Comparative Effectiveness of Supine Avoidance versus Continuous Positive Airway Pressure for Treating Supine-isolated Sleep Apnea: A Clinical Trial.

Rationale: About 20-35% of patients with obstructive sleep apnea (OSA) have supine-isolated OSA, for which supine sleep avoidance could be an effective therapy. However, traditional supine discomfort-based methods show poor tolerance and compliance to treatment and so cannot be recommended. Supine alarm devices show promise, but evidence to support favorable adherence to treatment and effectiveness at reducing excessive daytime sleepiness compared with continuous positive airway pressure (CPAP) remains limited. Objectives: To establish if alarm-based supine-avoidance treatment in patients with supine-isolated OSA is noninferior to CPAP in reducing daytime sleepiness. Methods: After baseline questionnaire administration and in-home supine-time and polysomnography assessments, patients with supine-isolated OSA and Epworth Sleepiness Scale scores ⩾8 were randomized to ⩾6 weeks of supine-avoidance or CPAP treatment, followed by crossover to the remaining treatment with repeat assessments. Noninferiority was assessed from change in Epworth Sleepiness Scale with supine avoidance compared with CPAP using a prespecified noninferiority margin of 1.5. Average nightly treatment use over all nights and treatment efficacy and effectiveness at reducing respiratory disturbances were also compared between treatments. Results: The reduction in sleepiness score with supine avoidance (mean [95% confidence interval], -1.9 [-2.8 to -1.0]) was noninferior to that with CPAP (-2.4 [-3.3 to -1.4]) (supine avoidance-CPAP difference, -0.4 [-1.3 to 0.6]), and the lower confidence limit did not cross the noninferiority margin of 1.5 (P = 0.021). Average treatment use was higher with supine avoidance compared with CPAP (mean ± standard deviation, 5.7 ± 2.4 vs. 3.9 ± 2.7 h/night; P < 0.001). Conclusions: In patients with supine-isolated OSA, vibrotactile supine alarm device therapy is noninferior to CPAP for reducing sleepiness and shows superior treatment adherence. Clinical trial registered with www.anzctr.org.au (ACTRN 12613001242718).

Improved depressive symptoms, and emotional regulation and reactivity, in individuals with obstructive sleep apnea after short- and long-term CPAP therapy use.

Obstructive Sleep Apnoea (OSA) is associated with high rates of depression; however, if and how treatment of OSA improves depressive symptoms is unclear. To further understand this link we considered the role of emotional regulation - the ability to control and express our emotional responses - thought to be a central component of depression. This study aimed to assess changes in depressive symptoms and emotional responses in individuals with OSA after 4- and 12-months of continuous positive airway pressure (CPAP) treatment. One-hundred and twenty-one OSA participants (50 female, Mage = 51.93; mean AHI = 36.27) were recruited from a tertiary clinical sleep service prior to CPAP initiation, and randomised to either a CPAP group or a 4 month wait-list group. Participants completed the Center for Epidemiological Studies Depression Scale, the Emotional Reactivity Scale and the Difficulties in Emotion Regulation Scale at baseline, and 1-, 2-, and 4-months follow-up. The CPAP group also completed the questionnaires 12-months after CPAP initiation. CPAP use at 1 month and 12 months was 5.1h/night and 4.9h/night, respectively. Significant improvements in depressive symptoms, emotional regulation and reactivity, and subjective sleepiness were observed after 4 months in both groups, however, the within group changes were only significant for those using CPAP. After 12-months of CPAP treatment, these improvements were maintained. There was no association between CPAP treatment adherence and improvements in any outcome. CPAP treatment for 12 months may reduce symptoms of depression and improve emotional regulation in individuals with OSA.

Associations Between Amyloid Burden, Hypoxemia, Sleep Architecture, and Cognition in Obstructive Sleep Apnea.

