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Introduction: Temporal patterns for suicide over a 24-hour period have shown mixed results among prior studies. However, analyses of 24-hour temporal patterns for wakeful actions including suicidal behavior, should adjust for expected sleep requirements that inherently skew such activities to conventional wakeful times. This study analysed the time-of-day for suicide cases from the Australian population for the year 2017, adjusting for expected sleep patterns. Identification of time-of-day trends using this methodology may reveal risk factors for suicide and potentially modifiable contributors. Method(s): The Australian Coronal database was accessed and data for suicide deaths were extracted for the most recent completed year, 2017. Time of suicidal action is frequently unable to be pinpointed and for this analysis an estimation was performed from time last seen alive and time found subsequently using data extracted from police and coronial reports. Time of suicide was allocated to one of four 6-hourly time bins across 24 hours from the mid position of time last seen alive and time found subsequently. Cases were excluded if allocation to a time bin was not able to be confidently determined if time last seen and time found crossed both boundaries for a given time bin. Prevalence of suicide for each time bin was adjusted for the likelihood of being awake for each bin according to sleep-wake norms published in 2020 from a large Australian community survey of 1966 subjects. Observed prevalence of suicide were compared to expected values predicted from likelihood of being awake across each time bin calculated as a standardised incidence ratio (SIR). Result(s): For year 2017 there were 2208 suicides for which 1407 were able to be allocated into one of four 6-hourly time bins. Reasons for exclusion were cases for which allocaton into a time bin was not able to be performed. When adjusted for the likelihood of being awake based from population norms, cases were significantl

Introduction: Obstructive sleep apnea (OSA) is a chronic medical condition, characterised by recurrent episodes of partial and complete collapse of the upper airway during sleep. Untreated, OSA is associated with long-term health consequences. Recently, the use of hypoglossal nerve stimulation (HGNS) has shown promise in addressing OSA through dose-titratable electrical stimulation to reduce disease severity and provide symptom relief. However, current HGNS systems are contraindicated for OSA patients with complete concentric collapse (CCC) of the retropalatal airway. Therefore, a multicentre, prospective, open-label, two group study was designed to assess the safety and performance of a bilateral HGNS system in adult patients with moderate-to-severe OSA with and without CCC. Method(s): Participants with moderate-to-severe OSA and body mass index <=32 kg/m2 who failed, refused or did not tolerate positive airway pressure therapy were enrolled, provided they met additional inclusion/exclusion criteria. At screening, polysomnographies (PSGs) and drug induced sleep endoscopies (DISEs) were performed. DISE recordings were assessed for presence of CCC by an independent core laboratory. Eligible participants received a bilateral HGNS system (Genio, Nyxoah SA, Belgium) via placement of an implantable stimulator through a single-incision under the chin. Devices were activated six weeks post-implant with monthly in-laboratory PSGs and therapy titrations performed up to the primary endpoint visit. Safety endpoint included the incidence of device-related serious adverse events (SAEs) from consent to 6 months post-implant. Safety events were adjudicated by an independent clinical events committee (CEC). Primary and exploratory efficacy endpoints were defined as a mean reduction in AHI (4% oxygen desaturation, AHI4) at 6 months post-implant for the entire cohort and for the CCC subgroup, respectively, as determined by an independent statistician. Scoring followed the American Ac

Background: CPAP is widely accepted as the gold standard treatment for severe OSA, however low socioeconomic status is associated with poor uptake and adherence to therapy. CPAP treatment is not universally subsidised under any Australian Government scheme, limiting access to CPAP for low income earners with severe OSA. The Monash CPAP Program is run through a public hospital clinic and offers significantly subsidised CPAP treatment to Pensioner Concession Card holders with at least moderate OSA and who meet clinical and adherence criteria. We studied a group of patients enrolled into the program to determine their baseline characteristics, the time on the waitlist for a CPAP machine, as well as their adherence at follow up. Method(s): We identified patients who met the eligibility criteria and placed on the waitlist between 1st January 2015 to 31st December 2015. Baseline demographic information, polysomnography data and time on the waitlist were determined from a database. We reviewed the medical records for follow up and any missing data. If no follow up was recorded, the patient was contacted and asked a short questionnaire regarding their adherence to therapy. Progress to date: 194 patients were waitlisted over the 12 month study period. Mean total AHI was 52.4/hr at the time of waitlisting. Mean time spent on the waitlist was 193 days. Preliminary analysis based on 25 patients shows an adherence rate of 70% after at least 6 months. Intended outcome and impact: Our primary aim is to identify the level of adherence to CPAP in the study population. We hypothesise adequate adherence will be present in > 50% of subjects, based on previously published data. Secondary aims will examine the effects of time on the waitlist, baseline OSA severity and symptoms on adherence. This analysis will be useful in assessing the impact of funded CPAP and provide a guide as to whether patients most in need are receiving access to treatment in a timely fashion., T. Cheung, Monash Health, Australia, CONFERENCE ABSTRACT

Introduction: REM Behaviour Disorder (RBD) is characterised by abnormal behaviours during REM sleep associated with REM sleep Without Atonia (RWA). The American Academy of Sleep Medicine (AASM) describes PSG features of RWA as either sustained muscle activity in REM Sleep in the Chin EMG and/or excessive transient muscle activity during REM sleep in the chin or limb EMG. Aim(s): This study aimed to investigate how well the periodic limb movement index (PLMi) in REM sleep performs as a marker for RWA. Method(s): All sleep studies from 1/1/2019 to 1/6/2019 were reviewed for RWA, Limb movements and criteria for RWA. N = 590 (242 female). BMI = 32 +/- 8 kg/m2 and age 49 +/- 16 years). 60% of the patients with RWA had REM PLMi > 5 compared to 35 (6%) of patients without RWA. Odds ratio 22.7 (p < 0.05). Sensitivity = 0.6, specificity = 0.94. However, because of the low prevalence of RWA, positive predictive value for PLMI > 5 indicating RWA was 30% (95% CI: 0.2, 0.4) and negative predictive value was 98% (95% CI: 0.96, 0.99) Conclusion(s): Patients with RWA are far more likely to have elevated REM PLMi than those without. This overlap is likely due to similarities in the scoring of limb movements and transient EMG increases. The presence of an elevated REM PLMi should prompt further investigation of RWA. Notably, the prevalence of RWA in this sample may underrepresented as upper limb movements were not measured. This is an area of future research.

Introduction/Aim. Nasal high flow (NHF) may improve symptoms of dyspnoea in both stable and acutely exacerbating chronic obstructive lung disease (COPD). This may reduced symptoms are readmission rate. Method(s): This was a feasibility study prospectively recruiting subjects admitted to hospital for acute uncomplicated exacerbations of COPD.Consenting subjects were commenced on NHF and discharged when clinically stable determined by the clinical team who were not part of the study. NHF was maintained for minimum of 6 hours per day in the home setting for 30 days under supervision of HITH. Outcome measures were compared to matched retrospective controls Conclusion. The addition of NHF to the discharge plan supported by HITH was not associated with reduced LOS but was associated with low 30 day readmission rate.

Background: Obstructive sleep apnoea (OSA) is a common sleep disorder that can present with a variety of clinical symptoms. Continuous positive airways pressure (CPAP) therapy is the treatment of choice in moderate to severe OSA, however long-term adherence to treatment can be challenging. Recent studies have attempted to identify clinical phenotypes which may aid in guiding treatment and thus improve clinical outcomes. This study's aim was to determine the symptom profile at presentation of a cohort of patients with suspected sleep apnoea and how they relate to treatment choice and adherence. Method(s): Retrospective review of new referrals for suspected obstructive sleep apnoea between July 2017 and June 2018 for 2 physicians. Referral letters, physician review letters, polysomnography results and practice management software data were reviewed to establish presenting symptoms, OSA severity, treatment recommendations and CPAP adherence. We attempted to group patients into the clusters as defined by Keenan et al (Sleep 2018), however patients were not clearly demarcated into the published groups. Adequate CPAP adherence was defined as an average of >=4 hr per night. Progress to date: Data on N = 119 patients were reviewed. Of 119 patients, 15 (12.6%) had no OSA, 27 (22.7%) had mild, 31 (26%) moderate and 46 (38.7%) severe OSA. Mean (+/-SD) age, BMI, ESS and AHI were: 53.8 (+/-14.8) years, 32.9 (+/-8) kg/m2, 8.3 (+/-5.4) and 29.4 (+/-24.3) events/hr respectively. Patients frequently presented with more than one symptom group, with 48 patients reporting one symptom category, 45 with two, 20 with three and 6 with 4 symptom categories. The most common symptom on presentation was loud snoring (n = 65), followed by excessive daytime sleepiness (n = 46) and witnessed apnoeas/gasping (n = 44). Other presenting symptom categories included disturbed sleep, tiredness/fatigue and co-morbid risk factors. CPAP therapy was recommended for 73 patients (61%). 25% of patients prescr

