bluuebunny/crossref_metadata_2025 huggingface dataset:
O013 Anxiety and depression in adults referred for diagnostic sleep studies at an Australian tertiary sleep referral centre
Authors: Gordon A , Pradeepan S , Paech G
Published: November 2022

Background

Depression, anxiety and sleep disorders are frequently comorbid. Our study sought to understand local prevalence of depression and anxiety; and their interaction with sleep disordered breathing, sleep quality and sleepiness.

Methods

Apnoea hypopnoea index (AHI), arousal index (AI) and sleep efficiency (SE) were extracted from sequential in-laboratory diagnostic sleep studies (n=996) over three years and linked to demographic data and routine patient questionnaires (Epworth Sleepiness Scale (ESS), Hospital Anxiety and Depression Scores (HADS), and comorbidities). Anxiety or depression was either self-reported, or determined by HADS A ≥11 or D ≥8. Regression modelling was used to determine the effect of anxiety and depression on ESS, AHI, SE and AI. Significance was p<0.05 and mean±SD or median(IQR) are reported.

Progress/Results

Participants were: 49.3% male, BMI 34±8.9Kg/m2, and age 50±17.0 years. Sleep indices were: AHI 18.2(5.3-43.6)/h, AI 17.7(9.8-30.9)/h, and SE 77.2±13.4%. Anxiety alone, depression alone or both were present in 75 (7.5%), 177 (17.8%) and 359 (36%) patients respectively. Raised HADS anxiety/depression scores in the absence of self-reported diagnoses were present in 91 (9.1%) and 136 (13.7%) subjects. The presence of anxiety or depression did not affect AHI, but increased ESS by 2.2 (p<0.001), AI by 3.3/h (p<0.01) and reduced SE by 1.7% (p=0.05) compared to their absence.

Intended outcome/Discussion

Diagnoses of depression or anxiety are associated with poorer sleep quality and increased sleepiness despite similar AHI. Screening patients for depression/anxiety is suggested given frequent raised HADS scores without a formal diagnosis, and the higher prevalence compared to the general population.
O016 Actigraphy: A review of practice down under
Authors: Pham H , Saunders T , Vandeleur M
Published: November 2022

Background

In 2018, the American Academy of Sleep Medicine (AASM) published practice guidelines for use of actigraphy in evaluating adult and paediatric patients with suspected sleep disorders. Whilst there is significant evidence of actigraphy use in research, this study aims to evaluate current and future intended use of actigraphy in paediatric clinical cohorts across Australia and New Zealand (NZ).

Methods

A 16-item survey was electronically distributed to medical leads from Australian and NZ paediatric sleep centres. Questions enquired on sleep centre logistics, current actigraphy practice behaviours and qualitative assessments on future use.

Progress to date

The survey was distributed on July 22nd. Thus far, 8 responses have been returned, representing a range of locales, centre types and actigraphy practices. Findings will be collated and presented.

Intended outcome and impact

This study will provide an understanding for the contemporary trends in actigraphy use through Australia and NZ. This is particularly relevant given changes across recent years with both an increase in commercial prevalence for consumer sleep health devices as well as a surge in ambulatory medical services following the COVID-19 pandemic. It will identify barriers limiting its universal utility and explore clinician preferences for future practice. Such findings can guide actions around improving clinical services, product design and government funding advocacy.
O017 Utility of Inpatient Overnight Oximetry
Authors: Witt A , Goldin J
Published: November 2022

Background

Overnight pulse oximetry is a non-invasive method of monitoring oxygen saturations. It has a myriad of clinical applications; including screening for moderate to severe sleep disordered breathing, identification and qualification of nocturnal hypoxia in patients who may benefit from domiciliary nocturnal oxygen and detection of nocturnal hypoventilation in patients with severe respiratory or neuromuscular disease. In our tertiary hospital, overnight oximetry is ordered at the discretion of sleep and respiratory physicians, without formal guidelines.

Methods

A retrospective review of patients who underwent inpatient overnight oximetry for any clinical indication in the period between January 2019 and December 2019 was performed. Electronic and paper-based medical records were reviewed and analysed. Subsequent in-laboratory polysomnography data and outpatient clinic review documentation was reviewed to determine the medium term impact of the oximetry.

Progress to date

58 inpatient pulse oximetry studies were performed in the period examined. The indications for overnight oximetry fell into 4 groups - screening for sleep disordered breathing in patients with a high pre-test probability, assessment for domiciliary nocturnal home oxygen, assessment of adequacy of nocturnal oxygen therapy and assessment of adequacy of established positive airway pressure therapy.

Intended Outcome and Impact

There is no existing guidance on the use of overnight oximetry in adult inpatients. Our data shows that in patients with a high clinical suspicion of sleep disordered breathing, inpatient overnight oximetry frequently diagnosed sleep disordered breathing. In other patient groups, inpatient oximetry infrequently altered management. This data will help guide appropriate guidelines for inpatient overnight oximetry.
O022 Response of Sleep and the Circadian System to a Long Summer Photoperiod at High Latitude
Authors: Guzzetti J , Sundelin T , Holding B , Wright K , Axelsson J
Published: November 2022