BACKGROUND: Obstructive sleep apnea (OSA) is associated with an increased risk of amyloid-ß (Aß) burden, the hallmark of Alzheimer's disease, and cognitive decline. OBJECTIVE: To determine the differential impacts of hypoxemia and slow-wave sleep disruption on brain amyloid burden, and to explore the effects of hypoxemia, slow-wave sleep disruption, and amyloid burden on cognition in individuals with and without OSA. METHODS: Thirty-four individuals with confirmed OSA (mean±SD age 57.5±4.1 years; 19 males) and 12 healthy controls (58.5±4.2 years; 6 males) underwent a clinical polysomnogram, a NAV4694 positron emission tomography (PET) scan for Aß burden, assessment of APOEɛ status and cognitive assessments. Linear hierarchical regressions were conducted to determine the contributions of demographic and sleep variables on amyloid burden and cognition. RESULTS: Aß burden was associated with nocturnal hypoxemia, and impaired verbal episodic memory, autobiographical memory and set shifting. Hypoxemia was correlated with impaired autobiographical memory, and only set shifting performance remained significantly associated with Aß burden when controlling for sleep variables. CONCLUSIONS: Nocturnal hypoxemia was related to brain Aß burden in this sample of OSA participants. Aß burden and hypoxemia had differential impacts on cognition. This study reveals aspects of sleep disturbance in OSA that are most strongly associated with brain Aß burden and poor cognition, which are markers of early Alzheimer's disease. These findings add weight to the possibility that hypoxemia may be causally related to the development of dementia; however, whether it may be a therapeutic target for dementia prevention in OSA is yet to be determined.

A randomized controlled trial of a multi-dimensional intervention to improve CPAP use and self-efficacy.

OBJECTIVES: To assess the utility of a tailored intervention program to improve continuous positive airway pressure (CPAP) use and self-efficacy in individuals with obstructive sleep apnea (OSA). METHODS: 81 participants (mean age 52.1 ± 11.6 years; 35 females) with OSA were randomized to either a multi-dimensional intervention (PSY CPAP, n = 38) or treatment as usual (TAU CPAP, n = 43). The intervention included a psychoeducation session prior to CPAP initiation, a booster psychoeducation session in the first weeks of commencing CPAP, follow-up phone calls on days 1 and 7, and a review appointment on day 14. CPAP use was compared between the PSY CPAP and TAU CPAP groups at 1 week, 1 month, and 4 months. Self-efficacy scores (risk perception, outcome expectancies, and CPAP self-efficacy) were compared between groups following the initial psychoeducation session and again at 1 month and 4 months. RESULTS: CPAP use was higher in the PSY CPAP group compared to the TAU CPAP group for all time points (p = .02). Outcome expectancies improved significantly over time in PSY CPAP participants (p = .007). Change in risk perception was associated with CPAP use at 1 week (p = .02) for PSY CPAP participants. However, risk perception did not mediate the effect between group and CPAP use at 1 week. CONCLUSIONS: Interventions designed to increase self-efficacy and administered prior to CPAP initiation, repeated in the early stages of CPAP therapy, and combined with a comprehensive follow-up regime are likely to improve CPAP use. Sustained improvement in CPAP use is the ultimate goal but remains to be investigated.

The impact of alcohol consumption on commercial eye blink drowsiness detection technology.

INTRODUCTION: Driver drowsiness detection technology that assesses eye blinks is increasingly being used as a safety intervention in the transport industry. It is unclear how alcohol consumption to common legal driving limits impacts upon this technology. The aim of the study was to assess the impact of a blood alcohol content (BAC) of 0.05% and of 0.08% on drowsiness detection technology during simulated driving. METHODS: Participants completed a 60-min driving simulation and sleepiness questionnaire under three conditions: 1-0.00% BAC, 2-0.05% BAC and 3-0.08% BAC. During the driving simulation task participants wore a commercial eye blink drowsiness detection technology (Optalert) with the drowsiness alarms silenced. RESULTS: Twelve participants (3 female) completed all alcohol conditions. Relative to baseline, all eye blink parameters were affected at 0.08% BAC (all p < 0.05), whereas 0.05% BAC only affected the composite eye blink drowsiness measure (the Johns Drowsiness Scale). CONCLUSIONS: Alcohol consumption to 0.08% BAC impaired eye blink measures to a level that would be considered a moderate drowsiness risk. Therefore, employers should be aware that drowsiness alerts from these technologies may increase after alcohol consumption.

