bluuebunny/crossref_metadata_2025 huggingface dataset:
O011 Associations between sleep and Alzheimer’s disease biomarkers within the EPAD cohort
Authors: Naismith S , Palmer J , Leng Y , Lucey B
Published: October 2021

Background

Changes in sleep quality are common in Alzheimer’s Disease (AD) and may contribute to the onset and accumulation of disease. However, in preclinical stages, it is unclear whether sleep quality or sleep disturbance relate to disease pathology after controlling for known AD risk factors. This study aimed to determine if self-reported sleep quality is associated with AD biomarkers after accounting for such factors.

Method

Data were obtained from the European Prevention of Alzheimer’s Disease (EPAD) Longitudinal Cohort Study (LCS; v1500.0). CSF samples were collected for measurement of β-amyloid (Aβ42) and phosphorylated tau (p-tau). Self-reported sleep quality was assessed by the PSQI. Linear regression was used to determine whether p-tau/Aβ42 was associated with PSQI component scores when controlling demographics, ApoE4, depressive symptoms, BMI, vascular risks, smoking status, use of psychotropics, white matter lesions, and hippocampal volume. PSQI component scores of 2 or 3 were combined due to small numbers of component scores of 3.

Results

A total of 1239 participants were included (mean age=65.30 years, SD=7.11; mean PSQI total score=5.31, SD=3.38). After adjustment for all covariates, higher p-tau/Aβ42 was found to be associated with longer sleep latency (component score of 1: β=0.16, p=0.007; component score of 2/3: β=0.12, p=0.134) and better sleep efficiency (component score of 1: β=-0.22, p=0.04; component score of 2/3: β=-0.31, p=0.009)

Conclusion

These findings contribute to growing evidence suggesting sleep is an important early marker of underlying neurodegeneration. Longitudinal assessment of EPAD-LCS participants will allow for evaluation of self-reported sleep as a predictive marker of neurodegeneration.
O012 A prospective evaluation of the nature and time course of sleep disordered breathing and respiratory failure in patients with motor neurone disease (MND): the BreatheMND-1 study
Authors: Aiyappan V , Catcheside P , Antic N , Grivell N , Hansen C , Schultz D , Graham K , Allcroft P , Glaetzer K , McEvoy D
Published: October 2021

Introduction

Sleep disordered breathing (SDB) is a well-recognised but heterogeneous complication in MND and may herald the onset of respiratory failure. This study examined the nature and time course of SDB, sleep disruption and respiratory failure in MND patients.

Methods

The BreatheMND-1 study recruited MND patients for prospective evaluation of muscle strength,supine and prone dyspnea, quality of life, pulmonary function, arterial blood gas and polysomnographic sleep measurements at baseline and, where possible, 3, 6 and 12 months for exploratory analyses.

Results

35 MND patients completed baseline and 25 at least one follow-up visit (median [IQR] follow-up time 8.7 [7.1–10.2] months). At baseline, patients were aged 64 [55–70] years, 16/35 (46%) female, with reduced FVC (77[59–92] %predicted) but relatively normal BMI (26.2[23.7–27.7] kg/m²) and PaCO2 (38.8[37.0–42.1] mmHg). At baseline and last follow-up, the prevalence of respiratory failure (PaCO2>45 mmHg or HCO3>27 mmol/l) was 9/33 (27%) and 12/27 (44%) respectively (p=0.186). Total sleep time and sleep efficiency were poor at baseline (5.2[4.6–5.9] h and 67.6[63.0–78.8]%) and declined at follow-up (by 1[0.3–1.9] h, p=0.020 and 7.9[-2.3–14.2]%, p=0.017 respectively). AHI was 7.2[2.8–14.6] /h and remained unchanged. In regression model,sleep time and efficiency were not predictive of respiratory failure, but the percentage of deep and REM sleep at last follow-up were (ROC area under curve 0.73±0.11, p=0.048 and 0.84±0.09, p=0.001).

Discussion

Sleep quality in MND is remarkably poor, irrespective of SDB, and could reflect and/or impact MND progression. Thus, further strategies to monitor & improve sleep are clearly warranted in patients with MND.
O013 The pathogenesis of obstructive sleep apnea in individuals with comorbid insomnia and obstructive sleep apnoea (COMISA)
Authors: Brooker E , Thomson L , Landry S , Edwards B , Drummond S
Published: October 2021

Obstructive sleep apnea (OSA) and Insomnia are prevalent sleep disorders which are highly comorbid. This frequent co-occurrence suggests a shared etiology may exist. OSA is caused by the interaction of four pathophysiological traits: a highly collapsible upper airway, elevated loop gain, a low arousal threshold, and poor muscle compensation. No study has ascertained whether these traits are influenced by insomnia. We aimed to quantify the four traits which contribute to OSA in individuals diagnosed with comorbid insomnia and OSA (COMISA). We non-invasively determined these traits in 52 COMISA patients (Age: 56±14 years) with mild-to-severe OSA (AHI=21.2±10.63 events/h) using polysomnography. Our results indicated that 83% of COMISA patients had a low arousal threshold and only 2% of patients exhibited a highly collapsible airway using previously defined thresholds. Multiple linear regression revealed the arousal threshold (b=0.24, 95%CI[0.11, 0.37], β=0.47, p<0.001) and loop gain (b=23.6, 95%CI[7.02, 40.18], β=0.33, p<0.01) were the strongest predictors of OSA severity in our sample. There was no significant relationship between the arousal threshold and insomnia severity measured by the insomnia severity index (ISI). Further work is being performed to compare these findings with a matched sample of OSA only participants. Our preliminary findings demonstrate OSA in COMISA is characterized by a mildly collapsible airway/low arousal threshold phenotype and is largely driven by non-anatomical factors including a low arousal threshold and high loop gain. OSA treatments which are effective in patients with mild anatomical compromise and raise the arousal threshold may provide therapeutic benefit in COMISA patients.
O018 Changes in sleep parameters in children with Down Syndrome following treatment
Authors: Chawla J , Burgess S , Heussler H
Published: October 2021

Introduction

There is limited evidence about how sleep changes in children with Down syndrome (DS) following sleep interventions. This study evaluated changes in sleep over time in children receiving treatment comparing to a control group who did not.