The light-dark cycle is the primary time cue for the synchronization of the internal human circadian system with the external world. Our previous research has shown the capacity of the circadian system to adapt to seasonal variations in the light-dark cycle at latitude ~40oN in the Rocky Mountains following curtailment of artificial light exposure. In the current study, we examined the circadian response to a longer photoperiod in summer by measuring melatonin timing before and after a week of camping outdoors in Sweden. Actigraphy-derived (Actiwatch Spectrum) assessments of sleep, activity and light exposure were carried out for 2 weeks. Week 1 was under modern urban living conditions with exposure to natural and artificial light in Stockholm, Sweden (~59oN; 18 hr 37 min: 5 hr 23 min light-dark cycle). Week 2 was spent rough camping in nature with exposure to only natural light at the Swedish High Coast (~63oN; 20 hr 40 min: 3 hr 20 min). Dim-light melatonin onset (DLMO) assessments were conducted in laboratory over two 24 hr periods immediately before and after camping to assess melatonin levels in hourly saliva samples. On average, participants’ (n = 10) melatonin midpoint and offset advanced ~0.7 and ~1.3 hr (p < 0.01), respectively, with no change in onset (p = 0.45). As sleep duration, and timing were similar between environments (p > 10), melatonin offset occurred closer to sleep offset after camping. Consistent with prior findings, the end of biological night is timed closer to waketime in the natural environment.
O025 Boarding school students sleep better than day-student peers! The positive effects of bedtime routine and restricting technology use at night
Authors: Lushington K , Reardon A , Agostini A
Published: November 2022

Introduction

Boarding students face unique challenges when entering school including separation from family and adapting to a novel environment. A particular challenge is sleep. The aim of this study was to examine the sleep and psychological wellbeing of boarding student versus day-student peers.

Methods

59 boarding students and 250 day-students (one Adelaide school Years 10-12) completed the School Sleep Habits Survey, Depression-Anxiety-Stress-Scale-21, and Flourishing Scale. Boarding students additionally completed the Utrecht Homesickness Scale and a further 13 participated in a focus group examining the experiences of sleeping in a boarding house.

Results

Boarding compared to day-students reported 40 minutes more sleep per school night (p < .001), with earlier sleep onset (p = .026) and later wake up (p = .008) times. No significant differences in psychological variables were observed between groups. For both groups, hierarchical regression revealed longer sleep predicted better psychological wellbeing. In boarding students, homesickness-loneliness and homesickness-ruminations predicted psychological wellbeing. Thematic analysis of boarding students’ focus group responses revealed that night-time routine, and restricting technology use at night facilitated sleep.

Conclusion

Surprisingly boarding students reported better sleep than day-students—a finding attributable to boarding students having structured night-time routines and the boarding house restrictions on technology use at night. Nonetheless, in boarding students poor sleep and homesickness were predictive of worse psychological wellbeing. This study highlights the importance of strategies which promote sleep and minimise homesickness in boarding school students, but also the importance of routine and restricting technology at bedtime for adolescent sleep in general.
O028 Combination Pharmacological Therapy Targeting Multiple Mechanisms of Sleep Apnea
Authors: Sands S , Hess L , Bertisch S , Collet J , Gell L , Calianese N , Vena D , Azarbarzin A , Taranto-Montemurro L , Wellman A , Landry S , Thomson L , Joosten S , Hamilton G , Edwards B
Published: November 2022

Introduction

Currently two leading experimental pharmacological interventions are under investigation for obstructive sleep apnea (OSA). Acetazolamide, which acts to stabilise ventilatory control, lowers the apnea-hypopnea index (AHI) by ∼38%. More recently, atomoxetine-plus-oxybutynin (“AtoOxy”), acting via improvements to dilator muscle responsiveness and baseline tone, was found to lower AHI by >50%. Given that each potential therapy targets a different pathophysiology, we tested whether combined AtoOxy-plus-acetazolamide would be more efficacious than AtoOxy alone.

Methods

In a multicenter randomised crossover trial, 19 patients with moderate-to-severe OSA received AtoOxy (80/5mg respectively), acetazolamide (500mg), AtoOxy-plus-acetazolamide, or placebo at bedtime for 3 nights (half-dose on first night); outcomes were assessed at baseline and night 3 of each treatment period. Primary outcome: mixed model analysis compared the reduction in AHI(3% desaturation or arousal criterion) from baseline between AtoOxy-plus-acetazolamide and AtoOxy. Secondary outcomes included hypoxic burden, arousal index, and visual analog scale for sleep quality.

Results

Compared with placebo, AHI was lowered with AtoOxy by +49 [33, 62] %baseline (estimate [95%CI]), AtoOxy-plus-acetazolamide by +47 [31, 61]%baseline, and acetazolamide by +34 [14, 50]%baseline. However, there was no effect of AtoOxy-plus-acetazolamide vs. AtoOxy alone (−3 [−33, 20]%baseline, P=0.8). Secondary outcomes: AtoOxy, acetazolamide and combined AtoOxy-plus-acetazolamide each lowered hypoxic burden and arousal index, but no differential effect of combination therapy was observed. There was no impact on the visual analog scale for sleep quality.

Conclusions

While AtoOxy halved AHI, and acetazolamide lowered AHI by a third, the combination of these leading experimental interventions provided no greater efficacy than AtoOxy alone.
O030 Reduction in fall risk markers following CPAP treatment of obstructive sleep apnoea in people over 65 years
Authors: Stevens D , Barr C , Bassett K , Oh A , Lord S , Crotty M , Bickley K , Mukherjee S , Vakulin A
Published: November 2022

Objectives

Falls in older people can lead to serious injury and significant societal health and financial burden. Obstructive sleep apnoea (OSA) is associated with impaired gait/balance and may increase fall risk, yet few studies examined whether treating OSA reduces fall risk. This study examined the effect of continuous positive airway pressure (CPAP) on fall risk markers in people over 65yrs diagnosed with OSA.