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.

Fetal heart rate events during sleep, and the impact of sleep disordered breathing, in pregnancies complicated by preterm fetal growth restriction: An exploratory observational case-control study.

OBJECTIVES: To evaluate fetal heart rate (FHR) patterns during sleep in pregnancies complicated by preterm fetal growth restriction (FGR). To determine whether co-existing sleep-disordered breathing (SDB) impacts on acute FHR events or perinatal outcome. DESIGN: Observational case control study. SETTING AND POPULATION: Women with preterm FGR and gestation-matched well grown controls (estimated fetal weight above the 10th percentile with normal Doppler studies); tertiary maternity hospital, Australia. METHODS: A polysomnogram, a test used to measure sleep patterns and diagnose sleep disorders, and concurrent cardiotocography (CTG), were analysed for respiratory events and FHR changes. MAIN OUTCOME MEASURES: Frequency of FHR events overnight in FGR cases versus controls and in those with or without SDB. RESULTS: Twenty-nine patients with preterm FGR and 29 controls (median estimated fetal weight 1st versus 60th percentile, P < 0.001) underwent polysomnography with concurrent CTG at a mean gestation of 30.2 weeks. The median number of FHR events per night was higher among FGR cases than among controls (3.0 events, interquartile range [IQR] 1.0-4.0, versus 1.0 [IQR 0-1.0]; P < 0.001). Women with pregnancies complicated by preterm FGR were more likely than controls to be nulliparous, receive antihypertensive medications, be supine at sleep onset, and to sleep supine (32.9% of total sleep time versus 18.3%, P = 0.03). SDB was common in both FGR and control pregnancies (48% versus 38%, respectively, P = 0.55) but was generally mild and not associated with an increase in overnight FHR events or adverse perinatal outcome. CONCLUSIONS: Acute FHR events overnight are more common in pregnancies complicated by preterm FGR than in pregnancies with normal fetal growth. Mild SDB was common in late pregnancy and well tolerated, even by fetuses with preterm FGR. TWEETABLE ABSTRACT: Mild sleep-disordered breathing seems well tolerated even by highly vulnerable fetuses.

Polysomnographic analysis of maternal sleep position and its relationship to pregnancy complications and sleep-disordered breathing.

Links between supine "going to sleep" position and stillbirth risk have led to campaigns regarding safe maternal sleep position. This study profiles the distribution of sleep positions overnight and relationships to sleep onset position during pregnancy, and the relationships between supine sleep, sleep-disordered breathing (SDB), and pregnancy outcomes. Data from three prospective cohort studies evaluating SDB in healthy and complicated pregnancies were pooled. All participants underwent one night of polysomnography in late pregnancy and birth outcome data were collected. 187 women underwent polysomnography at a median gestation of 34 weeks'. The left lateral position was preferred for falling asleep (52%) compared to supine (14%), but sleep onset position was the dominant sleep position overnight in only half (54%) of women. The median percentage of sleep time in the supine position was 24.2%; women who fell asleep supine spent more time supine overnight compared to those who began non-supine (48.0% (30.0,65.9) vs. 22.6% (5.7,32.2), p < .001). Women with growth-restricted fetuses were more likely to fall asleep supine than those with well-grown fetuses (36.6% vs. 7.5%, p < .001). Positional SDB was observed in 46% of those with an RDI ≥ 5. Sleep onset position was the dominant position overnight for half of the sample, suggesting that sleep onset position is not always a reliable indicator of body position overnight. Supine sleep was related to fetal growth restriction and birthweight at delivery, though causality cannot be inferred. It is critical that we pursue research into verifying the important relationship between supine sleep and increased stillbirth risk, and the mechanisms behind it.

Maternal sleep behaviours preceding fetal heart rate events on cardiotocography.