Methods

Children with DS, 3-16yrs, attending the sleep clinic were followed for 24-months. Sleep parameters including parent completed child sleep habits questionnaire (CSHQ), PSG and home sleep diary were obtained pre and post sleep interventions for children undergoing treatment. Data was obtained at similar intervals for the control group who were followed over the same time period.

Results

Data was obtained for 41 participants, 16 children received an intervention and 25 did not. Interventions included ENT surgery (7), CPAP (4), melatonin (3) or a combination (2). The intervention group had a significantly higher average total CSHQ score overall than those in the control group (0.01). Scores decreased over time but remained higher than in controls throughout, and were clinically significant in both groups (>41). Sleep diary estimated average total sleep duration did not differ between groups and was 10hrs/night. PSG showed improvement in OAHI in those children undergoing pre and post intervention studies.

Discussion

Evaluation of sleep parameters in this referred cohort of children with Down syndrome demonstrates total sleep duration in keeping with national recommendations and improvement in obstruction with treatment. However, CSHQ results indicate ongoing sleep difficulties reported by parents, despite standard sleep interventions. This may reflect persisting non-respiratory sleep disorders, which are not being adequately addressed at present.
O034 Rockabye sailor: investigating the impact of simulated motion on sleep and cognitive performance
Authors: Matthews R , Fraysse F , Daniell N , Schumacher P , Banks S
Published: October 2021

Background

Many naval vessels are designed with sleeping berths orientated in a fore/aft direction. Reorientating the berths changes the rocking from side-to-side to head-to-foot. It is unknown what effect rocking orientation may have on sleep.

Aim

This study aimed to investigate the impact of a simulated fore/aft orientation (side-to-side motion) with a simulated athwartships berth orientation (head-to-foot motion), on sleep quality and quantity, and cognitive performance.

Method

21 participants (13M/8F; 24.0±4.8 years; BMI 21.1±2.5) slept in berths on a motion platform replicating vessel motion. In a repeated measures design, each participant slept under three conditions in randomised order: 1) no motion, 2) fore/aft orientation (side-to-side motion), and 3) athwartships orientation (head-to-foot motion). Measurements of sleep (ambulatory polysomnography), sleepiness (Karolinska Sleepiness Scale: KSS), and vigilance (Psychomotor Vigilance Test: PVT) were analysed using Mixed Effects ANOVA.

Results

Participants’ total sleep time was shorter (p<0.001), sleep efficiency was reduced (p<0.001), they woke more frequently (p<0.001), and their sleep contained less REM (p<0.001) in the athwartships orientation (head-to-foot motion) compared to the no motion, and fore/aft orientation (side-to-side motion) conditions. Participants’ also reported significantly higher sleepiness on KSS (p=0.006), poorer subjective sleep quality (p<0.001), and displayed worse vigilant attention on PVT (p=0.03) following the athwartships orientation compared to the two other conditions.

Discussion

The simulated athwartships bunk orientation (head-to-foot motion) negatively impacted sleep and cognitive performance. These results may have implications for crew wellbeing. The data also gives unique theoretical insight into the effects of different types of rhythmic movement on sleep.

Funding

DSTG
O041 The impact of including oxygen desaturations occurring during awake epochs on the oxygen desaturation index
Authors: Whenn C , Wilson D , Churchward T , Ruehland W , Worsnop C , Tolson J
Published: October 2021

Introduction

The oxygen desaturation index (ODI) is an important measure of sleep disordered breathing during polysomnography (PSG) however there is no accepted standard for its calculation. The AASM Manual for the Scoring of Sleep and Associated events (V2.6) does not specify whether oxygen desaturations occurring during awake epochs should be included. More generally, epoch-based scoring is potentially problematic for accurate ODI calculation. This study aims to compare the calculation of ODI including and excluding oxygen desaturations occurring during awake epochs and to determine the impact of sleep efficiency (SE) on any discrepancy.

Methods

Using twenty-one consecutive unattended PSG’s for investigation of OSA, two oxygen desaturation indices were calculated from each PSG; one excluding (ODIsleep) and one including (ODIall) oxygen desaturations marked in awake epochs.

Results

The median (IQR) ODIall was 19.3/h (10.3, 27.0) and ODIsleep was 13.0/h (6.6, 16.7). The median (IQR) difference (ODIall - ODIsleep) was 5.2/h (2.7, 10.4). This difference was greater with decreasing SE (r = -.63, p = .002). Patients with SE ≤ 75% (n=10) had a median ODI difference of 11.5/h (4.0, 17.6), and those with SE > 75% (n=11) had a difference of 2.8/h (2.0, 5.5) (p = .02).

