Tailoring cognitive behavioural therapy for insomnia across contexts, conditions, and individuals: What do we know, where do we go?

Cognitive behavioural therapy for insomnia (CBT-I) is considered the front-line treatment for insomnia. Despite the demonstrated effectiveness of CBT-I, it is necessary to consider how CBT-I may be tailored to different individuals. The purpose of the present review is to provide a summary of literature on tailoring CBT-I to different individuals and provide directions for future research. This review focused on the following domains of adaptation: (i) tailoring CBT-I components to individuals with comorbid mental or physical health conditions such as comorbid depression and pain; (ii) adapting CBT-I delivery for different contexts in which individuals exist, such as inpatient, educational, and different social/cultural settings, (iii) adapting CBT-I to specific individuals via case-formulation in clinical settings. We highlight current gaps in the exploration of tailored CBT-I, including a lack of research methodology to evaluate tailored interventions, a need for the integration of ongoing individualised assessment to inform treatment, and the necessary involvement of consumers and stakeholders throughout the research and treatment development process. Together, this review showed abundant adaptations in CBT-I already exist in the literature. Future research is needed in understanding when and how to apply adaptations in CBT-I and evaluate the benefits of these adaptations.

Pilot feasibility testing of biomathematical model recommendations for personalising sleep timing in shift workers.

Sleep disturbances and circadian disruption play a central role in adverse health, safety, and performance outcomes in shift workers. While biomathematical models of sleep and alertness can be used to personalise interventions for shift workers, their practical implementation is undertested. This study tested the feasibility of implementing two biomathematical models-the Phillips-Robinson Model and the Model for Arousal Dynamics-in 28 shift-working nurses, 14 in each group. The study examined the overlap and adherence between model recommendations and sleep behaviours, and changes in sleep following the implementation of recommendations. For both groups combined, the mean (SD) percentage overlap between when a model recommended an individual to sleep and when sleep was obtained was 73.62% (10.24%). Adherence between model recommendations and sleep onset and offset times was significantly higher with the Model of Arousal Dynamics compared to the Phillips-Robinson Model. For the Phillips-Robinson model, 27% of sleep onset and 35% of sleep offset times were within ± 30 min of model recommendations. For the Model of Arousal Dynamics, 49% of sleep onset, and 35% of sleep offset times were within ± 30 min of model recommendations. Compared to pre-study, significant improvements were observed post-study for sleep disturbance (Phillips-Robinson Model), and insomnia severity and sleep-related impairments (Model of Arousal Dynamics). Participants reported that using a digital, automated format for the delivery of sleep recommendations would enable greater uptake. These findings provide a positive proof-of-concept for using biomathematical models to recommend sleep in operational contexts.

The impact of break duration, time of break onset, and prior shift duration on the amount of sleep between shifts in heavy vehicle drivers.

This study aimed to examine the impact of break duration between consecutive shifts, time of break onset, and prior shift duration on total sleep time (TST) between shifts in heavy vehicle drivers (HVDs), and to assess the interaction between break duration and time of break onset. The sleep (actigraphy and sleep diaries) and work shifts (work diaries) of 27 HVDs were monitored during their usual work schedule for up to 9 weeks. Differences in TST between consecutive shifts and days off were assessed. Linear mixed models (followed by pairwise comparisons) assessed whether break duration, prior shift duration, time of break onset, and the interaction between break duration and break onset were related to TST between shifts. Investigators found TST between consecutive shifts (mean [SD] 6.38 [1.38] h) was significantly less than on days off (mean [SD] 7.63 [1.93] h; p < 0.001). Breaks starting between 12:01 and 8:00 a.m. led to shorter sleep (p < 0.05) compared to breaks starting between 4:01 and 8:00 p.m. Break durations up to 7, 9, and 11 h (Australian and European minimum break durations) resulted in a mean (SD) of 4.76 (1.06), 5.66 (0.77), and 6.41 (1.06) h of sleep, respectively. The impact of shift duration prior to the break and the interaction between break duration and time of break were not significant. HVDs' sleep between workdays is influenced independently by break duration and time of break onset. This naturalistic study provides evidence that current break regulations prevent sufficient sleep duration in this industry. Work regulations should evaluate appropriate break durations and break onset times to allow longer sleep opportunities for HVDs.

