrient intake differ between work and non-workdays in shift workers? A mixed methods study

Shift workers are at increased risk of obesity and metabolic diseases, but their eating patterns on work and non-workdays are understudied. We aimed to examine whether energy intake and macronutrient intake of day and night shift nurses were different during work and non-workdays. We used a mixed-methods approach to study food intake of shift working nurses from two hospitals during day and night shifts. Participants completed baseline questionnaires about eating behaviour, sleep, chronotype, mood and shift work disorder. Participants then completed a 4-d food diary which included a non-workday prior to the first shift, the first and last shift (either day or night) and the following non-workday. After completion of the food diaries, we used semi-structured interviews to explore the qualitative aspects of eating behaviours. Seventy-nine shift-working nurses participated in the study. Daily energy intake was not significantly different on work and non-workdays in day or night shift workers (p > 0.05). Whilst macronutrient consumption was also not different between day and night shift workers (p > 0.05), sugar intake was higher in day compared to night shift workers (p = 0.02) on the non-workday prior to the first workday. In qualitative interviews, participants reported their eating to be different on day and night shifts as well as work and non-workdays. Eating behaviour in day and night shift workers was highly influenced by food availability, convenience, peers, and family members. Nurses qualitatively report that night and day shifts result in them eating differently despite no statistically discernible difference in energy intake.

Pilot Randomized, Double-Blind, Placebo-Controlled Crossover Trial Evaluating the Feasibility of an Intranasal Oxytocin in Improving Social Cognition in Individuals Living with Alzheimer's Disease

Background

Individuals living with Alzheimer's disease (AD) demonstrate extensive deficits in social cognition. To date, no studies have investigated the feasibility of an intranasal oxytocin (INOT) treatment to improve social cognition in individuals living with AD.

Objective

We conducted a pilot trial to determine recruitment feasibility, enrolment acceptability, and adherence to an INOT treatment to inform on the subsequent design of a future randomized controlled trial (RCT). We also estimated the effect sizes of potential social cognitive function outcome measures related to participants and their caregivers.

Methods

Four individuals with AD were enrolled in a single-center, randomized, double-blind, placebo-controlled crossover trial involving a one-week treatment period with both INOT (72 IU twice daily) and placebo.

Results

All participants reported no treatment-causative or serious adverse events following repeated INOT administration. While enrolment acceptability (100%) and INOT adherence (placebo, 95%; INOT, 98%) were excellent, feasibility of recruitment was not acceptable (i.e., n = 4/58 individuals screened met inclusion criteria). However, positive/large effects were associated with secondary outcomes of self-reported health and wellbeing, caregiver 'burden', intimacy and interpersonal-bonding, following repeated INOT administration. No positive effects were associated with participant outcomes of social cognition.

Conclusion

This pilot RCT provides first evidence that INOT administration in individuals living with AD is safe and well-tolerated. Despite limitations in sample size, moderate-to-large effect size improvements were identified in participant health outcomes as well as core social cognitive functions and 'burden' as reported by a caregiver. This suggests potential broad-ranging beneficial effects of INOT which should be assessed in future RCTs.

Strategies to Assess the Effect of Continuous Positive Airway Pressure on Long-Term Clinically Important Outcomes among Patients with Symptomatic Obstructive Sleep Apnea: An Official American Thoracic Society Workshop Report

Continuous positive airway pressure (CPAP) is the first-line treatment for obstructive sleep apnea (OSA). Although CPAP improves symptoms (e.g., daytime sleepiness), there is a lack of high-quality evidence that CPAP prevents many long-term outcomes, including cognitive impairment, myocardial infarction, and stroke. Observational studies suggest that patients with symptoms may be particularly likely to experience these preventive benefits with CPAP, but ethical and practical concerns limited the participation of such patients in prior long-term randomized trials. As a result, there is uncertainty about the full benefits of CPAP, and resolving this uncertainty is a key priority for the field. This workshop assembled clinicians, researchers, ethicists, and patients to identify strategies to understand the causal effects of CPAP on long-term clinically important outcomes among patients with symptomatic OSA. Quasi-experimental designs can provide valuable information and are less time and resource intensive than trials. Under specific conditions and assumptions, quasi-experimental studies may be able to provide causal estimates of CPAP's effectiveness from generalizable observational cohorts. However, randomized trials represent the most reliable approach to understanding the causal effects of CPAP among patients with symptoms. Randomized trials of CPAP can ethically include patients with symptomatic OSA, as long as there is outcome-specific equipoise, adequate informed consent, and a plan to maximize safety while minimizing harm (e.g., monitoring for pathologic sleepiness). Furthermore, multiple strategies exist to ensure the generalizability and practicality of future randomized trials of CPAP. These strategies include reducing the burden of trial procedures, improving patient-centeredness, and engaging historically excluded and underserved populations.

Heart rate variability during slow wave sleep is linked to functional connectivity in the central autonomic network

Reduced heart rate variability can be an early sign of autonomic dysfunction in neurodegenerative diseases and may be related to brain dysfunction in the central autonomic network. As yet, such autonomic dysfunction has not been examined during sleep-which is an ideal physiological state to study brain-heart interaction as both the central and peripheral nervous systems behave differently compared to during wakefulness. Therefore, the primary aim of the current study was to examine whether heart rate variability during nocturnal sleep, specifically slow wave (deep) sleep, is associated with central autonomic network functional connectivity in older adults 'at-risk' of dementia. Older adults (n = 78; age range = 50-88 years; 64% female) attending a memory clinic for cognitive concerns underwent resting-state functional magnetic resonance imaging and an overnight polysomnography. From these, central autonomic network functional connectivity strength and heart rate variability data during sleep were derived, respectively. High-frequency heart rate variability was extracted to index parasympathetic activity during distinct periods of sleep, including slow wave sleep as well as secondary outcomes of non-rapid eye movement sleep, wake after sleep onset, and rapid eye movement sleep. General linear models were used to examine associations between central autonomic network functional connectivity and high-frequency heart rate variability. Analyses revealed that increased high-frequency heart rate variability during slow wave sleep was associated with stronger functional connectivity (F = 3.98, P = 0.022) in two core brain regions within the central autonomic network, the right anterior insular and posterior midcingulate cortex, as well as stronger functional connectivity (F = 6.21, P = 0.005) between broader central autonomic network brain regions-the right amygdala with three sub-nuclei of the thalamus. There were no significant associations between high-frequency heart rate variability and central autonomic network connectivity during wake after sleep onset or rapid eye movement sleep. These findings show that in older adults 'at-risk' of dementia, parasympathetic regulation during slow wave sleep is uniquely linked to differential functional connectivity within both core and broader central autonomic network brain regions. It is possible that dysfunctional brain-heart interactions manifest primarily during this specific period of sleep known for its role in memory and metabolic clearance. Further studies elucidating the pathophysiology and directionality of this relationship should be conducted to determine if heart rate variability drives neurodegeneration, or if brain degeneration within the central autonomic network promotes aberrant heart rate variability.

