bluuebunny/crossref_metadata_2025_split huggingface dataset:
P104 Exploring the heterogeneity of psychiatric symptom profiles in sleep clinic patients using a cross-cutting dimensional approach
Authors: Saunders W , Wellecke C , Spina M , Lu S , Ng Y , Wasgewatta S , Cahill F , Jenkins C , Rajaratnam S , Hamilton G , Mansfield D , Bei B 
Published: November 2022

Abstract

Introduction
Individuals attending sleep services commonly present with comorbid psychiatric symptoms. This study reports our ongoing effort to characterise presenting psychiatric symptom profiles of individuals seeking treatment at a sleep clinic and classify heterogenous subgroups within a large sample.

Method
Data were collected at a university-based multidisciplinary sleep clinic via opt-out consent. Prior to treatment, individuals completed the Cross-Cutting Symptom Measure (CCSM), which provides a transdiagnostic symptom profile by measuring 13 domains of mental health (e.g., anger, anxiety, depression, psychosis, mania, memory). Additional questions on demographics and the Morningness-Eveningness Questionnaire Reduced (rMEQ) were also administered.

Results
1263 participants (52.9% male; age M±SD= 43.53±16.06) completed the CCSM and were analysed. Latent class analysis revealed 3 distinct profiles: Low-Symptom subgroup (n=655, 51.9%) reported mild affective and somatic symptoms; Psychopathology subgroup (n=342, 27.1%) reported moderate to severe psychopathology including psychosis, dissociation, and suicidality, in conjunction with severe affective, obsessive-compulsive, and somatic symptoms, and significant interference with memory and personality functioning; Affective-Disturbance subgroup (n=266, 21.1%) reported moderate affective and somatic symptoms, and some interference with memory and personality functioning. The three subgroups did not differ significantly on key demographics or the rMEQ.

Discussion
There was heterogeneity in psychiatric symptoms experienced by sleep clinic patients. Affective and somatic disturbances were common across subgroups whilst severe psychopathology appeared in a sizeable (one in four) proportion of patients. These findings solidified the need for careful assessment of a wide range of psychiatric symptoms to inform treatment planning in sleep services.
P105 Women with greater post-traumatic stress symptom severity and less disrupted sleep have improved fear extinction recall compared to men
Authors: Schenker M , Ince S , Ney L , Hsu C , Zuj D , Jordan A , Nicholas C , Felmingham K 
Published: November 2022

Abstract
Sleep has been found to play a key role in fear conditioning, extinction learning and extinction recall, the paradigm modelling the development, maintenance and treatment of anxiety disorders including post-traumatic stress disorder (PTSD), which are disorders commonly associated with sleep disturbances. Previous studies examining associations between sleep and fear or extinction processes predominately focused on objectively measured sleep architecture using polysomnography, and the majority of the research has been done in healthy populations. To date, little research has focused on subjective sleep measures and particularly in clinical populations including PTSD, which often experience subjectively poor sleep. Here we investigated whether subjective sleep disturbance, sleep onset latency, wake after sleep onset or sleep efficiency were related to fear conditioning, extinction learning or extinction recall in a large sample of individuals with a range of PTSD symptom severity and healthy controls. Overall, we did not find that sleep was associated with fear conditioning extinction learning or extinction recall. However, emerging evidence highlighting the critical role of sex in PTSD risk, fear conditioning processes, as well as in the sleep-fear conditioning relationship. Exploratory analyses examining sex-specific effects found that shorter sleep onset latency and greater sleep efficiency during the previous night were associated with improved extinction recall in women with higher PTSD symptom severity. This suggests that less time falling asleep and longer time asleep while in bed may be protective against the commonly observed impaired extinction recall in PTSD in highly symptomatic women, but is not relevant in men.
P115 Exploring the effectiveness of Fatigue Risk Management Systems
Authors: Sprajcer M , Thomas M , Sargent C , Crowther M , Boivin D , Wong I , Smiley A , Dawson D 
Published: November 2022

Abstract

Introduction
Fatigue Risk Management Systems (FRMS) are increasingly being used in a range of safety-critical industries to manage fatigue-related risk. These data-driven practices use a risk-based approach to managing fatigue, rather than solely relying on prescriptive hours of work limits. However, some organisations are reluctant to implement FRMS as evidence of effectiveness is unclear. A review was undertaken to evaluate the available evidence on FRMS effectiveness, and to provide evidence-based policy guidance for FRMS use and implementation.