The role of circadian phase in sleep and performance during Antarctic winter expeditions.

The Antarctic environment presents an extreme variation in the natural light-dark cycle which can cause variability in the alignment of the circadian pacemaker with the timing of sleep, causing sleep disruption, and impaired mood and performance. This study assessed the incidence of circadian misalignment and the consequences for sleep, cognition, and psychological health in 51 over-wintering Antarctic expeditioners (45.6 ± 11.9 years) who completed daily sleep diaries, and monthly performance tests and psychological health questionnaires for 6 months. Circadian phase was assessed via monthly 48-h urine collections to assess the 6-sulphatoxymelatonin (aMT6s) rhythm. Although the average individual sleep duration was 7.2 ± 0.8 h, there was substantial sleep deficiency with 41.4% of sleep episodes <7 h and 19.1% <6 h. Circadian phase was highly variable and 34/50 expeditioners had sleep episodes that occurred at an abnormal circadian phase (acrophase outside of the sleep episode), accounting for 18.8% (295/1565) of sleep episodes. Expeditioners slept significantly less when misaligned (6.1 ± 1.3 h), compared with when aligned (7.3 ± 1.0 h; p < .0001). Performance and mood were worse when awake closer to the aMT6s peak and with increased time awake (all p < .0005). This research highlights the high incidence of circadian misalignment in Antarctic over-wintering expeditioners. Similar incidence has been observed in long-duration space flight, reinforcing the fidelity of Antarctica as a space analog. Circadian misalignment has considerable safety implications, and potentially longer term health risks for other circadian-controlled physiological systems. This increased risk highlights the need for preventative interventions, such as proactively planned lighting solutions, to ensure circadian alignment during long-duration Antarctic and space missions.

Exploring the associations between shift work disorder, depression, anxiety and sick leave taken amongst nurses.

This study aimed to evaluate the association between shift work disorder and mental health in hospital-based nurses. Staff completed an online survey comprising demographic questions, the Shift Work Disorder Questionnaire, Patient Health-9 and the General Anxiety Disorder-7 scale. Sick leave data were collected from archival records from the Human Resources Department. Two hundred and two nurses (95% female; age M = 35.28 years ± SD = 12) participated (42% of eligible staff). Those at high risk of shift work disorder had higher depression (M = 7.54 ± SD = 4.28 vs. M = 3.78 ± SD = 3.24; p < 0.001) and anxiety (M = 5.66 ± SD = 3.82 vs. M = 2.83 ± SD = 3.33, p < 0.001) compared to those at low risk. Linear regression models showed that being at high risk of shift work disorder was the most significant predictor of depression, explaining 18.8% of the variance in depression (R2  = 0.188, adjusted R2  = 0.184, F(1, 200) = 46.20, p < 0.001). Shift work disorder combined with the number of night shifts and alcoholic drinks on non-work days accounted for 49.7% of the variance in anxiety scores (R2  = 0.497, adjusted R2  = 0.453, F(3, 35) = 11.51, p < 0.001). Mean sick leave in those with high risk of shift work disorder was 136.17 hr (SD = 113.11) versus 103.98 hr (SD = 94.46) in others (p = 0.057). Depression and years of shift work accounted for 18.9% of the variance in sick leave taken (R2  = 0.189, adjusted R2  = 0.180, F(2, 175) = 20.36, p < 0.001). Shift work disorder is strongly associated with depression and anxiety, providing a potential target to improve mental health in shift workers. Depression, in turn, is a significant contributing factor to sick leave.

A PERIOD3 variable number tandem repeat polymorphism modulates melatonin treatment response in delayed sleep-wake phase disorder.

