bluuebunny/crossref_metadata_2025 huggingface dataset:
O070 Objective impact of daylight-savings time shifts on sleep: a global-scale study
Authors: Pinilla L , Nguyen P , Lechat B , Scott H , Manners J , Sansom K , Dunbar C , Fitton J , Vakulin A , Catcheside P , Eckert D
Published: December 2024

Introduction

The twice-yearly transitions between standard time and daylight-savings time (DST) introduce mild circadian misalignments, which are associated with disrupted sleep, and increased risks for adverse public health and safety consequences. Previous evidence is based on self-reported data, limited geographical locations, and relatively small sample sizes. Here, we quantify the acute impact of seasonal clock time changes on objective measures of sleep in a large global sample.

Methods

Data were collected from users of a validated under-the-mattress sleep sensor between March 2018 and September 2023, located across 27 countries covering 36 different clock-timed regions (>500 users/region) where DST changes occur. Total sleep time and sleep offset timing on the dates of clock adjustment were compared to the Sunday immediately preceding each time shift, using linear mixed models with a random intercept for time zone.

Results

Data from >60,000 individuals were analysed (82% males, age 49±13 years). Setting the clock forward was associated with a reduction in sleep duration of 13.7 minutes (95%CI 9.1 to 16.1), and a sleep offset timing delay of 33.1 minutes (28.9 to 37.4). The end of DST (clock backwards) was related to longer sleep durations, increasing by 9.84 minutes (6.9 to 12.78), and earlier sleep offset times by 33.6 minutes (29.1 to 38.1).

Conclusions

This large-scale global study shows that clock time adjustments derived from daylight saving regulations have immediate repercussions on objective sleep duration and timing. These findings may help inform the ongoing policy debate of the impact of DST on sleep and associated consequences.
O071 Chronic non-cancer pain in patients attending a diagnostic sleep study
Authors: Jarvie L , O’Driscoll D , Young A , Obadara O , Ogeil R
Published: December 2024

Introduction

Chronic non-cancer pain (CNCP) is the leading cause of disability globally affecting 20% of adults in Australia. It is associated with poor sleep and increased substance use including prescription medications. This study aimed to determine its prevalence in patients attending a tertiary referral sleep laboratory and assess impact on sleep and the nature of substance use.

Methods

Participants (n=245, 112 females, 50.0 ± 15.3 years) completed in-lab overnight diagnostic polysomnography and validated pain and sleep questionnaires (including Brief Pain Inventory [BPI]). Pain questionnaires (BPI [Yes/No] and Pain Sleep Questionnaire [75+]) were used to indicate probable CNCP. Fifteen participants with CNCP completed an interview exploring pain and sleep.

Results

59.6% indicated CNCP. Those with CNCP were more likely to be older (CNCP 51.6, Controls 47.6, p<0.05), female (p<0.001), had higher BMI (p=0.008) and to rate sleep as fairly or very bad (p<0.05).

Participants with BPI interference 5+ (clinically significant) had a higher AHI (p=.028), increased REM latency (p<0.001) and %REM sleep (p<.001).

Interviewees indicated poor sleep to be a consequence of pain. Nine described misusing medication including taking more than prescribed (2), medication prescribed to someone else (5), pain medication for sleep (3), and six misusing alcohol (6).

Discussion

CNCP prevalence in patients attending for a diagnostic sleep study is triple that of the general population.

There is concern regarding misuse of prescription medication and alcohol in people with sleep disturbance and CNCP. Consideration should be given to an interdisciplinary approach to pain and sleep management.
O072 Sex-based differences in pain perception with short sleep: an experimental study in healthy individuals
Authors: Rouhi S , Brumley N , Jordan A
Published: December 2024

Introduction

Experimental sleep deprivation has been shown to induce pain hypersensitivity, with more pronounced impacts on females than males. However, whether the effect of chronic short sleep on pain perception differs between sexes is unclear. This study investigated the effects of chronic self-reported short sleep (<6 hrs) on pain perception in males and females.

Methods

Objective sleep data were collected using a Somfit device. Quantitative sensory testing, including heat, cold, and pressure pain thresholds, temporal summation and conditioned pain modulation of pain, was conducted in the morning following sleep monitoring to measure pain perception.

Results

The study included 25 healthy participants (15 females) with an average age of 23.16±4.8. Both sexes exhibited similar (short) total sleep times (TST: Males: 232.4 ± 14.9 minutes vs. Females: 244.7 ± 11.7 minutes; p = 0.52). However, females experienced significantly longer REM latency, as compared to males (Males: 62.5 ± 14 minutes vs. Females: 101.1 ± 11.5 minutes; p=.04). All other sleep stages were comparable between sexes (p > 0.05). A General Linear Model revealed significant sex-based differences in pain perception between males and females (F = 5.1; B = 0.66; power = 0.97; p = 0.002), primarily driven by conditioned pain modulation (mean difference = 98.77 ± 33.9; 95% CI: 28.6 to 168.89; p = 0.008).

Discussion

These preliminary results suggest that short sleeping females have a dysfunctional pain suppressive response, while sleep-deprived males exhibited stronger pain inhibitory response, despite similar (low) sleep amounts.
O073 The effect of blue-enriched light in older adults with sleep disturbance on sleep and daytime performance: A randomised, placebo-controlled crossover trial
Authors: Pun T , Phillips C , Marshall N , Rahimi M , Wassing R , Comas M , D’Rozario A , Hoyos C , Bartlett D , Hu W , Naismith S , Cain S , Postnova S , Grunstein R , Gordon C
Published: December 2024

Introduction

Light therapy is a non-pharmacological intervention for circadian and sleep disorders. However, there is limited evidence about the effect on electroencephalographic (EEG) sleep in older individuals with sleep disturbance.