In Australia, a significant proportion of stillbirths remain unexplained. Recent research has highlighted nocturnal maternal behaviours as potentially modifiable contributors. This study determined whether sleep-related behaviours including sleep position and sleep-disordered breathing adversely affect fetuses overnight, in both uncomplicated pregnancies and those at increased risk due to hypertensive disorders or fetal growth restriction (FGR). All participants underwent polysomnography with time-synchronized fetal heart rate (FHR) monitoring (cardiotocography - CTG) in late pregnancy. CTGs were analysed for abnormal FHR events, including decelerations and reduced variability, by two blinded observers and exported into the sleep study to temporally align FHR events with sleep behaviours. For each FHR event, 10 control epochs with normal FHR were randomly selected for the same participant. Conditional logistic regression assessed the relationships between FHR events and sleep behaviours. From 116 participants, 52 had a total of 129 FHR events overnight; namely prolonged decelerations and prolonged periods of reduced variability. Significantly more FHR events were observed in women with FGR and/or a hypertensive disorder compared with uncomplicated pregnancies (P = 0.006). FHR events were twice as likely to be preceded by a change in body position within the previous 5 min, compared with control epochs (P = 0.007), particularly in hypertensive pregnancies both with and without FGR. Overall, FHR events were not temporally related to supine body position, respiratory events or snoring. Our results indicate that most fetuses tolerate sleep-related stressors, but further research is needed to identify the interplay of maternal and fetal conditions putting the fetus at risk overnight. KEY POINTS: Maternal sleep behaviours including supine position and sleep-disordered breathing are potential contributors to stillbirth but much of this work is based on self-reported data. Using time-synchronized polysomnography and cardiotocography, we found that nocturnal fetal heart rate decelerations were more likely to be preceded by a change in body position compared with epochs containing normal fetal heart rate, particularly in hypertensive pregnancies with or without fetal growth restriction. There was no temporal relationship between maternal sleeping position, snoring or apnoeic events and an abnormal fetal heart rate overnight. We conclude that most fetuses can tolerate sleep-related stressors with no evidence of fetal heart rate changes indicating compromised wellbeing. Further work needs to identify how sleep behaviours contribute to stillbirth risk and how these intersect with underlying maternal and fetal conditions.

The effectiveness of an individualized sleep and shift work education and coaching program to manage shift work disorder in nurses: a randomized controlled trial.

STUDY OBJECTIVES: While insomnia and sleepiness symptoms are common in shift workers, 20%-30% experience more severe symptoms and meet the criteria for shift work disorder (SWD). SWD can lead to impairments in cognitive function, physical and mental health, and reduced productivity and increased risk of workplace injury. The aim of this study was to deliver and evaluate a shift work individual management coaching program, focusing on sleep education, promoting good sleep hygiene, and providing individualized behavioral strategies to cope with shift schedules. METHODS: A clustered randomized controlled trial of sleep education and sleep disorders screening was undertaken, based on hospital wards at a tertiary hospital in Melbourne, Australia. Participants identified as high risk for SWD underwent one of two 8-week programs, a shift work individualized management program, or an active control. The primary outcome was ward-based sick leave. Secondary outcomes were SWD risk, sleep hygiene, insomnia, depression, and anxiety. A total of 149 nurses, across 16 wards (96% female, 34.66 ± 11.99 years) completed both baseline and follow-up questionnaires (23.9% were high risk SWD). RESULTS: There was no significant reduction in sick leave between intervention and control wards (mean difference = 1.2 days, P = .063). Improvements were seen in insomnia (P < .0001) and depression (intervention, P ≤ .0001, control, P = .023) in both groups, but were not significantly different between programs. Anxiety (P = .001. control P = .079) and Functional Outcomes of Sleep Questionnaire 10 (P = .001 control P = .056) improved only for the intervention. CONCLUSIONS: This SWD intervention trial did not reduce sick leave compared to the active control but there was an improvement. Improvements in sleep hygiene, insomnia, depression, and anxiety severity were seen for both groups. Future intervention trials should consider including both sleep and mental health interventions, strategies to avoid between group contamination and the duration of programs for optimal behavioral modification. CLINICAL TRIAL REGISTRATION: Registry: Australian New Zealand Clinical Trials Registry; Name: Sleep Health Management for Healthcare Workers; URL: https://anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12616000369426; Identifier: ACTRN12616000369426. CITATION: Booker LA, Sletten TL, Barnes M, et al. The effectiveness of an individualized sleep and shift work education and coaching program to manage shift work disorder in nurses: a randomized controlled trial. J Clin Sleep Med. 2022;18(4):1035-1045.