We examined whether a polymorphism of the PERIOD3 gene (PER3; rs57875989) modulated the sleep-promoting effects of melatonin in Delayed Sleep-Wake Phase Disorder (DSWPD). One hundred and four individuals (53 males; 29.4 ±10.0 years) with DSWPD and a delayed dim light melatonin onset (DLMO) collected buccal swabs for genotyping (PER34/4 n = 43; PER3 5 allele [heterozygous and homozygous] n = 60). Participants were randomised to placebo or 0.5 mg melatonin taken 1 hour before desired bedtime (or ~1.45 hours before DLMO), with sleep attempted at desired bedtime (4 weeks; 5-7 nights/week). We assessed sleep (diary and actigraphy), Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), Patient-Reported Outcomes Measurement Information System (PROMIS: Sleep Disturbance, Sleep-Related Impairment), Sheehan Disability Scale (SDS) and Patient- and Clinician-Global Improvement (PGI-C, CGI-C). Melatonin treatment response on actigraphic sleep onset time did not differ between genotypes. For PER34/4 carriers, self-reported sleep onset time was advanced by a larger amount and sleep onset latency (SOL) was shorter in melatonin-treated patients compared to those receiving placebo (P = .008), while actigraphic sleep efficiency in the first third of the sleep episode (SE T1) did not differ. For PER3 5 carriers, actigraphic SOL and SE T1 showed a larger improvement with melatonin (P < .001). Melatonin improved ISI (P = .005), PROMIS sleep disturbance (P < .001) and sleep-related impairment (P = .017), SDS (P = .019), PGI-C (P = .028) and CGI-C (P = .016) in PER34/4 individuals only. Melatonin did not advance circadian phase. Overall, PER34/4 DSWPD patients have a greater response to melatonin treatment. PER3 genotyping may therefore improve DSWPD patient outcomes.

Temporal dynamics of circadian phase shifting response to consecutive night shifts in healthcare workers: role of light-dark exposure.

KEY POINTS: Shift work is highly prevalent and is associated with significant adverse health impacts. There is substantial inter-individual variability in the way the circadian clock responds to changing shift cycles. The mechanisms underlying this variability are not well understood. We tested the hypothesis that light-dark exposure is a significant contributor to this variability; when combined with diurnal preference, the relative timing of light exposure accounted for 71% of individual variability in circadian phase response to night shift work. These results will drive development of personalised approaches to manage circadian disruption among shift workers and other vulnerable populations to potentially reduce the increased risk of disease in these populations. ABSTRACT: Night shift workers show highly variable rates of circadian adaptation. This study examined the relationship between light exposure patterns and the magnitude of circadian phase resetting in response to night shift work. In 21 participants (nursing and medical staff in an intensive care unit) circadian phase was measured using 6-sulphatoxymelatonin at baseline (day/evening shifts or days off) and after 3-4 consecutive night shifts. Daily light exposure was examined relative to individual circadian phase to quantify light intensity in the phase delay and phase advance portions of the light phase response curve (PRC). There was substantial inter-individual variability in the direction and magnitude of phase shift after three or four consecutive night shifts (mean phase delay -1:08 ± 1:31 h; range -3:43 h delay to +3:07 h phase advance). The relative difference in the distribution of light relative to the PRC combined with diurnal preference accounted for 71% of the variability in phase shift. Regression analysis incorporating these factors estimated phase shift to within ±60 min in 85% of participants. No participants met criteria for partial adaptation to night work after three or four consecutive night shifts. Our findings provide evidence that the phase resetting that does occur is based on individual light exposure patterns relative to an individual's baseline circadian phase. Thus, a 'one size fits all' approach to promoting adaptation to shift work using light therapy, implemented without knowledge of circadian phase, may not be efficacious for all individuals.

Efficacy of melatonin with behavioural sleep-wake scheduling for delayed sleep-wake phase disorder: A double-blind, randomised clinical trial.