Design

Single arm intervention study

Setting

University and tertiary care CPAP clinic.

Participants

Individuals over 65 years diagnosed with OSA and recommended CPAP.

Intervention

3-6 months CPAP therapy

Measurements

All participants had a physiological profile assessment (PPA) at baseline and following 3-6 months of CPAP. The PPA examines visual contrast sensitivity, lower limb proprioception, knee extension strength, reaction time and postural sway to generate a fall risk score (FRS). t-tests were used to determine difference between pre- and post-treatment FRS. Regression was used to examine the associations between CPAP use and daytime sleepiness with FRS.

Results

CPAP significantly reduced the FRS ([Mean±SD] 0.59±1.0 vs 0.04±1.1, p=0.016), contrast sensitivity and lower limb proprioception (P<005). Increased CPAP use was associated with improvement in FRS in unadjusted analysis (β=-0.213, 95%CI -0.371 to -0.056, p=0.01). Reduction in Epworth sleepiness score was associated with a reduction in FRS in unadjusted (p=0.02) and adjusted analysis (p<0.03).

Conclusions

CPAP may reduce fall risk in people over 65yrs, possibly related to better CPAP adherence and reduced daytime sleepiness. Future controlled trials and mechanistic studies are needed to elucidate how CPAP may reduce fall risk.
O035 Elevated liver enzymes in paediatric sleep disordered breathing
Authors: Noone A , Lao Y , Crawford T , Kennedy D , Martin J , Ferrante A , Wabnitz D , Kontos A
Published: November 2022

Introduction

Paediatric sleep disordered breathing (SDB) is associated with adverse cardiovascular outcomes. Non-alcoholic fatty liver disease (NAFLD) and dyslipidaemia are potential modifiable risk factors for cardiovascular disease, often coexisting in adults with SDB. Increases in lipid outputs from the liver have been identified in obese adults and children with SDB. Whether children with SDB compared to healthy non-snoring controls have evidence of elevated serum lipids and associated liver enzyme changes were assessed.

Methods

Seventy-five children (SDB=49, controls=26) between the ages of 6-17 years matched for age, gender and BMI underwent overnight polysomnography to measure SDB severity and provided a fasting blood sample to assess lipid and liver panels.

Results

OAHI was significantly increased in children with SDB compared to healthy non-snoring controls (p < 0.05). Serum potassium, alanine aminotransferase and lactate dehydrogenase were significantly increased in children with SDB, while albumin was significantly decreased (p < 0.05). No differences were found between serum lipid levels.

Conclusion

The presence of paediatric SDB may increase the risk of developing NAFLD. Further investigation is required to determine whether routine assessment of liver enzymes should be implemented in paediatric SDB. Whether surgical removal of the adenoids and tonsils to treat paediatric SDB can stabilise liver enzyme levels requires further research.
O036 Melatonin down-scheduling: An exploration of caregiver and pharmacist perspectives towards melatonin use in school-aged children and adolescents
Authors: Lee S , Tan E , Cairns R , Smith L , Cheung J
Published: November 2022

Background

Melatonin is a widely used paediatric sleep-aid. Recent regulatory changes in Australia have widened public access to proprietary melatonin products through community pharmacies. Yet little is known about how pharmacists and caregivers have responded to these regulatory changes. This study aims to explore the impact of melatonin down-scheduling on caregivers and pharmacists.

Methods

A mixed-methods study was conducted in a convenience sample of caregivers with school-aged children/adolescents taking melatonin, and community pharmacists/interns. Participants completed an online questionnaire and were given an option to participate in an in-depth semi-structured interview. The interviews were digitally recorded, transcribed verbatim and analysed using the Framework Approach to identify emergent themes.

Results

53 surveys were returned (caregivers, n=41; pharmacists, n=12). Caregivers (mean age=44.5±5.6; 98.0% female) reported moderate carer burden (18.8±6.8 points) and commonly cared for children (mean age=11.7±2.9) with comorbid autism spectrum disorder (n=18;43.9%) and ADHD (n=17;41.5%). Pharmacists (mean age=28.9±9.6; 71.4% female) handled 12.9±12.4 sleep-related enquires/day and received direct requests for melatonin 19.5±15.9 times/week. Preliminary analyses identified three key themes: (1) product cost and formulation availability; (2) differing safety endpoints; and (3) gaps in patient/clinical education. Caregivers and pharmacists highlighted the need for affordable proprietary products with flexible dosing options. The “naturalness” of melatonin was often conflated with long-term safety by caregivers, and lower abuse/misuse potential by pharmacists. Targeted melatonin education resources were needed for both caregivers and pharmacists.

Conclusion

Findings allude to the need to further refine existing educational, clinical and distribution/supply processes involved around melatonin products used in school-aged children/adolescents.
O037 Understanding ventilatory control in children with Prader-Willi syndrome
Authors: Patoglu O , Davey M , Nixon G , Edwards B , Horne R
Published: November 2022

Background

Children with Prader-Willi syndrome (PWS) are at risk of both central and obstructive sleep apnoea (OSA), and have abnormal respiratory control during wakefulness. Many children with PWS are treated with growth hormone (GH) however, GH has been associated with the development of OSA. In this pilot study, we aimed to determine whether sleep and respiratory control (i.e. loop gain, LG) characteristics were altered by GH in children with PWS.