Methods

Twelve participants (8 female; mean ± SD age, 65.6 ± 8.7 years) with self-reported poor sleep completed two randomly allocated 72-hour in-laboratory visits separated by 2 weeks. The intervention light condition consisted of blue-enriched light (melanopic EDI=843.6 lux) during the day and blue-depleted light (melanopic EDI=49.5 lux) 3-hours before lights out. The control light condition consisted of polychromatic light (melanopic EDI=215.8 lux) during the day and reduced light (melanopic EDI=60.8 lux) 3-hours before lights out. The primary outcome was wake after sleep onset (WASO), with secondary outcomes of sleep micro-architecture parameters (256-channel high-density EEG) and neurobehavioural performance.

Results

The intervention light did not improve WASO compared to the control (p=0.338) but there was a significant increase in N1 sleep (p=0.046). The only neurobehavioural difference was in Stroop text accuracy (2.2%, p=0.028). High-density EEG analysis showed the intervention light significantly increased sigma activity (12–16 Hz) in the frontal and parietal cortex during N2 sleep relative to control light (p=0.017).

Conclusions

Overall, blue-enriched light over three days did not improve EEG sleep (WASO) or neurobehavioural performances except for accuracy (Stroop) in older adults with sleep disturbance. Further research is required to determine the ideal intensity, spectral composition, duration and timing of blue-enriched lighting on objective sleep outcomes in individuals with poor sleep quality.
O074 “We just have to be there; we just have to listen”: Experiences of staff supporting older adults with sleep disturbances in aged residential care
Authors: Gibson R , Dustin J , Koreshi S , Webster L
Published: December 2024

Introduction

Deterioration of sleep is acknowledged as a key factor associated with older adults, particularly those with dementia, (transitioning into formal care. However, further research is required concerning sleep status within such facilities.

Methods

Semi-structured interviews were conducted with 11 Care Partners from two New Zealand care homes. Interviews covered types of sleep disturbances encountered; the impact of sleep disturbances for residents, co-residents, staff and wider networks; and strategies for supporting sleep. Recordings were transcribed, coded, and analysed thematically.

Results

Many sleep ‘disturbances’ were not considered abnormal in the context of aged care. These included confusion between night and day, fatigue associated with illness, continence needs, and/or confusions or hallucinations at night. Sleeplessness was largely discussed in relation to residents feeling lonely, confused, or depressed as well as fears around falling asleep. The challenge of moving into a new living and sleeping environment was also raised as key, along with the ‘domino affect’ that sleep disturbances can have for other residents. Strategies to support sleep (and wakefulness) were presented in relation to key frameworks around person-centred care. This included acknowledging residents’ sleep and routine preferences whilst balancing opportunities for social connection, maintaining regular fluid and nutritional needs, and reducing the risk of falls. Overarching was the sense of being patient and present for the residents ‘around the clock’.

Discussion

Findings provide psychosocial insights into the nature of sleep in the context of aged care. Highlighting staff’s beliefs and attitudes around problematic sleep, current strategies, and future needs.
O076 The use of home humidified high-flow nasal cannula therapy for children with sleep-disordered breathing
Authors: Krishnananthan T , Saddi V , Teng A
Published: December 2024

Background

Humidified High-flow nasal cannula (HHFNC) therapy is a method of respiratory support that facilitates delivery of humidified heated air or oxygen at a high flow rate. The physiological benefits of HHFNC include generation of a low level of positive airway pressure leading to alveolar recruitment and an increase in functional residual capacity; improvement in oxygenation, decrease in nasal resistance and washout of nasopharyngeal dead space. Whilst HHFNC is now used widely for children hospitalised with acute indications including bronchiolitis, there is a paucity of data on HHFNC in the home setting.

Methods

Single centre retrospective study of children treated with home HHFNC. Data include demographic parameters, clinical indication, previous CPAP/BPAP use, age at initiation and flow rate, polysomnography results and adverse events.

Progress

A literature review about the use of HHFNC in the home setting has been undertaken. Median (Interquartile range [IQR]) age of initiating home HFNC in 11 children was 60 (12.5, 138) months. Indications were obstructive sleep apnoea (3; 27%), neuromuscular disease (4; 36%), hypoventilation (2; 18%), chronic lung disease (1; 9%) and central sleep apnoea (1; 9%). HHFNC was instituted as palliative management for five patients. Ten (91%) patients failed CPAP/BPAP. No serious adverse effects were observed. Issues with HHFNC included increased secretions (1, 9%), increased moisture (1, 9%) and higher flow rate (2; 18%).

Intended outcome and impact

The study aims to describe the safety and tolerability of HHFNC in the home setting and add to the literature on its use across different clinical settings.
O077 Nocturia as a Marker for Cardiovascular Risk in Obstructive Sleep Apnoea
Authors: Graffen S , Bin Y , Kairaitis K , Wheatley J , Yee B , Piper A , Cistulli P
Published: December 2024

Background

Obstructive Sleep Apnoea (OSA) is highly prevalent and is associated with cardiovascular (CV) risk. Factors beyond AHI alone appear to influence this risk. Clinical biomarkers of cardiovascular risk in OSA are needed to assist clinicians in making treatment decisions. Nocturia is a commonly reported symptom in OSA. This study aims to assess the association between nocturia and cardiovascular risk.