Discussion

ODI was greater when including oxygen desaturations during awake epochs, with this discrepancy being greatest when SE is ≤ 75%. We plan to confirm these findings in a larger sample. This investigation informs clinical practice, highlights the difficulties of epoch scoring, and informs future standards for the scoring of sleep and associated events.
O042 Impact of supine REM AHI on diagnostic sleep studies for OSA
Authors: Callum J , Stranks L , Melehan K , Yee B
Published: October 2021

Introduction

A conventional belief is that REM exacerbates positional OSA (POSA). Subsequently, PSGs often report on presence of supine REM with the presumption that without supine REM, the AHI may be underestimated. This study explores the impact of REM upon obstructive respiratory events in sleep when supine.

Methods

From 1/1/2019 through 31/12/2020 PSGs for OSA diagnosis performed using Sleepware G3 were reviewed. A subgroup analysis was conducted within POSA patients defined as 1) total AHI>10/hour and non-supine AHI<10/hr, 2) supine AHI>2x non-supine AHI and 3) at least 15min of supine and non-supine sleep. Data was analysed with Pearson’s Chi Squared Test using Stata 16.1.

Results

Supine REM occurred in 97% of the 467 PSG’s. The supine REM AHI was 32.1(95%CI 29.1–35.2), compared to supine NREM AHI of 36.6(33.5–39.6), non-supine REM AHI of 21.3(18.8–23.9) and non-supine NREM AHI of 19.9(17.3–22.5).

Among 109 POSA patients the supine REM AHI was 31.7(26.1–37.4) compared to 28.9(24.8–32.9) in supine NREM, 9.5(6.1–12.9) in non-supine REM and 3.5(3.0–4.0) in non-supine NREM.

The average duration of obstructive respiratory events was 27.3 seconds (26.2–28.5) in REM compared to 23.5 seconds (22.8–24.2) in NREM. This statistically significant difference did not persist in POSA patients.

Discussion

The results do not support an additive effect of REM beyond supine positioning among patients with POSA, however there is evidence that REM lengthens respiratory events, which may reduce AHI. In the POSA subgroup analysis, there was an increased AHI in REM compared to NREM only in the non-supine position.
O043 “My Fitbit tells me I don’t sleep” – Validation of a consumer-wearable device (Fitbit Charge 3TM) using gold standard in-laboratory polysomnography to assess sleep in adults presenting for medical evaluation in a sleep laboratory
Authors: Munsif M , Jumabhoy R , Rangamuwa K , Mansfield D , Drummond S , Dabscheck E
Published: October 2021

Background

There has been a rapid growth in wearable devices marketed for sleep. Trackers such as the Fitbit collect data through an accelerometer and use heart rate variability to estimate the sleep-wake state. Currently, Fitbit validation studies have only been with “healthy” adults and Insomnia Disorder.

Aims

The purpose of this study is to evaluate the accuracy of Fitbit Charge3TM compared to in-lab polysomnography (PSG) in patients with sleep disorders. Our hypothesis is that Fitbit Charge 3TM will perform with less sensitivity and specificity relative to PSG in the presence of sleep disorders.

Methods

A prospective study of patients attending a PSG through Epworth Camberwell Sleep Lab between 2019–2021 will be conducted. Fitbit Charge3TM will be worn on the wrist with concurrent PSG monitoring.

Parameters measured with both PSG and Fitbit Charge3TM will include total sleep time, Sleep onset latency, wake after sleep onset and time spent in N1, N2, N3 and REM sleep (min). Standard PSG data will be evaluated to diagnose sleep-disordered breathing.

Progress to date:Ethics approval has been obtained, and 110 participants have been recruited. 30-second epoch-by-epoch analysis will now be conducted. Bland-Altman analyses will be performed to assess agreement between the Fitbit and PSG.

Intended outcome and impact: Our novel study findings will provide evidence to address queries regarding the accuracy of the Fitbit trackers to evaluate sleep and may support the use of Fitbit Charge3TM as an initial screening device to assess sleep duration and sleep architecture in select patients.
O045 Anxiety and daytime sleepiness scores have a weak but statistically significant correlation with apnoea-hypopnoea index
Authors: Lachowicz J , Kee K , Wallbridge P , Stonehouse J , Perkins A
Published: October 2021

Background

Previous datasets demonstrate inconsistent relationships between apnoea-hypopnoea index (AHI) and questionnaire measures of daytime sleepiness, anxiety and depression.

Methods

1149 consecutive diagnostic polysomnograms at a quaternary hospital were retrospectively analysed (2020–2021). Relationships between age, sex, AHI, Epworth Sleepiness Scale (ESS) and Hospital Anxiety and Depression Scales (HADS-A and HADS-D) were reviewed.

Progress to date:Mean age was 47.8+/-15.7 years, with male gender bias (59%). 49.9% had elevated HADS-A (>7; mean 8.1+/-4.5). 33.7% had elevated HADS-D (>7; mean 6.2+/-4.0). 29.6% had sleepiness (ESS >10; mean 7.9+/-5.0). Mean AHI was 23.5+/-27.9 events/hour. 69.7% had obstructive sleep apnoea (OSA); 45.0% were moderate-severe (AHI >14/h).

HADS-A (9.1 versus 7.3; P<0.001; 95% CI [-2.32, -1.25]), HADS-D (6.9 versus 5.8; P<0.001; 95% CI [-1.62, -0.67]) and ESS (8.2 versus 7.7; P=0.039; 95% CI [-1.21, -0.03]) were higher in females. Males had greater OSA severity (AHI 27.0/h versus 18.6/h; p<0.001; 95% CI [5.15, 11.67]).