Methods

Pre- and post-GH polysomnographic data in children (aged 0-18 years) were retrospectively collected. LG was quantified in periods of NREM sleep by fitting a model of ventilatory control to the respiratory pattern following spontaneous sighs.

Results

Results (n=15, range 5-134 months, 46.7%F) were compared pre- and post-GH. No significant differences in total sleep time (474 [447, 498] vs 475 [451, 495.5]; p=0.81), percentage time in NREM and REM sleep, the obstructive apnoea-hypopnoea (OAHI) index (0.0 [0.0, 0.4] vs 0.3 [0.0, 0.7]; p=0.15) or the central apnoea-hypopnoea index (CAHI) (3.0 [0.7, 6.3] vs 2.8 [1.4, 4.6]; p=0.63) were found however, 1 child developed OSA. GH had no impact on LG (0.4 ± 0.1 vs 0.4 ± 0.1; p=0.99) and the change in OAHI/CAHI showed no correlation with the change in LG.

Conclusions

In this small cohort of children, the administration of GH had no impact on sleep and respiratory characteristics (including LG). A larger sample size maybe required to gain a more comprehensive understanding of the impacts of GH on ventilatory control in children with PWS.
O040 Associations between Sleep Irregularity and Hypertension: Sleep Sensor Data from Over Two Million Nights
Authors: Scott H , Lechat B , Reynolds A , Lovato N , Escourrou P , Catcheside P , Eckert D
Published: November 2022

Introduction

Irregular sleep has been associated with worse cardio-metabolic health compared to regular sleep, but prior studies are limited in sample size and have assessed sleep irregularity over short assessment periods (7-14 days). This study investigated associations between sleep irregularity and hypertension in a large, global sample over multiple months.

Methods

Data from 12,300 participants (Mean ± SD; 50 ± 12 years, 12% females) who used an under-mattress sleep device and a portable blood pressure monitor between July 2020 and March 2021 were included. Each participant had ~180 nights of recordings and ~70 blood pressure entries. Sleep duration regularity was assessed as the standard deviation of device-assessed total sleep time. Sleep timing regularity was assessed as the standard deviation of sleep onset time and sleep midpoint. Logistic regressions were conducted, controlling for age, sex, BMI, and mean total sleep time.

Results

Across total sleep time quartiles, sleep duration irregularity was consistently associated with a 9-15% increase in hypertension risk. A 38-minute increase in sleep midpoint irregularity was associated with an 11% (1.11 [1.03, 1.20]) increase in hypertension risk, independent of mean total sleep time and mean sleep midpoint. Similarly, a ~31-minute increase in sleep onset time irregularity was associated with a 29% increased risk of hypertension (1.29 [1.18, 1.42]).

Conclusions

Irregular sleep, regardless of average total sleep time, was associated with increased hypertension risk. Further assessment of day-to-day fluctuations in sleep duration and timing for potential effects on next-day blood pressure and cardiovascular health outcomes is warranted.
O043 Pre-trauma sleep difficulties and fatigue predict trauma-induced changes in mental health symptoms in police recruits
Authors: Wolkow A , Kaldewaij R , Klumpers F , Koch S , Drummond S , Roelofs K
Published: November 2022

Introduction

Police are at risk of trauma and related mental health outcomes. Sleep disturbances and fatigue predict poor mental health in other populations, thus it is critical we determine whether they represent risk factors for mental health problems in first responders. We examined if pre-trauma sleep and fatigue experienced by police recruits predicted trauma-related mental health changes.

Methods

This study utilised data from the Police-in-Action Study, a longitudinal study which assessed police recruits (n=340) pre- (baseline) and post-15 months of emergency work (follow-up). Participants self-reported depression (Beck Depression Inventory; BDI), PTSD (PTSD Checklist for DSM-5; PCL-5), anxiety (State-Trait Anxiety Inventory) and stress (Perceived Stress Scale). Baseline sleep was measured using sleep items on the BDI and PCL-5, and the BDI fatigue item assessed baseline fatigue. Linear regressions examined whether baseline sleep and fatigue predicted the development of mental health symptoms (i.e., change in symptoms over time) while controlling for demographics, baseline mental health and trauma severity. Analyses were restricted to participants experiencing their core traumatic event between time-points (n=225), determined using the Clinician Administered PTSD Scale.

Results

Sleep difficulties in police at baseline predicted the development of depression (b=0.371 [0.109,0.633], p=0.006) and stress (b=2.430 [0.756,4.484], p=0.021) post-trauma. Baseline fatigue predicted post-trauma development of depression (b=0.272 [0.045,0.500], p=0.019) and anxiety (b=0.060 [0.007,0.113], p=0.028).

Discussion

Poor sleep and fatigue are pre-trauma risk factors for the development of mental health outcomes in new police. This suggests the need to investigate interventions targeting sleep and fatigue to reduce trauma-related mental health outcomes in police.
O045 Sleep management strategies among medical students
Authors: Duthie C , Cameron C , Smith-Han K , Beckert L , Delpachitra S , Garland S , Sparks B , Wibowo E
Published: November 2022

Introduction

Medical students are undertaking an intense curriculum, the stress of which may cause or worsen insomnia and depressive symptoms. We aim to investigate factors which might affect the sleep of medical students, and how they currently manage their sleep.