Methods

Patients with OSA (AHI>5/h) were selected from the Sydney Sleep Biobank. Patients aged 30-74yrs who had adequate data to calculate an office-based Framingham Risk Score (FRS) and who had answered the relevant question relating to nocturia in Pittsburgh Sleep Quality Index. The sample was divided into groups based on FRS or pre-existing cardiovascular disease. We then compared the frequency of significant nocturia, defined as ≥3 times per week disrupting sleep.

Progress to Date

605 patients (69% male, mean [±sd] age 52.9 ± 13.6 years, body mass index (32.8 ± 8.6) were included. 55% reported significant nocturia. FRS was low in 16.9%, moderate in 36.4% and high in 35.0% and pre-existing cardiovascular disease was reported in 11.7% and nocturia was reported by 56%, 71%, 81%, and 83% of those groups respectively. Nocturia was associated with increased cardiovascular risk (χ² = 21.1, df 2 with p<0.001).

Intended Outcome and Impact

Patient reported nocturia was associated with increased CVD risk. This exploratory study is limited by a lack of detailed reporting on nocturia, but suggests clinical utility of nocturia for assessment of CVD risk. Further analysis is planned regarding confounding factors.
O081 Neural aperiodic activity as a novel objective measure of wakefulness in patients undergoing a maintenance of wakefulness test
Authors: Seow K , Chatburn A , Bay M , Kang T , Johnston S , Yeo A , Lushington K
Published: December 2024

Background

The maintenance of wakefulness test (MWT) measures the ability of an individual to stay awake and is used to assess treatment response for conditions of hypersomnolence. The MWT is a laborious test with a strict and standardised protocol. The interpretation of a MWT and what is deemed ‘normal’ is also fraught with debate.

Wake and sleep states are characterised by oscillatory activity on EEG namely delta, theta, alpha, beta and gamma. There is also a less utilised non-oscillatory component of background neural activity (aperiodic activity) which can be calculated from the EEG. There is emerging evidence that shows clinical associations of aperiodic activity with cognition, visuomotor learning, schizophrenia and anaesthesia.

We aim to determine if there is a relationship between EEG aperiodic activity and the ability of an individual to maintain wakefulness.

Methods

All patients who underwent a MWT from 2010 to 2023 will be included. Clinical data including demographics, comorbidities and mean sleep latency will be extracted from the sleep study database of the Royal Adelaide Hospital. Raw EEG data will be obtained from the ProFusion Study Manager software. Statistical analysis (linear mixed models) will be performed to determine if there is a correlation between the aperiodic exponent and the mean sleep latency.

Progress

Awaiting ethics committee approval

Intended outcome

To demonstrate that a longer mean sleep latency in the MWT will be associated with a higher aperiodic exponent which could lead to further research into the utility of aperiodic activity as a novel measure of wakefulness.
P001 Sleep disturbance in patients with long-term neurological sequelae of COVID-19
Authors: Lung K , Brown E , Bilston L , Juge L , Cysique L
Published: December 2024

Introduction

Post COVID-19 neurological sequelae (popularly termed “Long COVID”), which include chronic sleep disruption and “brain fog” are widespread; however, studies have not yet comprehensively evaluated the concurrent effects of these disruptions of neurocognitive function and their relationship to sleep disturbance.

Methods

Participants aged between 40-65, with no more than 2 cardiovascular risk factors were stratified into three groups of ten: Group 1 (pre-pandemic datasets), Group 2 (individuals recovered from COVID-19), and Group 3 (individuals diagnosed with Long COVID under the WHO criteria). Polysomnography (PSG), Multiple Sleep Latency Test (MSLT), participant surveys and neurocognitive testing, among other data, were collected.

Results

Control group 1 included more participants (70%) with obstructive sleep apnoea (OSA) compared to the Long COVID group, resulting in a markedly greater arousal index (ANOVA p=0.03), but no significant differences in percentage of Slow Wave Sleep (SWS) and Rapid Eye Movement (REM) sleep were observed between all three groups (ANOVA p=0.29). The Long COVID group displayed heightened daytime sleepiness, based on MSLT, Epworth Sleepiness Scores, and fatigue severity scores (Group 2: 28±10 vs Group 3:44±11, unpaired t-test p=0.01).

Discussion

Initial observations suggest sleep architecture (proportion of SWS and REM sleep) in Long COVID does not differ from controls, however the reduced sleep latency and elevated subjective fatigue suggest dysfunction of sleep in Long COVID which needs to be further explored.
P003 Effect of ethnicity on positive airway pressure acceptance for obstructive sleep apnoea
Authors: Cheng T , Young A , Tolson J , O’Driscoll D
Published: December 2024

Introduction

Despite having a similar prevalence, OSA in patients of Chinese descent is driven more by anatomical factors compared to Caucasians. However, there is a dearth of evidence investigating the effect of ethnicity on acceptance and usage of positive airway pressure (PAP). This study investigated the PAP acceptance rate and predictors in an ethnically diverse population referred for PAP acclimatisation in a tertiary referral hospital.

Methods

A retrospective analysis of consecutive PAP acclimatisation trials between 2014-2020 was performed. Patient demographics, polysomnographic variables, and PAP trial variables were compared between groups. Multivariate stepwise logistic regression analyses were performed to identify predictors of PAP acceptance in each group.

