bluuebunny/crossref_metadata_2025 huggingface dataset:
O053 Obstructive sleep apnea is a distinct physiological phenotype in individuals with comorbid insomnia and sleep apnea (COMISA)
Authors: Brooker E , Thomson L , Landry S , Drummond S , Edwards B
Published: November 2022

Introduction

Obstructive sleep apnea (OSA) pathophysiology varies among individuals, though the influence of comorbid insomnia on this pathophysiology is unknown. We examined whether upper airway collapsibility, muscle compensation, loop gain, and the arousal threshold differ between OSA patients with and without comorbid insomnia disorder.

Methods

We noninvasively determined the four traits using the ventilatory flow pattern captured from standard polysomnography in 34 comorbid insomnia and obstructive sleep apnea (COMISA) and 34 OSA patients without insomnia (OSA-only). Participants had mild-to-severe OSA (

AHI

25.8±2.0 events/h) and were matched according to age (50.2±1.5 years) sex (42M:26F), and body mass index (29.3±0.6 kg/m²).

Results

COMISA patients had significantly lower respiratory arousal thresholds (128.9 [118.1–137.1] vs. 147.7 [132.3–165.0] %Veupnea, U=261, p<.001), less collapsible upper airways (i.e., higher

Vpassive

88.2 [85.5–94.6] vs. 72.9 [64.7–79.2] %Veupnea, U=1081, p<.001) and more stable ventilatory control (i.e., lower loop gain: 0.51 [0.44–0.56] vs. 0.58 [0.49–0.70], U=402, p=.03) relative to OSA-only controls. Muscle compensation did not significantly differ between groups.

Discussion

OSA patients with comorbid insomnia appear to have OSA driven more by heightened nocturnal arousability than by the contribution of anatomical factors, compared to OSA patients without insomnia. Heightened nocturnal arousability as the driver of apneic events in COMISA suggests the conditioned arousal perpetuating insomnia may also increase risk or severity of OSA. Further research should investigate whether targeting increased arousal propensity (e.g., through CBT-I) provides therapeutic benefit to individuals with COMISA.
O057 Effects of oral appliance therapy on upper airway collapsibility pre- versus post-treatment
Authors: Osman A , Eckert D
Published: November 2022

Introduction

A key predictive mechanism of improvement in obstructive sleep apnoea (OSA) severity with oral appliance therapy (OAT) is a less collapsible upper airway. In this study, we investigate the effects of acute versus longer-term use of OAT on upper airway collapsibility.

Methods

To investigate potential changes in upper airway collapsibility we studied 10 treatment naïve people (2 female) with OSA (AHI=40±31events/h, age=51±11years, BMI=29±4kg/m-2) at baseline and following 4-6 weeks oral appliance therapy acclimatization. The upper airway collapsibility index was measured during wakefulness with/without the oral appliance in place at two time points (pre/post treatment). All participants were instrumented with standard polysomnography equipment, two pressure catheters (one at the level of the choanae, and the other at the epiglottis), a pneumotachograph, sealed nasal mask and a short tubing connected to a breathing circuit to allow rapid delivery of negative pressure ~-11cmH₂O to the mask.

Results

The upper airway collapsibility index measured during early inspiration was reduced by 11% (33±19 vs. 22±16%, n=10, p=0.02) with OAT in place in treatment naïve participants. Similarly, following acclimatization, the upper airway collapsibility index also reduced by 7% with OAT in place (25±15 vs. 18±15%, n=9, p=0.03).

Conclusions

While further work is required to determine if long-term OAT independently improves upper airway collapsibility, these data show sustained improvements in upper airway collapsibility with OAT over time and highlight the potential for this approach to help predict OAT treatment outcomes.
O062 Sleep behaviour modification in shift workers: Applying models of arousal dynamics tailored to individual shift schedules and personal commitments
Authors: Varma P , Postnova S , Rajaratnam S , Phillips A , Howard M , Sletten T
Published: November 2022

Introduction

Circadian-based biomathematical models of sleep-wake and alertness regulation can improve sleep health in shift workers by providing physiologically optimal times for sleep. It is unclear whether they can be successfully implemented in real-world contexts. This study, for the first time examined associations between model-based sleep-wake recommendations and modification of sleep behaviours in shift workers.

Methods

Nurses (n=28; 37.2±9.6yrs) with matching-rotating shift schedules received personalised sleep recommendations from either the Phillips-Robinson Model or Model of Arousal Dynamics. Nurses used sleep diaries to record sleep-wake behaviours: (i) pre-exposure to recommendations (baseline, 1-week), (ii) upon exposure (1-week) and completed PROMIS-sleep disturbance, sleep-related impairments pre and post.

Results

During baseline, participants usual bedtimes and waketimes were at least 180mins away from recommended times from both models. Upon exposure to recommendations, sleep behaviours were aligned within: (i) 62±11mins for bedtime, 71±9mins for waketime (Model of Arousal Dynamics), (ii) 104±16mins for bedtime, 89±12mins for waketime (Phillips-Robinson model) with large effect sizes (p<.00001 for both models). Participants sleep windows had better compliance with recommended sleep windows for the CRC Alertness model (79% overlap) compared to the Phillips-Robinson model (69% overlap). Sleep disturbance and sleep-related impairments improved significantly upon study conclusion (small-effect sizes both groups). Participants reported that automated recommendation delivery, and use of diurnal preference and real-time sleep behaviours to further personalise recommendations will facilitate greater uptake.