Methods

A brief online survey was sent to medical students, consisting of validated questionnaires, and questions related to sleep management strategies.

Results

We recruited 828 participants—49.5% reported insomnia symptoms and 51.4% reported depressive symptoms. After adjusting for gender, ethnicity and age, depressive symptoms (Mild: odds ratio (OR) = 6.26; Moderate: OR = 18.13; Severe: OR = 15.57), and sleep hygiene (OR = 1.07) were associated with insomnia symptoms. Commonly endorsed strategies for sleep management by students were undertaking regular exercise (80.1%), having consistent sleep-wake time (71.3%), and limiting caffeine intake (70.3%). Few were willing to see a clinician (23.4%) or take medication (22.3%). Participants with insomnia symptoms were more likely to prefer limiting their alcohol intake (OR = 1.77), limiting daytime naps (OR = 1.5), seeing clinicians (OR = 1.86), and taking sleep medication (OR = 3.98), but less likely to prefer avoiding intense work (OR = 0.71) or minimizing using electronics (OR = 0.60) close to bedtime than those without insomnia symptoms. High sleep self-efficacy was associated with lower odds for having insomnia symptoms (OR = 0.74 (0.70, 0.77)).

Discussion

Self-reported insomnia and depression are common among medical students. Increased awareness and greater resources are needed to support the sleep health and emotional well-being of medical students.
O046 Poor sleep quality is associated with unemployment and lower levels of participation in people living with spinal cord injury
Authors: Graco M , Arora M , Berlowitz D , Craig A , Middleton J
Published: November 2022

Introduction

Poor sleep is common among people with spinal cord injury (SCI), yet little is known about its impact on employment and participation outcomes. This study aimed to describe the sleep quality of a large sample of Australians with SCI; examine associations between sleep quality and participant characteristics; and explore the relationship between sleep and outcomes.

Methods

Cross-sectional Australian survey, including 1579 community-dwelling people with SCI, aged 18 years and over. Sleep quality was assessed with the Pittsburgh Sleep Quality Index (PSQI). Relationships between participant characteristics, sleep and other outcomes were examined with linear and logistic regression.

Results

The PSQI was completed by 1172 individuals; 68.4% reported poor sleep (PSQI>5). Subjective sleep quality in people with SCI was poor (mean(SD) PSQI global score=8.5(4.5). Financial hardship and problems with other secondary health conditions were significantly associated with worse sleep quality (p<0.05). Poor sleep quality was strongly associated with lower emotional wellbeing and energy, and greater problems with participation (p<0.001). Individuals engaged in paid work reported better sleep quality than unemployed individuals (mean(SD) PSQI=8.1(4.3) vs 8.7(4.6), p<0.05). Following adjustment for age, pre-injury employment, injury severity and years of education, better sleep quality remained strongly associated with being employed (OR=0.95, 95% CI=0.92-0.98), p=0.003).

Conclusions

This study has demonstrated pervasive and impactful relationships between sleep quality and important SCI outcomes. Poor sleep quality was strongly associated with worse emotional wellbeing and vitality, unemployment and lower participation. Determining whether treating sleep problems can improve outcomes for people living with SCI deserves more attention.
O048 Help seeking behaviours of Australian adults with insomnia in a community sample
Authors: Haycock J , Lack L , Hoon E , Sweetman A , Appleton S , Reynolds A , Gill T , Adams R , Lovato N
Published: November 2022

Introduction

Chronic insomnia negatively impacts quality of life for millions of Australians. Most people with insomnia do not receive the recommended treatment Cognitive Behavioural Therapy for insomnia (CBTi), and many are prescribed sedative-hypnotic medications. This study aims to better understand the help seeking behaviours of people with insomnia, and to identify barriers to treatment and improve access to evidence-based care.

Methods

A total of 2044 people in a community sample (Age M = 46.6, SD = 17.3, 51.3% Female) completed the 2019 Sleep Health Foundation Insomnia Survey which included questions on sleeping difficulties, daytime impairment and help seeking behaviours. Chronic insomnia was identified using the ICSD-3 diagnostic criteria.

Results

Preliminary analysis shows 37% of participants with chronic insomnia (N=303) discussed sleep with their GP in the past year. The most common help seeking behaviours for participants with insomnia are strict sleep habits (50%), adjusting time in bed (47%), relaxation (40%), alcohol (39%), and meditation (37%). Participants with undiagnosed insomnia (N=275) are much less likely to engage in help seeking behaviours than those with a diagnosis. Most participants who discussed sleep with a psychologist (N=104) reported a diagnosis of depression (77%) or anxiety (80%), rather than insomnia (30%).

Discussion

Despite evidence-based guidelines recommending CBTi as the ‘first line’ treatment for insomnia, in Australia most people manage their insomnia with strict sleep habits or relaxation techniques. These findings highlight the importance of GPs discussing sleep with patients, and having knowledge and access to appropriate treatment and referral pathways for management of insomnia.
O052 Association of co-morbid insomnia and sleep apnoea (COMISA) symptoms with all-cause mortality: Analysis of the NHANES 2005-2008 data
Authors: Sweetman A , Lechat B , Appleton S , Reynolds A , Adams R , Melaku Y
Published: November 2022

Introduction

Co-morbid insomnia and sleep apnoea (COMISA) is a highly prevalent condition associated with negative health outcomes. This population-based study aimed to investigate the association between COMISA and all-cause mortality.