How long does a single oral dose of cannabidiol persist in plasma? Findings from three clinical trials

A growing number of clinical trials (CTs) are investigating the therapeutic potential of cannabidiol (CBD), a non-intoxicating phytocannabinoid found in Cannabis sativa. These CTs often use crossover experimental designs requiring 'washout' (clearance) periods. However, the length of time CBD persists in plasma (its 'window of detection') is unclear and could be significant. Indeed, the structurally related phytocannabinoid, Δ⁹ -tetrahydrocannabinol (THC), has a long window of detection in plasma. We investigated the extent to which CBD and its major metabolites persist in plasma. Data from three CTs that measured plasma cannabinoid concentrations ≥7 days after administering a single oral dose of CBD were pooled. The CBD doses were as follows: CT #1: 300 mg; CT #2: 200 mg (and 10 mg THC); and CT #3: 15, 300 and 1500 mg (one per treatment session). Thirty-two participants were included in the analysis, 17 of whom (from CT #3) provided repeated measures. Overall, 0% (15 mg), 60% (200 mg), 28% (300 mg) and 100% (1500 mg) of participants had detectable concentrations (i.e., >0.25 ng·ml^-1 ) of CBD in plasma ≥7 days post-treatment (some, several weeks post-treatment). A zero-inflated negative binomial mixed-effects regression analysis (R² _m  = 0.44; R² _c  = 0.73) predicted that, on average, a 13 day washout period would reduce plasma CBD concentrations to 'zero' (i.e., <0.25 ng·ml^-1 ) if a single oral dose of 300 mg was consumed. Higher doses require longer washout periods; concomitant medications may also affect clearance. In conclusion, CBD has a long window of detection in plasma. Crossover studies involving CBD should, therefore, be conducted with caution, particularly when higher doses and/or chronic dosing regimens are used.

Current Insights into the Risks of Using Melatonin as a Treatment for Sleep Disorders in Older Adults

Exogenous melatonin is commonly used for sleep disorders in older adults, and its use is increasing over time. It appears to have modest efficacy in treating insomnia and circadian rhythm sleep-wake disorders. Melatonin is commonly perceived to be a safe alternative to other hypnotics and is available without prescription in some jurisdictions. New evidence suggests that endogenous melatonin has pleomorphic effects on multiple organ systems, many of which are poorly understood. This narrative review summarizes the current evidence regarding the safety of melatonin in older adults (defined by age over 65 years). Melatonin appears to have a favorable safety profile in this population, however there is a dearth of evidence regarding the safety of prolonged use. There are several factors which increase the risk of adverse effects of melatonin in older adults, and these should be taken into consideration when prescribing to this population.

The relationship between midlife dyslipidemia and lifetime incidence of dementia: A systematic review and meta-analysis of cohort studies

Introduction

We conducted a systematic review and meta-analysis to review the relationship between midlife dyslipidemia and lifetime incident dementia.

Methods

The databases Medline, Embase, Scopus, Web of Science, and Cochrane were searched from inception to February 20, 2022. Longitudinal studies examining the relationship between midlife lipid levels on dementia, dementia subtypes, and/or cognitive impairment were pooled using inverse-variance weighted random-effects meta-analysis.

Results

Seventeen studies (1.2 million participants) were included. Midlife hypercholesterolemia was associated with increased incidence of mild cognitive impairment (effect size [ES] = 2.01; 95% confidence interval [CI] 1.19 to 2.84; I² = 0.0%) and all-cause dementia (ES = 1.14; 95% CI: 1.07 to 1.21; I² = 0.0%). Each 1 mmol/L increase in low-density lipoprotein was associated with an 8% increase (ES = 1.08, 95% CI: 1.03 to 1.14; I² = 0.3%) in incidence of all-cause dementia.

Discussion

Midlife dyslipidemia is associated with an increased risk of cognitive impairment in later life.

Effects of cannabidiol on simulated driving and cognitive performance: A dose-ranging randomised controlled trial

BACKGROUND

Cannabidiol (CBD), a major cannabinoid of Cannabis sativa, is widely consumed in prescription and non-prescription products. While CBD is generally considered 'non-intoxicating', its effects on safety-sensitive tasks are still under scrutiny.

AIM

We investigated the effects of CBD on driving performance.

METHODS

Healthy adults (n = 17) completed four treatment sessions involving the oral administration of a placebo, or 15, 300 or 1500 mg CBD in a randomised, double-blind, crossover design. Simulated driving performance was assessed between ~45-75 and ~210-240 min post-treatment (Drives 1 and 2) using a two-part scenario with 'standard' and 'car following' (CF) components. The primary outcome was standard deviation of lateral position (SDLP), a well-established measure of vehicular control. Cognitive function, subjective experiences and plasma CBD concentrations were also measured. Non-inferiority analyses tested the hypothesis that CBD would not increase SDLP by more than a margin equivalent to a 0.05% blood alcohol concentration (Cohen's d_z = 0.50).

RESULTS

Non-inferiority was established during the standard component of Drive 1 and CF component of Drive 2 on all CBD treatments and during the standard component of Drive 2 on the 15 and 1500 mg treatments (95% CIs < 0.5). The remaining comparisons to placebo were inconclusive (the 95% CIs included 0 and 0.50). No dose of CBD impaired cognition or induced feelings of intoxication (ps > 0.05). CBD was unexpectedly found to persist in plasma for prolonged periods of time (e.g. >4 weeks at 1500 mg).

CONCLUSION

Acute, oral CBD treatment does not appear to induce feelings of intoxication and is unlikely to impair cognitive function or driving performance (Registration: ACTRN12619001552178).