Methods
Seven electronic databases (MEDLINE (Ovid), PsycINFO, IEEE Xplore Digital Library, Scopus, Web of Science, MESH Occupational Health, NIOSHTIC II) were searched for relevant peer reviewed and grey literature. Documents were included if they addressed fatigue management interventions. Screening was performed on a total of 2129 documents, with 231 included in the final review.

Results
Few (n = 5) documents evaluated FRMS as a whole. However, components of FRMS (e.g., performance monitoring, fatigue detection technology, prior sleep wake behaviour assessment) appeared to improve key safety and fatigue outcomes.

Discussion
The effectiveness of FRMS components suggests that FRMS as a whole is likely to improve organisational safety outcomes. Key implementation enablers included organisational and worker commitment, and safety culture. Where organisations have limited resources and/or immature safety cultures, FRMS may not be appropriate. As such, we propose that a hybrid or transitional model of fatigue management (including risk-based and prescriptive components) could be implemented – so organisations can increase operational flexibility while improving safety.
P117 A pilot study of a novel electrode system for brainwave acquisition during sleep: Tripolar Concentric Ring Electrodes
Authors: Stuart N , Manners J , Scott H , Lechat B , Kemps E , Catcheside P 
Published: November 2022

Abstract

Introduction
Tri-concentric ring electrodes (TCRE) evaluate current density underlying each electrode rather than a voltage difference between two conventionally placed electroencephalography (EEG) electrodes. TCRE signals are more focal and show improved signal-to-noise with markedly reduced electromyographic interference compared to conventional EEG. This pilot study is the first to evaluate sleep using TCRE and power spectral analysis of TCRE versus conventional EEG emulated (eEEG) recordings obtained from TCRE and the outer rings of paired electrodes.

Method
Twenty healthy sleepers (8 men, mean±SD age 27.8±9.6 y) completed a single overnight sleep study with a 9-hr sleep opportunity. Participants were set up for polysomnography recording using TCRE for brain activity (18 sites) and conventional gold-cup electrodes for eye movements, muscle activity, and heart rate. A fast Fourier transform using multitaper-based estimation was applied in 5-s epochs to calculate relative powers in delta, alpha, theta, sigma and beta frequency bands for eEEG and TCRE signals throughout sleep.

Results
At the Cz position, TCRE showed greater relative delta power and reduced beta powers across sleep stages compared to eEEG. For example, TCRE had higher delta activity during NREM stage 2 sleep than eEEG (mean [SD]; 89% [5.7] vs 64% [6]) and lower beta activity during wake (3.4% [2] vs 17.3% [7.9]). Ongoing analyses will compare outcomes across electrode locations.

Conclusions
Brain activity acquisition via TCRE may reduce artefact interference and potentially identify new markers during sleep that are associated with sleep quality, health, and functioning.
P118 The use of cumulative frequency curves to analyse sedated patients
Authors: Sturdy G , Hillman D , Wilbrow B , Singh B 
Published: November 2022

Abstract

Introduction
Excessive or inadequate sedation in intubated patients are both associated with increased morbidity and mortality. However, it is difficult to quantify the level of sedation accurately. Conventional sleep analysis does not quantify sedation effectively. Specific sedation analysis techniques have been developed but are labour-intensive and difficult to apply. We explored the potential of cumulative frequency curves of electroencephalograms (EEG) to quantify the level of sedation.

Methods
Left frontal EEG was obtained over 12-24 hours in 20 sedated and 2 non-sedated patients. Six hours of time correlated data (00:00-06:00) were analysed. Cumulative frequency curves were created for each patient. Measurements obtained were: peak (frequency in Hz occurring most often, x axis), areas under the curve at five frequencies (percentage time at the selected frequency) and average signal amplitude, at peak using a power calculation on y axis.

Results
For the 20 sedated patients 72±13,% (mean±SD) of study time was recorded at &lt;1Hz and 91% ±5.7 at &lt;4Hz (compared to 57.8 and 84.3% respectively for non-sedated patients). The peak amplitude of the signal took place at 0.45±0.32 Hz in sedated patients. The comparative amplitude determined by a comparative power determinant was 50.8±3.8 in sedated patients (c.f. 46 in non-sedated patients).