Pearson’s tests demonstrated a statistically significant but weak positive correlation between AHI and HADS-A (P=0.021, R=0.07, N=1096), and AHI and ESS (P=0.042, R=0.06, N=1135). AHI and HADS-D showed no correlation. ESS weakly correlated with HADS-A (P<0.001, R=0.237, N=1104).

Intended outcome and impact:Severity of sleep apnoea as defined by AHI only explains a small proportion of the variance in daytime sleepiness and anxiety as measured by the ESS and HADS-A, respectively, with weak linear relationships demonstrated. Neither ESS nor HADS-A were helpful in predicting the presence of OSA. Further study is required to determine optimal polysomnographic correlates of sleep apnoea symptoms.
O046 Association of sleep characteristics with low muscle strength: the Hypnolaus cohort study
Authors: Piovezan R , Yu S , Hirotsu C , Marques-Vidal P , Visvanathan R , Heinzer R
Published: October 2021

Background

Muscle deterioration is a hallmark of aging and sleep may play a role in the development of sarcopenia. Population-based studies including objective evaluation of sleep characteristics and disorders may provide evidence of how sleep affects muscle function across adulthood. We aimed to evaluate associations of sleep characteristics with handgrip strength in a population-based cohort study.

Methods

Participants of the HypnoLaus study (Lausanne, Switzerland) aged >40 years were cross-sectionally evaluated through questionnaires and PSG. Muscle strength was assessed by hand dynamometer and low muscle strength (LMS) was defined according to the criteria for sarcopenia (<27 kg for men, <16 kg for women). Multivariate logistic regression analysis controlling for potential confounders wereapplied.

Results

1902 participants (mean [SD] age, 57.4 [10.5] years; 968 [50.9%] female) were enrolled. LMS was detected in 95 (5.0%) participants. After controlling for sociodemographic characteristics, lifestyle factors, and comorbidities, objectively measured long sleep duration (>8h) was independently associated with LMS (OR=2.41, 95%CI=1.36–4.27). Subjective measures of sleep duration and quality, excessive daytime sleepiness, and other sleep characteristics obtained by PSG were not associated with LMS.

Conclusions

Objectively measured long sleep duration rather than short sleep duration was associated with LMS in a population-based study including participants aged >40 years. Self-reported sleep duration was not associated with LMS. The findings suggest long sleep duration measured by PSG is a potential risk factor for sarcopenia and should be considered as a target in preventive and therapeutic strategies against the development of muscle health decline observed with aging.
O047 Sleep quality and fatigue in children and adolescents with multiple sclerosis
Authors: Tran J , Yiu E , Vandeleur M , Adams A
Published: October 2021

Background

Fatigue is common in children and adolescents with multiple sclerosis (MS) and its aetiology is assumed to be multifactorial, however, its relationship to sleep quality in this population remains unknown. This study aims to examine the prevalence of fatigue and sleep disturbance in this population and their relationship to mood, quality of life, physical activity, and MS disease characteristics.

Methods

Children with pediatric onset multiple sclerosis (POMS) aged 0–18 were recruited. Subjective sleep quality was assessed by the Pediatric Daytime Sleepiness Scale (PDSS), Sleep Disturbance Scale for Children (SDSC) and OSA-18. All children were referred for polysomnography (PSG) including transcutaneous CO2 and video monitoring. Fatigue was assessed using the PedsQL Multidimensional Fatigue Scale (PedsQL-MFS).

Progress to date: Fifteen children with relapsing remitting MS (mean age 15.73±1.44, mean EDSS score 1.11±1.12) have been enrolled to date. 73% of children were fatigued according to the PedsQL-MFS (mean transformed score 52.04). 67% and 60% of children scored higher than the clinical cutoff for the PDSS (17.87) and SDSC (42.73) respectively. However, all children scored within the normal range for the OSA-18 (34.00). To date, eleven children have completed PSG.

Intended outcome and impact: This is the first study utilising PSG to objectively assess sleep quality in children with POMS. Findings from this study will document the magnitude of sleep disturbance in this population and have implications for the management of fatigue and other related impairments observed in paediatric MS.
P026 Sleep during the transition to shift work: Preliminary findings of a longitudinal field study of commencing paramedics
Authors: Crowther M , Ferguson S , Adams R , Reynolds A
Published: October 2021

Paramedics are at increased risk of occupational injuries, mental illness and poor health outcomes. Little is known however about the role of poor sleep in such outcomes and the way in which sleep may change as an individual commences work as a paramedic. The aim of the present study is to investigate changes in sleep as paramedics commence work.

As part of an ongoing, longitudinal study of Australian paramedics, participants undertake a baseline assessment prior to commencing work and a follow up every three months for a year. At each time point paramedics wear an actigraph (GENEActiv) for seven days, and complete an online survey including the Pittsburgh Sleep Quality Index (PSQI). The present preliminary analysis utilised linear mixed models to test the effect of commencing work as a paramedic on participants’ sleep quality.

Preliminary results from the first cohort of recruits are reported (n=9 commencing paramedics, mean age (+SD) = 25.2±4.4, 56% female). There was a significant increase in PSQI scores from baseline (T0: 2.4±1.4) to three months (T1: 5.2±3.9) (F(1, 8) = 5.47, p = 0.05). The percentage of individuals with clinically poor sleep (PSQI ≥5) increased from 0% (n=0) at T0 to 56% (n=5) at T1.

