Tesis: "Obstructive sleep apnoea"

1

Gunaratnam, Kogulan. "OBSTRUCTIVE SLEEP APNOEA AND PERIODONTITIS". Thesis, Faculty of Dentistry, 2008. http://hdl.handle.net/2123/4057.

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Obstructive sleep apnoea (OSA) and its associated daytime symptoms form a syndrome, obstructive sleep apnoea-hypopnoea syndrome (OSAHS) that affects about 5% of the population worldwide (Young et al 2002a, Pack 2006). OSA is characterized by repeated episodes of upper airway obstruction during sleep, resulting in recurrent hypoxemia and sleep fragmentation (Hensley & Ray 2005). These in turn are associated with neurocognitive disorders, hypertension and cardiovascular complications (Pack 2006). Current therapies for this condition include surgical interventions, oral appliances and continuous positive airways pressure (CPAP). Systemic and local airway inflammation has recently been linked to OSA and is hypothesized to increase the risk of cardiovascular complications (Lavie 2005). While the exact mechanism is not certain, it is believed that the underlying systemic inflammation from OSA is due to the hypoxia/reperfusion injury from intermittent hypoxia that occurs with OSA (Lavie 2005). Specifically, the episodic hypoxia in OSA leads to increased production of reactive oxidative species (ROS) and, via various pathways, in the formation of systemic inflammatory mediators. The resultant inflammatory response is then responsible for the increased cardiovascular morbidity and mortality by potentiating disease in those that already have inflammatory disease or triggering inflammatory diseases in people with existing genetic, behavioural and environmental exposure. Periodontitis involves the supporting structures of the tooth and is a disease caused by specific bacteria that triggers an inflammatory response (Kinane 2001). Tissue damage and destruction, including loss of the connective tissue attachment between the tooth and the jaw, together with resorption of supporting bone, is initiated by the micro-organisms and mediated by the host response. Periodontitis, which is a severe form of periodontal disease, is one of the most common chronic infections in the world. The prevalence of moderate to severe periodontitis across the globe is in the range of 5 to 20 % (Burt 2005). Recent studies have speculated on an association between periodontitis and systemic inflammation in, for example, diabetes (Soskolne & Klinger 2001), rheumatoid arthritis (Mercado et al. 2000) and cardiovascular disease (CVD) (Beck & Offenbacher 2005), but no research has been undertaken on the link between OSA and periodontitis. This review will focus on features of OSA, inflammation and periodontitis to examine if there is a possible link between OSA and periodontitis by means of systemic inflammation.

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2

Mason, Rebecca Helen. "Vascular complications of obstructive sleep apnoea". Thesis, University of Bristol, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619138.

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Obstructive sleep apnoea (OSA) is the third commonest respiratory condition after Asthma and COPD and has been increasingly linked to cardiovascular consequences. This thesis examines how OSA might affect different vascular beds; large (the aorta), medium (the carotid artery) and small (retinal and cerebral blood vessels) through five different studies. Each study will be reported as a separate chapter and a final discussion will assess the overall conclusions. Methodology Study one examines the prevalence of OSA in individuals with an abdominal aortic aneurysm and demonstrates the increased prevalence and rate of aneurysm expansion in those with severe OSA. Study two demonstrates the increased prevalence of OSA in individuals with type two diabetes and clinically significant diabetic macular oedema (CS MO). Study three examines the clinical benefit of continuous positive airway pressure (CPAP) in individuals with OSA and CS MO and demonstrates an improvement in visual acuity when CPAP is used for >2.5hrs per night. Study four is a retrospective examination of the effect of snoring on carotid vessel disease and shows no significant difference between the severity of snoring and degree of carotid artery stenosis. Study five describes the effect of minimally symptomatic obstructive sleep apnoea on cerebrovascular disease and shows no association between OSA and small white matter change but, does confirm the association of increasing age and hypertension. Discussion This thesis adds to our understanding of the association of OSA and vascular disease and the potential therapeutic benefits of CPAP in these individuals.

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3

Papaioannou, Ioannis. "Glucose intolerance in obstructive sleep apnoea". Thesis, Imperial College London, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516557.

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4

Davies, David Paul. "Snoring, obstructive sleep apnoea and stroke". Thesis, University of Newcastle Upon Tyne, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364858.

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5

McMillan, Alison. "Obstructive sleep apnoea in older people". Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/28969.