Actigraphic and melatonin alignment in older adults with varying dementia risk

Circadian rhythms alter with ageing and may be aetiologically linked to neurodegeneration. This study explored the association between clinical markers and 1) dim light melatonin onset (DLMO) time and 2) phase angle derived from sleep midpoint, in older adults with varying dementia risks. Participants completed 14 days of actigraphy followed by in-lab measurement of salivary melatonin, from which DLMO time and phase angle were computed. Eighty participants (age = 65.5, SD = 9.6), 44 males (55%), MMSE (28.6, SD = 1.5) were included in the analysis. Sex (t = 2.15, p = .04), sleep onset (r = 0.49, p < .001) and midpoint (r = 0.44, p < .001) also correlated with DLMO time. Multiple linear regression showed chronotype, average actigraphy-derived light exposure during the DLMO window (window 2 h prior to DLMO to 2 h post), early biological day (6-10 h post DLMO time) and late biological day (10-14 h post DLMO time) were predictive of DLMO time (adjusted R² = 0.75). Sleep offset, depression severity, average light exposure during the early biological night and early and late biological day were shown to be predictive variables in the estimation of phase angle (adjusted R² = 0.78). The current study highlights the potential use of clinical variables, such as actigraphy-derived light, as circadian markers in ageing which could be easily implemented into existing clinical practice and could yield potential targets focusing on chronotherapeutic interventions.

The Effect of Light Therapy on Electroencephalographic Sleep in Sleep and Circadian Rhythm Disorders: A Scoping Review

Light therapy is used to treat sleep and circadian rhythm disorders, yet there are limited studies on whether light therapy impacts electroencephalographic (EEG) activity during sleep. Therefore, we aimed to provide an overview of research studies that examined the effects of light therapy on sleep macro- and micro-architecture in populations with sleep and circadian rhythm disorders. We searched for randomized controlled trials that used light therapy and included EEG sleep measures using MEDLINE, PubMed, CINAHL, PsycINFO and Cochrane Central Register of Controlled Trials databases. Five articles met the inclusion criteria of patients with either insomnia or delayed sleep−wake phase disorder (DSWPD). These trials reported sleep macro-architecture outcomes using EEG or polysomnography. Three insomnia trials showed no effect of the timing or intensity of light therapy on total sleep time, wake after sleep onset, sleep efficiency and sleep stage duration compared to controls. Only one insomnia trial reported significantly higher sleep efficiency after evening light therapy (>4000 lx between 21:00−23:00 h) compared with afternoon light therapy (>4000 lx between 15:00−17:00 h). In the only DSWPD trial, six multiple sleep latency tests were conducted across the day (09:00 and 19:00 h) and bright light (2500 lx) significantly lengthened sleep latency in the morning (09:00 and 11:00 h) compared to control light (300 lx). None of the five trials reported any sleep micro-architecture measures. Overall, there was limited research about the effect of light therapy on EEG sleep measures, and studies were confined to patients with insomnia and DSWPD only. More research is needed to better understand whether lighting interventions in clinical populations affect sleep macro- and micro-architecture and objective sleep timing and quality.

Cannabinoids, Insomnia, and Other Sleep Disorders

Sleep disturbances are often cited as a primary reason for medicinal cannabis use, and there is increasing clinical interest in the therapeutic potential of cannabinoids in treating sleep disorders. Burgeoning evidence suggests a role of the endocannabinoid system in regulating the circadian sleep-wake cycle, highlighting a potential avenue for developing novel therapeutics. Despite widespread use of cannabis products as sleep aids globally, robustly designed studies verifying efficacy in sleep-disordered populations are limited. Although some study outcomes have suggested cannabinoid utility in insomnia disorder and sleep apnea, most studies to date are limited by small sample sizes, lack of rigorously controlled study designs, and high risk of bias. This critical review summarizes the current evidence for the use of cannabinoids as a treatment for sleep disorders and provides an overview of endocannabinoid modulation of sleep-wake cycles, as well as the sleep-modulating effects of plant-derived cannabinoids such as delta-9-tetrahydrocannbinol, cannabidiol, and cannabinol. The review also discusses practical considerations for clinicians regarding cannabinoid formulations, routes of administration, respiratory concerns, dosing, potential side effects, drug interactions, and effects relevant to driving, tolerance, and withdrawal. Although current interest in, and uptake of, medicinal cannabis use for sleep disorders may have surpassed the evidence base, there is a strong rationale for continued investigation into the therapeutic potential of cannabinoids.

Improvements in cognitive function and quantitative sleep electroencephalogram in obstructive sleep apnea after six months of continuous positive airway pressure treatment

STUDY OBJECTIVES

Untreated obstructive sleep apnea (OSA) is associated with cognitive deficits and altered brain electrophysiology. We evaluated the effect of continuous positive airway pressure (CPAP) treatment on quantitative sleep electroencephalogram (EEG) measures and cognitive function.

METHODS

We studied 167 patients with OSA (age 50 ± 13, AHI 35.0 ± 26.8) before and after 6 months of CPAP. Cognitive tests assessed working memory, sustained attention, visuospatial scanning, and executive function. All participants underwent overnight polysomnography at baseline and after CPAP. Power spectral analysis was performed on EEG data (C3-M2) in a sub-set of 90 participants. Relative delta EEG power and sigma power in NREM and EEG slowing in REM were calculated. Spindle densities (events/min) in N2 were also derived using automated spindle event detection. All outcomes were analysed as change from baseline.

RESULTS

Cognitive function across all cognitive domains improved after six months of CPAP. In our sub-set, increased relative delta power (p < .0001) and reduced sigma power (p = .001) during NREM were observed after the 6-month treatment period. Overall, fast and slow sleep spindle densities during N2 were increased after treatment.

CONCLUSIONS

Cognitive performance was improved and sleep EEG features were enhanced when assessing the effects of CPAP. These findings suggest the reversibility of cognitive deficits and altered brain electrophysiology observed in untreated OSA following six months of treatment.

Sleep Deficiency and Cardiometabolic Disease

Epidemiologic studies have demonstrated that short sleep duration is associated with an increased risk of cardio-metabolic health outcomes including cardiovascular disease mortality, coronary heart disease, type 2 diabetes mellitus, hypertension, and metabolic syndrome. Experimental sleep restriction studies have sought to explain these findings. This review describes the main evidence of these associations and possible mechanisms explaining them. Whether sleep extension reverses these now widely acknowledged adverse health effects and the feasibility of implementing such strategies on a public health level is discussed.