Conclusion
This proof of concept study shows that signal amplitude and frequency can be measured using the cumulative frequency methodology and appears to differ between sedated and non-sedated patients. This methodology has the potential to provide a useful, simple and reproducible mechanism to analyse depth of sedation in intubated patients.
P119 Co-morbid insomnia is associated with worse health, and lower CPAP recommendation rates and nightly use in people with sleep apnoea
Authors: Tan D , Appleton S , Chai-Coetzer C , Lovato N , Vakulin A , Adams R , Grivell N , Sweetman A 
Published: November 2022

Abstract

Introduction
Co-morbid insomnia and sleep apnoea (COMISA) is associated with poor health and reduced adherence to continuous positive airway pressure (CPAP) therapy in sleep clinic samples. However, health and treatment correlates of COMISA in community-based samples of obstructive sleep apnoea (OSA) are poorly described.

Methods
Australian adults previously diagnosed with OSA were surveyed online. COMISA was defined as co-morbid OSA and nocturnal insomnia symptoms (difficulties falling asleep, maintaining sleep, and/or early morning awakenings at least a few nights a week over the past month). Logistic regression and ANCOVAs determined associations of COMISA with medical conditions and general health, controlling for age, gender, and body mass index. Treatment recommendation rates and average nightly use were compared between those with COMISA versus OSA-alone.

Results
Among 412 participants (54.6% male, mean age 58.5 [SD=13.9] years), 74.8% had COMISA. Compared to OSA-alone, COMISA was associated with higher rates of fair/poor general health (60.4% versus 46.6%, p=0.010), lower EQ-5D overall health (mean difference 7.55 [SD=2.73], p=0.010), and greater rates of depression diagnoses (56.3% versus 28.0%, p&lt;0.001), which persisted after adjustment for covariates. People with COMISA reported lower rates of CPAP therapy recommendation (82.8%, versus 95.2%, p=0.002), and nightly use (mean difference 0.54 [SD=0.13] hours/night, p&lt;0.001), and greater rates of upper-airway surgery recommendations (14%, versus 2.9%, p=0.002) and completion (13%, versus 1.9%, p=0.001).

Conclusions
COMISA was associated with worse health, depression, lower CPAP recommendations and use, and greater upper-airway surgery compared to those with OSA-alone.
P122 Association between variability of respiratory sleep indices and ambulatory blood pressure
Authors: Thant A , Ou Y , Seah S , Chiu S , Chan S , Teo Y , Wong S , Khoo C , Barbé F , Lee C 
Published: November 2022

Abstract

Study Objectives
Respiratory sleep indices are traditionally reported on the basis of the average total sleep time. The relationship between the hour-to-hour variability of these parameters and blood pressure (BP) has not been reported.

Methods
We evaluated the associations of the hour-to-hour variability of the apnea–hypopnea index (AHI), oxygen desaturation index (ODI), and lowest oxygen saturation with the 24-hour ambulatory BP in patients with hypertension and newly diagnosed obstructive sleep apnea. A total of 147 patients underwent polysomnography, based on which obstructive sleep apnea was diagnosed in 106

patients
these patients underwent 24-hour ambulatory BP monitoring within the next 30 days. Each polysomnogram was divided into hourly reports to calculate the variability of the respiratory sleep indices. Variability independent of the mean was considered the primary measure of variability.

Results
The median number of hourly polysomnogram reports was 7 (range, 4–8).The hour-to-hour variability of both AHI and ODI, but not of the lowest oxygen saturation, was correlated with the 24-hour pulse pressure, 24-hour systolic BP, and awake systolic BP (p &lt; 0.05 for all). The fully adjusted linear regression analysis indicated that the hour-to-hour variability of AHI and ODI remained associated with the 24-hour pulse pressure (AHI: β coefficient, 0.264 [95% CI, 0.033–0.495],p =0.026; ODI: β coefficient, 0.450 [95% CI, 0.174 - -0.726],p = 0.002).