Commencing paramedics report significantly poorer sleep quality compared to their pre-commencement levels. Interestingly, baseline PSQI scores indicate no participants were experiencing clinically defined poor sleep. However, at follow-up over half the sample reported clinically defined poor sleep. Findings of objective sleep and wake outcomes are anticipated for the meeting in October.
P034 Inter-scorer concordance impacts MSLT results
Authors: Eriksson N , Teuwen P , Mateus E , Shim C , Scott A
Published: October 2021

Introduction

A retrospective study on the effect of inter-scorer concordance and impact of analysing polysomnography (PSG) data prior to the Multiple Sleep Latency Test (MSLT) on clinical interpretation of Narcolepsy (N) and Idiopathic Hypersomnolence (IH).

Methods

Data of four individuals was randomly selected from a cohort of patients that participated in MSLT studies. De-identified MSLT fragments from four nap periods (n=16) were scored in two groups: analysis of PSG conducted prior to the respective MSLT fragments, and analysis without access to prior PSG. Individual scorers were compared to a master score set, by consensus from two experienced sleep scientists.

Spearman correlation and percentage agreement statistics were applied to calculate the inter-scorer concordance in sleep latency and REM latency. Mann-Whitney test was utilised to assess differences between the two groups. A positive result was assigned as: mean (n=4) sleep latency of <10min (IH), and mean (n=4) sleep latency of <8min including (n=2) SOREMs (N).

Results

From 16 sets of data, four false positive results were identified when PSG was not analysed prior to scoring the MSLT fragments. Additionally, statistically significant differences were present when PSG analysis was conducted prior to scoring MSLT sleep latency and REM latency data.

Discussion

These results support a recommendation that PSG analysis (sleep and REM latency) should be encouraged prior to MSLT studies and performed by the same sleep scientist. Furthermore, including MSLT data in intra-lab concordance activities is important, particularly in relation to medical interpretation and practice.
P038 Insomnia - Going backward to go forward
Authors: Fothergill T , Cunnington D
Published: October 2021

Background

Although there are common features in people with insomnia, for each individual there are possible different contributing factors and pathophysiological processes; each needing specific tailoring of treatment. We aim to understand treatments undertaken prior to specialist referral, common features on presentation and contributing factors in individual cases identified as part of their assessment.

Methods

We will undertake a retrospective audit of consecutive patients presenting with insomnia to a single private practice with a high insomnia case-load. We are collecting demographic data, details of prior and current treatments, clinical characteristics at presentation, outcomes of investigations and classification insomnia sub-type using the International Classification of Sleep Disorders-2 (ICSD-2). Data will be descriptive to allow understanding of the type and nature of patients presenting with insomnia and a deconstruction of contributing factors to the presenting problem of insomnia.

Progress to date

Low-risk ethics approval submitted via St Vincent’s Human Research Ethics Committee.

Literature review in progress.

Intended outcome and impact

The umbrella term “insomnia” belies its heterogeneity. Although there are common factors in most insomnia presentations, recognised in the simplification of diagnostic criteria in ICSD-3 and DSM 5, in managing individual patients it is also important to understand characteristics that are particular to the person. Whilst generic cognitive behavioural therapy for insomnia (CBTi) has been proven to be effective, in expert hands the response rate is still in the region of 60%, potentially reflecting a role for more tailored treatments for individuals to complement CBTi.
P041 The Impact of Simulated Night Shifts on Executive Functioning
Authors: Greer E , Matthews R , Centofanti S , Yates C , Stepien J , Dorrian J , Wittert G , Noakes M , Banks S
Published: October 2021

Nightwork is associated with fatigue, decreased sleep quality, and impairments in cognitive function. While attentional tasks have been widely investigated, there are limited data on more complex tasks, such as executive functioning during nightwork. Workers often need to rapidly shift between tasks, adapting to new and complex situations. The aim of this study was to investigate the impact of nightwork on executive functioning.

Healthy, non-shift working individuals (N=8; 5F, 24.8±5.0y) participated in a 7-day live-in laboratory study. Participants underwent an 8h TIB baseline sleep, followed by 4 consecutive simulated nightshifts with 7h TIB sleep during the day and an 8h TIB recovery sleep. Participants were assessed for executive function at 2000h, 2200h, 0100h and 0400h. Executive functioning was assessed with a mental flexibility switching task where a 3D rotation and math task were displayed simultaneously with an arrow indicating which task to complete in a random order. Resulting throughput data were analysed using linear mixed models.

There was a main effect of time of night (F(3,77)=4.81,p=.004) on throughput such that there was a speed accuracy trade off over the night shift with slower switching ability later in the shift. There was also a main effect of nightshift (F(2,77)=54.33,p<.001) where participants’ performance improved on the task with each nightshift.

This study suggests executive functioning is impaired on nightshift with worse performance at 0400h. Task improvements over consecutive nightshifts may have been due to learning or acclimation to nightwork. Understanding complex task performance on nightshift is important for tailoring countermeasures.
P043 Telehealth-supported Level 2 paediatric home polysomnography
Authors: Griffiths A , Mukushi A , Adams A
Published: October 2021

Introduction

The gold standard for diagnosis of paediatric obstructive sleep apnoea (OSA) is attended in-laboratory level 1 polysomnography (PSG). In our service, we select some children for unattended home level 2 PSG (HPSG) with telehealth support. We audited our HPSG service from 2013 to 2020.