The ASA acknowledges that sleep study analysis remains a partially subjective endeavour and requires accredited sleep services to periodically assess inter-scorer variability through external proficiency testing programs. These programs assess en masse scoring of PSG records and allow individuals and lab groups to determine their general compliance with the wider field. These programs do not directly assess the application of specific AASM rules. Given the frequent changes to the AASM respiratory scoring rules and the subtle ambiguities in some of their wording, we suspected significant variability in the analysis of certain types of respiratory events. To test this, we developed a simple quiz comprised of six carefully chosen respiratory events and distributed it to the major public teaching hospitals in Melbourne. The events were depicted in a simplified and idealised manner via thermistor and summed respiratory effort traces. Participants were asked to mark the duration of each event and to classify it as a Hypopnoea, Obstructive, Central, or Mixed Apnoea. A cut-off of 80% was used to define satisfactory concordance. A total of 55 scorers from nine labs participated. Combined responses satisfactorily classified two respiratory events, with agreements of 93% and 96%. The remaining events achieved unsatisfactory agreement of between 65% and 71%. Four labs achieved satisfactory internal concordance, with the remaining labs achieving unsatisfactory internal concordances between 65% and 79%. Analysis of event duration showed only three of six durations were scored with acceptable agreement. These results show that unsatisfactory levels of inter-scorer variability persist despite the use of external proficiency testing programs. These results also suggest that the current approach to proficiency testing should be complimented by a more focused approach that elicits correct interpretations of the AASM rules.

Background: Upper airway surgery (UAS) is an accepted treatment alternative to continuous positive airway pressure therapy (CPAP) for patients with Obstructive Sleep Apnoea (OSA). Current clinical tools cannot accurately predict who will respond to UAS for OSA. Whilst Computed Tomography has been used extensively to evaluate the effects of UAS on the upper airway, Magnetic Resonance Imaging (MRI) is emerging as a useful imaging modality with the advantages of superior resolution of soft tissue boundaries and the avoidance of radiation exposure. Segmentation, the process of software-assisted image analysis to identify anatomical boundaries to allow accurate calculation of cross-sectional areas and volumes, has been used in conjunction with MRI to understand how alternatives to CPAP therapy such as oral appliances improve the upper-airway and whether this information can be used to predict response to therapy. However, to our knowledge, MRI-based segmentation has not been used to study patients undergoing UAS. Our aim is to use these advanced imaging analysis techniques to quantify changes in the dimensions of upper airway structures before and after surgery and to identify the changes that predict a favourable surgical outcome. Method(s): In an ongoing prospective study, 17 patients with OSA deemed suitable for UAS underwent a volumetric T1-weighted MRI scan of the upper airway at baseline and again three months after UAS. Single-night polysomnography was performed before and after in each case to assess for presence and severity of OSA. Using an open source software platform for medical image processing and analysis, the upper airway was segmented slice-by-slice in the axial plane by one author blinded to the operative status of the patient (i.e. pre-UAS vs. post-UAS). Analysis of the data was performed by an unblinded author not involved in the airway segmentation. Progress to date: Preliminary analysis of the total airway volume of 15 patients showed that the airw

Introduction: The efficacy of cognitive behavioural therapy for insomnia (CBT-I) is well-established but its implementation in practice is less known. This case series describes the uptake and outcomes of low-cost CBT-I in patients attending a multidisciplinary sleep clinic. Method(s): Self-report questionnaires and extraction of medical records. Result(s): 205 adult patients met DSM-5 criteria for insomnia (mean age 45.1 years, age range 18.1-84.9 years, and 41.5% male). Following sleep physician assessment, 194 (94.6%) were referred to psychologists for CBT-I. Of these, 121 (62.4%) commenced CBT-I at the present clinic, 11 (5.7%) participated in a research CBT-I trial, and 4 (2.1%) were referred for CBT-I elsewhere. 58 (29.9%) did not see a sleep psychologist despite recommendation. Of those who commenced CBT-I, 45 (37.2%) completed and were discharged, whilst 68 (56.2%) did not complete. 18 patients completed Insomnia Severity Index (ISI) questionnaires pre-and post-treatment. Mean reduction in ISI score was 10.2 (95% CI 7.4 to 12.9, p < 0.001). 88.9% of these patients reported that most or almost all of their needs were met. Discussion(s): These real-world findings from a multidisciplinary sleep clinic demonstrated about 30% of patients with insomnia did not proceed with recommended CBT-I. Furthermore, over half the patients who started seeing a sleep psychologist did not complete the program. The small number of patients who completed ISI questionnaires following CBT-I had improved ISI scores and most found the program beneficial. More work is required to identify factors predicting which patients will engage in and benefit from CBT-I.

Introduction: Upper airway surgery (UAS) is often recommended as a treatment for patients with obstructive sleep apnoea (OSA) who cannot tolerate continuous positive airway pressure (CPAP). Unfortunately, the efficacy of UAS can be highly variable and there are no reliable clinical predictors of which patients are likely to have their OSA resolved following UAS. The key to providing robust predictors of OSA resolution following UAS is to recognise that OSA is caused by multiple interactive anatomical and non-anatomical traits [i.e. i) ability of airway muscles to reopen the airway; ii) respiratory arousal threshold; and iii) ventilatory control system sensitivity-loop gain]. Importantly, it is unknown how surgery alters these traits which may impact treatment efficacy. Therefore, we aimed to examine the effect of UAS on the OSA trait(s) and whether knowledge of these traits can assist in predicting success to surgery (i.e. responder analysis). Method(s): In an on-going prospective study, 19 OSA patients scheduled for UAS (i.e. uvulopalatopharyngoplasty +/- tongue coblation +/- tonsillectomy +/- nasal surgery) have been studied before and 3-months post-surgery. In each condition, participants underwent clinical polysomnography to determine OSA severity and research polysomnography to measure the OSA traits using a validated technique that manipulates a participant's CPAP level and assesses the accompanying changes in ventilation. Values are presented as mean +/- standard error of the mean (SEM). For the responder analysis, responders were defined as having a reduction in apnoea-hypopnoea index (AHI) >= 50% from baseline. Result(s): Surgery reduced both the AHI (44.2 +/- 6.1 vs. 25.5 +/- 5.8 events/hr; p = 0.02) and Epworth sleepiness scale (median [interquartile range]:11 [10-14] vs. 7 [3-10]; p < 0.001). There was a strong trend for surgery to improve upper airway collapsibility (-15.6 +/- 12.8 vs. 22.0 +/- 15.3 %eupnoeic ventilation; p = 0.07) but had no impact on

Introduction: REM Behaviour Disorder (RBD) is characterised by abnormal behaviours during REM sleep associated with REM sleep Without Atonia (RWA). The American Academy of Sleep Medicine (AASM) describes PSG features of RWA as either sustained muscle activity in REM Sleep in the Chin EMG and/or excessive transient muscle activity during REM sleep in the chin or limb EMG. Aim(s): This study aimed to investigate how well the periodic limb movement index (PLMi) in REM sleep performs as a marker for RWA. Method(s): All sleep studies from 1/1/2019 to 1/6/2019 were reviewed for RWA, Limb movements and criteria for RWA. N = 590 (242 female). BMI = 32 +/- 8 kg/m2 and age 49 +/- 16 years). 60% of the patients with RWA had REM PLMi > 5 compared to 35 (6%) of patients without RWA. Odds ratio 22.7 (p < 0.05). Sensitivity = 0.6, specificity = 0.94. However, because of the low prevalence of RWA, positive predictive value for PLMI > 5 indicating RWA was 30% (95% CI: 0.2, 0.4) and negative predictive value was 98% (95% CI: 0.96, 0.99) Conclusion(s): Patients with RWA are far more likely to have elevated REM PLMi than those without. This overlap is likely due to similarities in the scoring of limb movements and transient EMG increases. The presence of an elevated REM PLMi should prompt further investigation of RWA. Notably, the prevalence of RWA in this sample may underrepresented as upper limb movements were not measured. This is an area of future research.