BACKGROUND: Delayed Sleep-Wake Phase Disorder (DSWPD) is characterised by sleep initiation insomnia when attempting sleep at conventional times and difficulty waking at the required time for daytime commitments. Although there are published therapeutic guidelines for the administration of melatonin for DSWPD, to our knowledge, randomised controlled trials are lacking. This trial tested the efficacy of 0.5 mg melatonin, combined with behavioural sleep-wake scheduling, for improving sleep initiation in clinically diagnosed DSWPD patients with a delayed endogenous melatonin rhythm relative to patient-desired (or -required) bedtime (DBT). METHODS: This randomised, placebo-controlled, double-blind clinical trial was conducted in an Australian outpatient DSWPD population. Following 1-wk baseline, clinically diagnosed DSWPD patients with delayed melatonin rhythm relative to DBT (salivary dim light melatonin onset [DLMO] after or within 30 min before DBT) were randomised to 4-wk treatment with 0.5 mg fast-release melatonin or placebo 1 h before DBT for at least 5 consecutive nights per week. All patients received behavioural sleep-wake scheduling, consisting of bedtime scheduled at DBT. The primary outcome was actigraphic sleep onset time. Secondary outcomes were sleep efficiency in the first third of time in bed (SE T1) on treatment nights, subjective sleep-related daytime impairment (Patient Reported Outcomes Measurement Information System [PROMIS]), PROMIS sleep disturbance, measures of daytime sleepiness, clinician-rated change in illness severity, and DLMO time. FINDINGS: Between September 13, 2012 and September 1, 2014, 307 participants were registered; 116 were randomised to treatment (intention-to-treat n = 116; n = 62 males; mean age, 29.0 y). Relative to baseline and compared to placebo, sleep onset occurred 34 min earlier (95% confidence interval [CI] -60 to -8) in the melatonin group. SE T1 increased; PROMIS sleep-related impairment, PROMIS sleep disturbance, insomnia severity, and functional disability decreased; and a greater proportion of patients showed more than minimal clinician-rated improvement following melatonin treatment (52.8%) compared to placebo (24.0%) (P < 0.05). The groups did not differ in the number of nights treatment was taken per protocol. Post-treatment DLMO assessed in a subset of patients (n = 43) was not significantly different between groups. Adverse events included light-headedness, daytime sleepiness, and decreased libido, although rates were similar between treatment groups. The clinical benefits or safety of melatonin with long-term treatment were not assessed, and it remains unknown whether the same treatment regime would benefit patients experiencing DSWPD sleep symptomology without a delay in the endogenous melatonin rhythm. CONCLUSIONS: In this study, melatonin treatment 1 h prior to DBT combined with behavioural sleep-wake scheduling was efficacious for improving objective and subjective measures of sleep disturbances and sleep-related impairments in DSWPD patients with delayed circadian phase relative to DBT. Improvements were achieved largely through the sleep-promoting effects of melatonin, combined with behavioural sleep-wake scheduling. TRIAL REGISTRATION: This trial was registered with the Australian New Zealand Clinical Trials Registry, ACTRN12612000425897.

Efficacy of melatonin for sleep disturbance following traumatic brain injury: a randomised controlled trial.

BACKGROUND: The study aimed to determine the efficacy of melatonin supplementation for sleep disturbances in patients with traumatic brain injury (TBI). METHODS: This is a randomised double-blind placebo-controlled two-period two-treatment (melatonin and placebo) crossover study. Outpatients were recruited from Epworth and Austin Hospitals Melbourne, Australia. They had mild to severe TBI (n = 33) reporting sleep disturbances post-injury (mean age 37 years, standard deviation 11 years; 67% men). They were given prolonged-release melatonin formulation (2 mg; Circadin®) and placebo capsules for 4 weeks each in a counterbalanced fashion separated by a 48-hour washout period. Treatment was taken nightly 2 hours before bedtime. Serious adverse events and side-effects were monitored. RESULTS: Melatonin supplementation significantly reduced global Pittsburgh Sleep Quality Index scores relative to placebo, indicating improved sleep quality [melatonin 7.68 vs. placebo 9.47, original score units; difference -1.79; 95% confidence interval (CI), -2.70 to -0.88; p ≤ 0.0001]. Melatonin had no effect on sleep onset latency (melatonin 1.37 vs. placebo 1.42, log units; difference -0.05; 95% CI, -0.14 to 0.03; p = 0.23). With respect to the secondary outcomes, melatonin supplementation increased sleep efficiency on actigraphy, and vitality and mental health on the SF-36 v1 questionnaire (p ≤ 0.05 for each). Melatonin decreased anxiety on the Hospital Anxiety Depression Scale and fatigue on the Fatigue Severity Scale (p ≤ 0.05 for both), but had no significant effect on daytime sleepiness on the Epworth Sleepiness Scale (p = 0.15). No serious adverse events were reported. CONCLUSIONS: Melatonin supplementation over a 4-week period is effective and safe in improving subjective sleep quality as well as some aspects of objective sleep quality in patients with TBI. TRIAL REGISTRATION: Identifier: 12611000734965; Prospectively registered on 13 July 2011.