The effect of body position on maternal cardiovascular function during sleep and wakefulness in late pregnancy.

INTRODUCTION: An association between the increased risk of late stillbirth and the maternal supine sleeping position has been recently established. The risk of stillbirth following supine sleep has been suspected to occur as a result of aortocaval compression by the gravid uterus. A number of studies conducted during wakefulness have reported compromised cardiovascular function during supine rest, as demonstrated by reductions in cardiac output, blood pressure and utero-placental blood flow. It remains unclear whether similar effects are also present during sleep, due to the presence of key sleep-specific changes in cardiovascular function. OBJECTIVE: To investigate the changes in maternal cardiovascular function between the supine and left-lateral positions during wakefulness and non-rapid eye movement (NREM) sleep in late pregnancy. METHODS: Twenty-nine women with a singleton pregnancy between 24.7 and 36.7 weeks' gestation participated in a single overnight sleep study. Physiological measures (blood pressure, heart rate, heart rate variability - HRV, and pulse arrival time - PAT) were measured and recorded throughout the night using standard polysomnography equipment and the Portapres Model-2 device. As the present study evaluated cardiovascular changes during natural rest and sleep in pregnancy, participants were not given explicit instructions on which position to adopt. Body position was continuously recorded using a position monitor and verified with video recording. RESULTS: No changes in systolic, diastolic or mean arterial blood pressure were observed between the left-lateral and supine positions during wakefulness or sleep. However, heart rate was significantly higher in the supine position compared to the left during wakefulness (p= .03), with a similar trend present during sleep (p= .11). A significantly shorter PAT was measured in the supine position (compared to the left) during wakefulness (p= .01) and sleep (p= .01). No change in HRV measures was observed between the left and supine positions in either state. CONCLUSION: Blood pressure did not appear to differ significantly between the left-lateral and supine positions during wakefulness and sleep. The lack of blood pressure differences may reflect elevated sympathetic activity during rest and sleep in the supine position (compared to the left), suggesting that some degree of compensation for aortocaval compression may still be possible during sleep.

The impact of aging on driving performance in patients with untreated obstructive sleep apnea.

OBJECTIVE: To determine the influence of age on sleepiness-related driving performance in individuals with obstructive sleep apnea (OSA). DESIGN: Extended wakefulness protocol comparing simulated driving performance in younger and older individuals with OSA. PARTICIPANTS: Fifty-two individuals with OSA (15 female) were median split into younger (≤55 years, n = 26) and older (>55 years, n = 26) groups. MEASUREMENTS: Participants underwent polysomnography to derive sleep parameters and confirm OSA diagnosis. One-to-2 weeks following polysomnography, participants completed a 60-minute driving simulation 4 hours prior to their habitual bedtime. Participants remained awake to 3 hours post habitual bedtime before repeating the task. RESULTS: Median age was 44.5 years (25th, 75th centiles = 37.0, 48.0) for the younger group and 64.5 years (60.0, 70.0) for the older group. When comparing the performance change between baseline and extended wakefulness, the younger patients had greater deterioration on all driving simulator parameters (crashes, standard deviation of lateral position, speed deviation and braking reaction time, all p < .05), compared to the older group. Linear regression found a 10-year age increase was associated with an a ∼30%-41% reduction in crash occurrence when accounting for covariates (p = .023). Age also predicted standard deviation of lateral position deviation, but not when sleep efficiency and self-reported sleepiness were included as covariates. CONCLUSION: Older participants with OSA were less vulnerable than younger participants to sleepiness-related driving simulator impairment when assessed at night-time following extended wakefulness. Future work should assess naturalistic on-road driving to determine if this extends to a variety of challenging driving scenarios.

The impact of 7-hour and 11-hour rest breaks between shifts on heavy vehicle truck drivers' sleep, alertness and naturalistic driving performance.