Methods

We retrospectively audited level 2 home PSG reports in children aged 5–18 years referred for suspected OSA between 2013 and 2020. Tests were performed with the Compumedics Somte PSG acquisition device. The primary outcome was % of studies achieving a technically adequate diagnosis. Secondary outcomes included sleep duration, sleep efficiency and parental acceptance by non-validated service-specific questionnaire. Data was analysed using descriptive & inferential statistics. χ² tests were used for categorical variables.

Results

There were 235 (140 male, 59.6%) patients studied between 2013 and 2020 (7 years). The mean age was 10.8 (SD 3.6) years. 69 patients (29.4%) had co-morbidities. Repeat studies were indicated in 10.2% (24/235) due to technical failure. There was no significant difference between failed studies set up by HITH nurses compared with Sleep scientists (p=0.1). A technically acceptable diagnosis was made in 87% (205/235) patients, with no reason for under-estimation in 74.9%, and potential under-estimation in 17.9%. No diagnosis was achieved in 7.2%. 6 hrs or more sleep was obtained in 83%. Parental questionnaires revealed 89% perceived high-level care, 91% perceived increased convenience and 76% good/excellent telehealth support.

Discussion

Telehealth-supported paediatric HPSG achieves a technically adequate diagnosis in 87%, with 83% achieving ≥6 hrs sleep duration, and excellent family acceptability.
P046 More teaching, less sleeping: The impact of stressful periods of the school year on the sleep of Australian schoolteachers
Authors: Friday M , Gupta C , Ferguson S
Published: October 2021

Introduction

There are approximately 270,00 schoolteachers in Australia and this population experience multiple stressors at work. This can lead to poor sleep quality and quantity and, consequently, adverse outcomes for both schoolteachers and students. While it is well-established that certain periods of the year may lead to increased stress for schoolteachers, the impact of this on sleep is unknown. The current study aimed to investigate the effect of stressful periods of the school year on the sleep of schoolteachers.

Methods

The Pittsburgh Sleep Quality Inventory (PSQI) and questions on stressful school periods (including report writing, standardised testing, school appraisal, and teacher performance) were completed online by 775 Australian primary and secondary schoolteachers (89.1% female, 29.9% 25–34 years). Pearson Chi-square analyses were performed.

Results

Scores on the PSQI indicated that 611 (79.0%) of participants were experiencing poor sleep quality. There were significant relationships between each of the stressful periods of the year and PSQI score, such that increased stress during periods of report writing (p<0.001), standardised testing (p<0.001), school appraisal (p<0.001), and teacher performance (p<0.001) was associated with poor sleep quality.

Discussion

Australian schoolteachers are at risk of poor sleep quality and quantity, and this is exacerbated by stressful periods of the school year. Given the vital role schoolteachers play in the community, organisations should be mindful of these periods of the year in order to improve the sleep of schoolteachers.
P051 SLEEP SPINDLES AND SWA DIFFERENTIALLY CORRELATE WITH OVERNIGHT EPISODIC AND VISUOSPATIAL MEMORY CONSOLIDATION IN OLDER ADULTS WITH AND WITHOUT MILD COGNITIVE IMPAIRMENT
Authors: Haroutonian C , D’Rozario A , Terpening Z , Lewis S , Naismith S
Published: October 2021

Introduction

Sleep microarchitecture disruption is a feature of ageing that is further altered in neurodegenerative disorders. Sleep-memory links in younger adults have been established, however mechanistic pathways of this uncoupling in ageing is poorly understood.

Method

Our sample consisted of n=46 mild cognitively impaired (MCI) older adults and n=32 cognitively-intact controls who underwent overnight polysomnography and episodic (Rey Auditory Verbal Learning test) and visuospatial (Rey-Osterrieth Complex Figure task) memory tasks that were administered before and after sleep. We examined group differences in overnight memory % retention and associations with NREM slow oscillations (SO, 0.25–1 Hz), delta power (0.5–4 Hz), N2 spindle events (occurrence [11–16 Hz] and slow [11–13 Hz] and fast [13–16 Hz] spindle density p/min) and REM theta power (4.5–8 Hz).

Results

Repeated measures ANCOVA, controlling for age, indicated greater memory scores in Controls compared to MCI on the episodic task, F=6.7 (p=.01), and no group differences in the visuospatial task (F=1.8, p=.17). In Controls, greater delta power was associated with increased episodic memory retention (r=.515, p=.006). In the MCI group, episodic memory was associated with fast spindle density (r=-.352, p=.04), and visuospatial memory was also associated with fast spindle density (r=-.385, p=.01) and spindle occurrence (r=-.479, p=.003).

Conclusion

Sleep spindles appear to be negatively associated with memory retention, specifically in MCI. However, given the heterogeneity of MCI, further analysis of its cognitive subtypes is warranted. Comprehensive cognitive and neural pathophysiology profiling are required to better delineate the function of spindles in ageing.
P053 Management of insomnia by Australian psychologists
Authors: Haycock J , Hoon E , Sweetman A , Lack L , Lovato N
Published: October 2021

Introduction

Insomnia is the most common sleep disorder, 10–30% of adults have regular difficulties falling and/or staying asleep that cause significant daytime impairments. General Practitioner (GP) clinical guidelines recommend Cognitive Behavioural Therapy for insomnia (CBTi) as the first-line treatment rather than medications. However, most GPs do not have the time or training to administer CBTi, and consequently, many patients are prescribed sedative-hypnotic medicines. Psychologists have training in CBT and may be well placed to deliver behavioural therapy for insomnia. However, the amount of sleep-specific training, and knowledge of CBTi among Australian psychologists remains unknown. Identifying key barriers and enablers in the management of insomnia within psychology provides a first step in engaging with psychologists about the delivery of evidence-based insomnia treatment.