The ability to self-monitor cognitive performance during 60 h total sleep deprivation and following 2 nights recovery sleep.

We aimed to investigate whether self-monitoring of performance is altered during 60 h of total sleep deprivation, following 2 nights of recovery sleep, and by task difficulty and/or subjective sleepiness. Forty adults (22 females, aged 19-39 years) underwent a 5-day protocol, with a well-rested day, 66 h total sleep deprivation (last test session at 60 h), and 2 nights of 8 h recovery sleep. An arithmetic task (MATH) with three difficulty levels assessed working memory. The Psychomotor Vigilance Task assessed sustained attention. Arithmetic accuracy and Psychomotor Vigilance Task median reaction time measured objective performance. Subjective performance was measured with self-reported accuracy and speed. Objective-subjective differences assessed self-monitoring ability. The performance on both tasks declined during total sleep deprivation and improved following recovery. During total sleep deprivation, participants accurately self-monitored performance on the Psychomotor Vigilance Task; however, they overestimated cognitive deficits on MATH, self-reporting performance as worse than actually observed. Following recovery, participants overestimated the extent of performance improvement on the Psychomotor Vigilance Task. Task difficulty influenced self-monitoring ability, with greater overestimation of performance deficits during total sleep deprivation as difficulty increased. Subjective sleepiness predicted subjective performance ratings at several time points, only for the Psychomotor Vigilance Task. The ability to self-monitor performance was impaired during total sleep deprivation for working memory and after recovery sleep for the Psychomotor Vigilance Task, but was otherwise accurate. The development of self-monitoring strategies, assessing both subjective perceptions of performance and subjective sleepiness, within operational contexts may help reduce the consequences of sleep-related impairments.

Randomised controlled trial of the efficacy of a blue-enriched light intervention to improve alertness and performance in night shift workers.

OBJECTIVES: Night workers often experience high levels of sleepiness due to misalignment of the sleep-wake cycle from the circadian pacemaker, in addition to acute and chronic sleep loss. Exposure to light, in particular short wavelength light, can improve alertness and neurobehavioural performance. This randomised controlled trial examined the efficacy of blue-enriched polychromatic light to improve alertness and neurobehavioural performance in night workers. DESIGN: Participants were 71 night shift workers (42 males; 32.8±10.5 years) who worked at least 6 hours between 22:00 and 08:00 hours. Sleep-wake logs and wrist actigraphy were collected for 1-3 weeks, followed by 48-hour urine collection to measure the circadian 6-sulphatoxymelatonin (aMT6s) rhythm. On the night following at least two consecutive night shifts, workers attended a simulated night shift in the laboratory which included subjective and objective assessments of sleepiness and performance. Workers were randomly assigned for exposure to one of two treatment conditions from 23:00 hours to 07:00 hours: blue-enriched white light (17 000 K, 89 lux; n=36) or standard white light (4000 K, 84 lux; n=35). RESULTS: Subjective and objective sleepiness increased during the night shift in both light conditions (p<0.05, ηp2=0.06-0.31), but no significant effects of light condition were observed. The 17 000 K light, however, did improve subjective sleepiness relative to the 4000 K condition when light exposure coincided with the time of the aMT6s peak (p<0.05, d=0.41-0.60). CONCLUSION: This study suggests that, while blue-enriched light has potential to improve subjective sleepiness in night shift workers, further research is needed in the selection of light properties to maximise the benefits. TRIAL REGISTRATION NUMBER: The Australian New Zealand Clinical Trials Registry ACTRN12610000097044 (https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=320845&isReview=true).

A randomized controlled trial of cognitive behavioral therapy for insomnia: an effective treatment for comorbid insomnia and depression.