Conclusion

The study provides positive proof-of-concept for the implementation of biomathematical models of sleep-wake dynamics in shift work contexts. Accounting for individual differences may improve applicability of recommendations.
O063 Impact of sleep deprivation on distributed team performance and cohesion
Authors: Greer E , Matthews R , Owen M , Grosser L , Roma P , Banks S
Published: November 2022

Distributed teams often have limited contact resulting in less effective collaboration and decreased cohesion. Those in 24/7 industries are further impacted by fatigue and sleep loss which threatens workers’ safety, productivity, and performance. To date little is known about distributed team cohesion with extended periods of time awake. Hence, this study examined the impact of sleep deprivation on distributed team performance and cohesion.

22 healthy individuals (M=22.81,SD=4.4 years,11f) aged 18-45 years participated in a five-day sleep study. Participants were randomly allocated into teams consisting of four members and underwent 62h of total sleep deprivation (TSD). Distributed teams completed the COHESION task at 10h intervals throughout the wake period. COHESION required distributed teams to attempt resource movements, while avoiding visible and invisible barriers. Team members could dedicate time to reveal barriers to all, making successful resource movements easier. Distributed team performance was assessed using team successful resource movements. Distributed team cohesion was assessed through team members’ barrier reveal responses in relation to their total responses.

Data were analysed using linear mixed models. Results showed that distributed team cohesion decreased with TSD (F(5,495.19)=3.18,p=.008), and there were significant differences between teams (F(5,21.99)=8.74,p<.001). Team performance also decreased with TSD (F(5,144)=3.01,p=.013), with significant differences between teams (F(5,21.01)=7.03,p<.001).

This study found distributed team cohesion was reduced with TSD, as was overall team performance. We found each distributed team used a different strategy to manage the team task during sleep deprivation and these differences impacted their overall team performance.
O065 The impact of breaking up sitting on vigilant attention during the workday when sleep restricted
Authors: Gupta C , Ferguson S , Vandelanotte C , Duncan M , Tucker P , Lastella M , Tuckwell G , Vincent G
Published: November 2022

Introduction

Sleep restriction is associated with impairments to cognitive performance. A current strategy to improve cognitive performance at work is breaking up prolonged sitting with light-intensity walking. However, it is unknown whether this strategy can counteract the impact of sleep restriction. This study investigated the effect of breaking up sitting on cognitive performance under conditions of sleep restriction.

Method

84 healthy adults (age M±

SD

23.1±4.5 years; 41 females) participated in a 7-day laboratory study, with 5 simulated workdays (0900-1700). Participants were randomly allocated to a condition: Breaking up sitting and 9-h sleep (Break9; n=20), Breaking up sitting and 5h sleep (Break5; n=20), Sedentary and 9-h sleep (Sit9; n=22), Sedentary and 5-h sleep (Sit5; n=22). Sleep opportunity prior to each workday was 9-h (2200-0700) or 5-h (0200-0700) depending on condition. Every 30-min during the workday participants in the breaking up sitting conditions completed 3-min bouts of light-intensity walking, while participants in the sedentary conditions remained sitting. At 0900, 1100, 1300, 1500, and 1700, participants completed a 10-min Psychomotor Vigilance Task and the Karolinska Sleepiness Scale.

Results

Mixed model ANOVAs revealed no significant 2-way or 3-way interactions between condition (Break9, Break5, Sit9 and Sit5), time of day, and workday for vigilant attention (reciprocal mean response time and mean lapses) or subjective sleepiness.

Discussion

Breaking up prolonged sitting with light-intensity walking did improve cognitive performance. Higher doses of physical activity may be needed to counteract the effects of sleep restriction on cognitive performance. Findings highlight the acute cognitive deficits associated with inadequate sleep.
O071 The performance accuracy of wrist-worn oximetry and its automated output parameters for screening obstructive sleep apnoea in children
Authors: Ohn M , Maddison K , Evans D , Nguyen J , Bear N , Khan N , Eastwood P , von Ungern-Sternberg B S , Wilson A , Walsh J
Published: November 2022

Introduction

Children with obstructive sleep apnea (OSA) are at increased risk for perioperative adverse events. Whilst polysomnography (PSG) remains the reference standard for OSA diagnosis, oximetry is a valuable screening tool; visual analysis of desaturation clusters derived from a tabletop oximeter is the traditional practice. However, wearable oximetry with automated analysis could be an alternative option. This study investigated the accuracy of a wrist-worn oximeter as an OSA screening tool for a paediatric surgical population.

Method

Children scheduled for adenotonsillectomy without significant co-morbidities underwent concurrent overnight PSG and oximetry (Nonin WristOx2 3150) preoperatively. To determine the obstructive apnea-hypopnea index (OAHI), PSG was scored manually, and oximetry data were auto-analysed by Nonin proprietary software to determine the 3% oxygen desaturation index (oximetric ODI3). Logistic regression assessed the predictive performance of ODI3 and covariates (age, gender, BMI z-score) for detecting any OSA and moderate-severe OSA.