BACKGROUND: An inadequate rest break between shifts may contribute to driver sleepiness. This study assessed whether extending the major rest break between shifts from 7-hours (Australian industry standard) to 11-hours, improved drivers' sleep, alertness and naturalistic driving performance. METHODS: 17 heavy vehicle drivers (16 male) were recruited to complete two conditions. Each condition comprised two 13-hour shifts, separated by either a 7- or 11-hour rest break. The initial 13-hour shift was the drivers' regular work. The rest break and following 13-hour shift were simulated. The simulated shift included 5-hours of naturalistic driving with measures of subjective sleepiness, physiological alertness (ocular and electroencephalogram) and performance (steering and lane departures). RESULTS: 13 drivers provided useable data. Total sleep during the rest break was greater in the 11-hour than the 7-hour condition (median hours [25th to 75th percentile] 6.59 [6.23, 7.23] vs. 5.07 [4.46, 5.38], p = 0.008). During the simulated shift subjective sleepiness was marginally better for the 11-hour condition (mean Karolinska Sleepiness Scale [95th CI] = 4.52 [3.98, 5.07] vs. 5.12 [4.56, 5.68], p = 0.009). During the drive, ocular and vehicle metrics were improved for the 11-hour condition (p<0.05). Contrary to expectations, mean lane departures p/hour were increased during the 11-hour condition (1.34 [-0.38,3.07] vs. 0.63 [-0.2,1.47], p = 0.027). CONCLUSIONS: Extending the major rest between shifts substantially increases sleep duration and has a modest positive impact on driver alertness and performance. Future work should replicate the study in a larger sample size to improve generalisability and assess the impact of consecutive 7-hour major rest breaks.

Does continuous positive airways pressure treatment improve clinical depression in obstructive sleep apnea? A randomized wait-list controlled study.

BACKGROUND: Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder that is associated with a range of adverse daytime sequelae, including significantly higher rates of clinical depression than is seen in the general community. Improvements in depressive symptoms occur after treatment of the primary sleep disorder, suggesting that comorbid depression might be an intrinsic feature of OSA. However, there are limited data on whether treatment for OSA in patients diagnosed with clinical depression improves mood symptoms meaningfully enough to lead to the remission of the psychiatric diagnosis. METHODS: N = 121 untreated OSA patients were randomized to either continuous positive airway pressure (CPAP) treatment or waitlist control, and depressive symptoms, sleepiness and clinical depression (using a structured clinical interview) were assessed at baseline and 4 months. Linear and logistic regression analyses were conducted, controlling for baseline scores, stratification factors and antidepressant use. RESULTS: Depressive symptoms (odds ratio [OR] = -4.19; 95% confidence interval [CI] = -7.25, -1.13; p = .008) and sleepiness (OR = -4.71; 95% CI = -6.26, -3.17; p < .001) were significantly lower at 4 months in the CPAP group compared to waitlist. At 4 months, there was a significant reduction in the proportion of participants in the CPAP group meeting criteria for clinical depression, compared to the waitlist controls (OR = 0.06, 95% CI = 0.01, 0.37; p = .002). CONCLUSION: Treatment of OSA may be a novel approach for the management and treatment of clinical depression in those with comorbid sleep disordered breathing. Larger trials of individuals with clinical depression and comorbid OSA are needed.

Severe Obstructive Sleep Apnea Is Associated with Higher Brain Amyloid Burden: A Preliminary PET Imaging Study.

BACKGROUND: Obstructive sleep apnea (OSA) has been linked to an increase risk of dementia. Few studies have cross-sectionally examined whether clinically-confirmed OSA is associated with a higher brain amyloid burden. OBJECTIVE: The aim of this study was to compare brain amyloid burden in individuals with untreated OSA and healthy controls, and explore associations between amyloid burden and polysomnographic and subjective measures of sleep, demographics, and mood. METHODS: Thirty-four individuals with OSA (mean age 57.5±4.1 y; 19 males) and 12 controls (mean age 58.5±4.2 y; 6 males) underwent a clinical polysomnogram and a 11C-PiB positron emission tomography (PET) scan to quantify amyloid burden. RESULTS: Amyloid burden was elevated in the OSA group relative to controls, and was significantly higher in those with severe OSA relative to mild/moderate OSA. Correlation analyses indicated that higher amyloid burden was associated with a higher Non-REM apnea hypopnea index, poorer sleep efficiency, and less time spent in stage N3 sleep, when controlling for age. CONCLUSION: Severe OSA is associated with a modest elevation of brain amyloid, the significance of which should be further investigated to explore the implications for dementia risk.