Conclusions
The hour-to-hour variability of AHI and ODI is independently associated with the 24-hour pulse pressure. Further investigations are warranted to evaluate the clinical relevance of this new-found association.
P129 Neck circumference versus body mass index to predict moderate to severe obstructive sleep apnoea
Authors: Wang D , Huang H 
Published: November 2022

Abstract

Introduction
Neck circumference (NC) and body mass index (BMI) are both markers of obesity and established parameters in clinical models for the prediction of obstructive sleep apnoea (OSA). It is unclear if one parameter is superior for the prediction of OSA severity or if the addition of both parameters significantly enhances the accuracy of the clinical model. In this study, we evaluated the performance of NC and BMI as predictors for moderate to severe OSA (AHI≥15) when adjusted for age and male gender.

Methods
A retrospective chart review of all diagnostic sleep studies (SS) conducted from November 2017 to October 2018 was performed. All SS which were reported as normal and all SS with a diagnosis of OSA were included. Three multiple regression models were constructed with AHI≥15 as the dependent variable and the following independent variables: NC + Age + Gender (NAG), BMI + Age + Gender (BAG), and BMI + NC + Age + Gender (BNAG). The Akaike information criterion (AIC) was used for model comparison. A model that was more than 2 AIC units lower was considered to be the superior model.

Results
112 SS had AHI&lt;15 and 193 SS had AHI≥15. The AIC for NAG, BAG and BNAG models were 333.9, 343.8 and 334.7 respectively.

Discussion
The NAG model had the lowest AIC. NC was superior to BMI for the prediction of AHI≥15. The performance of the clinical model incorporating both NC and BMI was not significantly different from the model incorporating only NC.
P130 The lived experience of shift work, sleep loss and fatigue in Australian paramedics
Authors: Wanstall S , Naweed A , Brown B , Rayner T , Adams R , Reynolds A 
Published: November 2022

Abstract

Introduction
Paramedics are essential health workers, and are regularly exposed to shift work, which negatively impacts sleep and fatigue. Paramedics also experience adverse mental health outcomes and sleep disorders at higher rates than the general population. Consequently, retention and occupational burnout issues are common. However, the relationship between shift work, sleep disorders, fatigue, and mental wellbeing in paramedics is poorly understood, limiting our ability to design and implement effective interventions.

Method
This study uses a qualitative action research design involving one-to-one interviews, with an intended sample of 30 paramedics (completion Aug 2022). The Scenario Invention Task Technique is used, requiring workers to explore how they engage and interact with their work. Participants generate challenging scenarios specific to their work when feeling rested, and then consider the same scenario when feeling extremely fatigued. Data are analysed using an inductive thematic structure.

Results
Analysis of preliminary data (n=10) indicates sleep loss and fatigue negatively impact workers’ ability to manage challenging scenarios and the self-regulation of emotions. While participants know sleep problems impact their wellbeing, limited knowledge on identification and management of sleep disorders is apparent. Early findings suggest an optimal window for better sleep education would be during internship, and paramedics suggest the information needs to be provided by an expert, and trusted, voice.

Discussion
Study findings will help inform sleep education, screening and support toolkits about sleep, fatigue and shift work tailored to paramedics in order to support wellbeing and sustainable careers.
P133 Modelling REM-NREM activity cycling in infants
Authors: Webb L , Phillips A , Roberts J 
Published: November 2022

Abstract
Sleep states in infancy differ from adult sleep states. Due to different cortical and physical manifestations, the REM and NREM equivalent sleep states in infants are often denoted as Active and Quiet sleep. Key differences in infant REM-NREM cycling include rapid cycling, and commencement of sleep in the REM state, instead of NREM. The physiological mechanisms underlying developmental changes in REM-NREM cycling in infancy are not well understood.
We extended an existing, physiologically based model of sleep-wake behaviour to include a REM-on group and REM-off group, with mutual inhibition between these providing the basis for REM-NREM cycling. We model a REM pressure driving the REM-NREM cycling, similar to other proposed models and motivated by the known phenomenon of increased REM sleep following REM deprivation.
We found parameter combinations that produce the REM-NREM cycling observed in infancy and early childhood. Through varying the parameters governing the dynamics of the REM pressure drive, the model is able to reproduce both newborn infant Wake-REM-NREM behaviours and the older Wake-NREM-REM pattern. Our results suggest that REM pressure clearance plays a dominant role in determining the initial sleep state, and increases in REM pressure from wake/NREM controls REM latency and duration.
We have identified a plausible mechanism for the immature sleep state cycling observed in infants. In line with theories of REM sleep’s purpose in cortical synaptic remodelling, a process which evolves rapidly in infancy, we found that REM pressure clearance times likely vary along early development, triggering a switch from REM-first to NREM-first sleep.
P138 Inter-observer agreement and sensitivity of definitions for hypoventilation in children with neuromuscular disorders
Authors: Withers A , Wilson A , Downs J , Jacoby P , Hall G , Gauld L , O'Donnell A , Chacko A , Schultz A 
Published: November 2022