UNLABELLED: Insomnia and depression are highly comorbid conditions that show a complex, bidirectional relationship. This study examined whether cognitive-behavioral therapy for insomnia (CBT-I) delivered by a therapist compared with self-help CBT-I (written materials only) reduces insomnia and depression severity in individuals with comorbid insomnia and depression. A total of 41 participants (18-64 years; 25 females) with comorbid depression and insomnia, treated with antidepressants for at least 6 weeks, were randomized to receive 4 sessions of either CBT-I or self-help CBT-I over 8 weeks. Insomnia (Insomnia Severity Index [ISI]) and depression (Beck Depression Inventory-II [BDI-II]) were assessed at baseline, following each session, and at 3-month follow-up. Secondary outcomes were sleep quality and duration (actigraphy and diaries), anxiety, fatigue, and daytime sleepiness. Compared with self-help CBT-I, BDI-II scores in the CBT-I group dropped by 11.93 (95% confidence interval [CI] [6.60, 17.27], p < .001) more points, and ISI scores dropped by 6.59 (95% CI [3.04, 10.15], p = .001) more points across treatment. At 3-month follow-up, 61.1% of CBT-I participants were in clinical remission from their insomnia and depression, compared with 5.6% of the self-help group. CONCLUSIONS: CBT-I administered by a therapist produced significant reductions in both insomnia and depression severity posttreatment and at follow-up, compared with a control condition in which participants received only written CBT-I material. Targeting insomnia through CBT-I is efficacious for treating comorbid insomnia and depression, and should be considered an important adjunct therapy for patients with depression whose symptoms have not remitted through antidepressant treatment.

Circadian adaptation to night shift work is associated with higher REM sleep duration.

OBJECTIVE: To investigate the influence of the degree of circadian adaptation to night work on sleep architecture following night shift. METHODS: Thirty four night workers (11 females; 33.8 ± 10.1years) completed a simulated night shift following 2-7 typical night shifts. Participants completed a laboratory-based simulated night shift (21:00-07:00 hours), followed by a recovery sleep opportunity (∼09:00-17:00 hours), recorded using polysomnography. Urinary 6-sulphatoxymelatonin (aMT6s) rhythm acrophase was used as a marker of circadian phase. Sleep duration and architecture were compared between individuals with aMT6s acrophase before (unadapted group, n = 22) or after (partially adapted group, n = 12) bedtime. RESULTS: Bedtime occurred on average 2.16 hours before aMT6s acrophase in the partially adapted group and 3.91 hours after acrophase in the unadapted group. The partially adapted group had more sleep during the week before the simulated night than the unadapted group (6.47 ± 1.02 vs. 5.26 ± 1.48 hours, p = .02). After the simulated night shift, both groups had similar total sleep time (partially adapted: 6.68 ± 0.80 hours, unadapted: 6.63 ± 0.88 hours, p > .05). The partially adapted group had longer total rapid eye movement sleep duration than the unadapted group (106.79 ± 32.05 minutes vs. 77.90 ± 28.86 minutes, p = .01). After 5-hours, rapid eye movement sleep accumulation was higher in the partially adapted compared to the unadapted group (p = .02). Sleep latency and other stages were not affected by circadian adaptation. DISCUSSION: Partial circadian adaptation to night shift was associated with longer rapid eye movement sleep duration during daytime sleep, highlighting the influence of entrainment between the sleep-wake cycle and the circadian pacemaker in night workers. The findings have important implications for sleep and subsequent alertness associated with shift work.

SleepSync: Early Testing of a Personalised Sleep-Wake Management Smartphone Application for Improving Sleep and Cognitive Fitness in Defence Shift Workers.