Methods

This qualitative study used a pragmatic inductive approach. Semi-structured interviews were conducted with 26 Australian psychologists. Interviews included case study scenarios to provide an in-depth exploration of psychologists’ knowledge and skills in the management of insomnia, and attitudes towards further training in CBTi. Interview transcripts were analysed using thematic analysis to identify themes.

Results

Preliminary themes identified in the data include; psychologists believe sleep is important for general well-being, insomnia is usually seen as secondary to other co-morbid disorders such as depression and anxiety that are the focus of treatment, most psychologists surveyed lack training and knowledge in CBTi.

Discussion

Most Australian psychologists are not well prepared to manage insomnia effectively with CBTi. Along with other primary health care professionals, psychologists need training in the management of insomnia.
P068 Improving patient streaming for Chronic insomnia: Single centre retrospective cohort study
Authors: Krebs L , Ellender C
Published: October 2021

Background

Insomnia is a common sleep disorder associated with significant morbidity and psychological distress. Cognitive Behavioural Therapy for insomnia (CBTi) is the gold standard intervention typically delivered by sleep psychologists. High demand has driven an interest in determining the case mix and characteristics of patients referred with insomnia to identify patients that may be suitable for an alternative direct-to-psychology model of care.

Methods

A retrospective cohort study was performed, including cases referred to the Princess Alexandra Hospital Sleep Centre in 2016 – 2020. Patients were categorised as either “suitable for direct-to-psychology” or “required medical review”. “Direct to psychology” patients were defined as (i) referred for insomnia; or (ii) Insomnia Severity Index score ≥15/28; or (iii) diagnosed with insomnia per ICSD-3 by treating specialist; or (iv) patients referred for sleep psychology. Exclusion criteria were significant sleep disordered breathing (mean SpO2 <85%, Epworth sleepiness scale >16, driving inattention), highly co-morbid patients (neuromuscular weakness, COPD) and diagnosis of hypersomnia. These patients were categorised as “requiring medical review”. The demographic and polysomnographic characteristics of these two groups were then compared.

Progress

The study protocol is complete, ethical approval obtained (EX/2021QMS/76783), and data extraction has been competed. Analysis underway currently.

Intended outcome/impact

We aim to establish the characteristics of patients suitable for a direct to psychology pathway. This data will be used for service provision planning, could reduce patient waiting list times, and improve patient care. This model could then be explored for safety and efficacy and form the basis of future service provision work.
P070 Oronasal masks are associated with increased airway collapsibility and increased therapeutic CPAP requirements
Authors: Landry S , Mann D , Beare R , Joosten S , Hamilton G , Edwards B
Published: October 2021

Introduction

Continuous positive airway pressure (CPAP) delivered via oronasal masks are associated with lower adherence, higher residual AHI and CPAP requirement in comparison to nasal masks. Mechanisms contributing to increased CPAP requirement are not well understood. This physiological study aimed to assess the effect of mask type on upper airway anatomy and collapsibility.

Methods

13 OSA patients, underwent a sleep study during which they wore both nasal and oronasal mask for half the night each (order randomized). CPAP was manually titrated to determine therapeutic pressure. Passive upper airway collapsibility was assessed using the Pcrit technique. Participants then underwent an MRI wearing both the nasal and oronasal mask. Cine MRI was used to dynamically assess cross-sectional area of the retroglossal airway across the respiratory cycle with each mask interface. Scans were repeated at 4cmH2O, as well as at the nasal and oronasal therapeutic pressures.

Results

The oronasal mask was associated with both higher therapeutic pressure requirements (∆M±SEM; +2.6±0.5, p<0.001) and higher Pcrit (+2.4±0.5cmH2O, p=0.001) compared to the nasal mask. The change in therapeutic pressure between masks was strongly correlated with the change in Pcrit (r2= 0.73, p=0.003). Preliminary MRI analyses indicate robust increases in cross-sectional area associated with increasing pressure. After controlling for pressure and breath-phase, the retroglossal area was larger when using a nasal compared to an oronasal mask (+12.42±5.87mm2, p=0.03).

Conclusions

These preliminary findings suggest that oronasal masks worsen the collapsibility of the airway which likely contributes to the need for an elevated therapeutic pressure relative to nasal masks.
P071 Listening to Beyoncé: factors associated with non-attendance at an outpatient sleep clinic
Authors: Lau H , O’Brien D , Hundloe J , Samaratunga D
Published: October 2021

Introduction

Patient non-attendance at outpatient sleep clinics is common and costly. Little is known about the factors associated with sleep clinic non-attendance, especially in an Australian context. The goal of our audit was to identify the patient, referral, and appointment factors that may affect attendance at an outpatient sleep clinic.

Methods

A case-control study was performed in 171 patients (57 cases / non-attenders and 114 controls / attenders) who had a sleep clinic appointment between September 20th, 2020 and March 21st, 2021. Statistical analysis was performed using the two-sided chi-square test with a 5% significance level.