Results

543 PAP acclimatisation trials were included (10.7% Chinese patients). There were no differences in age, gender or AHI between groups, however the Chinese group had a lower BMI (p<0.001), and higher ESS (p<0.05). There was no difference between groups for average PAP use, residual AHI or PAP acceptance rate (86% vs 92%). Logistic regression analysis revealed that PSG AHI, residual AHI and average PAP usage were predictors of PAP acceptance in Caucasians (adjusted ORs 1.03, 0.90 and 1.01 respectively), but only residual AHI and PAP usage were predictors in Chinese patients (adjusted ORs 0.86, 1.01).

Conclusion

PAP acceptance was similar in Chinese and Caucasian patients, however severity of disease did not predict acceptance in Chinese patients. Future research should focus on determining if Chinese versus Caucasian ethnicity is an important contributing factor to clinical outcomes and therapeutic responses in OSA.
P005 Sex differences in the association between sleep and depressive symptoms in an outpatient sleep disorders clinic
Authors: Zhong Y , Saunders W , Yap R , Ng Y , Lu S , Cahill F , Oh S , Chen A , Thornton T , Stout J , Rajaratnam S , Hamilton G , Mansfield D , Bei B
Published: December 2024

Introduction

Inadequate sleep duration and quality increases the risk and severity of depressive symptoms. Sex differences may influence these associations, but research findings are inconsistent and largely based on healthy populations. This study examined sex differences in the association between sleep and depressive symptoms in people seeking treatment primarily for sleep disorders at an outpatient clinic.

Methods

1806 participants were recruited from an outpatient multidisciplinary sleep clinic (48% female; Mean-age = 43.93±16.00 years). Participants self-reported sleep duration, sleep quality (rated 1-4, higher scores represent better sleep quality), and depressive symptoms (PROMIS Short Form v1.0 - Depression 8a) prior to receiving treatment.

Results

Participants self-reported sleeping 6.49±1.73 hours and depressive symptoms were above population mean (55.95±10.09). Males reported more depressive symptoms than females (p <.001), however there were no significant sex differences in the association between sleep variables and depressive symptoms. Overall, lower sleep quality was associated with greater depressive symptoms (p <.001); and there was a U-shape relationship between sleep duration and depressive symptoms (p =.003), in which both shorter and longer sleep are associated with greater depressive symptoms.

Conclusion

This study revealed that depressive symptoms were elevated in an outpatient sleep clinic sample compared to population norm, underscoring the importance of recognising and addressing mental health symptoms that coexist with sleep problems. Associations between sleep and depressive symptoms were similar between males and females, but males reported significantly higher depressive symptoms than females. Future studies should explore biopsychosocial factors that may contribute to sex differences in depressive symptoms.
P006 Effect of CPAP on Heart Rate and Heart Rate Variability in Patients with Obstructive Sleep Apnoea
Authors: Suryo A , McDermott E , Cuesta R , Spiteri M , Nguy R , Davies S , Kaur-Bains S , Slater B , VanBraak E , Beranek R , Roebuck T , Naughton M , Dal Corso S
Published: December 2024

Introduction

Heart Rate (HR) and Heart Rate Variability (HRV) are both indicators of the autonomic nervous system. Both low HR and high HRV indicate greater vagal/sympathetic ratio consistent with better sleep quality. However, high HRV may also reflect untreated OSA due to the large negative intra-thoracic pressure swings. Thus, effects of CPAP treatment of OSA on HR and HRV are poorly described.

Aim

To assess HRV and HR in patients with OSA before and after CPAP controlled for sleep stage (SS) and body position.

Methods

15 Patients (age 33-75, (8M/7F), average BMI 33.7kg/m2) with a confirmed diagnosis of sleep-disordered breathing, mean AHI of 42.9 (range: 23.8-118.0), underwent a diagnostic and CPAP in-laboratory polysomnography. HR and HRV were measured using 5-10min blocks in each SS (wake, N2, N3, REM) in lateral, prone and supine positions using ProfusionTM PSG4 (Compumedics, Abbotsford). LabChart® (ADInstruments, Dunedin) was used for HRV analysis. HRV was measured using the non-linear metrics of SD1 and SD2, derived from Poincaré plots. HRV and HR were then compared off and on CPAP.

Results

Preliminary results in 5 patients (age 33-72, 4M/1F, average BMI 30.5kg/m2) show HR decreased 9.6±2.4% and R-R interval increased 12.2±2.3% with CPAP. Preliminary analysis does not show that HRV decreased with CPAP (Diagnostic vs CPAP, SD1: 33.3 + 10.5ms vs 34.5 + 12.9ms and SD2: 76.3 + 18.6ms vs 73.6 + 22.1ms, respectively).

Conclusion

CPAP treatment of OSA is associated with a fall in HR representing a rise in vagal/sympathetic ratio. Further analysis may be needed to determine whether there is a rise in HRV.
P012 Sleeping on Clouds; a comparison of the impact of polysomnography versus remote determination on non-invasive ventilation device settings
Authors: Ridgers A , Ruehland W , Hannan L , Bruzzese K , Rajan A , Rautela L , Berlowitz D , Howard M
Published: December 2024

Introduction

Non-invasive ventilation (NIV) with home mechanical ventilators is an effective treatment for chronic respiratory failure. Optimal therapy requires titration of NIV settings to ensure adherence. Modern ventilators produce ventilator data for review via cloud-based platforms. The impact of relying on this data for NIV titration compared with polysomnography (PSG) is unknown. The aim of this study was to compare the agreement of ventilator settings based on summarised ventilator data and NIV PSG within participants.