Abstract

Background
hypoventilation occurs in neuromuscular disorders with respiratory muscle weakness. There are numerous definitions of hypoventilation. This study aimed to determine which definitions of hypoventilation had the highest inter-observer agreement and sensitivity in children with neuromuscular disorders.

Methods
twenty polysomnograms from children with neuromuscular disorders were examined by six paediatric sleep physicians to determine whether hypoventilation was present and which definitions of hypoventilation were used. Inter-observer agreement for the diagnosis of hypoventilation was calculated, with sensitivity determined in an exploratory analysis.

Results
mean inter-observer agreement was excellent at 82% (κ=0.533), higher for the absence (84%) than the presence (70%) of hypoventilation. Some physicians used more than one definition to diagnose hypoventilation for the same polysomnogram. Even when agreement was substantial, the definitions chosen varied between physicians.The objective defiitions used most frequently when inter-observer agreement was substantial that hypoventilation was present were; average increase in pCO2 ≥3mmHg from NREM to REM (n=15), increase of ≥10mmHg from awake to asleep (n=10) and pCO2 &gt;50mmHg &gt;25% total sleep time (n=8). The sensitivity for these definitions was 83%, 67% and 50%.

Conclusions
even when inter-observer agreement was high that hypoventilation was present, there was a lack of consistency between physicians when defining hypoventilation. An average increase in pCO2 ≥3mmHg from NREM to REM sleep had the highest inter-observer agreement and sensitivity. Alternative definitions in cases without a rise of pCO2 in REM are pCO2 &gt;50mmHg for 25% total sleep time and/or an increase of ≥10mmHg from awake to asleep.
P139 What threshold of total sleep time of hypercapnia should define hypoventilation in children with neuromuscular disorders?
Authors: Withers A , Wilson A , Downs J , Jacoby P , Hall G , Gauld L , O'Donnell A , Chacko A , Schultz A 
Published: November 2022

Abstract

Background
there are numerous definitions of hypoventilation, the most commonly used for children being pCO₂ &gt;50mmHg &gt;25% total sleep time. There are concerns that a total sleep time threshold of &gt;25% is not sensitive enough in children and individuals with neuromuscular disorders. Alternative thresholds of 2%, 5% and 10% total sleep time have been suggested.

Methods
the relationship between percentage of total sleep time with pCO₂ &gt;50mmHg and the presence of hypoventilation (determined by physician diagnosis) was examined in a small exploratory analysis of children with neuromuscular disorders. ROC curves were constructed to determine the impact of changing cut-off thresholds for total sleep time with pCO₁ &gt;50mmHg to define hypoventilation.

Results
the mean percentage of total sleep time that pCO₂ &gt;50mmHg was higher for the studies with hypoventilation (50% vs.10%). The mean difference (40%) was not statistically significant, likely due to the small number of studies (n=6) with hypoventilation. The AUC for percentage of total sleep time with pCO₂ &gt;50mmHg was 0.808 (p=0.035, CI 0.6 to 1.0). For thresholds of total sleep time with pCO₂ &gt;50mHg to define hypoventilation of 20% and 27%, sensitivity was 50%. For thresholds of 11%, 5% and 3%, sensitivity was 67%, 100% and 100% respectively.

Conclusions
in this study the upper limit of total sleep time with pCO₂ &gt;50mmHg in children with neuromuscular disorders without hypoventilation was 10%. Thresholds lower than 25% of total sleep time with pCO₂ &gt;50mmHg to define hypoventilation had higher sensitivity for diagnosing hypoventilation in this population.