Shift work, long work hours, and operational tasks contribute to sleep and circadian disruption in defence personnel, with profound impacts on cognition. To address this, a digital technology, the SleepSync app, was designed for use in defence. A pre-post design study was undertaken to examine whether four weeks app use improved sleep and cognitive fitness (high performance neurocognition) in a cohort of shift workers from the Royal Australian Air Force. In total, 13 of approximately 20 shift-working personnel from one base volunteered for the study. Sleep outcomes were assessed using the Insomnia Severity Index (ISI), the Patient-Reported Outcomes Measurement Information System (PROMIS), Sleep Disturbance and Sleep-Related Impairment Scales, the Glasgow Sleep Effort Scale, the Sleep Hygiene Index, and mental health was assessed using the Depression, Anxiety, and Stress Scale-21. Sustained attention was measured using the 3-min Psychomotor Vigilance Task (PVT) and controlled response using the NBack. Results showed significant improvements in insomnia (ISI scores 10.31 at baseline and 7.50 after app use), sleep-related impairments (SRI T-scores 53.03 at baseline to 46.75 post-app use), and healthy sleep practices (SHI scores 21.61 at baseline to 18.83 post-app use; all p < 0.001). Trends for improvement were recorded for depression. NBack incorrect responses reduced significantly (9.36 at baseline; reduced by -3.87 at last week of app use, p < 0.001), but no other objective measures improved. These findings suggest that SleepSync may improve sleep and positively enhance cognitive fitness but warrants further investigation in large samples. Randomised control trials with other cohorts of defence personnel are needed to confirm the utility of this intervention in defence settings.

Assessment and management of sleep disorders in shift workers: Challenges and considerations for general practice.

BACKGROUND: Shift work is characterised by displaced sleep opportunities and associated sleep disturbance. Shift workers often report sleepiness and other wake time symptoms associated with poor sleep. However, clinical sleep disorders are also prevalent in shift workers. Although prevalence rates are similar or higher in shift workers compared with the general population, help seeking in shift workers with sleep disorders is low. OBJECTIVE: This article aims to provide general practitioners with a contemporary overview of the prevalence rates for sleep disorders in shift workers, to clarify the existing evidence relating to mental and physical health consequences of sleep disorders in shift workers and to highlight the need to consider undiagnosed sleep disorders before attributing sleep-related symptoms solely to work schedules. DISCUSSION: Symptoms of sleep loss associated with shift work overlap with symptoms experienced by individuals living with sleep disorders. Although >40% of middle-aged Australians live with a sleep disorder that requires investigation and management, symptoms in shift workers are often attributed to the work schedule and, as a result, might not be investigated for appropriate diagnosis and treatment. We argue that screening for sleep disorders in shift workers with sleep complaints should be a priority.

Objective and subjective measures of sleepiness, and their associations with on-road driving events in shift workers.

To assess the relationships between sleepiness and the incidence of adverse driving events in nurses commuting to and from night and rotating shifts, 27 rotating and permanent night shift-working nurses were asked to complete daily sleep and duty logs, and wear wrist-activity monitors for 2 weeks (369 driving sessions). During all commutes, ocular measures of drowsiness, including the Johns Drowsiness Scale score, were assessed using the Optalert™ system. Participants self-reported their subjective sleepiness at the beginning and end of each drive, and any events that occurred during the drive. Rotating shift nurses reported higher levels of sleepiness compared with permanent night shift nurses. In both shift-working groups, self-reported sleepiness, drowsiness and drive events were significantly higher during commutes following night shifts compared with commutes before night shifts. Strong associations were found between objective drowsiness and increased odds of driving events during commutes following night shifts. Maximum total blink duration (mean = 7.96 s) during the drive and pre-drive Karolinska Sleepiness Scale (mean = 5.0) were associated with greater incidence of sleep-related events [OR, 5.35 (95% CI, 1.32, 21.60), OR, 1.69 (95% CI, 1.04, 2.73), respectively]. Inattention was strongly associated with a Johns Drowsiness Scale score equal to or above 4.5 [OR, 4.58 (95% CI, 1.26-16.69)]. Hazardous driving events were more likely to occur when drivers had been awake for 16 h or more [OR, 4.50 (95% CI, 1.81, 11.16)]. Under real-world driving conditions, shift-working nurses experience high levels of drowsiness as indicated by ocular measures, which are associated with impaired driving performance following night shift work.

The importance of sleep regularity: a consensus statement of the National Sleep Foundation sleep timing and variability panel.