Methods

Sleep data in 6,877 participants (Age median [IQR]=45 [33,57], 50.1% male) were drawn from the National Health and Nutrition Examination Survey (2005-2008). Insomnia was defined as difficulties initiating sleep, long awakenings, and/or early morning awakenings on ≥16 nights/month, with daytime impairment. The STOP-Bang questionnaire was used to identify participants at high risk of obstructive sleep apnoea (OSA). COMISA was defined if participants met criteria for insomnia and high risk of OSA. The median (IQR) follow-up for mortality was 8.6 (7.8, 9.8) years. Cox regression models were used to determine the association between COMISA and all-cause mortality, controlling for socio-demographic characteristics, behavioural factors and chronic conditions.

Results

The prevalence of no insomnia/OSA, insomnia-alone, OSA-alone, and COMISA were 73.5, 3.0, 20.1, and 3.3%, respectively, and 6.7% of participants died by 11-year follow-up. Compared to participants with no insomnia/OSA, higher mortality risk was observed in participants with COMISA (HR=1.9; 95%CI=1.3-2.8) and insomnia alone (HR=1.5; 95%CI=1.0-2.3) after adjusting for socio-demographic characteristics, and behavioural factors. The relationship between COMISA and mortality persisted after additionally controlling for chronic conditions, sleep duration and sleeping pill use (HR=1.6; 95%CI=1.1-2.3), but the relationship between insomnia-alone and mortality did not (HR=1.4; 95%CI=0.9-2.3).

Discussion

Co-morbid insomnia and high-risk OSA is associated with increased risk of all-cause mortality. More research is needed to identify effective treatments for COMISA.
O054 Genioglossus neural drive and upper airway dilation in people with obstructive sleep apnoea during wakefulness
Authors: Jugé L , Liao A , Yeung J , Knapman F , Burke P , Brown E , Gandevia S , Eckert D , Butler J , Bilston L
Published: November 2022

Introduction

Genioglossus neural drive and the ensuing tongue dilatory movement may be dissociated in obstructive sleep apnoea (OSA), but this has not been studied. This study aimed to investigate this relationship and its potential role in OSA pathophysiology.

Methods

During awake nasal breathing in the supine position, inspiratory tongue dilatory movement, quantified with tagged magnetic resonance imaging, and inspiratory peak genioglossus electromyography (EMG) normalised to the maximum voluntary contraction (tongue protrusion), were measured in 4 tongue neuromuscular compartments from 8 controls [apnea-hypopnea index (AHI)<5 events/h] and 34 patients with untreated OSA [AHI>10 events/h].

Results

Although larger inspiratory dilatory movement was associated with increased drive to genioglossus (partial Spearman, r=0.23, p=0.016, n=115/68% of compartments), in 14% of the compartments (n=16), there was a large dilatory (>1mm) movement but minimal EMG (<4th percentile). This occurred only in the horizontal compartment. In another group of 18 compartments (16%), there was a large peak EMG (>4th percentile) but minimal dilatory movement (<1mm). This occurred more commonly in the oblique compartments. Dissociation between the amplitude of the peak EMG and inspiratory tongue dilatory movement was most commonly seen in severe OSA patients (AHI>30 events/h, Fisher's exact test, p=0.047).

Conclusions

Inspiratory tongue dilatory function generally remains closely linked to muscle drive during wakefulness, with larger movement associated with higher peak EMG. However, for approximately one-third of the neuromuscular tongue compartments, neural drive was dissociated from the dilatory motion in severe OSA patients. This may contribute to OSA pathogenesis and have implications for neural stimulation therapy targets.
O055 Flow limitation and sleepiness in individuals without sleep apnea
Authors: Mann D , Georgeson T , Azarbarzin A , Wellman A , Redline S , Terrill P , Sands S
Published: November 2022

Introduction

Moderate-Severe Obstructive Sleep Apnea (OSA, AHI>15) disturbs sleep through frequent bouts of apnea and is associated with daytime sleepiness. However, many individuals without moderate or severe OSA (i.e. AHI≤15) also report sleepiness. We propose that sleepiness may be a consequence of substantial flow limitation, even in the absence of overt reductions in airflow (apnea/hypopnea).

Methods

2060 participants from the MESA sleep cohort were analysed using our validated method to estimate frequency of certain flow limitation from the airflow signal. Individuals with Epworth Sleepiness Scale ≥11 points were considered ‘sleepy’. Logistic regression was conducted to investigate the association between sleepiness (binary dependent variable) and frequency of flow limitation (continuous) in individuals without moderate-to-severe OSA AHI≤15. Models were adjusted for age, sex, race, BMI and self-reported sleep duration.

Results

N=832 individuals with AHI≤15 were included in primary models: The odds ratio (OR) for flow limitation predicting sleepiness was 2.14 (CI 1.27-3.61, per 2SD increase in flow limitation frequency i.e. +11% of sleep) and 2.08 (1.19-3.64) when adjusted for AHI. No association between flow limitation and sleepiness was observed in moderate-severe OSA (AHI>15, OR=1.01, 0.7-1.46).