Safety of higher doses of melatonin in adults: A systematic review and meta-analysis

Melatonin is commonly used for sleep and jetlag at low doses. However, there is less documentation on the safety of higher doses, which are being increasingly used for a wide variety of conditions, including more recently COVID-19 prevention and treatment. The aim of this review was to investigate the safety of higher doses of melatonin in adults. Medline, Scopus, Embase and PsycINFO databases from inception until December 2019 with convenience searches until October 2020. Randomised controlled trials investigating high-dose melatonin (≥10 mg) in human adults over 30 years of age were included. Two investigators independently abstracted articles using PRISMA guidelines. Risk of bias was assessed by a committee of three investigators. 79 studies were identified with a total of 3861 participants. Studies included a large range of medical conditions. The meta-analysis was pooled data using a random effects model. The outcomes examined were the number of adverse events (AEs), serious adverse events (SAEs) and withdrawals due to AEs. A total of 29 studies (37%) made no mention of the presence or absence of AEs. Overall, only four studies met the pre-specified low risk of bias criteria for meta-analysis. In that small subset, melatonin did not cause a detectable increase in SAEs (Rate Ratio = 0.88 [0.52, 1.50], p = .64) or withdrawals due to AEs (0.93 [0.24, 3.56], p = .92), but did appear to increase the risk of AEs such as drowsiness, headache and dizziness (1.40 [1.15, 1.69], p < .001). Overall, there has been limited AE reporting from high-dose melatonin studies. Based on this limited evidence, melatonin appears to have a good safety profile. Better safety reporting in future long-term trials is needed to confirm this as our confidence limits were very wide due to the paucity of suitable data.

Brain oxidative stress and cognitive function in older adults with diabetes and pre-diabetes who are at risk for dementia

AIMS

Diabetes is an established risk factor for dementia. This study aimed to examine the relationship between various cognitive domains, brain oxidative stress and markers of diabetes in older adults at risk for dementia.

METHODS

Older adults at risk for dementia underwent comprehensive neuropsychological and medical assessment. At risk was defined as those with subjective and/or objective cognitive impairment. Pre-diabetes and type 2 diabetes were defined using American Diabetes Association definitions for fasting blood glucose and HbA1c. Brain oxidative stress as indicated by glutathione (GSH) was assessed via magnetic resonance spectroscopy in the anterior cingulate cortex.

RESULTS

One-hundred and forty-seven older adults completed a neuropsychological assessment and fasting blood sample with 63 also undergoing magnetic resonance spectroscopy. Those with pre-diabetes/diabetes according to FBG had impaired memory retention, set-shifting and response inhibition, compared to those with normal blood glucose. In contrast, there were no significant differences in any cognitive outcome using the HbA1c definition. Increasing glucose and HbA1c levels were associated with reduced GSH concentration in the anterior cingulate.

CONCLUSIONS

This study demonstrates that in older adults at risk for dementia, having pre-diabetes or diabetes is associated with impaired memory and executive dysfunction. It also highlights the potential role of oxidative stress as a pathophysiological mechanism that may underpin the link between diabetes and cognitive dysfunction.

The influence of oxytocin-based interventions on sleep-wake and sleep-related behaviour and neurobiology: A systematic review of preclinical and clinical studies

The oxytocin (OXT) system has garnered considerable interest due to its influence on diverse behaviours. However, scant research has considered the influence of oxytocin on sleep-wake and sleep-related behaviour and neurobiology. Consequently, the objective of this systematic review was to assess the extant preclinical and clinical evidence for the influence of oxytocin-based interventions on sleep-wake outcomes. The primary search was conducted on 22/7/2020 using six electronic databases; 30 studies (19 preclinical, 11 clinical) were included based on inclusion criteria. Studies were evaluated for risk of bias using the SYRCLE tool and the Cochrane risk of bias tools for preclinical and clinical studies, respectively. Results indicated manipulation of the OXT system can influence sleep-wake outcomes. Preclinical evidence suggests a wake-promoting influence of OXT system activation whereas the clinical evidence suggests little or no sleep-promoting influence of OXT. OXT dose was identified as a likely modulatory factor of OXT-induced effects on sleep-wake behaviour. Future studies are necessary to validate and strengthen these tentative conclusions about the influence of OXT on sleep-wake behaviour.

Effect of Continuous Positive Airway Pressure on Weight and Local Adiposity in Adults with Obstructive Sleep Apnea: A Meta-Analysis

Rationale: Evidence suggests that continuous positive airway pressure (CPAP) treatment promotes weight gain in patients with obstructive sleep apnea (OSA). It is unclear whether weight gain is influenced by CPAP adherence or comorbid disorders. Objectives: To examine the CPAP effects on body mass index (BMI) and local adiposity and the potential moderators of CPAP effects on BMI in patients with OSA. Methods: We searched PubMed/Medline, Embase, and Cochrane through December 2019. Randomized controlled trials of CPAP versus control treatment with ⩾4 weeks' treatment were included. Results: A total of 39 randomized controlled trials with 6,954 subjects were included. In intention-to-treat analysis, the BMI increased significantly after CPAP treatment compared with control treatment (weighted mean difference [WMD], 0.148 kg/m²; 95% confidence interval, 0.04-0.26; P = 0.001). In studies demonstrating an increase in the BMI, waist and neck circumferences were also significantly increased. Subgroup analyses revealed that an increased BMI was attributable to CPAP use of ⩽5 h/night (WMD, 0.231) but was not attributable to CPAP use of >5 h/night (WMD, 0.001; between-group P value = 0.049). Furthermore, the BMI increased significantly in patients without cardiovascular disease (CVD; WMD, 0.200), whereas it decreased significantly in those with CVD at baseline (WMD, -0.188; between-group P value < 0.001). Moreover, the BMI increased significantly in patients with dysglycemia (WMD, 0.499) but did not increase in those without dysglycemia at baseline (WMD, 0.100; between-group P value = 0.032). Meta-regression confirmed the subgroup findings. Conclusions: The BMI increased significantly in patients with OSA after CPAP treatment, especially in those with CPAP use of ⩽5 h/night, without CVD and/or with dysglycemia at baseline. CPAP use of at least 5 h/night seems to be necessary in mitigating the risk for weight gain in patients with OSA.