Results

Seventy-six children (34 females, aged (mean±SD) 5.7±1.6years) were classified based on PSG-derived OAHI as having no OSA (n=31), mild (n=31), and moderate-severe OSA (n=14). The moderate-severe OSA (OAHI≥5 events/hr) prediction analysis showed that oximetric ODI3 (OR 1.38, 95% CI 1.15, 1.65, p=0.001) was the sole OSA predictor. At a cut-off of ODI3=5events/hr, sensitivity and specificity were 78.6% and 75.8%, respectively, capturing all severe OSA cases (ROC-AUC=0.857). For any OSA (OAHI≥ 1 event/hr), prediction analysis showed reduced accuracy in performance: 75.6% sensitivity, 61.3% specificity (ROC-AUC=0.7097).

Conclusion

Wrist-worn oximetry-derived automated ODI3 can reliably identify moderate-severe OSA. Easy acquisition and interpretation may expedite the preoperative identification of OSA at-risk children.
O072 Episodes of drowsiness present during cognitively demanding tasks
Authors: Gnani Srinivasan A , Mann D , Smith S , Gadam S , Shekari Soleimanloo S
Published: November 2022

Introduction

Insufficient sleep is associated with impaired performance in cognitive tasks and executive functioning. Adolescence is a time of increasing autonomy and lifestyle changes, where social, educational, and work demands often impact on sleep opportunity. The impact of habitual short sleep opportunity on cognitive functioning is poorly understood. We examined the difference in EEG-based alertness during low and high load cognitive tasks in sleep restricted young adults.

Methods

Ninety-nine habitually sleep restricted young adults (M=20.65, SD=1.91, 73% female) participated in the study. EEG-based (F4-M1, O2-M1) alertness was examined under two conditions: (1) low load; a simulated slow drive and (2) high load; a weekly activity mapping task. A novel model predicted alertness as a continuous function of EEG power in beta, alpha, theta, and delta frequency bands. Model output 1 indicates alertness (i.e., wake), while values approaching zero indicate reductions in alertness. Statistical significance was assessed by two-tailed t-test (unequal variance), and effect size reported by Cohen’s D.

Results

Mean model output values were significantly (p<0.0001) lower during the driving task (0.16, 95%CI=0.12-0.19) compared to the mapping task (0.92, 0.87-0.97), with substantial effect size (D=3.9).

Conclusions

This study demonstrates that sleep restricted young adults are less alert during tasks with low cognitive demands, even though the task we tested (simulated drive) represents high real-world risk. In contrast, these individuals show elevated levels of alertness during cognitively demanding tasks despite absence of real-world risk. Further study investigating potential mitigating effects through sleep modulation may reveal simple health recommendations
P016 Evaluating the effectiveness of an interactive educational intervention on sleep health for second-year pharmacy students
Authors: Basheti M , Bussing J , Grunstein R , Gordon C , Saini B
Published: November 2022

Background

Pharmacists are usually the most frequently consulted professionals in primary care for health concerns, such as sleep disturbances. However, conventionally, curricular space devoted to sleep health has been insufficient and this eventuates in suboptimal care provision. For example, pharmacists often provide over the counter/complementary medicines rather than the recommended behavioural counselling for insomnia management. Clearly, pedagogically informed learning experiences about sleep health/insomnia management are important to improve practice.

Objectives

To develop, implement and evaluate an interactive sleep health educational intervention for 2nd year pharmacy students.

Methods

An educational intervention utilising a flipped classroom approach, with interactive lectures, self-reflection around personal sleep habits, and role-playing behavioural treatment provision was designed and implemented. A questionnaire assessing pre- and post-intervention changes in knowledge about and attitudes towards sleep as well as post-intervention learning satisfaction, was administered to students.

Results

Mean total knowledge scores for participating students (n=125, 70.4% females) improved significantly post-intervention from a baseline of 11.1 ± 3.8 to 17.1 ± 3.5 post-intervention, p <0.05 (Score range= 0-25). The mean total attitudes scores also improved from 28.8 ± 3.2 at baseline to 29.4 ± 3.8 (Score range= 10-50), p=0.07; however, this change was insignificant.

Conclusion

Carefully crafted educational interventions for pharmacy students can help improve sleep health knowledge. Whilst a trend to improved sleep health attitudes was evident, it was not significant, possibly because of positive sleep health attitudes even at baseline. Such programs should be incorporated into pharmacy pre-registration curricula to potentially enhance future pharmacists’ skills in sleep health provision.
P025 Using questionnaires to predict OSA in patients presenting to sleep clinics
Authors: Brink A , Munns S , Nolan G , Pyne N
Published: November 2022

Purpose

In sleep clinics, the Epworth Sleepiness Scale (ESS) and STOP-Bang (SB) questionnaire are widely used to determine the probability that a patient has obstructive sleep apnoea (OSA), though neither were designed as a triaging tool specifically for patients with suspected OSA. Previously we found that ESS had poor correlation with OSA presence and severity as determined by the apnoea-hypopnoea index (AHI) >15. In this paired clinical chart audit, we determined if the SB has improved predictive ability and thus better suitability for triaging sleep clinic patients suspected of OSA compared to ESS.

Method

101 sleep clinic patients (56 male, 45 female) completed both ESS and SB questionnaires and underwent overnight polysomnography (OPSG) to determine AHI. Correlation of ESS and SB to AHI was determined using Spearman’s rho, and predictive ability of each questionnaire was determined using ROC curves and logistic regression.

Results

ESS was not significantly correlated to AHI in men (p=0.208) or women (p=0.533) and had poor sensitivity (60.2%) and specificity (47.8%). In contrast, SB was correlated to AHI in both men (p=<.001) and women (p=0.045), and had improved sensitivity (94.1%). An ESS>8 was not predictive of clinically significant OSA (AHI>15, p=0.244), whereas SB>3 was associated with 4.4 times higher odds of clinically significant OSA (p=.007).