Results

The overall rate of non-attendance was 10.8%. The rates of non-attendance between new and review cases were similar. Being single (odds ratio [OR]: 2.49; p = 0.010), middle-aged (OR: 4.39; p < 0.001 vs. older-aged), or female (OR: 2.08; p = 0.026) was associated with a higher rate of non-attendance. English was the primary language for all non-attenders. A higher proportion of non-attenders than attenders were born in Australia. For new cases, the source of referral, reason for referral, and triage category did not affect attendance rates. Likewise, the patient’s primary sleep disorder and treatment status did not affect attendance for review cases.

Conclusion

Factors associated with non-attendance at an outpatient sleep clinic include being single, middle-aged, or female. By identifying patients at higher risk of clinic non-attendance, a more tailored approach can be developed to mitigate this issue.
P074 Night-to-night variability in obstructive sleep apnoea severity is associated with hypertension and high misdiagnosis rates
Authors: Lechat B , Naik G , Reynolds A , Aishah A , Scott H , Loffler K , Vakulin A , McEvoy R , Adams R , Catcheside P , Eckert D
Published: October 2021

Introduction

The impact of night-to-night variability in obstructive sleep apnoea (OSA) severity on important health outcomes such as blood pressure is unknown. This study aimed to determine the effects of night-to-night variability in the apnoea/hypopnoea index (AHI) on hypertension risk and OSA misdiagnoses.

Methods

In-home nightly monitoring of 67,278 participants from 151 countries, over ~170 nights per participant between July 2020 to March 2021 using a validated under mattress sleep analyser. Blood pressure measurements were available in 12,295 participants. OSA was defined as a mean nightly AHI >15events/h. Night-to-night variability was assessed as the standard deviation of AHI across nights.

Results

22.6% (95% CI: 20.9–24.3) of the cohort (13% of women, 25% of men) had an average AHI> 15 events/h sleep. The average nightly AHI variability ranged from 3±1 in people without OSA to 14±6 in people with severe OSA. Higher mean AHI (OR [95% CI], 1.44 [1.29, 1.61]) and greater nightly variability in AHI (1.57 [1.39, 1.76]) were associated with hypertension. In people with a mean AHI of ≥5 events/h, high night-to-night AHI variability was associated with a ~30% increased risk in hypertension, independent of OSA severity category. Likelihood of misdiagnosis of OSA based on a single night compared to the mean across all nights was ~20%; this decreased with more monitoring nights.

Conclusions

These findings highlight the novel, important information that simple multi-night monitoring of OSA can yield. This includes the potential importance of night-to-night variation and its contribution to hypertension and increased confidence of OSA diagnoses.
P083 Age of Nap Cessation and Short-term Social-Emotional Functioning in Early Childhood
Authors: Loeffler A , Rankin P , Thorpe K , Staton S
Published: October 2021

Background

Daytime nap cessation, in which sleep transitions from biphasic to monophasic sleep, is a common feature of early childhood sleep patterns. Yet, to date, understanding of the meaning of this transition for children’s development is not well understood. The aim of this study is to investigate the relationship between the age of nap cessation and behavioral and social functioning in young children.

Methods

Parent report data from the Effective Early Educational Experiences (E4Kids) study of N=1700 children from across Queensland and Victoria is analysed. Data on age of nap cessation, Strengths and Difficulties Questionnaire (SDQ), and Social Skills Improvement Scale (SSIS) is examined to determine whether age of nap cessation is associated with internalizing and externalizing behaviour and social skills in early childhood.

Progress to date

Data collection and cleaning are complete. Initial descriptive analyses and identification of significant covariates are underway, and final regressions will be run shortly.

Intended outcome/ Impact

This study provides new evidence on the relationship between age of napping cessation and social-emotional outcomes in young children. Such evidence is important for building an understanding of the role of sleep cessation in children’s early development, and to inform practitioners and parents responsible for supporting children’s sleep.
P085 Body composition effects of High Intensity Functional Exercise training during rapid weight loss in obese patients with obstructive sleep apnoea: A pilot randomised controlled trial
Authors: Lowrie F , Phillips C , Yee B , Gordon C , Marshall N , Cayanan E
Published: October 2021

Introduction

While Very Low Energy Diets (VLEDs) have been proven to reduce weight in patients with obstructive sleep apnoea (OSA) and co-morbid obesity, they can also result in excessive loss of muscle mass which adversely impacts health. Concurrent exercise training is considered an effective method of preventing muscle mass loss.

Methods

This prospective randomised controlled trial will recruit 30 overweight and obese men with untreated moderate-to-severe OSA to undergo a 12-week VLED with or without high-intensity functional exercise (HIFE) training. HIFE will be delivered through a commercially available supervised exercise program and incorporates interval training with a combination of progressively graded aerobic and anaerobic exercise.

The primary outcome measures are changes in body composition, assessed by dual x-ray absorptiometry (DEXA), and OSA severity (measured by apnoea hypopnea index). Secondary outcomes include glucose tolerance, ventilatory response, and peak oxygen uptake.

Data will be analysed on an intention-to-treat basis. Paired T-tests will be used to test the treatment effect of exercise compared to control. Confidence intervals will be used to analyse change in muscle mass and other secondary outcomes.

Results

Only one participant has completed the protocol to date. No results are available at this time.

Discussion

The results of this pilot study will look to confirm whether HIFE can protect against muscle mass loss, and additively benefit OSA severity during VLED, compared to VLED alone. It will also inform estimation of feasibility for a larger definitive study.