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Obstructive sleep apnoea (OSA) is common and the prevalence increases with age. When OSA leads to sleep disruption and excessive daytime sleepiness, it is referred to as obstructive sleep apnoea syndrome (OSAS). The aim of this thesis was to investigate the consequences of OSAS in older people (˃ 65 years) and the effect of continuous positive airway pressure (CPAP) therapy. CPAP is the treatment of choice in moderate to severe OSAS in middle aged people. However, there is a paucity of evidence on the therapeutic and economic benefits of CPAP in older people with OSAS. The two studies in this thesis aimed to address this by comparing outcomes in older people with OSAS before and after treatment with CPAP. The first study presented is the thesis is the PREDICT trial; a multicentre randomised controlled trial of CPAP in older people with OSAS. The trial studied the clinical efficacy of CPAP after 3 months, while determining the cost effectiveness of treatment over 12 months. The results of the trial showed that CPAP was an effective treatment for reducing excessive daytime sleepiness by -2.1 (95%CI -3.0 to -1.3); p < 0.001 points as measured by the Epworth sleepiness scale. CPAP also improved quality of life, with a statistically significant increase in the quality adjusted life years calculated with the SF-6D, equating to one week. The CPAP group also accrued marginally lower health care costs over 12 months compared to the group treated with best supportive care alone. Overall the economic benefit of CPAP was linked to the reduced healthcare usage offsetting the cost of the equipment. The second study presented in the thesis was a single centre randomised controlled trial to investigate the impact of CPAP on cognitive function and brain morphology in older people with minimally symptomatic OSAS after 6 months of treatment. In this study I tested the hypothesis that older patients with OSAS have cognitive impairment and corresponding brain changes which would be modifiable with treatment. The results of this study suggested older people with minimally symptomatic OSAS had normal cognitive function but impaired attention and executive function. CPAP treatment improved one aspect of attention, although memory and overall cognitive function were unchanged. The results of the brain MRI scans are not presented, and are in the process of being analysed. In conclusion the data presented in this thesis support the use of CPAP therapy in older people with excessive daytime sleepiness due to OSAS.

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6

Turino, Cecilia. "A new approach to obstructive sleep apnoea management". Doctoral thesis, Universitat de Lleida, 2021. http://hdl.handle.net/10803/673267.

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L'aplicació de la pressió positiva contínua en la via aèria superior (CPAP) representa el mètode terapèutic de referència de la Síndrome d'Apnea Obstructiva del Son (SAOS). No obstant això, la SAOS es considera una malaltia amb múltiples fenotips i resposta al tractament variable. Per tant, el tractament amb CPAP hauria d'aconsellar-se segons el fenotip dels pacients. Així doncs, es necessiten noves estratègies per millorar el compliment del mateix tractament. En el primer article hem identificat algunes variables relacionades amb la SAOS . En el segon article hem definit el perfil general dels pacients de Catalunya tractats amb CPAP i hem identificat sis clústers de pacients amb diferents patrons de comorbiditats, mortalitat i ús dels recursos sanitaris. En el tercer article la telemedicina va demostrar més cost efectivitat que el maneig tradicional del tractament amb CPAP. En el quart article, el Sistema Intel•ligent de Monitoratge (MiSAOS) va demostrar més cost efectiu que el maneig tradicional del tractament amb CPAP.
La aplicación de la presión positiva continua en la vía aérea superior (CPAP) representa el método terapéutico de referencia del Síndrome de Apneas Obstructivas del Sueño (SAOS) . Sin embargo, el SAOS se considera una enfermedad con múltiples fenotipos, por lo tanto, el tratamiento con CPAP debería aconsejarse según el fenotipo de los pacientes. Por otro lado, también se necesita nuevas estrategias para mejorar el cumplimento del mismo tratamiento. En el primer artículo hemos identificado algunas variables relacionadas con el SAOS . En el segundo artículo hemos definido el perfil general de los pacientes SAOS de Cataluña tratados con CPAP y hemos identificado seis clústers de pacientes con diferentes patrones de comorbilidades, mortalidad y uso de los recursos sanitarios. En el tercer artículo la telemonitorización demostró más coste efectividad que el manejo tradicional del tratamiento con CPAP. En el cuarto artículo, el Sistema Inteligente de Monitorización (MiSAOS) del cumplimiento con CPAP se demostró más coste efectivo que el manejo tradicional.
The application of continuous positive pressure (CPAP) represents the first line treatment for patients with Obstructive Sleep Apnoea (OSA) . However, OSA is now regarded as a disorder characterized by multiple phenotypes with variable response to treatment. Thus, CPAP treatment should be recommended according to phenotypes. On the other hand, new methods for improving CPAP compliance are required. In the first article we found some variables associated with OSA . In the second article, we defined a general profile of the entire CPAP-treated OSA population of Catalonia and identified six patient groups characterized by different patterns of comorbidities, mortality, and healthcare resource use. In the third article telemedicine did not improve CPAP compliance but was more cost effective than traditional follow-up. Finally, in the fourth article, the MiSAOS Intelligent Monitoring System for improving CPAP compliance resulted more cost effective than traditional management.

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7

West, Sophie Diana. "Obstructive sleep apnoea and type 2 diabetes". Thesis, University of Leicester, 2007. http://hdl.handle.net/2381/29539.