Discussion

In our cohort, SB is more suitable than ESS for triaging patients presenting to sleep clinics due to its higher predictive ability for OSA. This finding has important implications for OPSG rebates and patient access to publicly funded treatment schemes.
P030 A systematic review of the influence of nature play and exposure on sleep measures in children aged 3-13 years old
Authors: Coussens S , McLoughney T
Published: November 2022

Introduction

There are significant benefits to exposing children to nature, including reduced risk of mental illness, enhanced attentional capacity, and greater circadian synchronisation. Furthermore, recent findings indicate exposure to greenspace is positively associated with improved sleep quality and quantity in adults. However, there is conflicting evidence regarding the impact of nature exposure and outdoor play on sleep measures for children. This systematic review aims to investigate whether nature experience through play or education has a significant effect on sleep measures in children.

Methods

Articles were searched for using 7 databases and Google Advanced Search for grey literature searching. The review is in accordance with PRISMA guidelines and is registered with PROSPERO. Articles were screened using Covidence. The target population included children aged 3 to 13 years old. The main outcome was sleep measures (i.e., sleep latency, duration, and/or quality), and the intervention was (including, but not limited to) outdoor play, nature exposure, or/and nature education.

Results

The article search returned 2538 articles; 9 of those articles contained adequate results for direct inclusion and analysis. The majority of the 9 articles demonstrated no association between increased outdoor play or nature exposure and sleep outcomes. However, the results are not yet finalised with further data to potentially be included.

Discussion

Preliminary observations posit there is insufficient literature to determine the influence of nature play and education on children’s sleep outcomes. It may be suggested that future research focuses more directly on the relationship between nature and children’s sleep.
P033 Associations between sleep and emotional self-regulation in toddlers
Authors: D'Cruz A , Downing K , Sciberras E , Hesketh K
Published: November 2022

Introduction

Emotional self-regulation (ESR) skills are vital for mental and physical health. There is growing evidence linking sleep to ESR in school-aged children, but associations in toddlers remain unclear. The current study examined associations between toddlers’ sleep duration and behaviors and ESR.

Materials and methods

This study utilized baseline data from 1358 toddlers (Mage=26±3.9mo) from the Let’s Grow trial. Total sleep duration was calculated by summing parent-reported average nighttime sleep and daytime nap duration. Sleep behaviors (bedtime routine, bedtime resistance, sleep latency, and night waking) were assessed using the Children’s Sleep Habits Questionnaire and Brief Infant Questionnaire. Toddlers’ ESR skills were assessed via a 4-item parent-report scale adopted from the Fast Track Project Child Behaviour Questionnaire, with a lower score indicating better ESR. Linear regression models assessed associations of sleep duration and behaviors with ESR.

Results

Toddlers’ average daily total sleep, nighttime sleep, and nap duration were 12.1h, 10.6h, and 1.5h, respectively. Girls and boys had similar nighttime sleep, total sleep, and ESR scores. However, girls had longer naps than boys (1.6h vs 1.4h, t=-3.5, p=0.0004). Total sleep, nighttime sleep, and nap duration were inversely associated with ESR (all p<0.01), indicating that higher sleep duration was associated with better ESR. Sleep behaviors were positively associated with ESR (all p<0.01), with more problem sleep behaviors associated with poorer ESR.

Conclusion

Initial results suggest that improving sleep duration and behaviors are associated with better ESR in toddlers. Supporting parents to improve their toddlers’ sleep may help foster better ESR skills.
P034 Measurement Type Moderates the Relationship between Sleep and Aggression: A Meta-Analytic Investigation
Authors: Demichelis O , McKay K , Grainger S , Henry J
Published: November 2022

Introduction

A recent meta-analysis showed that poor sleep is both associated with and can directly cause increased aggression. However, no assessment was made of whether objective indicators of sleep and subjective perceptions of sleep contributed equally or differentially to these effects.

Methods

To test this question, the present meta-analysis directly tests the role of measurement (objective vs subjective) in understanding the relationship between sleep and aggression.

Results

By integrating 94 effect sizes using multi-level meta-analysis, the results revealed that aggression is significantly associated with both subjective and objective sleep estimates. Importantly, measurement type emerged as a significant moderator of this relationship, with subjective sleep more strongly associated with aggression than objective sleep.

Conclusion

This finding is discussed in relation to the broader implications for how behavioral, or sleep, interventions and research are conducted.
P042 Actigraphy-derived sleep characteristics of healthy children who benefit the most from a sleep extension protocol
Authors: Galland B , Haszard J , Morrison S , Jackson R , Meredith-Jones K , Elder D , Beebe D , Taylor R
Published: November 2022

Introduction

Although experimental manipulation of sleep can extend children’s sleep via earlier bedtimes, this is not always possible. We aimed to determine true sleep gains made with a one hour earlier bedtime, and which actigraphy variables at baseline predicted the best gains.

Methods

Secondary analysis within a randomised crossover trial (99 children; 49.5% female; mean age=10.3 years, range 8-12 years). Each child underwent one week of sleep restriction and extension in a random order (1h later or earlier bedtime respectively) separated by a one-week washout. Sleep data comparing baseline and extension weeks were analysed using linear or logistic regression, controlling for randomised order.