Introduction/Aim. Nasal high flow (NHF) may improve symptoms of dyspnoea in both stable and acutely exacerbating chronic obstructive lung disease (COPD). This may reduced symptoms are readmission rate. Method(s): This was a feasibility study prospectively recruiting subjects admitted to hospital for acute uncomplicated exacerbations of COPD.Consenting subjects were commenced on NHF and discharged when clinically stable determined by the clinical team who were not part of the study. NHF was maintained for minimum of 6 hours per day in the home setting for 30 days under supervision of HITH. Outcome measures were compared to matched retrospective controls Conclusion. The addition of NHF to the discharge plan supported by HITH was not associated with reduced LOS but was associated with low 30 day readmission rate.

Background: Obstructive sleep apnoea (OSA) is a common sleep disorder that can present with a variety of clinical symptoms. Continuous positive airways pressure (CPAP) therapy is the treatment of choice in moderate to severe OSA, however long-term adherence to treatment can be challenging. Recent studies have attempted to identify clinical phenotypes which may aid in guiding treatment and thus improve clinical outcomes. This study's aim was to determine the symptom profile at presentation of a cohort of patients with suspected sleep apnoea and how they relate to treatment choice and adherence. Method(s): Retrospective review of new referrals for suspected obstructive sleep apnoea between July 2017 and June 2018 for 2 physicians. Referral letters, physician review letters, polysomnography results and practice management software data were reviewed to establish presenting symptoms, OSA severity, treatment recommendations and CPAP adherence. We attempted to group patients into the clusters as defined by Keenan et al (Sleep 2018), however patients were not clearly demarcated into the published groups. Adequate CPAP adherence was defined as an average of >=4 hr per night. Progress to date: Data on N = 119 patients were reviewed. Of 119 patients, 15 (12.6%) had no OSA, 27 (22.7%) had mild, 31 (26%) moderate and 46 (38.7%) severe OSA. Mean (+/-SD) age, BMI, ESS and AHI were: 53.8 (+/-14.8) years, 32.9 (+/-8) kg/m2, 8.3 (+/-5.4) and 29.4 (+/-24.3) events/hr respectively. Patients frequently presented with more than one symptom group, with 48 patients reporting one symptom category, 45 with two, 20 with three and 6 with 4 symptom categories. The most common symptom on presentation was loud snoring (n = 65), followed by excessive daytime sleepiness (n = 46) and witnessed apnoeas/gasping (n = 44). Other presenting symptom categories included disturbed sleep, tiredness/fatigue and co-morbid risk factors. CPAP therapy was recommended for 73 patients (61%). 25% of patients prescr

The ASA acknowledges that sleep study analysis remains a partially subjective endeavour and requires accredited sleep services to periodically assess inter-scorer variability through external proficiency testing programs. These programs assess en masse scoring of PSG records and allow individuals and lab groups to determine their general compliance with the wider field. These programs do not directly assess the application of specific AASM rules. Given the frequent changes to the AASM respiratory scoring rules and the subtle ambiguities in some of their wording, we suspected significant variability in the analysis of certain types of respiratory events. To test this, we developed a simple quiz comprised of six carefully chosen respiratory events and distributed it to the major public teaching hospitals in Melbourne. The events were depicted in a simplified and idealised manner via thermistor and summed respiratory effort traces. Participants were asked to mark the duration of each event and to classify it as a Hypopnoea, Obstructive, Central, or Mixed Apnoea. A cut-off of 80% was used to define satisfactory concordance. A total of 55 scorers from nine labs participated. Combined responses satisfactorily classified two respiratory events, with agreements of 93% and 96%. The remaining events achieved unsatisfactory agreement of between 65% and 71%. Four labs achieved satisfactory internal concordance, with the remaining labs achieving unsatisfactory internal concordances between 65% and 79%. Analysis of event duration showed only three of six durations were scored with acceptable agreement. These results show that unsatisfactory levels of inter-scorer variability persist despite the use of external proficiency testing programs. These results also suggest that the current approach to proficiency testing should be complimented by a more focused approach that elicits correct interpretations of the AASM rules.

Introduction: The efficacy of cognitive behavioural therapy for insomnia (CBT-I) is well-established but its implementation in practice is less known. This case series describes the uptake and outcomes of low-cost CBT-I in patients attending a multidisciplinary sleep clinic. Method(s): Self-report questionnaires and extraction of medical records. Result(s): 205 adult patients met DSM-5 criteria for insomnia (mean age 45.1 years, age range 18.1-84.9 years, and 41.5% male). Following sleep physician assessment, 194 (94.6%) were referred to psychologists for CBT-I. Of these, 121 (62.4%) commenced CBT-I at the present clinic, 11 (5.7%) participated in a research CBT-I trial, and 4 (2.1%) were referred for CBT-I elsewhere. 58 (29.9%) did not see a sleep psychologist despite recommendation. Of those who commenced CBT-I, 45 (37.2%) completed and were discharged, whilst 68 (56.2%) did not complete. 18 patients completed Insomnia Severity Index (ISI) questionnaires pre-and post-treatment. Mean reduction in ISI score was 10.2 (95% CI 7.4 to 12.9, p < 0.001). 88.9% of these patients reported that most or almost all of their needs were met. Discussion(s): These real-world findings from a multidisciplinary sleep clinic demonstrated about 30% of patients with insomnia did not proceed with recommended CBT-I. Furthermore, over half the patients who started seeing a sleep psychologist did not complete the program. The small number of patients who completed ISI questionnaires following CBT-I had improved ISI scores and most found the program beneficial. More work is required to identify factors predicting which patients will engage in and benefit from CBT-I.

Background: Upper airway surgery (UAS) is an accepted treatment alternative to continuous positive airway pressure therapy (CPAP) for patients with Obstructive Sleep Apnoea (OSA). Current clinical tools cannot accurately predict who will respond to UAS for OSA. Whilst Computed Tomography has been used extensively to evaluate the effects of UAS on the upper airway, Magnetic Resonance Imaging (MRI) is emerging as a useful imaging modality with the advantages of superior resolution of soft tissue boundaries and the avoidance of radiation exposure. Segmentation, the process of software-assisted image analysis to identify anatomical boundaries to allow accurate calculation of cross-sectional areas and volumes, has been used in conjunction with MRI to understand how alternatives to CPAP therapy such as oral appliances improve the upper-airway and whether this information can be used to predict response to therapy. However, to our knowledge, MRI-based segmentation has not been used to study patients undergoing UAS. Our aim is to use these advanced imaging analysis techniques to quantify changes in the dimensions of upper airway structures before and after surgery and to identify the changes that predict a favourable surgical outcome. Method(s): In an ongoing prospective study, 17 patients with OSA deemed suitable for UAS underwent a volumetric T1-weighted MRI scan of the upper airway at baseline and again three months after UAS. Single-night polysomnography was performed before and after in each case to assess for presence and severity of OSA. Using an open source software platform for medical image processing and analysis, the upper airway was segmented slice-by-slice in the axial plane by one author blinded to the operative status of the patient (i.e. pre-UAS vs. post-UAS). Analysis of the data was performed by an unblinded author not involved in the airway segmentation. Progress to date: Preliminary analysis of the total airway volume of 15 patients showed that the airw

Introduction: Upper airway surgery (UAS) is often recommended as a treatment for patients with obstructive sleep apnoea (OSA) who cannot tolerate continuous positive airway pressure (CPAP). Unfortunately, the efficacy of UAS can be highly variable and there are no reliable clinical predictors of which patients are likely to have their OSA resolved following UAS. The key to providing robust predictors of OSA resolution following UAS is to recognise that OSA is caused by multiple interactive anatomical and non-anatomical traits [i.e. i) ability of airway muscles to reopen the airway; ii) respiratory arousal threshold; and iii) ventilatory control system sensitivity-loop gain]. Importantly, it is unknown how surgery alters these traits which may impact treatment efficacy. Therefore, we aimed to examine the effect of UAS on the OSA trait(s) and whether knowledge of these traits can assist in predicting success to surgery (i.e. responder analysis). Method(s): In an on-going prospective study, 19 OSA patients scheduled for UAS (i.e. uvulopalatopharyngoplasty +/- tongue coblation +/- tonsillectomy +/- nasal surgery) have been studied before and 3-months post-surgery. In each condition, participants underwent clinical polysomnography to determine OSA severity and research polysomnography to measure the OSA traits using a validated technique that manipulates a participant's CPAP level and assesses the accompanying changes in ventilation. Values are presented as mean +/- standard error of the mean (SEM). For the responder analysis, responders were defined as having a reduction in apnoea-hypopnoea index (AHI) >= 50% from baseline. Result(s): Surgery reduced both the AHI (44.2 +/- 6.1 vs. 25.5 +/- 5.8 events/hr; p = 0.02) and Epworth sleepiness scale (median [interquartile range]:11 [10-14] vs. 7 [3-10]; p < 0.001). There was a strong trend for surgery to improve upper airway collapsibility (-15.6 +/- 12.8 vs. 22.0 +/- 15.3 %eupnoeic ventilation; p = 0.07) but had no impact on