Methods

A prospective cohort of 30 individuals with chronic respiratory failure were established on NIV. One month later, participants were administered questionnaires to assess NIV satisfaction, underwent in-lab PSG, and their data from the ventilator cloud-based platform was reviewed. Optimal NIV settings were separately determined by blinded review of the summarised ventilator data and PSG data by a respiratory and sleep physician.

Results

20/30 users experienced discomfort whilst using NIV therapy. Ventilator prescription using NIV PSG and Airview data were different. Inspiratory positive airway pressure (IPAP) and pressure support (PS) were an average of 2.76cmH2O (95% confidence interval 2.0,3.5) and 1.8cmH2O (95%CI 1.1,2.5) lower based on ventilator data. Comparative analysis with Bland Altman plots demonstrated a mean difference (MD) in IPAP of 1.4cmH2O (limits of agreement (LOA) -4.47 to 7.29) and PS MD of 0.96cmH2O (LOA -3.43 to 5.36).

Conclusion

User reported discomfort with NIV therapy was common. Differences in IPAP and PS were observed with lower prescribed pressures when titration was performed using ventilator data compared with NIV PSG. This may influence the titration of NIV therapy; however, the clinical impact of this difference on users is currently unknown.
P014 Bioinformatic analysis of gene expression profiling data on shift work sleep disorder
Authors: Chae H , Kim M , Lee E
Published: December 2024

Introduction

Shift work sleep disorder (SWSD) is a circadian rhythm sleep disorder affecting individuals who work nontraditional hours, such as night shifts. The complexity of SWSD arises from the altered interactions between thousands of genes, making it challenging to prioritize disease mechanism, biomarkers, and drug targets. This study aims to identify the patterns of pathways and upstream regulators involved in SWSD using a transcriptome from isolated peripheral blood mononuclear cells (PBMCs) of hospital nurses.

Method

We conducted bioinformatic analyses on the GSE122541 dataset, which includes RNA samples from PBMCs collected from night-shift and day-shift nurses under controlled laboratory conditions. Total RNA was obtained from isolated PBMCs every three hours. Differentially expressed genes (DEGs) were identified by comparing the night-shift condition to the day-shift condition. These DEGs were subjected to pathway and biomarker analyses using bioinformatic tools.

Results

A total of 773 DEGs were identified when comparing night-shift to day-shift conditions. These DEGs were analyzed using ingenuity pathway analysis (IPA). The pathway analysis revealed several significantly decreased pathways, including interferon alpha/beta signaling, interferon signaling, and OAS antiviral response. The upstream regulator analysis included predicted inhibited upstream regulators, such as IFNA2 and IFNL1, supporting the inhibited pathways. The one of top diseases associated with the night-shift condition included cancer with highest score.

Conclusion

Despite the identification of numerous DEGs, the bioinformatic analysis highlighted significant inhibited pathways and upstream regulators between night-shift and day-shift conditions. Combining pathway analyses of microarray data with bioinformatic tools can provide insights into the pathogenic relevance of SWSD.
P016 A data-driven comparison of commonly used roster patterns within the Western Australian fly-in-fly-out mining context
Authors: Smithies T , Ferguson S , Vincent G , Maisey G , Bennett J , Fraser H , Dunican I
Published: December 2024

Introduction

Shift and roster design is integral to an effective Fatigue Risk Management System, and can impact worker safety, health outcomes, workplace satisfaction, productivity, and cost. However, fatigue-based roster design decisions are frequently made using little or no supporting data. This analysis aims to provide objective fatigue-risk data for roster patterns commonly used within Western Australian (WA) mining fly-in-fly-out (FIFO) operations.

Methods

Ten of the most common roster patterns (sequencing of work hours and rest periods) within the abovementioned context have been identified, as have two pertinent factors: day/night shift start time, and commute duration to/from individuals’ home airports. In total, 150 combinations of roster patterns, start times, and commute durations will be analysed using the Fatigue Audit InterDyne (FAID®, Interdynamics Pty Ltd) Standard and Quantum biomathematical models.

Results

All analyses will be completed prior to the conference start date. Outputs of all combinations will be provided, with emphasis placed on time spent above a FAID score of 90 on the ‘Standard’ model and a predicted KSS above 7 on the FAID Quantum model (both indicative of high fatigue-risk). The impact of start times, commute durations, and their interaction, will be described and visualised.

Discussion

This will be the first publicly available data-driven comparison of FIFO shifts and rosters specific to WA FIFO mining operations. The results from this novel analysis should not be used in a prescriptive manner; however, they aim to provide new insight that may assist decision-making around shift and roster design for FIFO mining operations globally.
P018 Impact of academic, sports, and extracurricular activities on sleep patterns in early adolescents
Authors: Yap R , Lewis N , Phillips A , Hand A , Chachos E , Carskadon M , Lockley S , Wiley J , Stone J , Rajaratnam S , Bei B , Lu S
Published: December 2024

Introduction

Adolescents often report insufficient sleep and poor sleep quality, potentially due to busy schedules with academic tasks, sports, and extracurricular activities. This study investigated the impact of these activities on sleep onset, wake time and sleep duration in early adolescents.

Methods

Participants were 167 secondary school students in Melbourne, Australia (Mean age = 12.81±0.41 years, 56% female). During the school term, participants reported sleep-wake patterns over 2 weeks (sleep diaries). They also reported their weekly hours spent on academic, sports, and extracurricular activities outside of school, and the number of days they engaged in these activities before or after school (School and Sleep Habits Survey). Multiple linear regression analyses controlling for age, sex, ethnicity and COVID restrictions were conducted.