Results

The mean (SD) difference in total sleep time (TST) with sleep extension was 14.3 (44.1) min/night. Thirty-three percent extended their sleep by at least 30 min/night. At baseline, having lower sleep quantity (TST) and quality (efficiency, WASO, waking frequency) significantly predicted more sleep gain. For each 1 h lower TST at baseline, 29.7 min (95%

CI

19.4, 40.1) more sleep was gained. At baseline, a TST below 8 h 49 min was the optimal cut-point to predict whether children could extend their sleep by at least 30 min/night (found in 40% of children). Adjusting for relevant demographics and sleep hygiene made little difference.

Conclusion

Children who slept less than 8 h 49 min/night obtained the most sleep gain from a 1 hour earlier bedtime maintained over a week. Maintenance over the longer term is unknown. Findings have implications for understanding the sleep requirements of children.
P048 Polysomnographic titration of non-invasive ventilation in motor neurone disease (3TLA): Protocol for a process evaluation of a clinical trial
Authors: Graco M , Berlowitz D , Sawyer A , Carey K , Holland A , Lannin N
Published: November 2022

Introduction

We are undertaking a multicentre randomised controlled trial to determine the effectiveness of including a sleep study (polysomnography, PSG) to assist the commencement of non-invasive ventilation (NIV) in people with motor neurone disease (MND); the PSG4NIVinMND trial. A process evaluation will be conducted alongside the clinical trial. The aim of the process evaluation is to understand: 1) the implementation of the PSG4NIVinMND intervention in the seven trial sites, including the barriers and enablers; and 2) the causal mechanisms through which the PSG4NIVinMND intervention produces change.

Methods

The process evaluation has a mixed-methods design, comprising qualitative and quantitative components, and is guided by two theoretical frameworks: RE-AIM (Reach, Effectiveness, Adoption, Implementation and Maintenance) and the Theoretical Domains Framework (TDF). Qualitative data include semi-structured interviews with clinical trial participants (people with MND) and their carers, and focus groups and surveys with health professionals involved in delivering the intervention. Quantitative process data will also be collected from the clinical trial. Data will be analysed iteratively throughout the trial.

Results

Six of the seven sites have commenced recruitment to the PSG4NIVinMND trial. Baseline focus groups and surveys have been completed with health professionals from these sites. Data collection and analysis will continue until the PSG4NIVinMND trial has concluded.

Conclusion

This process evaluation will provide valuable insights into how the PSG4NIVinMND intervention was implemented in the trial sites, for whom and how the PSG4NIVinMND intervention was (and was not) effective, and how it could be implemented into routine clinical practice.
P057 Prevalence of poor sleep in First Nations peoples across the globe: A systematic review
Authors: Jabran D , Potia A , Smith S , Solomon S , Fernandez D , Fatima Y
Published: November 2022

This review aims to collate and assess the extant literature on the prevalence of sleep issues among First Nations peoples across the globe.

A systematic literature search, was conducted across key academic databases and grey literature sources to retrieve studies published until November 2021. Studies offering quantitative data on sleep issues in First Nations Peoples were included. The NIH Quality Assessment Tool was used to assess the methodological quality and an adapted version of the Indigenous Quality Appraisal tool was used to evaluate First Nations' engagement in research. Results: A total of 65 studies,(28 longitudinal, 37 cross-sectional) met the inclusion criteria for this review. The included evidence indicated that the First Nations Australians reported night-time awakenings (22%), severe daytime sleepiness (27%), short sleep duration (35%) and long sleep duration (41%). The Māori population from New Zealand consistently reported insufficient sleep (36%) and short sleep duration (28.6%). The First Nations Americans / Alaska Native populations reported insomnia (25% to 33%) and insufficient sleep (15% to 40%). The Cree First Nations from Canada had a higher prevalence of insomnia (38.5%) and sleep deprivation (25% to 40%). Most studies scored "quality" in quality assessment. However, First Nations' engagement in research could not be adequately assessed due to limited information.

The review findings highlight that a significant proportion of First Nations peoples are experiencing poor sleep. Considering the established link between poor sleep and adverse health outcomes, sleep health equity in First Nations communities should be a high priority for service providers and policymakers.
P059 Respiratory control stability in posttraumatic stress disorder
Authors: Jordan A , Tjondrorahardja E , Poon T , Felmingham K
Published: November 2022

Rationale

A recent meta-analysis indicated that 75.7% of individuals with posttraumatic stress disorder (PTSD) also suffer from obstructive sleep apnoea (OSA). The reason for the high prevalence of OSA in PTSD is currently unknown. This study investigated whether respiratory control stability (which is known to contribute to OSA in the general population) varies with PTSD symptoms.

Methods

First year University students were recruited and completed an online questionnaire battery including: Life Events Checklist (LEC), PTSD checklist for DSM-5 (PCL-5), Shortness of Breath Questionnaire (SOBQ) and Berlin Sleep Questionnaire. 1/3 of participants timed their maximum breath hold (performed at functional residual capacity) at home on 3 occasions using a stopwatch as per Messieno et al (2018).

Results

313 complete survey responses were obtained. The mean age of participants was 19.9 years and 214 respondents were women. 19 participants were at high risk of OSA based (Berlin Questionnaire) and 80 had probable PTSD (LEC items 1-16 “happened to me” or “witnessed it” plus PCL-5>33). In the whole sample, there was a significant relationship between PTSD symptoms and Shortness of Breath (Pearson p<0.001, r2=0.2). There was no relationship between PTSD symptoms and at-home measured maximum breath-hold duration (n=107, p=0.44, r2=0.006).