Discussion

In individuals with few scored respiratory events (non-OSA and mild-OSA), increased flow limitation frequency by 2 SD (11% of sleep) is associated with a 2-fold increase in risk for sleepiness. Increasing flow limited breaths by 11% increases the odds for being sleepy equivalent to 1.2 hrs less sleep. Flow limitation may be an independent target for ameliorating sleepiness even in the absence of OSA.
O058 Awareness of errors is impaired by sleep restriction but not total sleep deprivation
Authors: Boardman J , Cross Z , Bravo M , Andrillon T , Anderson C , Drummond S
Published: November 2022

Introduction

Detecting and correcting errors is important in preventing detrimental consequences of sleep loss. We report the first study to utilise both behavioural and EEG measures of error awareness, and we compare the effects of total sleep deprivation (TSD) and sleep restriction (SR).

Methods

Twenty-seven healthy adults (14F, age=27.2±5.1y) were studied both well-rested (

WR

9h sleep/night) and following SR (3 nights of 3h sleep/night), completing the Error Awareness Task (EAT) once/day (8-9h post-habitual wake). Thirteen healthy adults (3F, age=26.2±4.1y) underwent 34h TSD, completing the Error Awareness Task (at 3h and 27h post-wake). The EAT required participants to withhold responding to “nogo” stimuli and signal errors when they occurred. ERP measures included the Error Related Negativity (ERN) and Error Positivity (Pe).

Results

SR increased error rate (p<.001), decreased error awareness (p<.001) and slowed error recognition (p<.01). ERN amplitude was unaffected, and Pe amplitude was reduced. TSD did not significantly affect error rate, error awareness rate, the time taken to detect errors, or either ERP measure.

Discussion

SR impaired the ability to recognise errors in real time, despite a greater number of errors being made. EEG findings further indicate conscious error awareness is reduced following SR. However, unconscious error detection appears resilient to sleep loss. Findings suggest error awareness may be more sensitive to chronic versus acute sleep loss. In occupations where SR is common, recognition of errors may be reduced. Reduced error recognition may explain the increased accident and injury rates seen in contexts where sleep loss is common.
O060 The relationship between sleep and appetitive conditioning: A systematic review and meta-analysis
Authors: Kavaliotis E , Boardman J , Clark J , Ogeil R , Verdejo-Garcia A , Drummond S
Published: November 2022

Appetitive conditioning involves learning to associate previously neutral stimuli with pleasant or rewarding cues. Elements of appetitive conditioning underpin various maladaptive consummatory behaviours, including regular consumption of unhealthy foods, recreational substance use, and clinical symptoms of certain mental disorders (e.g., binge-eating disorder, substance use disorder). One modifiable mechanism underlying appetitive conditioning appears to be sleep, due to its critical role in new learning. This systematic review and meta-analysis (PROSPERO registration: CRD42021234793) examined the relationship between sleep and appetitive conditioning. Inclusion criteria included: a) appetitive conditioning paradigm; b) measure of conditioning; c) sleep measurement and/or sleep loss; and d) written in English. Searches of seven databases returned 3343 publications as of March 2022. The final sample consisted of 40 studies using animal models. No human studies were identified. We found: a) sleep loss interfered with appetitive conditioning tasks involving natural reinforcers (i.e., food; p < 0.001); b) tasks involving drug reinforcers showed potentiating effects of sleep loss (p < 0.001); c) extinction learning was negatively impacted by sleep loss, irrespective of reinforcer; and d) post-learning sleep was associated with increases in REM sleep (p = 0.02). Findings suggest sleep loss potentiates the impact of psychoactive substances to produce an increased risk of problematic substance use. This indicates sleep may be an important target in treating substance use disorders. In obese/overweight populations sleep loss may be associated with deficits in the conditioning and extinction of reward behaviours. Further research is needed to assess the relationship between sleep and appetitive conditioning in humans.
O061 Sleep hygiene guidelines for shift workers: consensus guidelines via a Delphi study
Authors: Shriane A , Bin Y , Ferguson S , Rigney G , Vincent G
Published: November 2022

Introduction

Current sleep hygiene guidelines are impractical for shift workers, given their inability to maintain regular sleep schedules. Further, the present guidelines contradict fatigue risk management advice (e.g., advising against caffeine and daytime napping). The aim of the present study is to develop a set of tailored sleep hygiene guidelines for shift workers via a Delphi approach.

Methods

Draft guidelines were developed by the research team, who reviewed the current guidelines and examined existing evidence on sleep hygiene in shift workers. Experts from sleep, shift work, and occupational health fields (n=155) were invited to review these draft guidelines via a three-round series of online questionnaires. In each round, experts voted on each guideline, with consensus reached once there was 70% agreement on including the item as written. Expert feedback from each round was discussed and incorporated by the research team as appropriate.

Results

The research team drafted 17 sleep hygiene recommendations, covering sleep scheduling, napping, sleep environment, substance consumption, diet, and exercise. Of those experts invited, 68 (44%) agreed to participate, with 55 of these (81%) completing all three rounds. Consensus was reached on all original items after three rounds, with two additional items (medication use and sleep inertia) and an introductory statement developed, to create a final set of guidelines with 19 items.