Sleep-disordered breathing does not impact maternal outcomes in women with hypertensive disorders of pregnancy.

OBJECTIVE: Sleep-disordered breathing (SDB) is characterised by intermittent hypoxemia, sympathetic activation and widespread endothelial dysfunction, sharing pathophysiologic features with the hypertensive disorders of pregnancy. We sought to determine whether coexisting SDB would adversely impact the outcomes of women with gestational hypertension (GH) and preeclampsia (PE), and healthy matched controls. STUDY DESIGN: Women diagnosed with GH or PE along with BMI- and gestation-matched normotensive controls underwent polysomnography in late pregnancy to establish the presence or absence of SDB (RDI ≥ 5). Clinical outcomes of hypertensive disease severity were compared between groups, and venous blood samples were taken in the third trimester and at delivery to examine for any impact of SDB on the anti-angiogenic markers of PE. RESULTS: Data was available for 17 women with PE, 24 women with GH and 44 controls. SDB was diagnosed in 41% of the PE group, 63% of the GH group and 39% of the control group. Women with PE and co-existing SDB did not have worse outcomes in terms of gestation at diagnosis of PE (SDB = 29.1 (25.9, 32.1) weeks vs. no SDB = 32.0 (29.0, 33.9), p = n.s.) and days between diagnosis of PE and delivery (SDB = 20.0 (4.0, 35.0) days vs. no SDB = 10.5 (9.0, 14.0), p = n.s.). There were also no differences in severity of hypertension, antihypertensive treatment and biochemical, haematological and anti-angiogenic markers of PE between SDB and no SDB groups. Similar results were observed among women with GH. Healthy control women with SDB were no more likely to develop a hypertensive disorder of pregnancy in the later stages of pregnancy (SDB = 5.9% vs. no SDB = 7.4%, p = n.s.). Increasing the threshold for diagnosis of SDB to RDI ≥ 15 did not unmask a worse prognosis. CONCLUSION: The presence of SDB during pregnancy did not worsen the disease course of GH or PE, and was not associated with high blood pressure or anti-angiogenic markers of hypertensive disease amongst healthy pregnant women. Given the numerous reports of the relationship between SDB and diagnosis of hypertensive disorders of pregnancy, it appears more work is required to distinguish causal, versus confounding, pathways.

Assessing the validity of eyelid parameters to detect impairment due to benzodiazepines.

OBJECTIVE: Benzodiazepines impair driving ability and psychomotor function. Eyelid parameters accurately reflect drowsiness; however, the effects of benzodiazepines on these measures have not been extensively studied. The aim of this study was to investigate the effect of benzodiazepines on eyelid parameters and evaluate their accuracy for detecting psychomotor impairment. METHODS: Eyelid parameters were recorded during a psychomotor vigilance task (PVT) and driving simulation over 2 days, baseline, and after 20-mg oral temazepam. The utility of eyelid parameters for detecting PVT lapses was evaluated using receiver operating characteristic curves, and cut-off levels indicating impairment (≥1 and ≥2 PVT lapses per min) were identified. The accuracy of these cut-off levels for detecting driving simulator crashes was then examined. RESULTS: PVT and driving simulator performance was significantly impaired following benzodiazepine administration (p < .05). Average eyelid closure duration (inter-event duration) was a reliable indicator of PVT lapses (area under the curve [AUC] of 0.87-0.90). The cut-off value of eyelid closure duration derived from PVT AUC was able to predict driving simulator crashes with moderately high sensitivity and specificity (76.23% and 75.00%). CONCLUSIONS: Eyelid parameters were affected by benzodiazepines and accurately detected the psychomotor impairment. In particular, eyelid closure duration is a promising real-time indicator of benzodiazepine impairment.

The presence of coexisting sleep-disordered breathing among women with hypertensive disorders of pregnancy does not worsen perinatal outcome.