Conclusions

In an unselected University student population, posttraumatic stress disorder symptoms are associated with self-reported shortness of breath during everyday activities. However, there was no evidence of a relationship between a surrogate of respiratory control stability (maximum breath-hold duration) and PTSD symptoms.
P062 Agreement between arterial and capillary CO2 level in patients undergoing sleep study for suspected hypoventilation
Authors: Kafili D , Bashford J , Erigadoo S
Published: November 2022

Background

Measurement of arterial CO2 (PaCO2) is the gold standard for diagnosis of sleep hypoventilation during polysomnography. However, arterial PaCO2 measurement is a labour-intensive and painful. Previous audit in our unit demonstrated ABGs are often delayed or omitted when requested. Continuous monitoring of transcutaneous carbon dioxide (TcCO2) is often used as a surrogate marker of PaCO2, however caution should be applied in interpreting TcCO2 due to the “sensor drift” phenomenon. Arterialized capillary blood gas (CBG) measurement has been described in various settings and is used in many respiratory units. Concordance with ABG and TcCO2, however, is poorly described in the literature. A retrospective review was performed to assess concordance of arterialized capillary CO2 level (PcCO2) with TcCO2 measured during routine polysomnography.

Methods

This is a retrospective audit of patients with provisional diagnosis of sleep-related hypoventilation syndrome who attended Sunshine Coast University Hospital Sleep Disorders Centre for overnight sleep studies. Continuous TcCO2 was monitored and arterialized PcCO2 measured at the outset and completion of study. CO2 results will be compared to assess concordance. Where an ABG was performed simultaneously with a CBG the concordance will be reported.

Progress to Date

Full results to follow. It is anticipated that 30-40 patients will be included. Few ABGs were performed.

Anticipated outcome

Initial evaluation suggests PcCO2 may be a viable alternative to ABG based on concordance with limited ABG data. PcCO2 may be superior to TcCO2 due to the common phenomenon of TcCO2 “drift”. A prospective study, utilising ABG, CBG and TcCO2 is needed.
P069 Sleep Restriction Impairs Integration of Multiple Information Sources in Probabilistic Decision-Making
Authors: Lim J , Boardman J , Anderson C , Dickinson D , Drummond S
Published: November 2022

Introduction

Sleep loss affects overall decision-making, but its effects on specific mechanisms of decision-making are less well-understood. Here, we examined the effects of sleep restriction (SR) on the ability to integrate multiple information sources on a probabilistic decision-making task.

Methods

We recruited 41 healthy participants (n=41; age=27.9±6.0years, 20F), 27 of whom underwent well-rested (

WR

4 nights of 9-hours time-in-bed) and SR (3 nights of 3-hours time-in-bed) conditions in counterbalanced order. On the last day of each lab stay, participants completed a probabilistic decision-making task twice – 2-hours after wake (AM) and 12-hours since habitual wake (PM). On each trial, participants were shown two boxes with different proportions of black/white balls. Eight balls were drawn randomly, with replacement, from an unknown box. Participants determined the selected box using easier-to-understand numerical odds and harder-to-understand draw outcome information. Mathematical modelling was used to infer weights placed on each source of information.

Results

For AM and PM sessions, participants placed significantly greater weights on odds relative to draw information during WR (p<.001 for both). For AM trials, SR significantly reduced weights given to draw information (p=.041), and reduced weights given to odds at marginally significant levels (p=.062). For PM trials, SR reduced weights given to draw information at marginally significant levels (p=.059).

Conclusion

While well-rested individuals generally rely more on easier-to-understand information, SR impairs decision-making by further reducing individuals’ ability to consider more complex information. This has implications for high-risk professions where SR is common (e.g. doctors) and impaired decision-making may pose serious consequences.
P070 Does exercise reduce fat free mass loss during very low energy diet-induced rapid weight loss? A systematic review and meta-analysis
Authors: Lowrie F , Phillips C , Hogan C , Tran D , Marshall N , Gordon C , Yee B , Cayanan E
Published: November 2022

A bi-directional relationship exists between obstructive sleep apnoea and obesity. Very low energy diets (VLEDs) have been show to significantly reduce weight in overweight and obese patients. However, they can cause excessive fat free mass (FFM) loss, which adversely impacts health. Concurrent exercise training is a potential method of mitigating FFM loss. This systematic review and meta-analysis aims to assess the impact of exercise on FFM loss during VLED-induced weight loss in the overweight and obese.

Medline, Embase, Cochrane Register of Controlled Trials and CINAHL were searched from inception to December 2021 for studies that compared VLED groups with and without concurrent exercise in overweight and obese adults. Studies were included if they reported changes in FFM, VLED was restricted to less than 800kcal/day and exercise programmes were at least low intensity.

Following duplicate removal, 6516 studies were screened and 63 full text articles were reviewed, of which 7 were included. The primary outcome is change in FFM between groups and a meta-analysis is planned if deemed appropriate. Results will be available in September.