Discussion

This is the first study to create evidence-based, expert-developed sleep hygiene guidelines for shift workers. Future research is planned to investigate the acceptability and implementation of the guidelines amongst end-users.
O067 The role of biological sex in the relationship between circadian alignment and well-being in elite athletes
Authors: Mascaro L , Rajaratnam S , Leota J , Hoffman D , Drummond S , Facer-Childs E
Published: November 2022

Introduction

Circadian rhythms govern physiological timing and influence sleep, well-being, and performance. Desynchrony between circadian timing and behaviours (circadian misalignment) can compromise daily functioning. We investigated sex differences in sleep and circadian timing, and their relationship with sleep and mental health outcomes in elite athletes.

Methods

Participants were 87 elite Australian Rules Football (AFL) athletes (43% female; M-age =23.8±4.0 years). Data were collected prior to the start of the 2021 and 2022 AFL seasons (n= 54 participating in a repeat assessment). Circadian phase was assessed via salivary DLMO (collected hourly from 5hrs pre- to 1h post-habitual bedtime). A questionnaire battery, and two weeks of actigraphy were also completed.

Results

Female athletes had a significantly later circadian phase (DLMO; 20:42 vs 20:13) and midsleep time (03:24 vs 02:58), and worse self-reported athlete psychological strain (APSQ), daytime sleepiness, and insomnia, relative to male athletes. There was no sex difference in phase angle (interval between sleep onset and DLMO times; M = 2.5hrs ± 49 mins). DLMO time did not predict sleep efficiency, sleep latency, insomnia, sleepiness, or APSQ. Phase angle predicted APSQ for female athletes only, via a quadratic trend (p=.001): psychological strain was worse among female athletes with shorter and longer phase angles.

Discussion

Our results suggest female athletes have a later circadian phase, which is not associated with adverse outcomes except for higher psychological strain for those with greater circadian misalignment. Sports practitioners may require specific attention for circadian alignment in female athletes who are at particular risk when misaligned.
O068 Slow frequency wake EEG and hypoxemia during sleep predicts vigilance performance following extended wakefulness in patients with OSA
Authors: Choo G , Stevens D , Marshall N , Openshaw H , Bartlett D , Rae C , Wong K , McEvoy R , Grunstein R , D'Rozario A , Vakulin A
Published: November 2022

Study Objectives

Obstructive sleep apnea is highly prevalent, but heterogeneous making identifying patients at risk of driving impairment challenging. Resting wake electroencephalography (qEEG) is associated with vigilance performance in healthy subjects. We examined if qEEG and clinical measures predict vigilance impairment in OSA.

Methods

Fifty-four patients underwent baseline PSG and 28hr extended wakefulness (EW) with 2 hourly psychomotor vigilance test (PVT) and Karolinska drowsiness test and driving simulator performance at baseline and following EW. Resting wake EEG was subjected to fast Fourier transform analysis to derive EEG power in delta, theta, alpha and beta ranges. Cluster analysis assigned participants into groups of either resistant (n=39) or vulnerable (n=15) to alertness failure based on PVT and driving performance. Backward stepwise regression models were used to determine the strongest clincal and wake EEG predictors vigilance impairment.

Results

Compared with resistant patients, the vulnerable group exhibited increased wake EEG delta (p<0.001) and theta (p=0.003) power during eyes open across all testing periods. The only significant predictors of vulnerability to alertness failure (PVT and driving) included O2Nadir from baseline PSG and baseline wake EEG theta and delta (eyes open) respectively explaining 42 and 32% of the variance in vigilance outcome in models that included Age, BMI, ESS, SOL, TST, AHI, O2 Nadir.

Conclusions

Slow frequency wake EEG (delta and theta) and hypoxemia are predictive of future alertness failure and driving impairments in patients with OSA. These findings are important for fitness to drive assessment in OSA but require validation in independent sample.
O074 A systematic scoping review of minimally invasive respiratory monitoring
Authors: Bull C , Lovell N , Bilston L
Published: November 2022

Introduction

Respiratory rate (RR) is a key marker of stress with evidence that raised RR is the vital sign most predictive of cardiac events. Respiratory monitoring is critical to detecting Sleep Disordered Breathing (SDB). COVID-19 highlighted the importance of infection control, and methods of detecting RR without direct airstream contact have wide application for diagnostic and monitoring in respiratory medicine. This scoping review aims to provide an up-to-date overview of indirect respiratory monitoring.

Method

Systematic literature searches were conducted according to PRISMA-ScR guidelines on PubMed, Embase, ProQuest and Scopus covering articles published between January 2012, until February 2022. Data was extracted into the following categories : physiological signal, sensor type, sensor location and field of use. Analysis methods and effectiveness of each method were also assessed.

Results

10736 articles were screened, 236 articles were included for analysis. 61.9% (n=146) monitored respiration through periodic motion of the chest and abdomen, 22.5% (n=53) cardiorespiratory coupling 7.6% (n=18) airstream temperature, 2.5% (n=6) respiratory sounds, 0.4% (n=) remote airflow monitoring, and 5.1% (n=12) combined markers. Medical and clinical research accounted for 42.4% (n=100) of papers, health and exercise monitoring 28% (n=66), and sleep monitoring 16.9% (n=40).22 different sensor types were identified, the most common being remote radar monitoring 17.8% (n=42), photoplethysmography 14.8% (n=35), AI assisted video monitoring 9.7% (n=23) and thermal imaging 8.5% (n=20).

Discussion

Indirect RR monitoring technology that is typically unutilized in clinical settings. Continued development in AI assisted signal analysis will make these methods more accessible for clinical and consumer use.