Introduction: Although cognitive behavioural therapy is a recognised effective non-pharmacological treatment for insomnia, there is limited information regarding its uptake in clinical practice. This case series describes the participation rates and effectiveness of cognitive behavioural therapy for insomnia in patients attending a multidisciplinary sleep clinic. Material(s) and Method(s): Cognitive behavioural therapy was delivered by psychologists. Data were collected using self-report questionnaires and extraction of medical records through opt-out consent. A paired-samples t-test was conducted to compare pre- and post-treatment Insomnia Severity Index (ISI) scores. Result(s): 205 adult patients met the DSM-5 criteria for insomnia. Mean age was 45.1 years (range 18.1 to 84.9 years). 41.5% were male. Following assessment by a sleep physician, 194 (94.6%) were advised to see a psychologist for cognitive behavioural therapy. Of these patients, 121 (62.4%) saw a psychologist at our clinic, 11 (5.7%) participated in a cognitive behavioural therapy research study, and 4 (2.1%) were referred to a psychologist elsewhere. 58 (29.9%) did not see a psychologist despite recommendation from their sleep physician. Compared with the patients who proceeded to see a psychologist, the group that did not participate in cognitive behavioural therapy reported similar baseline rates of hypnotic medication usage. Of those who saw a psychologist at our clinic, 45 (37.2%) completed cognitive behavioural therapy and were discharged. 68 patients (56.2%) did not complete the cognitive behavioural therapy program. 18 patients submitted ISI questionnaires pre and post completion of cognitive behavioural therapy. The mean reduction in ISI score was 10.2 (95% CI 7.4 to 12.9, p< 0.001). Most of these patients (88.9%) reported that the program had met most or almost all of their needs. Conclusion(s): These real-world findings from our multidisciplinary sleep clinic demonstrated about 30% of patie

Introduction: Upper airway surgery (UAS) is often recommended as a treatment for patients with OSA who cannot tolerate continuous positive airway pressure (CPAP). Unfortunately, the efficacy of UAS can be highly variable and there are no reliable clinical predictors of which patients are likely to have their OSA resolved following UAS. The key to providing robust predictors of OSA resolution following UAS is to recognise that OSA is caused by multiple interactive anatomical (i.e. collapsibility) and non-anatomical traits [i.e. i) ability of airway muscles to reopen the airway; ii) respiratory arousal threshold; and iii) ventilatory control system sensitivity - loop gain]. Importantly, it is unknown how surgery alters these traits which may impact treatment efficacy. Therefore, we aimed to examine the effect of UAS on the OSA trait(s) and whether knowledge of these traits can assist in predicting success to surgery (i.e. responder analysis). Material(s) and Method(s): In a prospective study, 23 OSA patients scheduled for UAS have been studied before and 3-months post-surgery. In each condition, participants underwent clinical polysomnography to determine OSA severity and research polysomnography to measure the OSA traits using a gold-standard technique. Values are presented as Mean +/- SEM or as Median [Interquartile range]. For the responder analysis, responders were defined as having a reduction in apnea-hypopnea index (AHI) >=50% from baseline. Result(s): UAS reduced both the AHI (38.7[53.2] vs 22.0[36.3] events/h; p=0.009) and Epworth sleepiness scale (10 [7] vs 6 [6.5]; p< 0.001). There was a strong trend for UAS to improve upper airway collapsibility (pre vs post-surgery: -1.7+/-3.8 vs 0.2+/-4.6 L/min; p=0.09). There was a deterioration in the ability of airway muscles to reopen the airway (0.6[0.9] vs 0.4[0.5]; p=0.02) after UAS, but there was no impact on the other non-anatomical traits (i.e. loop gain and arousal threshold). 7/23(30%) patients were classifie

Background and aims: Sleep disturbances commonly occur following Traumatic Brain Injury (TBI); however, evidence-based treatments are lacking. The aim of this study was to determine the effectiveness and safety of melatonin supplementation for sleep disturbances in patients with TBI. Method(s): Randomised, double-blind, placebo-controlled, two-period, twotreatment (melatonin and placebo) crossover study. Outpatients were recruited from Epworth and Austin Hospitals Melbourne, Australia. Outpatients with mild to severe TBI (n = 33) reporting sleep disturbances post injury (mean age 37 (SD, 11) years; 67% men). Prolonged-release melatonin formulation (2mg; Circadin R ) and placebo capsules for 4weeks each in a counter-balanced fashion. Result(s): Melatonin supplementation significantly reduced global Pittsburgh Sleep Quality Index scores relative to placebo, indicating improved sleep quality (melatonin 7.68, vs. placebo 9.47, original score units; difference -1.79; 95% CI -2.70 to -0.89; p <= .0001). Melatonin had no effect on sleep onset latency (melatonin 1.37, vs. placebo 1.42, log units; difference -0.05; 95% CI -0.14 to 0.03; p = .23). Across secondary outcome measures, melatonin increased sleep efficiency, vitality andmental health. Melatonin also decreased anxiety and fatigue. Conclusion(s): Melatonin supplementation over a 4- week period is effective and safe in improving subjective sleep quality as well as some aspects of objective sleep quality in patients with TBI. .

Introduction: Obstructive sleep apnoea (OSA) commonly manifests with greater severity in the supine position. Over 60% of patients with OSA have supine predominant OSA (supine apnoea-hypopnoea index [AHI] greater than twice of non-supine AHI) and 25% have supine isolated OSA (non-supine AHI< 5 events/hour). Therefore, for the majority of patients, the proportion of total sleep time in the supine body position necessarily impacts on the severity of OSA assessed by polysomnography (PSG). We previously reported that the proportion of time in the supine position is significantly higher during laboratory PSG compared to habitual sleep. Here we report the interim results of our current study comparing sleeping position during unattended home PSG to habitual sleeping position. Material(s) and Method(s): This is a prospective observational study of patients referred for unattended PSG through our tertiary academic sleep unit. We use the Night ShiftTM positional therapy device to record body position during the unattended PSG and subsequently for up to three additional nights to sample habitual sleeping position. The Night ShiftTM was programmed to record only; the feedback intervention function was disabled. A paired t-test was used to compare the mean difference in proportion of sleep time in the supine position during unattended PSG compared to habitual sleep. We then calculated a modified AHI "corrected" for habitual sleeping position. Night-to-night variability in habitual sleeping position was assessed using a correlation matrix, and a repeated measures one-way ANOVA. Result(s): To date, fifty-two patients have been recruited, out of a target of 79 patients. 38.5% female, age 47 +/- 12.8 years, body mass index 30.9 (range: 27.5-37.5) kg/m2. Median total AHI 19 (range: 3.2-27.9) events/hour, supine AHI 22 (0.9-45.3) events/hour, non-supine AHI 9.4 (1.3-24.9) events/hour. Fifteen patients (29.4%) had supine predominant OSA and 1 (2%) had supine isolated OSA. Proportion o