This review will provide evidence regarding the impact of exercise on FFM loss when undertaken concurrently with a VLED. Furthermore, it will help inform practice guidelines around exercise prescription for preserving FFM while undertaking a VLED to ensure better patient health outcomes. It will also help inform translational studies for weight reduction in overweight and obese sleep apnoeics.
P074 Three models of pulse oximeters are within specifications when assessed using a benchtop pulse oximeter simulator
Authors: McDermott E , Cuesta R , Nguy R , VanBraak E , Naughton M , Roebuck T
Published: November 2022

To assess possible SpO2 accuracy differences between 3 different (oximeter & software) testing techniques. Hypothesised that differences in SpO2 would be within the oximeter manufacturer’s specification.

A synthetic digit, OX-1 OxSim® Optical SpO2 Pulse Oximeter Simulator (Pronk Technologies Inc., Sun Valley, CA) can provide simulated SpO2 & HR values : 85% (80BPM), 98% (80BPM), 98% (140BPM), 99% (80BPM) at low perfusion and 95% (40BPM) low HR. Simulated SpO2 delivered for 5 minutes, average calculated from signal recorded with corresponding download software: Rad-5 (Masimo, Irvine, CA, USA, 2sec averaging time) - Visi download (Stowood Scientific, Oxford, UK), the Rad-7 (Masimo, Irvine, CA, USA, 2-4sec averaging time) - PSG 4 (Compumedics, Melbourne, Australia), Wrist-Ox2® (Nonin Medical Inc, Plymouth, MN, USA, 3sec averaging time) - Noxturnal software (Nox Medical Inc, Reykjavik, Iceland). Four devices for each model Rad-5, Rad-7 and Nox Wrist-Ox2® were examined at 5 SpO2 & HR settings. The SpO2 downloaded from each device was compared with the OxSim® values. Oximeter reading v OxSim® : at 85%, Rad-5 (y = -0.146x + 14.375, R² = 0.9627 bias 0.606), Rad-7 (y = -0.0897x + 8.737, R² = 0.5295 bias 0.295), Wrist-Ox2® (y = -0.0161x + 1.2261, R² = 0.0481 bias -0.281). At all other comparison values, including low perfusion and low HR, all values fell within +/- 2% SpO2.

Small differences in the measured SpO2 for the 3 oximeter models & paired software were noted, however all devices gave SpO2 values within 2% of simulated SpO2 values as per manufacturer specifications.
P081 Assessing the role of mental health on the prevalence of sleep complaints amongst current and retired athletes
Authors: Montero A , Adams R , Baranoff J , Drummond M
Published: November 2022

Introduction

Validated sleep and mental health assessments are grossly underutilised in athletic populations. Previous studies have predominantly focused on elite competitors. To form a more representative view of sleep and mental health in athletes, we conducted a large-scale survey that is more inclusive of different competition levels and playing statuses.

Methods

Current and retired athletes (N=1007) participated in an online survey. Utilising validated tools, we screened for sleep difficulty and disordered breathing (ASSQ), depression (CESD-R), anxiety (GAD-7), and poor quality of life (PWI-A). Participants were categorised as currently competing, retired, or unable to play, from an amateur, sports institute/university, semi-professional, or professional level.

Results

Retired athletes (41.7%) were more likely to report sleep apnoea symptoms than competing athletes (24.5%) and those unable to play (27.1%) (p<.001). No differences in sleep difficulty were observed across playing status (p=.212). Competition level did not affect sleep difficulty (p=.595) or sleep apnoea symptomology (p=.274). Sleep apnoea symptomology was predicted by age (p<.001), BMI (p<.001), and quality of life (p=.002), but not anxiety (p=.544) or depression (p=.102). Sleep difficulty was predicted by the same factors, in addition to depression (p<.001).

Discussion

Findings suggest that sleep problems affect all athletic populations, with most respondents (72.4%) reporting mild to severe sleep difficulty. While competition level may not affect athletes’ sleep health, we identified athletic retirement, age, BMI, depression, and poor quality of life as risk factors for disordered sleep. Therefore, protective strategies for mental health are needed for athletes from all competition levels and playing statuses.
P086 The insomnia severity index is related to the respiratory arousal threshold in people with Co-Morbid Insomnia and Sleep Apnoea (COMISA)
Authors: Zheng J , Tong B , Sweetman A , Eckert D , Osman A
Published: November 2022

Introduction

People with co-morbid insomnia and sleep apnoea (COMISA) have worse symptoms and require a tailored therapy approach for their sleep disorders. The relationship between the respiratory arousal threshold, a key OSA non-anatomical contributor and insomnia symptoms is unclear. This study investigated the relationship between insomnia symptoms using the insomnia severity index (ISI) and the respiratory arousal threshold in people with OSA.

Methods

46 people with OSA (11 female, age=50±15years, BMI=29±6kgm-2, AHI=33±20events/h) participated in a physiology sleep study to predict response to oral appliance therapy and completed the ISI. Standard polysomnography, an epiglottic airway pressure sensor, bipolar intramuscular electrodes inserted into the genioglossus and a nasal mask with a pneumotachograph to quantify airflow were used. The respiratory arousal threshold was measured as the nadir epiglottic pressure during a respiratory event prior to a cortical arousal. Following this, participants trialled mandibular advancement therapy.

Results

There was no relationship between ISI (average=12±6) and the arousal threshold (-24±10cmH₂O) in participants with OSA (r=0.1, p=0.42, n=46). However, in the 59% of people with COMISA (ISI ≥11), there was a positive relationship between ISI and arousal threshold, with increasing insomnia severity associated with lower arousal threshold (r=0.5, p=0.017, n=27). People with a BMI<30kgm-2 (n=27), also had a positive linear relationship between ISI and improvement in oral appliance therapy (r=0.49, p<0.01, n=27).