Orally administered cannabidiol does not produce false-positive tests for Δ9 -tetrahydrocannabinol on the Securetec DrugWipe® 5S or Dräger DrugTest® 5000

Many jurisdictions use point‐of‐collection (POC) oral fluid testing devices to identify driving under the influence of cannabis, indexed by the presence of Δ⁹‐tetrahydrocannabinol (THC), an intoxicating cannabinoid, in oral fluid. Although the use of the non‐intoxicating cannabinoid, cannabidiol (CBD), is not prohibited among drivers, it is unclear whether these devices can reliably distinguish between CBD and THC, which have similar chemical structures. This study determined whether orally administered CBD produces false‐positive tests for THC on standard, POC oral fluid testing devices. In a randomised, double‐blind, crossover design, healthy participants (n = 17) completed four treatment sessions involving the administration of either placebo or 15‐, 300‐ or 1500‐mg pure CBD in a high‐fat dietary supplement. Oral fluid was sampled, and the DrugWipe®‐5S (DW‐5S; 10 ng·ml⁻¹ THC cut‐off) and Drug Test® 5000 (DT5000; 10 ng·mL⁻¹ THC cut‐off) devices administered, at baseline (pretreatment) and ~20‐, ~145‐ and ~185‐min posttreatment. Oral fluid cannabinoid concentrations were measured using ultra‐high performance liquid chromatography–tandem mass spectrometry. Median (interquartile range [IQR]) oral fluid CBD concentrations were highest at ~20 min, quantified as 0.4 (6.0), 15.8 (41.6) and 167 (233) ng·ml⁻¹ on the 15‐, 300‐ and 1500‐mg CBD treatments, respectively. THC, cannabinol and cannabigerol were not detected in any samples. A total of 259 DW‐5S and 256 DT5000 tests were successfully completed, and no THC‐positive tests were observed. Orally administered CBD does not appear to produce false‐positive (or true‐positive) tests for THC on the DW‐5S and DT5000. The likelihood of an individual who is using a CBD (only) oral formulation being falsely accused of DUIC therefore appears low.

Predictors of weight loss in obese patients with obstructive sleep apnea

PURPOSE

Consistent predictors of weight loss outcomes with very low-energy diets (VLEDs) in obstructive sleep apnea (OSA) have not been identified. This study aimed to identify variables predictive of weight loss success in obese patients with OSA undertaking an intensive weight loss programme.

METHODS

We analysed biological, psychological, and behavioural variables as potential predictors of weight loss in obese patients with OSA after a 2-month VLED followed by one of two 10-month weight loss maintenance diets. Actigraphy, in-lab polysomnography, urinary catecholamines, and various psychological and behavioural variables were measured at baseline, 2, and 12 months. Spearman's correlations analysed baseline variables with 2-month weight loss, and 2-month variables with 2-12 month-weight change.

RESULTS

Forty-two patients completed the VLED and thirty-eight completed the maintenance diets. Actigraphy data revealed that late bedtime (r_s =  - 0.45, p =  < 0.01) was correlated with 2-month weight loss. The change in the time that participants got out of bed (rise-time) from baseline to two months was also correlated with 2-month weight loss (r_s = 0.36, p = 0.03). The Impact of Weight on Quality of Life-Lite questionnaire (IWQOL) Public Distress domain (r_s =  - 0.54, p =  < 0.01) and total (r_s =  - 0.38, p = 0.02) scores were correlated with weight loss maintenance from 2 to 12 months.

CONCLUSIONS

Results from this small patient sample reveal correlations between actigraphy characteristics and weight loss in obese patients with OSA. We suggest the IWQOL may also be a useful clinical tool to identify OSA patients at risk of weight regain after initial weight loss.

CLINICAL TRIAL REGISTRATION

This clinical trial was prospectively registered on 18/02/2013 with the Australia and New Zealand Clinical Trials Registry (ACTRN12613000191796).

PUBLIC REGISTRY TITLE

Sleep, Lifestyle, Energy, Eating, Exercise Program for the management of sleep apnea patients indicated for weight loss treatment: A randomised, controlled pilot study. URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=363680.

Development and validation of a model for diagnosis of obstructive sleep apnoea in primary care

BACKGROUND AND OBJECTIVE

Use of in-laboratory polysomnography (PSG) to diagnose obstructive sleep apnoea (OSA) is cost and resource intensive. Questionnaires, physical measurements and home monitors have been studied as potential simpler alternatives. This study aimed to develop a diagnostic model for OSA for use in primary care.

METHODS

Primary care practitioners were trained to recognize symptoms of sleep apnoea and recruited patients based on the clinical need to investigate OSA. Assessment was by symptom questionnaires, anthropomorphic measurements, digital facial photography, and a single-channel nasal flow monitor (Flow Wizard©, DiagnoseIT, Sydney, Australia) worn at home for 3 nights. The in-laboratory PSG was the reference test, with OSA defined as apnoea-hypopnoea index (AHI) ≥10 events/h.

RESULTS

In the model development phase, 25 primary care practitioners studied 315 patients in whom they suspected OSA, of which 57% had AHI≥10 and 22% had AHI≥30. Published OSA questionnaires provided low to moderate prediction of OSA (area under the curve [AUC] 0.53-0.73). The nasal flow monitor alone yielded high accuracy for predicting OSA with AUC of 0.87. Sensitivity was 0.87 and specificity 0.77 at a threshold respiratory event index (REI) of 18 events/h. A model adding age, gender, symptoms and BMI to the nasal flow monitor REI only modestly improved OSA prediction (AUC 0.89), with similar AUC (0.88) confirmed in the validation population of 114 patients.

CONCLUSION

Sleep apnoea can be diagnosed in the primary care setting with a combination of clinical judgement and portable monitor test outcomes.

Bilevel Noninvasive Ventilation During Exercise Reduces Dynamic Hyperinflation and Improves Cycle Endurance Time in Severe to Very Severe COPD

BACKGROUND

During exercise, dynamic hyperinflation (DH), measured by a reduction in inspiratory capacity (IC), increases exertional dyspnea and reduces functional capacity in many patients with severe COPD. Although noninvasive ventilation (NIV) during exercise can improve exercise duration, the effect on DH is unclear.

RESEARCH QUESTIONS

In people with COPD, resting hyperinflation, and evidence of DH during exercise, does bilevel NIV during exercise reduce DH and increase endurance time compared with exercise with no NIV, and does NIV with an individually titrated expiratory positive airway pressure (T-EPAP) reduce DH and increase exercise endurance time more than does NIV with standardized EPAP (S-EPAP) of 5 cm H₂O?

STUDY DESIGN AND METHODS

A randomized crossover trial in which investigators and participants were blinded between NIV interventions was performed. Participants (N = 19; FEV₁ of 1.02 ± 0.24 L (39% ± 6% predicted) completed three constant work rate endurance cycle tests in random order-no NIV, NIV with S-EPAP, and NIV with T-EPAP-during exercise. Primary outcomes were isotime IC and exercise endurance time. Outcome measures from each intervention were compared at isotime and at end exercise by using a linear mixed-model analysis.

RESULTS

Compared with those with no NIV, isotime IC and endurance time were greater with both NIV with S-EPAP (mean difference: 95% CI, 0.19 L [0.10-0.28]; 95% CI, 153 s [24-280], respectively) and T-EPAP (95% CI, 0.22 L [0.13-0.32]; 95% CI, 145 s [28-259], respectively). There was no difference between NIV with S-EPAP and NIV with T-EPAP.