Results

Engaging in academic (Mean = 4.53 hours, Median = 3.00 hours), sports (Mean = 2.69 hours, Median = 2.00 hours), or extracurriculars activities (Mean = 1.02 hours, Median = 0.00 hours) weekly, whether in the morning or evening, was not independently or collectively associated with delayed bedtime, advanced wake times, or shortened sleep duration. However, more days spent engaging in evening sports during the week were associated with earlier bedtimes (p =.014).

Conclusion

More time spent on evening sports may be associated with earlier bedtime, but the study did not find associations between academic or other extracurricular activities and sleep during the school term. Further research is warranted to accurately quantify the types and intensity of these activities and their daily associations with sleep in adolescents.
P024 High resolution measurement of sleep position during pregnancy and the impact on infant birthweight
Authors: Wilson D , Mann D , Szollosi I , Callaway L , Kothari A , Terrill P
Published: December 2024

Introduction

Pregnant women are advised to sleep laterally from 28-weeks of gestation, due to increased risk of stillbirth in those who report “going-to-sleep” in the supine position. Historically, objectively-measured sleep position during pregnancy was classified as supine or lateral, potentially missing important subtleties regarding the mechanisms behind sleeping position and fetal wellbeing. This study aimed to characterise sleep position during pregnancy with precise measurement techniques and assess the impact of discretisation of supine sleep on infant birthweight.

Methods

A tri-axial accelerometer was worn around the abdomen for 7 nights, between 32-36 weeks of pregnancy. Body position was measured continuously in degrees of roll. Supine was defined crudely as 0°= fully supine to 45° left or right tilt versus more precisely as 0-15°, 15-30° and 30-45°. Birthweights were converted into customised centiles.

Results

A total of 368 nights were recorded across 56 women. The median (IQR) proportion of supine positioning (0-45°) across the week was 15.6% (4.9,26.5), equivalent to 74.5 (24.0,128.6) minutes per night. Of time spent supine, 32% was within 0-15°, compared to 28% and 41% in more tilted positions of 15-30° and 30-45° respectively. Birthweight centile was not related to supine (0-45°) time overnight (β=0.01, p=.85) or when constrained to 0-15° (β=0.17, p=.07).

Discussion

Half the women studied spent over an hour in the supine position overnight, although a 30-45° lateral tilt was favoured. Supine sleep was not associated with birthweight, suggesting that, at this supine exposure, the fetus is minimally impacted from aortocaval compression potentially impacting uteroplacental supply.
P030 Associations between objectively measured sleep and neurovascular coupling: preliminary results
Authors: Lester A , Fulford J , Mann D , Smith S , Taylor J , Bond B
Published: December 2024

Introduction

Habitual poor sleep is linked to cerebrovascular disease. Impairments in neurovascular coupling (NVC) are thought to precede cerebrovascular disease, however, the effect of sleep on NVC is poorly understood.

Methods

Total sleep time (TST) and time in deep sleep (N3) were quantified during three home sleep assessments using an electroencephalography-based device (Somfit) in 35 participants (22 female, age 10.5–73.6 years). Blood velocity through the middle (MCAv) and posterior (PCAv) cerebral arteries was measured using transcranial Doppler ultrasound. Percent change in PCAv from eyes closed to peak PCAv during visual stimuli was taken to represent NVC. Hierarchical multiple regressions were used to explore the associations between NVC, age and sleep.

Results

Sleep duration ranged from 5.46–9.65 hours, and time in N3 from 22–200 minutes. Resting MCAv and PCAv ranged from 47–104 cm/s, and 28–65 cm/s respectively. NVC responses ranged from 6.8–44.4%.

Age was associated with resting MCAv (R²=0.243, P=0.003), however, adding TST (F change=0.932) or time in N3 (F change=0.644) did not improve the model. Age was not associated with resting PCAv, and this did not change when TST or N3 sleep were added to the model (all R²<0.100, P>0.05). Similarly, no associations were found between NVC, age and TST/time in N3 (all R²<0.006, P>0.05.

Conclusions

Preliminary analyses reveal that resting MCAv decreases with age, while NVC does not. However, neither relationship was mediated by habitual sleep. Further data collection is being performed to capture a wider range of sleep patterns and ages.
P032 Can Capillary Blood Gases (CBGs) be used to determine drift in Transcutaneous Carbon Dioxide (TcCO2) measurements?
Authors: Slater D , Veldre T , Sigauke S , Wong S , Urban M , Figurski D , Huang H
Published: December 2024

Introduction

Capillary Blood Gases (CBGs) are used as an alternative method to measure pCO2 in the Canberra Hospital Sleep Disorders Unit. CBGs are simple to perform and have been shown to closely correlate to Arterial Blood Gases (ABGs) and nocturnal Transcutaneous Carbon Dioxide (TcCO2) in the measurement of pCO2. TcCO2 monitoring is an estimate of pCO2 and is prone to drift after continuous monitoring overnight. Our aim was to determine whether CBGs could be utilised to verify statistically significant drift in TcCO2 probes.

Methods

CBGs were sampled by Sleep Scientists to validate TcCO2 in both sleep lab rooms at the start and end of the sleep study (after ~8hrs applied to patient). A sum of 34 TcCO2/PcCO2 comparisons for each TcCO2 probe were collected over 3 months. Average differences between TcCO2 and PcCO2 were compared between the initial measurement and ~8hrs after the TcCO2 probe was placed. The significance of the drift was determined via ANOVA.

Results

Average drift (Bed 1 TcCO2) = -0.76mmHg (n = 34, p = 0.499).