Introduction: Although cognitive behavioural therapy is a recognised effective non-pharmacological treatment for insomnia, there is limited information regarding its uptake in clinical practice. This case series describes the participation rates and effectiveness of cognitive behavioural therapy for insomnia in patients attending a multidisciplinary sleep clinic. Material(s) and Method(s): Cognitive behavioural therapy was delivered by psychologists. Data were collected using self-report questionnaires and extraction of medical records through opt-out consent. A paired-samples t-test was conducted to compare pre- and post-treatment Insomnia Severity Index (ISI) scores. Result(s): 205 adult patients met the DSM-5 criteria for insomnia. Mean age was 45.1 years (range 18.1 to 84.9 years). 41.5% were male. Following assessment by a sleep physician, 194 (94.6%) were advised to see a psychologist for cognitive behavioural therapy. Of these patients, 121 (62.4%) saw a psychologist at our clinic, 11 (5.7%) participated in a cognitive behavioural therapy research study, and 4 (2.1%) were referred to a psychologist elsewhere. 58 (29.9%) did not see a psychologist despite recommendation from their sleep physician. Compared with the patients who proceeded to see a psychologist, the group that did not participate in cognitive behavioural therapy reported similar baseline rates of hypnotic medication usage. Of those who saw a psychologist at our clinic, 45 (37.2%) completed cognitive behavioural therapy and were discharged. 68 patients (56.2%) did not complete the cognitive behavioural therapy program. 18 patients submitted ISI questionnaires pre and post completion of cognitive behavioural therapy. The mean reduction in ISI score was 10.2 (95% CI 7.4 to 12.9, p< 0.001). Most of these patients (88.9%) reported that the program had met most or almost all of their needs. Conclusion(s): These real-world findings from our multidisciplinary sleep clinic demonstrated about 30% of patie

Introduction: Upper airway surgery (UAS) is often recommended as a treatment for patients with OSA who cannot tolerate continuous positive airway pressure (CPAP). Unfortunately, the efficacy of UAS can be highly variable and there are no reliable clinical predictors of which patients are likely to have their OSA resolved following UAS. The key to providing robust predictors of OSA resolution following UAS is to recognise that OSA is caused by multiple interactive anatomical (i.e. collapsibility) and non-anatomical traits [i.e. i) ability of airway muscles to reopen the airway; ii) respiratory arousal threshold; and iii) ventilatory control system sensitivity - loop gain]. Importantly, it is unknown how surgery alters these traits which may impact treatment efficacy. Therefore, we aimed to examine the effect of UAS on the OSA trait(s) and whether knowledge of these traits can assist in predicting success to surgery (i.e. responder analysis). Material(s) and Method(s): In a prospective study, 23 OSA patients scheduled for UAS have been studied before and 3-months post-surgery. In each condition, participants underwent clinical polysomnography to determine OSA severity and research polysomnography to measure the OSA traits using a gold-standard technique. Values are presented as Mean +/- SEM or as Median [Interquartile range]. For the responder analysis, responders were defined as having a reduction in apnea-hypopnea index (AHI) >=50% from baseline. Result(s): UAS reduced both the AHI (38.7[53.2] vs 22.0[36.3] events/h; p=0.009) and Epworth sleepiness scale (10 [7] vs 6 [6.5]; p< 0.001). There was a strong trend for UAS to improve upper airway collapsibility (pre vs post-surgery: -1.7+/-3.8 vs 0.2+/-4.6 L/min; p=0.09). There was a deterioration in the ability of airway muscles to reopen the airway (0.6[0.9] vs 0.4[0.5]; p=0.02) after UAS, but there was no impact on the other non-anatomical traits (i.e. loop gain and arousal threshold). 7/23(30%) patients were classifie

Background and aims: Sleep disturbances commonly occur following Traumatic Brain Injury (TBI); however, evidence-based treatments are lacking. The aim of this study was to determine the effectiveness and safety of melatonin supplementation for sleep disturbances in patients with TBI. Method(s): Randomised, double-blind, placebo-controlled, two-period, twotreatment (melatonin and placebo) crossover study. Outpatients were recruited from Epworth and Austin Hospitals Melbourne, Australia. Outpatients with mild to severe TBI (n = 33) reporting sleep disturbances post injury (mean age 37 (SD, 11) years; 67% men). Prolonged-release melatonin formulation (2mg; Circadin R ) and placebo capsules for 4weeks each in a counter-balanced fashion. Result(s): Melatonin supplementation significantly reduced global Pittsburgh Sleep Quality Index scores relative to placebo, indicating improved sleep quality (melatonin 7.68, vs. placebo 9.47, original score units; difference -1.79; 95% CI -2.70 to -0.89; p <= .0001). Melatonin had no effect on sleep onset latency (melatonin 1.37, vs. placebo 1.42, log units; difference -0.05; 95% CI -0.14 to 0.03; p = .23). Across secondary outcome measures, melatonin increased sleep efficiency, vitality andmental health. Melatonin also decreased anxiety and fatigue. Conclusion(s): Melatonin supplementation over a 4- week period is effective and safe in improving subjective sleep quality as well as some aspects of objective sleep quality in patients with TBI. .

Introduction: Obstructive sleep apnoea (OSA) commonly manifests with greater severity in the supine position. Over 60% of patients with OSA have supine predominant OSA (supine apnoea-hypopnoea index [AHI] greater than twice of non-supine AHI) and 25% have supine isolated OSA (non-supine AHI< 5 events/hour). Therefore, for the majority of patients, the proportion of total sleep time in the supine body position necessarily impacts on the severity of OSA assessed by polysomnography (PSG). We previously reported that the proportion of time in the supine position is significantly higher during laboratory PSG compared to habitual sleep. Here we report the interim results of our current study comparing sleeping position during unattended home PSG to habitual sleeping position. Material(s) and Method(s): This is a prospective observational study of patients referred for unattended PSG through our tertiary academic sleep unit. We use the Night ShiftTM positional therapy device to record body position during the unattended PSG and subsequently for up to three additional nights to sample habitual sleeping position. The Night ShiftTM was programmed to record only; the feedback intervention function was disabled. A paired t-test was used to compare the mean difference in proportion of sleep time in the supine position during unattended PSG compared to habitual sleep. We then calculated a modified AHI "corrected" for habitual sleeping position. Night-to-night variability in habitual sleeping position was assessed using a correlation matrix, and a repeated measures one-way ANOVA. Result(s): To date, fifty-two patients have been recruited, out of a target of 79 patients. 38.5% female, age 47 +/- 12.8 years, body mass index 30.9 (range: 27.5-37.5) kg/m2. Median total AHI 19 (range: 3.2-27.9) events/hour, supine AHI 22 (0.9-45.3) events/hour, non-supine AHI 9.4 (1.3-24.9) events/hour. Fifteen patients (29.4%) had supine predominant OSA and 1 (2%) had supine isolated OSA. Proportion o

The Multiple Sleep Latency Test (MSLT) is the internationally recognized gold standard method for objectively measuring sleepiness. MSLT results are ultimately expressed in terms of the overall Mean Sleep Latency (MSL) and the total number of Sleep Onset REM Periods (SOREMPs). Based on these measures, the International Classification of Sleep Disorders (ICSD) has developed firm diagnostic criteria by which Narcolepsy is defined by a MSL <= 8 min with <= 2 SOREMPs, while Idiopathic Hypersomnia is defined by a MSL <= 8 min with <= 1 SOREMP. Once diagnosed, the wakefulness-promoting agent Modafinil is recommended for the treatment of the daytime sleepiness associated with these conditions. In Australia, Modafinil is expensive and its long-term use can create significant financial stress for many patients. Fortunately, the Pharmaceutical Benefits Scheme offers subsidised Modafinil for patients who return a MSL <= 10 min. MSLT results can thus have a significant impact on patients' lives in terms of both disease diagnosis and treatment. Recognising this fact, our lab has recently come to appreciate the fact that MSLT analysis is subject to the same subjective interpretation and inter-scorer reliability issues as standard polysomnography. In response, we have developed a quality assurance program that seeks to safeguard the integrity of our MSLTs. In accordance with this program, our MSLTs are initially analysed by the scientist who conducts the MSLT. The lab Quality Manager then creates a new score-data record and assigns the record to a second scientist, who rescores it without reference to the original analysis. The Quality Manager then records and compares the results to determine if there is a significant difference between the analyses in terms of MSLs and SOREMP counts. A significant difference is MSLs is defined as a difference of <= 1 min., or a difference that would result in a change in diagnosis based on the 8-minute ICSD threshold or a change in Modafinil ava