INTERPRETATION

In people with COPD and DH during exercise, NIV during exercise reduced DH and increased cycle endurance time. An S-EPAP of 5 cm H₂O was adequate to obtain these benefits.

TRIAL REGISTRY

Australian New Zealand Clinical Trials Registry; No.: ACTRN12613000804785; URL: http://www.anzctr.org.au.

Altered heart rate variability during sleep in mild cognitive impairment

STUDY OBJECTIVES

Cardiovascular autonomic dysfunction, as measured by short-term diurnal heart rate variability (HRV), has been reported in older adults with mild cognitive impairment (MCI). However, it is unclear whether this impairment also exists during sleep in this group. We, therefore, compared overnight HRV during sleep in older adults with MCI and those with subjective cognitive impairment (SCI).

METHODS

Older adults (n = 210) underwent overnight polysomnography. Eligible participants were characterized as multi-domain MCI or SCI. The multi-domain MCI group was comprised of amnestic and non-amnestic subtypes. Power spectral analysis of HRV was conducted on the overnight electrocardiogram during non-rapid eye movement (NREM), rapid eye movement (REM), N1, N2, N3 sleep stages, and wake periods. High-frequency HRV (HF-HRV) was employed as the primary measure to estimate parasympathetic function.

RESULTS

The MCI group showed reduced HF-HRV during NREM sleep (p = 0.018), but not during wake or REM sleep (p > 0.05) compared to the SCI group. Participants with aMCI compared to SCI had the most pronounced reduction in HF-HRV across all NREM sleep stages-N1, N2, and N3, but not during wake or REM sleep. The naMCI sub-group did not show any significant differences in HF-HRV during any sleep stage compared to SCI.

CONCLUSIONS

Our study showed that amnestic MCI participants had greater reductions in HF-HRV during NREM sleep, relative to those with SCI, suggesting potential vulnerability to sleep-related parasympathetic dysfunction. HF-HRV, especially during NREM sleep, may be an early biomarker for dementia detection.

Does craniofacial morphology relate to sleep apnea severity reduction following weight loss intervention? A patient-level meta-analysis

STUDY OBJECTIVES

Obesity is a common and reversible risk factor for obstructive sleep apnea (OSA). However, there is substantial unexplained variability in the amount of OSA improvement for any given amount of weight loss. Facial photography is a simple, inexpensive, and radiation-free method for craniofacial assessment. Our aims were (1) to determine whether facial measurements can explain OSA changes, beyond weight loss magnitude and (2) whether facial morphology relates to how effective weight loss will be for OSA improvement.

METHODS

We combined data from three weight loss intervention trials in which participants had standardized pre-intervention facial photography (N = 91; 70.3% male, mean ± SD weight loss 10.4 ± 9.6% with 20.5 ± 51.2% apnea-hypopnea index [AHI] reduction). Three skeletal-type craniofacial measurements (mandibular length, lower face height, and maxilla-mandible relationship angle) were assessed for relationship to AHI change following weight loss intervention.

RESULTS

Weight and AHI changes were moderately correlated (rho = 0.3, p = 0.002). In linear regression, an increased maxilla-mandible relationship angle related to AHI improvement (β [95% CI] -1.7 [-2.9, -0.5], p = 0.004). Maxilla-mandible relationship angle explained 10% in the variance in AHI over the amount predicted by weight loss amount (20%). The relationship between weight change and AHI was unaffected by the maxilla-mandible relationship angle (interaction term p > 0.05).

CONCLUSIONS

Regardless of facial morphology, weight loss is similarly moderately predictive of OSA improvement. Increased maxilla-mandible relationship angle, suggestive of retrognathia, was weakly predictive of OSA response to weight loss. Although this is unlikely to be clinically useful, exploration in other ethnic groups may be warranted.

Feasibility of 3-month melatonin supplementation for brain oxidative stress and sleep in mild cognitive impairment: protocol for a randomised, placebo-controlled study

INTRODUCTION

Melatonin has multiple proposed therapeutic benefits including antioxidant properties, synchronisation of the circadian system and lowering of blood pressure. In this protocol, we outline a randomised controlled trial to assess the feasibility, acceptability and tolerability of higher dose (25 mg) melatonin to target brain oxidative stress and sleep disturbance in older adults with mild cognitive impairment (MCI).

METHODS AND ANALYSIS

The study design is a randomised double-blind, placebo-controlled, parallel group trial. Forty individuals with MCI will be recruited from the Healthy Brain Ageing Clinic, University of Sydney and from the community, and randomised to receive either 25 mg oral melatonin or placebo nightly for 12 weeks. The primary outcomes are feasibility of recruitment, acceptability of intervention and adherence to trial medication at 12 weeks. Secondary outcomes will include the effect of melatonin on brain oxidative stress as measured by magnetic resonance spectroscopy, blood pressure, blood biomarkers, mood, cognition and sleep. Outcomes will be collected at 6 and 12 weeks. The results of this feasibility trial will inform a future conclusive randomised controlled trial to specifically test the efficacy of melatonin on modifiable risk factors of dementia, as well as cognition and brain function. This will be the first trial to investigate the effect of melatonin in the population with MCI in this way, with the future aim of using this approach to reduce progression to dementia.

ETHICS AND DISSEMINATION

This protocol has been approved by the Sydney Local Health District Ethics Committee (X18-0077). This randomised controlled trial will be conducted in compliance with the protocol published in the registry, the International Conference for Harmonisation on Good Clinical Practice and all other applicable regulatory requirements. The findings of the trial will be disseminated via conferences, publications and media, as applicable. Participants will be informed of results of the study at the conclusion of the trial. Eligible authors will include investigators who are involved in the conception and design of the study, the conduct of the trial, the analysis of the results, and reporting and presentation of study findings.

TRIAL REGISTRATION NUMBER

Australian and New Zealand Clinical Trials Registry (ANZCTRN 12619000876190).

PROTOCOL VERSION

V.8 15 October 2020.

The effect of cannabidiol on simulated car driving performance: A randomised, double-blind, placebo-controlled, crossover, dose-ranging clinical trial protocol

OBJECTIVE

Interest in the use of cannabidiol (CBD) is increasing worldwide as its therapeutic effects are established and legal restrictions moderated. Unlike Δ9 -tetrahydrocannabinol (Δ9 -THC), CBD does not appear to cause cognitive or psychomotor impairment. However, further assessment of its effects on cognitively demanding day-to-day activities, such as driving, is warranted. Here, we describe a study investigating the effects of CBD on simulated driving and cognitive performance.