Conclusion

Greater insomnia symptoms in people with COMISA is associated with a lower respiratory arousal threshold. In non-obese people with OSA, higher ISI values are related to poor response to oral appliance therapy.
P095 Clinical and polysomnographic characteristics of Indigenous and non-Indigenous children undergoing adenotonsillectomy with clinically suspected sleep disorders at the Top End Northern Territory of Australia
Authors: Reyes-Chicuellar N , Howarth T , Crossland G , Patel H , Heraganahally S
Published: November 2022

Sleep apnoea and poor sleep quality are growing public health issues which may begin in childhood and progress to significant lifelong morbidity. Literature regarding the prevalence of surgery for obstructive sleep apnoea (OSA) among Indigenous Australian children however is sparse.

Children and polysomnographic (PSG) characteristics among children undergoing adenotonsillectomy (AT) for clinically suspected sleep-disordered breathing were assessed in this retrospective study. Paediatric patients Indigenous and non-Indigenous children referred for a diagnostic (PSG) via ENT service at the Top End Northern Territory of Australia for a sleep study between 2016 and 2020 were included.

Of the 375 patients referred through an ENT service for a diagnostic PSG, 115 were identified to have undergone an AT and were included.

The majority of patients were male (58%) and non-Indigenous (88%), in the normal weight category (64%) with a median age of 4.1 years. The median reported PDSS was 12, and snoring was reported in 77% of patients, with witnessed apnoeas in 31% and excessive daytime sleepiness in 23%. Most patients were identified to have OSA on PSG (65%, median AHI 1.6, 64% mild, 12% moderate, 23% severe). Median sleep efficiency was 85%, with a total sleep time of 520 minutes and WASO of 74 minutes. Total average SpO2 was a median of 93.5% and SpO2 Nadir 85%.

We discuss how our findings can translate to future service planning and delivery whilst respecting cultural safety and indigenous group engagement.
P120 Incidence, persistence and remission of co-morbid insomnia and sleep apnea (COMISA) over time in the Wisconsin Sleep Cohort data
Authors: Sweetman A , Lechat B
Published: November 2022

Introduction

Co-morbid insomnia and sleep apnea (COMISA) is a highly prevalent and debilitating condition that is more difficult to treat compared to either disorder alone. Previous studies have investigated the cross-sectional prevalence of COMISA, however no study has investigated rates of natural incidence, persistence, or remission of COMISA over time.

Methods

We used data from 566 people in the Wisconsin Sleep Cohort (Age M = 55.6 [sd = 7.5], 46.3% female). Symptoms of insomnia (difficulties initiating, maintaining sleep and/or early morning awakenings at least 5 times/month), and sleep apnea (AHI ≥ 5) were investigated at baseline, 4-years, and 8-years. COMISA was defined if both conditions were present.

Results

The prevalence of COMISA at baseline, year-4, and year-8 was 25.1%, 29.9%, and 25.8%, respectively. Among those with COMISA at baseline, 60.6% had persistent COMISA at year-4, and among people with COMISA at year-4, 46.8% had persistent COMISA at year-8. Very few people with COMISA experienced remission of both insomnia and sleep apnea at year-4 (5.6%) or year-8 (7.7%). There were 83 cases of incident COMISA at year-4 (19.6% of people without COMISA at baseline), and 67 cases of incident COMISA at year-8 (16.9% of people without COMISA at year-4).

Discussion

COMISA symptom prevalence was ≥25% at any given follow-up in this population-based sample. Approximately half of those with COMISA experienced persistent COMISA across any two follow-up occasions. Very few people with COMISA experience complete remission of both conditions. It is important to develop targeted treatments for this prevalent and persistent condition.
P125 The effect of glucocorticoids on rate of lung function decline in Duchenne Muscular Dystrophy patients receiving Non-Invasive Ventilation
Authors: Treanor D , Howard M , Griffiths A , Davidson Z
Published: November 2022

Background

Duchenne Muscular Dystrophy (DMD) causes progressive muscle weakness as a result of a mutation in the X-linked gene dystrophin. Recently glucocorticoid treatment has delayed deterioration in muscle strength prolonging survival. When respiratory failure develops, Non-invasive ventilation (NIV) is used to improve symptoms and prolong life. Recent research suggests the use of glucocorticoids with concomitant NIV may be associated with accelerated lung function decline.

Methods

To evaluate this we conducted a retrospective analysis of serial lung function data in patients with DMD across two healthcare campuses in Melbourne, Australia.

A database of all patients with a coded diagnosis of DMD was collated from 1980-2010. Patient records were examined to collect data on age, lung function (FEV1/FVC/FER), glucocorticoid use (y/n), daily glucocorticoid dose, date of NIV initiation, FVC at NIV commencement, date of death (where applicable) and concomitant diagnosis of scoliosis or cardiomyopathy. This data was analysed to see if a trend for accelerated lung function decline with the use of NIV was observed.

Progress to date

A total of 356 patients were identified of which 36 had transitioned to the Austin Hospital adult Ventilation Service with available serial lung function data. There was no statistical difference in mean rate of decline in lung function post NIV initation (n=26, p=0.527) with glucocorticoid treatment.

Intended outcome and impact

Our inital results are in line with the previously observed rates of decline in lung function from other studies and do not indicate a negative synergistic effect on NIV with glucorticoid therapy.