OBJECTIVE: To determine whether the presence of co-existing sleep-disordered breathing (SDB) is associated with worse perinatal outcomes among women diagnosed with a hypertensive disorder of pregnancy (HDP), compared with normotensive controls. STUDY DESIGN: Women diagnosed with HDP (gestational hypertension or preeclampsia) and BMI- and gestation-matched controls underwent polysomnography in late pregnancy to determine if they had coexisting SDB. Fetal heart rate (FHR) monitoring accompanied the sleep study, and third trimester fetal growth velocity was assessed using ultrasound. Cord blood was taken at delivery to measure key regulators of fetal growth. RESULTS: SDB was diagnosed in 52.5% of the HDP group (n = 40) and 38.1% of the control group (n = 42); p = .19. FHR decelerations were commonly observed during sleep, but the presence of SDB did not increase this risk in either the HDP or control group (HDP group-SDB = 35.3% vs. No SDB = 40.0%, p = 1.0; control group-SDB = 41.7% vs. No SDB = 25.0%, p = .44), nor did SDB affect the total number of decelerations overnight (HDP group-SDB = 2.7 ± 1.0 vs. No SDB = 2.8 ± 2.1, p = .94; control group-SDB = 2.0 ± 0.8 vs. No SDB = 2.0 ± 0.7, p = 1.0). Fetal growth restriction was the strongest predictor of fetal heart rate events during sleep (aOR 5.31 (95% CI 1.26-22.26), p = .02). The presence of SDB also did not adversely affect fetal growth; in fact among women with HDP, SDB was associated with significantly larger customised birthweight centiles (43.2% ± 38.3 vs. 16.2% ± 27.0, p = .015) and fewer growth restricted babies at birth (30% vs. 68.4%, p = .026) compared to HDP women without SDB. There was no impact of SDB on measures of fetal growth for the control group. Cord blood measures of fetal growth did not show any adverse effect among women with SDB, either in the HDP or control group. CONCLUSION: We did not find that the presence of mild SDB worsened fetal acute or longitudinal outcomes, either among women with HDP or BMI-matched normotensive controls. Unexpectedly, we found the presence of SDB conferred a better prognosis in HDP in terms of fetal growth. The fetus has considerable adaptive capacity to withstand in utero hypoxia, which may explain our mostly negative findings. In addition, SDB in this cohort was mostly mild. It may be that fetal sequelae will only be unmasked in the setting of more severe degrees of SDB and/or underlying placental disease.

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.

The role of sleep hygiene in the risk of Shift Work Disorder in nurses.

A high proportion (20%-30%) of shift workers experience Shift Work Disorder (SWD), characterized by chronic sleepiness and/or insomnia associated with work schedules. The reasons for individual variation in shift work tolerance are not well understood, however. The aim of this study was to identify individual factors that contribute to the risk of SWD. Nurses (n = 202) were categorized as low or high risk of SWD based on the Shift Work Disorder Questionnaire. Participants provided demographic and lifestyle information and completed the Sleep Hygiene Index (SHI) and Morningness-Eveningness Questionnaire (MEQ). High risk of SWD was associated with poorer sleep hygiene (SHI, 35.41 ± 6.19 vs. 31.49 ± 7.08, p < .0001) and greater eveningness (MEQ, 34.73 ± 6.13 vs. 37.49 ± 6.45, p = .005) compared to low risk. No other factors, including body mass index, marital status, having children, or caffeine or alcohol intake were significant. Logistic regression showed that SHI was the most significant contributing factor to SWD risk (odds ratio [OR] = 1.09, 95% confidence interval [CI] = 1.04 to 1.14). Standardized odds ratio further revealed that with every unit increase on the SHI score, the odds of being at high risk of SWD increased by 80% (OR = 1.84). Most individuals at high risk of SWD reported "always" or "frequently" going to bed at different times (79%) and waking at different times (83%; compared to 58%, p = .017, and 61%, p = .002, respectively for the low-risk group), as well as going to bed stressed/angry (67% vs. 41%, p < .0001) and/or planning/worrying in bed (54% vs. 22%, p < .0001). Interventions aimed at improving sleep hygiene practices and psychological health of shift workers may help reduce the risk of SWD.