METHODS

Thirty healthy individuals will be recruited to participate in this randomised, double-blind, placebo-controlled crossover trial. Participants will complete four research sessions each involving two 30-min simulated driving performance tests completed 45 and 210 min following oral ingestion of placebo or 15, 300, or 1,500 mg CBD. Cognitive function and subjective drug effects will be measured, and blood and oral fluid sampled, at regular intervals. Oral fluid drug testing will be performed using the Securetec DrugWipe® 5S and Dräger DrugTest® 5000 devices to determine whether CBD increases the risk of "false-positive" roadside tests to Δ9 -THC. Noninferiority analyses will test the hypothesis that CBD is no more impairing than placebo.

CONCLUSION

This study will clarify the risks involved in driving following CBD use and assist in ensuring the safe use of CBD by drivers.

Cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC) for chronic insomnia disorder ('CANSLEEP' trial): protocol for a randomised, placebo-controlled, double-blinded, proof-of-concept trial

INTRODUCTION

Insomnia is a highly prevalent and costly condition that is associated with increased health risks and healthcare utilisation. Anecdotally, cannabis use is frequently reported by consumers to promote sleep. However, there is limited research on the effects of cannabis on sleep and daytime function in people with insomnia disorder using objective measures. This proof-of-concept study will evaluate the effects of a single dose of an oral cannabis-based medicine on sleep and daytime function in participants with chronic insomnia disorder.

METHODS AND ANALYSIS

A randomised, crossover, placebo-controlled, single-dose study design will be used to test the safety and efficacy of an oral oil solution ('ETC120') containing 10 mg Δ9-tetrahydrocannabinol (THC) and 200 mg cannabidiol (CBD) in 20 participants diagnosed with chronic insomnia disorder. Participants aged 35-60 years will be recruited over an 18-month period commencing August 2019. Each participant will receive both the active drug and matched placebo, in a counterbalanced order, during two overnight study assessment visits, with at least a 1-week washout period between each visit. The primary outcomes are total sleep time and wake after sleep onset assessed via polysomnography. In addition, 256-channel high-density electroencephalography and source modelling using structural brain MRI will be used to comprehensively examine brain activation during sleep and wake periods on ETC120 versus placebo. Next-day cognitive function, alertness and simulated driving performance will also be investigated.

ETHICS AND DISSEMINATION

Ethics approval was received from Bellberry Human Research Ethics Committee (2018-04-284). The findings will be disseminated in a peer-reviewed open-access journal and at academic conferences.

TRIAL REGISTRATION NUMBER

ANZCTRN12619000714189.

Does CPAP treat depressive symptoms in individuals with OSA? An analysis of two 12-week randomized sham CPAP-controlled trials

BACKGROUND

Depression is common in patients with obstructive sleep apnea (OSA). Whether treating OSA with continuous positive airway pressure (CPAP) improves depressive symptoms remains inconclusive. We examined the impact of CPAP on depressive symptoms in OSA patients compared to sham CPAP.

METHODS

A sub-analysis of two previous randomized sham-controlled trials was conducted. 126 male OSA patients (age = 51 ± 11 years; BMI = 32.0 ± 5.1 kg/m²; apnea hypopnea index = 42.4 ± 22.6 events/hour) were randomised either to therapeutic CPAP (n = 65) or sham CPAP (n = 61). Depressive symptoms were measured using the Depression, Anxiety and Stress Scale (DASS). The main outcome was the change in the DASS depression score (DASSD) after three months between the therapeutic and sham CPAP arms.

RESULTS

The change in DASSD at three months did not differ between therapeutic and sham CPAP (mean difference: 0.5, 95% CI -3.6 to 4.6, p = 0.80). There was no significant between-group differences within the sub-groups of adherent users (device usage≥4hrs/day), or those with baseline depression (DASSD>9). In a secondary analysis of patients with baseline depression, adherent therapeutic CPAP use was associated with a greater reduction in DASSD scores compared to non-adherers (-10.0, 95% CI -18.3 to -1.8, p = 0.019).

CONCLUSIONS

Overall, three months of CPAP did not significantly improve depression scores in OSA patients. Adherent use of therapeutic CPAP in patients with baseline depressive symptoms was associated with a reduction in symptom score. Future trials involving OSA patients with higher depressive symptoms will enable us to understand the complex interaction between OSA and depression.

Circadian rhythm and sleep alterations in older people with lifetime depression: a case-control study

BACKGROUND

Depression is common in older people and is associated with underlying brain change increasing the risk of dementia. Sleep disturbance is frequently reported by those with lifetime depression, however whether circadian misalignment also exists is unclear. We aimed to examine circadian rhythms and sleep associations in older patients with and without lifetime depression.

METHODS

Thirty-four older people meeting DSM-IV criteria for lifetime major depression (mean age = 63.9 years), and 30 healthy controls (mean age = 65.7 years) were recruited. Participants underwent 2-weeks of actigraphy followed by a 3-night protocol including dim light melatonin onset (DLMO) assessment and overnight polysomnography (PSG) for sleep architecture. DLMO and phase angle of entrainment were computed.

RESULTS

Compared to controls, participants with depression had a significantly longer phase angle of entrainment (6.82 h ± 1.45 vs. 5.87 h ± 1.60, p = 0.02, Cohens-d = 0.62). A small to moderate yet non-significant difference in DLMO times, with earlier DLMO (34 ± 27 min) observed in depression (20:36 ± 1:48 vs. 21:10 ± 1:48, p = 0.22, Cohens-d = 0.32). Individuals with depression had longer sleep latency and latency to rapid eye movement sleep than controls (all p < 0.05).

CONCLUSION

Circadian advancement and alterations to the timing of sleep and REM onset are evident in older people with lifetime major depression, despite having only mild residual symptoms. Further research examining the prognostic significance of these changes is warranted as well as chronotherapeutic treatment studies.

Impact factor rankings for sleep research journals between 2005 and 2018

Impact factors and ranking lists of research journals are very often used to judge our career achievements and progression by employers and granting bodies. However, a comprehensive list for the interdisciplinary field of sleep research does not currently exist because our journals tend to be placed into discipline-specific lists that do not cope well with our historic interdisciplinarity, which embraces many core disciplines. We aimed to build a ranking list specifically for sleep research journals based on the journal impact factor and the google scholar H₅ indices. We then searched for all sleep journals given an impact factor by Thomson Reuters from 2005 to 2018 and all journals given a current H₅ index by Google Scholar. We provide a ranking list specifically for sleep journals that might be useful for researchers to cite when providing context in their applications for employment, promotion and funding.