OBJECTIVE: To develop and present consensus findings of the National Sleep Foundation sleep timing and variability panel regarding the impact of sleep timing variability on health and performance. METHODS: The National Sleep Foundation assembled a panel of sleep and circadian experts to evaluate the scientific evidence and conduct a formal consensus and voting procedure. A systematic literature review was conducted using the NIH National Library of Medicine PubMed database, and panelists voted on the appropriateness of 3 questions using a modified Delphi RAND/UCLA Appropriateness Method with 2 rounds of voting. RESULTS: The literature search and panel review identified 63 full text publications to inform consensus voting. Panelists achieved consensus on each question: (1) is daily regularity in sleep timing important for (a) health or (b) performance? and (2) when sleep is of insufficient duration during the week (or work days), is catch-up sleep on weekends (or non-work days) important for health? Based on the evidence currently available, panelists agreed to an affirmative response to all 3 questions. CONCLUSIONS: Consistency of sleep onset and offset timing is important for health, safety, and performance. Nonetheless, when insufficient sleep is obtained during the week/work days, weekend/non-work day catch-up sleep may be beneficial.

Mobile app for personalized sleep-wake management for shift workers: A user testing trial.

Objective: Development of personalized sleep-wake management tools is critical to improving sleep and functional outcomes for shift workers. The objective of the current study was to test the performance, engagement and usability of a mobile app (SleepSync) for personalized sleep-wake management in shift workers that aid behavioural change and provide practical advice by providing personalized sleep scheduling recommendations and education. Methods: Shift workers (n = 27; 20 healthcare and 7 from other industries) trialled the mobile app for two weeks to determine performance, engagement and usability. Primary outcomes were self-reported total sleep time, ability to fall asleep, sleep quality and perception of overall recovery on days off. Secondary performance outcomes included sleep disturbances (insomnia and sleep hygiene symptoms, and sleep-related impairments) and mood (anxiety, stress and depression) pre- and post-app use. Satisfaction with schedule management, integration into daily routine and influence on behaviour were used to determine engagement, while the usability was assessed for functionality and ease of use of features. Results: Total sleep time (P = .04), ability to fall asleep (P < .001), quality of sleep (P = .001), insomnia (P = .02), sleep hygiene (P = .01), sleep-related impairments (P = .001), anxiety (P = .001), and stress (P = .006) were all improved, with non-significant improvements in recovery on days off (P = .19) and depression (P = .07). All measures of engagement and usability were scored positively by the majority of users. Conclusions: This pilot trial provides preliminary evidence of the positive impact of the SleepSync app in improving sleep and mood outcomes in shift workers, and warrants confirmation in a larger controlled trial.

Sleep, alertness and performance across a first and a second night shift in mining haul truck drivers.

This study examined the impact of first and second night shift work on sleep and performance in mining haul truck drivers. Sleep-wake patterns were monitored using wrist actigraphy. The Karolinska Sleepiness Scale (KSS), Psychomotor Vigilance Test (PVT) and a truck simulator were administered at the start and end of the first (N1) or second (N2) night shift (19:00-07:00 h). Participants were categorised into those who demonstrated a decline in performance (increase of one or more PVT lapses [reaction time >500 msec] from the start to the end of shift) or those who did not demonstrate a decline in performance (no increase in lapses) from the start to the end of shift. Total sleep time (TST) was longer in the 24 h prior to N1 (9.05 ± 1.49 h) compared to N2 (5.38 ± 1.32 h). PVT lapses and the slowest 10% of reaction times were similar at the start and end of N1, while greater impairments on these outcomes were observed at the end of N2 compared to the end of N1 (p < .05). In contrast, subjective sleepiness was equally impaired at the end of both night shifts. PVT performance (lapses and slowest 10% of reaction times) and drive violations demonstrated a similar direction of change on N1 and N2. Participants who demonstrated a decline in performance showed reduced TST in the 48 h prior to shifts compared to those who demonstrated no decline in performance across the shift. Likely due to short sleep prior, the end of N2 was associated with pronounced performance impairments on the PVT and drive violations compared to the start of the shift. The findings suggest that drive violations may be more sensitive to sleep loss compared to the other driving measures examined in this study. This study also emphasizes the need for adequate recovery sleep between night shifts.