Introduction: Insomnia is frequently managed with medications in the community. Cognitive behavioural therapy (CBT) is an effective non-pharmacological treatment for insomnia. This case series evaluated preliminary outcomes following CBT delivered to patients presenting with insomnia complaints to a multidisciplinary outpatient sleep clinic. Method(s): Data were collected using self-report questionnaires and extraction of medical records through opt-out consent. A paired-samples t-test was conducted to compare pre-and post-treatment Insomnia Severity Index (ISI) scores. Result(s): 29 patients who received CBT submitted pre-and post-treatment questionnaires. Mean age was 48.4 years (range 18.0-80.9 years), and 24.1% were male. Of the 27/29 patients who completed the ISI questionnaires, the baseline mean ISI score was 17.6 (SD = 5.1), with 77.8% of the sample having a score <=15 (clinical insomnia with at least moderate severity). Following completion of treatment, the mean ISI score was 7.7 (SD = 5.6), with 14.8% having a score <=15. The mean reduction in ISI score was 9.9 (95% CI-11.9 to-7.8, p < 0.001). At baseline, 21/29 (72.4%) often or always had trouble sleeping in the preceding 7 days, whilst most (93.1%) were at least somewhat worried or distressed about their current sleep problem. Post-treatment, only 4/29 (13.8%) often had trouble sleeping in the preceding 7 days and 7/29 (24.1%) were at least somewhat worried or distressed about their current sleep problem. Prior to receiving CBT, about half the patients (55.6%) used medications at least once a week to help them sleep. After completing CBT, a third (33.3%) of patients took medications at least once a week to help them sleep. The majority of patients (93.1%) reported that the program had met most or almost all of their needs, and 100% felt that the services received helped them deal with sleep problems more effectively. Discussion(s): These preliminary findings from a multidisciplinary sleep clinic indicat

Introduction: Patients accessing sleep services present with a wide range of psychiatric symptoms, but these symptoms are not well characterised. This study aims to (a) characterise psychiatric symptom profiles in patients attending an outpatient sleep clinic, (b) identify heterogenous subgroups, and (c) explore differences in pre-treatment characteristics among subgroups. Method(s): Data was collected at a university-based multidisciplinary outpatient sleep clinic via opt-out consent. Before treatment, patients completed the Cross-Cutting Symptom Measure (CCSM), which uses a dimensional approach to measure 13 mental health domains (e.g., depression, anger, mania, anxiety, psychosis, memory) and provides a transdiagonistic symptom profile. Other measures included PROMIS Sleep Disturbance and Daytime Functioning, Insomnia Severity Index, Morningness-Eveningness Questionnaire Reduced, demographics, and polysomnography (PSG; subgroup). Result(s): 352 participants (55.2% female; age M +/- SD = 43.52 +/- 16.37) who completed the CCSM were included. Latent class analysis revealed 3 subgroups with distinctive psychiatric profiles: Affective-Disturbance subgroup (n = 199, 56.5%) reported moderate affective symptoms such as depression, anxiety, and anger; Psychopathology subgroup (n = 76, 21.6%) not only reported severe affective symptoms, but also expressed more severe psychopathology such as suicidality, psychosis, and dissociation; Low-Symptom subgroup (n = 77, 21.9%) reported mild affective symptoms and few other symptoms. Psychopathology subgroup is the youngest, showed the strongest in evening chronotype, and reported the highest sleep disturbance and daytime impairment (p-values <0.01). Discussion(s): Patients attending a sleep service presented with a diverse range of psychiatric symptoms, and symptom profiles were heterogenous. Subgroups identified in this study could inform subsequent treatment planning. In our sample, affective disturbance is a predominant feature

The Multiple Sleep Latency Test (MSLT) is the internationally recognized gold standard method for objectively measuring sleepiness. MSLT results are ultimately expressed in terms of the overall Mean Sleep Latency (MSL) and the total number of Sleep Onset REM Periods (SOREMPs). Based on these measures, the International Classification of Sleep Disorders (ICSD) has developed firm diagnostic criteria by which Narcolepsy is defined by a MSL <= 8 min with <= 2 SOREMPs, while Idiopathic Hypersomnia is defined by a MSL <= 8 min with <= 1 SOREMP. Once diagnosed, the wakefulness-promoting agent Modafinil is recommended for the treatment of the daytime sleepiness associated with these conditions. In Australia, Modafinil is expensive and its long-term use can create significant financial stress for many patients. Fortunately, the Pharmaceutical Benefits Scheme offers subsidised Modafinil for patients who return a MSL <= 10 min. MSLT results can thus have a significant impact on patients' lives in terms of both disease diagnosis and treatment. Recognising this fact, our lab has recently come to appreciate the fact that MSLT analysis is subject to the same subjective interpretation and inter-scorer reliability issues as standard polysomnography. In response, we have developed a quality assurance program that seeks to safeguard the integrity of our MSLTs. In accordance with this program, our MSLTs are initially analysed by the scientist who conducts the MSLT. The lab Quality Manager then creates a new score-data record and assigns the record to a second scientist, who rescores it without reference to the original analysis. The Quality Manager then records and compares the results to determine if there is a significant difference between the analyses in terms of MSLs and SOREMP counts. A significant difference is MSLs is defined as a difference of <= 1 min., or a difference that would result in a change in diagnosis based on the 8-minute ICSD threshold or a change in Modafinil ava

Introduction: Insomnia is frequently managed with medications in the community. Cognitive behavioural therapy (CBT) is an effective non-pharmacological treatment for insomnia. This case series evaluated preliminary outcomes following CBT delivered to patients presenting with insomnia complaints to a multidisciplinary outpatient sleep clinic. Method(s): Data were collected using self-report questionnaires and extraction of medical records through opt-out consent. A paired-samples t-test was conducted to compare pre-and post-treatment Insomnia Severity Index (ISI) scores. Result(s): 29 patients who received CBT submitted pre-and post-treatment questionnaires. Mean age was 48.4 years (range 18.0-80.9 years), and 24.1% were male. Of the 27/29 patients who completed the ISI questionnaires, the baseline mean ISI score was 17.6 (SD = 5.1), with 77.8% of the sample having a score <=15 (clinical insomnia with at least moderate severity). Following completion of treatment, the mean ISI score was 7.7 (SD = 5.6), with 14.8% having a score <=15. The mean reduction in ISI score was 9.9 (95% CI-11.9 to-7.8, p < 0.001). At baseline, 21/29 (72.4%) often or always had trouble sleeping in the preceding 7 days, whilst most (93.1%) were at least somewhat worried or distressed about their current sleep problem. Post-treatment, only 4/29 (13.8%) often had trouble sleeping in the preceding 7 days and 7/29 (24.1%) were at least somewhat worried or distressed about their current sleep problem. Prior to receiving CBT, about half the patients (55.6%) used medications at least once a week to help them sleep. After completing CBT, a third (33.3%) of patients took medications at least once a week to help them sleep. The majority of patients (93.1%) reported that the program had met most or almost all of their needs, and 100% felt that the services received helped them deal with sleep problems more effectively. Discussion(s): These preliminary findings from a multidisciplinary sleep clinic indicat

Background and Aim: Obesity is a strong risk factor for obstructive sleep apnoea (OSA) and bariatric surgery is an effective method to reduce and maintain long term weight loss. However, very few patients are cured of OSA following bariatric surgery despite significant reductions in OSA severity and its resolution cannot be predicted by their starting weight or post-intervention weight loss. Hence, we performed a systematic review to look at the effect of bariatric surgery on OSA and to determine if there were any clinical predictors of treatment success. Method(s): Our study protocol has been registered on PROSPERO (ID=CRD42017062359). Relevant studies were identified by searches of Medline, Embase, PubMed, Cochrane Library and Medline (In-Process & Other Non-Indexed Citations) on 8/4/2017. Studies included reported pre and post-surgery sleep study data (apnoea-hypopnoea index (AHI) or equivalent), body mass index (BMI) and timing of post-surgery sleep studies. Studies that enrolled patients with obesity hypoventilation syndrome (OHS) were excluded. Other data extracted included patient characteristics, type of bariatric surgery performed, sleep study type and scoring criteria used, study design and quality, and relevant sleep quality questionnaires. Result(s): A total of 3017 references were retrieved, with 24 studies included in the final analysis. Only two were randomised controlled trials, and 2/22 observational studies had a comparative arm (lifestyle intervention; continuous positive airway pressure). A total of 1101 patients had completed pre and post-surgery sleep studies, with sample size of the individual studies ranging from n = 8 to n = 205. 80% of studies conducted a level 1 sleep study. All studies showed a significant reduction in BMI and AHI post-surgery, however, 14 studies reported an overall post-surgery AHI >10 indicating the presence of residual OSA. A mixture of sleep scoring criteria were used and 29% of studies failed to specify which criter