Average drift (Bed 2 TcCO2) = 3.26mmHg (n= 34, p = 0.004).

Conclusions

The Bed 2 TcCO2 probe was shown to have a statistically significant drift via CBGs. This suggests that CBGs are a viable alternative to ABGs for quality control management of TcCO2 probes within the sleep laboratory context. This study may be limited by the large standard deviation in these measurements. Further analysis with a larger number of samples is required for additional validation.
P036 Evaluation of position sensors used during sleep studies
Authors: Churchward T , Ruehland W , Tolson J , Duce B , McDonald C , Worsnop C
Published: December 2024

Introduction/Background

Accurate body position measurement is used for diagnosing and managing obstructive sleep apnoea (OSA). Typically, position sensor data are corrected by experts using video recordings, but this is unavailable during unattended polysomnography (PSG). It is thus important to understand the accuracy of position sensors.

Aim

To evaluate the correction rates of position sensor measurements during PSG in a clinical laboratory setting.

Methods

We analysed 30 consecutive PSGs, all with video recordings, conducted in adults being assessed for OSA. The studies used Compumedics Ltd. (Abbotsford, Victoria, Australia) Grael™ PSG equipment with five-state (upright, left-lateral, right-lateral, prone, supine) body position sensors. After each study was completed the correct body position was determined in each thirty second epoch by viewing the video. These were then compared with the body position recorded by the position sensors for each epoch.

Results

A total of 28,377 30-second epochs from 30 PSGs (average: 946 epochs per study, range: 743-1249) were analysed. On average, across all studies 18.3% of epochs had the incorrect body position recorded by the position sensors. The degree of error within a study varied from 0.5% to 78% of epochs.

Discussion/Conclusion

Significant discrepancies in body position were found between the sensors and what was seen on video recordings of the studies. It is thus not possible to rely on position sensors when reporting sleep related OSA in sleep studies.
P037 Challenges and Facilitators in Adopting Healthy School Start Times: Key Stakeholders’ Perspectives
Authors: Barber C , Taylor R , Edmonds L , Signal L , Alansari M , Oldehaver J , Hetrick S , Galland B
Published: December 2024

Introduction

School start times no earlier than 9:45 a.m. for senior high students are considered “healthy” school start times (HSSTs) due to their potential to enhance teenagers’ health and well-being by accommodating their natural sleep patterns. Although many schools in Aotearoa New Zealand start one day a week later, daily implementation is rare. This study aimed to identify potential barriers and enablers for implementing HSSTs by gathering perspectives from key stakeholders in the education sector.

Methods

Semi-structured one-on-one Zoom interviews were conducted with nine key stakeholders involved in student transportation, timetabling, truancy, health (primary care and government level), and education (school leadership and government level). Interviews were audio-recorded, transcribed, and analysed inductively using thematic analysis.

Results

Four main themes emerged. First, Sleep Health Issues: Participants emphasised schools as ideal venues for sleep health education, highlighting the well-being benefits of HSSTs. Second, Education System Structures: The self-managing nature of schools was a barrier and an enabler. Flexible timetabling solutions were proposed, but the unpopularity of later school finishes posed a significant barrier. Third, Routines and Schedules: Consideration of wider whānau schedules was necessary. Off-peak hours could shorten bus rides and promote safer cycling, but resource intensive. Finally, Culturally Sustaining Practices and Multifaceted Needs: Enabling communities to develop autonomous implementation.

Discussion

Promoting a better understanding and prioritisation of sleep in educational settings is essential for advocating HSSTs. Emphasising the importance of sleep for overall well-being, while ensuring sleep advocacy initiatives foster autonomy and cultural safety, is crucial.
P041 Feasibility and accuracy of home polysomnography with transcutaneous carbon dioxide monitoring in children with neuromuscular disorders
Authors: Withers A , Pettigrew G , Filmer K , Lam J , Downs J , Wilson A
Published: December 2024

Objectives

clinical utility of home polysomnography is limited in children with neuromuscular disorders as CO2 is not measured and hypoventilation cannot be identified. This study performed home polysomnography with a Type 2 portable monitoring device and a portable transcutaneous CO2 monitor in children with neuromuscular disorders.

Methods

feasibility was defined as adequate data recorded from both devices to allow identification of sleep disordered breathing. Results of laboratory and home polysomnography were compared with Mann-Whitney U test and random intercept regression models.

Results

nineteen paired polysomnograms were performed for thirteen participants, including ten males, six with Duchenne Muscular Dystrophy. Median age was nine years. Feasibility was 68%, with adequate transcutaneous CO2 data in 89%. Statistically significant differences in sleep architecture were higher total sleep time, lower awake time and less N1 sleep during home polysomnography. No significant differences were seen in gas exchange parameters or apnoea hypopnoea indices. Home polysomnography had a sensitivity of 50% for diagnosis of hypoventilation and 78% for obstructive sleep apnoea. There was a concordant diagnosis of obstructive sleep apnoea in 7/9 home polysomnograms (78%), with an under-estimation of severity in three cases.