Objective measurement of sleep in mild cognitive impairment: A systematic review and meta-analysis

Older adults with mild cognitive impairment (MCI) are at-risk of developing dementia, particularly Alzheimer's disease. While some research suggests that alterations in sleep architecture may mediate cognitive decline, the nature and magnitude of changes to sleep macro- (sleep stages) and micro-architecture (electroencephalography (EEG) oscillations) in MCI is not yet clear. This study aimed to systematically review and meta-analyse case-control studies objectively measuring sleep in MCI. A systematic search was conducted using PubMed, Scopus, Web of Science, Embase and Psycinfo databases and after review, a total of 10 studies met inclusion criteria. Of these, all reported sleep macro-architecture and four reported micro-architecture outcomes. A combined total of 430 participants (209 with and 221 without MCI) underwent objective sleep assessments in the included full text articles. Findings show that compared to healthy controls, those with MCI have pronounced changes in sleep macro-architecture with greater wake after sleep onset, reduced total sleep time, lower sleep efficiency, longer sleep onset latency, longer rapid eye movement sleep (REM) latency, reduced REM sleep, greater N1 sleep, and worse severity of hypoxemia. Pooling of sleep micro-architecture EEG measures was not possible due to limited studies, however reduced spindles in non-REM sleep and greater EEG slowing in REM sleep were reported.

Magnesium supplementation for the treatment of restless legs syndrome and periodic limb movement disorder: A systematic review

Magnesium supplementation is often suggested for restless legs syndrome (RLS) or period limb movement disorder (PLMD) based on anecdotal evidence that it relieves symptoms and because it is also commonly recommended for leg cramps. We aimed to review all articles reporting the effects of magnesium supplementation on changes in RLS and/or PLMD. We conducted a systematic search looking for all relevant articles and then two reviewers read all article titles and abstracts to identify relevant studies. Eligible studies were scored for their quality as interventional trials. We found 855 abstracts and 16 of these could not be definitively excluded for not addressing all aspects of our research question. Seven full-text articles were unlocatable and one was ineligible which left eight studies with relevant data. One was a randomised placebo-controlled trial, three were case series and four were case studies. The RCT did not find a significant treatment effect of magnesium but may have been underpowered. After quality appraisal and synthesis of the evidence we were unable to make a conclusion as to the effectiveness of magnesium for RLS/PLMD. It is not clear whether magnesium helps relieve RLS or PLMD or in which patient groups any benefit might be seen.

Arterial stiffness relates to executive dysfunction in later life

Cardiovascular disease in older people is often linked with cognitive impairment, particularly in domains of executive function and processing speed. Our aims examined whether carotid-femoral pulse wave velocity (PWV) related to subtle changes of executive function and processing speed. Fifty-six individuals with subjective mood and/or cognitive concerns underwent PWV and neuropsychological assessments of processing speed (Trail Making Test Part A) and executive functioning (Delis Kaplan Executive Function System Stroop Task; Trail Making Test Part B, TMT-B). Individuals with high PWV (≥12.0m/s) had poorer performance on TMT-B, compared to low PWV (<12.0m/s), and a moderate negative correlation (r = -0.38, p = .004) between PWV and TMT-B performance. Our results confirm that in older adults at-risk for cognitive decline, early markers of CVD are associated with subtle decrements in rapid set-shifting (executive function), supporting efforts towards early detection of CVD as a secondary prevention strategy for older individuals with cognitive decline.

Associations Between Obstructive Sleep Apnea and Measures of Arterial Stiffness

STUDY OBJECTIVES

The aim of this study was to determine whether severity measures of obstructive sleep apnea (OSA) are associated with arterial stiffness and central blood pressure (two important cardiovascular risk factors) in a large group of patients with OSA.

METHODS

Baseline data from six studies on OSA in which arterial stiffness and central aortic blood pressure measures were determined using applanation tonometry were pooled. Associations between measures of arterial stiffness (heart rate corrected augmentation index [AI75]), central aortic blood pressure (central systolic pressure [CSP] and heart rate corrected central augmentation pressure [CAP75]) and measures of OSA severity were explored using stepwise regression modelling.

RESULTS

Data from 362 participants (M:F ratio 13:1) with mean (standard deviation) age 49.2 (11.0) years, body mass index 31.9 (5.3) kg/m², apnea-hypopnea index (AHI) 35.7 (20.7) events/h were included in the analyses. The AHI, oxygen desaturation index (ODI3%), and sleep time with SpO₂ < 90% (T90) were all associated with arterial stiffness (AI75), (AHI: adj. β = .069; P = .01; ODI3%: adj. β = .072; P = .01; T90: adj. β = .18; P < .0001) and CAP75 (AHI: adj. β = .030; P = .01; ODI3%: adj. β = .027; P = .02; T90: adj. β = .080; P < .0001). AHI was also associated with CSP (AHI: adj. β = .11; P = .002).

CONCLUSIONS

OSA severity was significantly associated with augmentation index and CAP75 although the relationships were not strong.

Dose-dependent effects of continuous positive airway pressure for sleep apnea on weight or metabolic function: Individual patient-level clinical trial meta-analysis

Therapeutic-continuous positive airway pressure seems to increase weight compared with placebo-continuous positive airway pressure. It is not known whether weight gain with therapeutic-continuous positive airway pressure dose is dependent or whether it causes metabolic dysfunction. Data synthesis of three randomised placebo-continuous positive airway pressure-controlled trials (2-3 months) was performed to test whether there is a dose-dependent effect of continuous positive airway pressure on weight. Fasting glucose, insulin, insulin resistance (homeostatic model assessment), lipids and visceral abdominal fat were also tested to determine any effect on metabolic function. Mixed-model analysis of variance was used to quantify these effects. One-hundred and twenty-eight patients were analysed. Overall there was a small increase in weight with therapeutic-continuous positive airway pressure use compared with placebo-continuous positive airway pressure (difference: 1.17 kg; 0.37-1.97, p = 0.005), which was greater with high-use therapeutic-continuous positive airway pressure compared with high-use placebo-continuous positive airway pressure (1.45 kg; 0.10-2.80, p = 0.04). Continuous positive airway pressure use as a continuous variable was also significantly associated with weight change in continuous positive airway pressure users (0.30 kg hr^-1  night^-1 ; 0.04-0.56, p = 0.001), but not in placebo users (0.04 kg hr^-1  night^-1 ; -0.22 to 0.26, p = 0.76). Neither therapeutic-continuous positive airway pressure nor the dose of therapeutic-continuous positive airway pressure caused any changes to metabolic outcomes. The weight gain effects of medium-term therapeutic-continuous positive airway pressure appear modest and are not accompanied by any adverse metabolic effects.