Background: CPAP is widely accepted as the gold standard treatment for severe OSA, however low socioeconomic status is associated with poor uptake and adherence to therapy. CPAP treatment is not universally subsidised under any Australian Government scheme, limiting access to CPAP for low income earners with severe OSA. The Monash CPAP Program is run through a public hospital clinic and offers significantly subsidised CPAP treatment to Pensioner Concession Card holders with at least moderate OSA and who meet clinical and adherence criteria. We studied a group of patients enrolled into the program to determine their baseline characteristics, the time on the waitlist for a CPAP machine, as well as their adherence at follow up. Method(s): We identified patients who met the eligibility criteria and placed on the waitlist between 1st January 2015 to 31st December 2015. Baseline demographic information, polysomnography data and time on the waitlist were determined from a database. We reviewed the medical records for follow up and any missing data. If no follow up was recorded, the patient was contacted and asked a short questionnaire regarding their adherence to therapy. Progress to date: 194 patients were waitlisted over the 12 month study period. Mean total AHI was 52.4/hr at the time of waitlisting. Mean time spent on the waitlist was 193 days. Preliminary analysis based on 25 patients shows an adherence rate of 70% after at least 6 months. Intended outcome and impact: Our primary aim is to identify the level of adherence to CPAP in the study population. We hypothesise adequate adherence will be present in > 50% of subjects, based on previously published data. Secondary aims will examine the effects of time on the waitlist, baseline OSA severity and symptoms on adherence. This analysis will be useful in assessing the impact of funded CPAP and provide a guide as to whether patients most in need are receiving access to treatment in a timely fashion.

Rationale: Upper airway surgery is often recommended to treat OSA patients who cannot tolerate continuous positive airways pressure (CPAP). However, the response to surgery is variable and predicting which patients will respond remains an ongoing clinical challenge. Surgical failure may, at least in part, be due to the fact that predictive tools used to select patients do not take account of the multifactorial nature of OSA pathogenesis in that a number of important non-anatomical factors (such as ventilatory control instability i.e. high loop gain, and low arousal threshold) also contribute to airway collapse. Because surgery is an anatomically directed treatment it may be that it does not affect the non-anatomical traits in which case measuring these traits clinically might predict responses to surgery. As such, our primary objective was to determine if surgery alters loop gain and arousal threshold and to test the predictive value of new clinical measures of loop gain and arousal threshold to predict surgical success (50% reduction in apnea-hypopnea index [AHI] and AHI <10 events/hr with surgery). Method(s): We retrospectively analyzed data from patients who underwent upper airway surgery for OSA (n = 46). In the vast majority of cases, patients underwent multilevel surgery. The surgery was directed by clinical assessment with nasendoscopy by board certified ear, nose and throat surgeons. Clinical estimates of loop gain and arousal threshold were calculated from routine polysomnographic recordings pre- and post-surgery. Result(s): Surgery reduced both the AHI (39.1 +/- 4.2 vs. 26.5 +/- 3.6 events/hr; p < 0.005) and estimated arousal threshold (-14.8 [-22.9 to -10.2] vs. -9.4 [-14.5 to -6.0] cmH2O) but did not alter loop gain (0.45 +/- 0.08 vs. 0.45 +/- 0.12; p = 0.278). Responders to surgery had a lower baseline loop gain (0.38 +/- 0.02 vs 0.48 +/- 0.01, p < 0.05) and were younger (31.0 [27.3 to 42.5] vs 43.0 [33.0 to 55.3] years, p < 0.05) than non-responders. L

Introduction: Insomnia is common, and is often managed with hypnotic medications in the community. Cognitive behavioural therapy for insomnia (CBT-I) is an effective non-pharmacological treatment. This study aims to obtain baseline data on communitybased clinical practices for patients presenting with insomnia to our multidisciplinary service. Subsequently this data can be used to evaluate the impact of our service on prescribing practices. Method(s): Data were collected using self-report questionnaires and extraction of medical records through opt-out consent. Result(s): Data collected by May 2017 consisted of 251 patients who consented to having data evaluated for research purposes. Of these subjects 239 (95.2%) patients reported using prescribed medications at least once a month to help them sleep (63 patients >=3 times/week) prior to attending our service. 239 (95.2%) patients reported using over-the-counter medications at least once a month to help them sleep (43 patients >=3 times/week). However only 77 (30.7%) patients reported that they had been previously diagnosed with insomnia by a doctor. Of these 77 patients, 58 (75.3%) were prescribed hypnotic medications, 43 (55.8%) took over-the-counter medications, 32 (41.6%) were given lifestyle advice, 44 (57.1%) were referred to a psychologist, 16 (20.8%) were referred to a psychiatrist, 9 (11.7%) were prescribed acupuncture or hypnotherapy, and 37 (48.1%) tried meditation, yoga or relaxation techniques. Medical data extraction regarding the changes in insomnia management after attending the multidisciplinary clinic is currently underway. Discussion(s): Prior to attending the multidisciplinary clinic, the number of patients taking hypnotic medications exceeded the number of patients with a prior diagnosis of insomnia. Of the patients diagnosed with insomnia by the referring doctor, pharmacological treatment was more frequently offered than non-pharmacological measures.

Background: CPAP is widely accepted as the gold standard treatment for severe OSA, however low socioeconomic status is associated with poor uptake and adherence to therapy. CPAP treatment is not universally subsidised under any Australian Government scheme, limiting access to CPAP for low income earners with severe OSA. The Monash CPAP Program is run through a public hospital clinic and offers significantly subsidised CPAP treatment to Pensioner Concession Card holders with at least moderate OSA and who meet clinical and adherence criteria. We studied a group of patients enrolled into the program to determine their baseline characteristics, the time on the waitlist for a CPAP machine, as well as their adherence at follow up. Method(s): We identified patients who met the eligibility criteria and placed on the waitlist between 1st January 2015 to 31st December 2015. Baseline demographic information, polysomnography data and time on the waitlist were determined from a database. We reviewed the medical records for follow up and any missing data. If no follow up was recorded, the patient was contacted and asked a short questionnaire regarding their adherence to therapy. Progress to date: 194 patients were waitlisted over the 12 month study period. Mean total AHI was 52.4/hr at the time of waitlisting. Mean time spent on the waitlist was 193 days. Preliminary analysis based on 25 patients shows an adherence rate of 70% after at least 6 months. Intended outcome and impact: Our primary aim is to identify the level of adherence to CPAP in the study population. We hypothesise adequate adherence will be present in > 50% of subjects, based on previously published data. Secondary aims will examine the effects of time on the waitlist, baseline OSA severity and symptoms on adherence. This analysis will be useful in assessing the impact of funded CPAP and provide a guide as to whether patients most in need are receiving access to treatment in a timely fashion.

Background and Aim: Obesity is a strong risk factor for obstructive sleep apnoea (OSA) and bariatric surgery is an effective method to reduce and maintain long term weight loss. However, very few patients are cured of OSA following bariatric surgery despite significant reductions in OSA severity and its resolution cannot be predicted by their starting weight or post-intervention weight loss. Hence, we performed a systematic review to look at the effect of bariatric surgery on OSA and to determine if there were any clinical predictors of treatment success. Method(s): Our study protocol has been registered on PROSPERO (ID=CRD42017062359). Relevant studies were identified by searches of Medline, Embase, PubMed, Cochrane Library and Medline (In-Process & Other Non-Indexed Citations) on 8/4/2017. Studies included reported pre and post-surgery sleep study data (apnoea-hypopnoea index (AHI) or equivalent), body mass index (BMI) and timing of post-surgery sleep studies. Studies that enrolled patients with obesity hypoventilation syndrome (OHS) were excluded. Other data extracted included patient characteristics, type of bariatric surgery performed, sleep study type and scoring criteria used, study design and quality, and relevant sleep quality questionnaires. Result(s): A total of 3017 references were retrieved, with 24 studies included in the final analysis. Only two were randomised controlled trials, and 2/22 observational studies had a comparative arm (lifestyle intervention; continuous positive airway pressure). A total of 1101 patients had completed pre and post-surgery sleep studies, with sample size of the individual studies ranging from n = 8 to n = 205. 80% of studies conducted a level 1 sleep study. All studies showed a significant reduction in BMI and AHI post-surgery, however, 14 studies reported an overall post-surgery AHI >10 indicating the presence of residual OSA. A mixture of sleep scoring criteria were used and 29% of studies failed to specify which criter