Discussion

This is the first study in children with neuromuscular disorders that demonstrates feasibility of transcutaneous CO2 monitoring during home polysomnography and directly compares Type 2 home and laboratory polysomnography. Differences in sleep architecture imply better sleep quality during home polysomnography. Although results indicate that home polysomnography is not sensitive enough to reliably identify sleep disordered breathing, our results are novel and show promise.
P048 Sleep in early childhood: Characteristics of infant sleep and mother-perceived sleep problems at 12-weeks postpartum, and the associations between perinatal depression and sleep in infants and preschoolers
Authors: Carter3 M , Paine S , Sweeney B , Taylor J , Signal T
Published: December 2024

Introduction

Sleep in the first years of life is the product of a complex interplay between numerous biopsychosocial factors. To further explore this, we first investigated sleep health equity in the infants of Māori (n=383) and non-Māori (n=702) mothers, the socio-ecological factors associated with infant sleep, and the characteristics of mother-perceived infant sleep problems. Next, we examined the role maternal depression in infant and preschooler sleep health.

Methods

Cross-sectional and longitudinal analysis of Moe Kura data collected in pregnancy(T1), 12-weeks postpartum(T2), and 3-years post-birth(T3). Multivariable and ordinal logistic models assessed the impact of different socio-ecological factors on infant sleep. Binary logistic models examined longitudinal associations between perinatal depression and infant and preschooler sleep, adjusting for key socio-demographic variables.

Results

Key developmental markers of infant sleep did not differ by maternal ethnicity. There were some ethnicity-based differences in sleep location. Bed-sharing and several socio-demographic factors were related to different dimensions of infant sleep, and mother-perceived sleep problems. Clinically significant prenatal depression was associated with less consolidated sleep in infants, and shorter sleep duration, greater average midsleep difference, CSHQ score, and sleep problems in preschoolers. Prenatal depressive remained independently associated with short sleep durations in preschoolers after controlling for key socio-demographic and sleep variables, and postnatal and concurrent depressive symptoms.

Discussion

Sleep at 12-weeks is highly variable and is associated with numerous socio-ecological factors. Sleep appears to be one pathway by which perinatal depression confers risk for poor child health outcomes. Findings support the need for more and better perinatal psychological services.
P049 Prevalence and Predictors of Comorbid Insomnia and Obstructive Sleep Apnoea in Chinese and Caucasian Patients
Authors: Mills B , Young A , O’Driscoll D
Published: December 2024

Introduction

Insomnia and obstructive sleep apnoea (OSA) often co-occur as co-morbid insomnia and obstructive sleep apnoea (COMISA). Despite having a comparable prevalence of OSA with Caucasians, Chinese patients have a distinct OSA phenotype that is less dependent on obesity. However, to date, no studies have investigated COMISA in this population. This study investigated the prevalence and predictors of COMISA in an ethnically diverse clinically referred population for investigation of sleep disordered breathing.

Methods

Data from 183 patients (27 Chinese, 156 Caucasian) undergoing in-laboratory diagnostic polysomnography were reviewed. COMISA was defined as an apnoea-hypopnea index (AHI) >5 events/hour and an Insomnia Severity Index (ISI) score ≥15. Multivariable logistic and linear regression analyses were carried out on demographic and polysomnographic variables to determine predictors of COMISA and their associations with ISI respectively.

Results

Despite a similar prevalence of OSA (Caucasian 84.0% vs Chinese 81.5%, p=n.s.), Chinese participants showed significantly higher rates of insomnia (77.8% vs 41.3%, p<0.001) and COMISA (59.3% vs 34.7%, p=0.028) than Caucasians. For Caucasians, Arousal Index (OR: 1.04, p=0.003) and Depression (OR: 1.15, p=0.019) were both significant predictors of COMISA. For Chinese participants, no predictors of COMISA were identified, however both Sleep Onset Latency (SOL) (B=-0.198, p=0.029) and AHI (B=-0.150, p=0.020) inversely predicted ISI.

Conclusion

In our clinical population, COMISA was more prevalent among Chinese patients, driven by a higher incidence of insomnia. Future research should focus on determining the relative contribution of ethnic physiological differences and immigratory stress to the potential existence of a distinct Chinese COMISA phenotype.
P050 Integrating a same day sleep apnoea assessment into a surgical pre-admission clinic (PAC)
Authors: Kathriachchige G , Cawson E , Dabscheck E , Miller B , Downey G , Naughton M
Published: December 2024

Introduction

Untreated obstructive sleep apnoea (OSA) is often unrecognised pre-operatively and is associated with increased post-operative complications and morbidity. Anaesthetist screening of OSA risk in pre-admission clinic (PAC) prompts referral to a sleep physician to investigate.

Aim

To explore the novel concept of integrating a sleep physician into PAC.

Methods

An audit sampling a PAC service was conducted at a tertiary hospital, pre and post integration of a sleep physician into PAC. Pre-integration, anaesthetists who identified patients at risk of OSA based on STOPBANG questionnaire were referred to the sleep clinic on a future date. Post integration, such patients were referred to the sleep physician in PAC on the same day. Demographic variables, times to assessments and hospital outcomes were reviewed.

Results

382 patients were reviewed in PAC pre-integration (26% bariatric, 31% orthopaedic, 43% other) and 355 post-integration (16% bariatric, 39% orthopaedic, 45% other). Comparing pre-integration with post-integration: 8 (2%) vs 71 (20%) patients were referred for sleep physician assessment. Mean days to: sleep physician assessment (120 vs 0), sleep study (91 vs 25), OSA management (138 vs 13) and surgery (261 vs 38). The 30-day mortality and unplanned non-invasive ventilation (NIV) post-operatively did not occur in either group referred for sleep assessment.

Discussion

Integration of a sleep physician into PAC resulted in 10 times more referrals for assessment of OSA. Time to: see a sleep physician, sleep study, management and surgery was reduced. Limitations of this study include a small sample size and confounders affecting clinical wait times.