Background: Numerous reports demonstrate an association with suspected (questionnaire based) or proven obstructive sleep apnoea (OSA) in patients undergoing major surgery and post-operative complications. It remains unclear if OSA causally impacts on complication rates or is a marker of associated comorbidity. We aim to establish if suspected OSA (STOP-Bang questionnaire) would predict for post-operative complications among a selected high-risk population with established major comorbidities. We hypothesise that a cohort selected for comorbidity diminishes its potential confounding influence. Method(s): This was a prospective observational cohort study of patients with major comorbidities attending a high-risk pre-admission clinic prior to major surgery. Patients were screened for OSA (STOP-Bang questionnaire) excluding those currently treated. Patient data and complications were obtained from the pre-admission clinic and subsequent inpatient medical record at discharge. Preliminary Results: 170 patients (79 male; aged 70+/-12 years (mean+/-SD); Body Mass Index (BMI) 32+/-8 kg/m2) were analysed. 21(12%) patients have documented OSA, not on current treatment. The majority underwent gastrointestinal, orthopaedic and gynaecological surgery (40%, 33% and 13% respectively), with 151(89%) patients receiving general anaesthesia. 44(26%) patients experienced 56 post-operative complications. 74% of the cohort had a STOP-Bang score of >= 3. After controlling for comorbidity, there was a strong trend for those with a STOP-Bang score of >= 5 to be more likely to have a post-operative complication (OR 1.90;95% CI, 0.85-4.10;p=0.098) with the majority being cardiovascular related complications, followed by neurological (predominantly delirium), respiratory and unplanned Intensive Care Unit (ICU) admissions. When the components of STOP-Bang were analysed individually, the signal was driven exclusively by the OSA specific question "witnessed apnoeas" (OR 6.06; 95% CI, 1.72-21.40;p=

Background: Obstructive sleep apnoea (OSA) leads to repetitive collapse of the upper airway during sleep. There are 4 key pathophysiological traits which contribute to OSA: 1) poor airway anatomy; 2) ineffective upper airway dilator muscle responsiveness; 3) low arousal threshold and 4) ventilatory control instability (high loop gain). Upper airway surgery (UAS) is a treatment for OSA which improves the airway anatomy and leads to significant improvement in ~25% of patients. Our team has recently shown that a high loop gain predicts a poor response to surgery. Given that oxygen therapy is known to lower loop gain, we therefore hypothesise that oxygen therapy will improve OSA in surgical "non-responders". Method(s): This is a prospective randomised control single blinded trial. Participants enrolled will have residual sleep apnoea despite having undergone UAS. Each participant will undergo two sleep studies over two nights - one night with supplemental oxygen (4 L/ min) and another night with room air (control). Measurements of breathing pattern, heart rate, blood pressure, eye movements, brain activity and oxygen levels in the blood will be compared between both conditions. Progress to date: Project approved by HREC. Recruitment and consent of 30 participants into the clinical trial has commenced. Participants will begin their sleep studies between May 2017 - October 2017. Preliminary results and conclusions will be ready for the conference. Intended outcome and impact: Establish that oxygen therapy lowers loop gain and therefore improves OSA to a significant degree in patients with residual OSA following UAS in those with a high loop gain at baseline. This could provide additional treatment options for sufferers of residual OSA despite surgical management.

Rationale: Upper airway surgery is often recommended to treat OSA patients who cannot tolerate continuous positive airways pressure (CPAP). However, the response to surgery is variable and predicting which patients will respond remains an ongoing clinical challenge. Surgical failure may, at least in part, be due to the fact that predictive tools used to select patients do not take account of the multifactorial nature of OSA pathogenesis in that a number of important non-anatomical factors (such as ventilatory control instability i.e. high loop gain, and low arousal threshold) also contribute to airway collapse. Because surgery is an anatomically directed treatment it may be that it does not affect the non-anatomical traits in which case measuring these traits clinically might predict responses to surgery. As such, our primary objective was to determine if surgery alters loop gain and arousal threshold and to test the predictive value of new clinical measures of loop gain and arousal threshold to predict surgical success (50% reduction in apnea-hypopnea index [AHI] and AHI <10 events/hr with surgery). Method(s): We retrospectively analyzed data from patients who underwent upper airway surgery for OSA (n = 46). In the vast majority of cases, patients underwent multilevel surgery. The surgery was directed by clinical assessment with nasendoscopy by board certified ear, nose and throat surgeons. Clinical estimates of loop gain and arousal threshold were calculated from routine polysomnographic recordings pre- and post-surgery. Result(s): Surgery reduced both the AHI (39.1 +/- 4.2 vs. 26.5 +/- 3.6 events/hr; p < 0.005) and estimated arousal threshold (-14.8 [-22.9 to -10.2] vs. -9.4 [-14.5 to -6.0] cmH2O) but did not alter loop gain (0.45 +/- 0.08 vs. 0.45 +/- 0.12; p = 0.278). Responders to surgery had a lower baseline loop gain (0.38 +/- 0.02 vs 0.48 +/- 0.01, p < 0.05) and were younger (31.0 [27.3 to 42.5] vs 43.0 [33.0 to 55.3] years, p < 0.05) than non-responders. L

Background: Use of unattended in-home Type 2 polysomnography (PSG) is increasing in popularity given easy accessibility, cost effectiveness and clinical equivalence when compared with attended in-laboratory sleep studies in patients with high pretest probability for moderate to severe obstructive sleep apnoea (OSA). Current literature suggests that home PSG has higher signal loss than laboratory PSG and approximately 10% of studies performed underestimate the apnoea-hypopnoea index (AHI), which may affect patient clinical outcomes. Hence we aimed to audit technical quality and the impact on clinical outcomes of unattended home PSG at our tertiary sleep center. Method(s): All home PSGs performed at Monash Health Sleep Centre between 1 January and 31 December 2016 will be reviewed. Information on data loss from all PSG signals will be collected and compared to the clinical determination of the need for repeat sleep testing or ongoing patient management. Patient demographics and PSG results will be compared to diagnostic laboratory PSG over the same time frame. Audit of waiting times at various stages of the clinical pathway will also be compared. Progress to date: Preliminary data analysis of 50 out of a total of 460 home based studies performed during last year indicate that technical problems with a partial degree of signal loss occurred in 14/ 50 studies (28%) The signal that was most likely to fail was oximetry (12%) followed by abdominal (8%), flow (6%) and thoracic signals (4%). However, all these studies were deemed diagnostically acceptable and resulted in a treatment decision without the need for re-testing. Further data collection and analysis is being conducted to cover all studies and outcomes. Intended outcome and impact: We expect to find frequent partial signal loss during home PSG, but without significant impact on the clinical utility of the test. With analysis of secondary outcomes, we predict fewer co-morbidities than in the cohort undergoing labora

Introduction: Insomnia is common, and is often managed with hypnotic medications in the community. Cognitive behavioural therapy for insomnia (CBT-I) is an effective non-pharmacological treatment. This study aims to obtain baseline data on communitybased clinical practices for patients presenting with insomnia to our multidisciplinary service. Subsequently this data can be used to evaluate the impact of our service on prescribing practices. Method(s): Data were collected using self-report questionnaires and extraction of medical records through opt-out consent. Result(s): Data collected by May 2017 consisted of 251 patients who consented to having data evaluated for research purposes. Of these subjects 239 (95.2%) patients reported using prescribed medications at least once a month to help them sleep (63 patients >=3 times/week) prior to attending our service. 239 (95.2%) patients reported using over-the-counter medications at least once a month to help them sleep (43 patients >=3 times/week). However only 77 (30.7%) patients reported that they had been previously diagnosed with insomnia by a doctor. Of these 77 patients, 58 (75.3%) were prescribed hypnotic medications, 43 (55.8%) took over-the-counter medications, 32 (41.6%) were given lifestyle advice, 44 (57.1%) were referred to a psychologist, 16 (20.8%) were referred to a psychiatrist, 9 (11.7%) were prescribed acupuncture or hypnotherapy, and 37 (48.1%) tried meditation, yoga or relaxation techniques. Medical data extraction regarding the changes in insomnia management after attending the multidisciplinary clinic is currently underway. Discussion(s): Prior to attending the multidisciplinary clinic, the number of patients taking hypnotic medications exceeded the number of patients with a prior diagnosis of insomnia. Of the patients diagnosed with insomnia by the referring doctor, pharmacological treatment was more frequently offered than non-pharmacological measures.