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Aims: To establish the prevalence of OSA in individuals with type 2 diabetes, and whether treatment with CPAP improves glycaemic control and insulin resistance. Methods and Results: A questionnaire was sent to 1682 men with type 2 diabetes from hospital and primary care databases. Fifty-six percent replied; 57% scored as 'high' and 39% as 'low' risk for OSA; 4% had known OSA. Overnight oximetry in 240 respondents from the 'high' and 'low' risk groups showed 31% and 13% respectively had significant OSA, verified by sleep studies. Exploration and oximetry data to the questionnaire respondent population suggests 23% have OSA. Comparison with a general population showed OSA prevalence to be significantly higher in the diabetes population (p<0.001). Multiple linear regression revealed diabetes was a significant independent OSA predictor after correction for BMI, explaining 8% of OSA variance (p<0.001). There was no correlation of OSA with HbA1c. A double blind randomized controlled trial of CPAP in men with type 2 diabetes and newly diagnosed OSA was performed. Forty-two men attended for baseline investigations and then received either therapeutic or placebo CPAP for 3 months; baseline tests were then repeated. In the therapeutic group, significantly improved subjective and objective sleepiness were noted, however no significant improvement in HbA1c, euglycaemic clamp, adiponectin or HOMA-%S were found. Conclusions: OSA is highly prevalent in men with type 2 diabetes; most individuals are undiagnosed. Diabetes may be a significant independent contributor to OSA risk. CPAP treatment of OSA does not improve insulin resistance or HbA1c in men with type 2 diabetes.

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8

Filtness, Ashleigh J. "Obstructive sleep apnoea and daytime driver sleepiness". Thesis, Loughborough University, 2011. https://dspace.lboro.ac.uk/2134/8338.

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Driver sleepiness is known to be a major contributor to road traffic incidents (RTIs). An initial literature review identified many studies reporting untreated obstructive sleep apnoea (OSA) sufferers as having impaired driving performance and increased RTI risk. It is consistently reported that treatment with continuous positive air pressure (CPAP) improves driving performance and decreases RTI risk, although most of these studies are conducted less than one year after starting treatment. UK law allows treated OSA patients to continue driving if their doctor states that treatment has been successful. Despite the wealth of publications surrounding OSA and driving, 6 key areas were identified from the literature review as not fully investigated, the: (i) prevalence of undiagnosed OSA in heavy goods vehicle (HGV) drivers in the UK; (ii) impact of sleep restriction on long term CPAP treated OSA compared with healthy controls; (iii) ability of treated OSA participants to identify sleepiness when driving; (iv) impact of one night CPAP withdrawal on driving performance; (v) individual difference in driving performance of long term CPAP treated OSA participants; (vi) choice of countermeasures to driver sleepiness by two groups susceptible to driver sleepiness, OSA and HGV drivers. Key areas (i) and (vi) were assessed using questionnaires. 148 HGV drivers were surveyed to assess OSA symptoms and preference of countermeasures to driver sleepiness. All participants completing the driving simulator study were also surveyed. 9.5% of HGV drivers were found to have symptoms of suspected undiagnosed OSA. Additionally the OSA risk factors were more prevalent for HGV drivers than reported in national statistics reports for the general population. The most effective countermeasures to driver sleepiness (caffeine and a nap) were not the most popular. Being part of a susceptible group (OSA or HGV driver) and prior experience of driver sleepiness did not promote effective choice of countermeasure. Key areas (ii) to (v) were assessed using a driving simulator. Driving simulators present a safe environment to test participants in a scenario where they may experience sleepiness without endangering other road users.

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9

Coughlin, Steven Robert. "The cardiovascular consequences of obstructive sleep apnoea". Thesis, University of Liverpool, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403099.

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Obstructive sleep apnoea (OSA) is associated with increased cardiovascular morbidity and mortality, possibly because it clusters with a number of cardiovascular risk factors that comprise and underpin the metabolic syndrome. These include, obesity, high blood pressure, insulin resistance, impaired glucose tolerance and dyslipidaemia, and an increased sympathetic activity, altered cardiac autonomic tone and reduced baroreceptor sensitivity. However, it is currently unclear whether OSA clusters with these risk factors independently of obesity as studies investigating these relationships generally used BMI as a surrogate marker of adiposity. Likewise, a lack of intervention studies for the majority of these risk factors makes it difficult to assess whether OSA directly influences their development. The first aim of this thesis was to determine whether OSA was associated with the cardiovascular risk factors that comprise the metabolic syndrome independently of obesity. This was accomplished by measuring these cardiovascular risk factors in two groups of subjects with and without OSA whom were closely matched for a range of obesity related variables. The second aim of this thesis was to determine whether these risk factors resolved with the application of nasal continuous positive airways pressure (CPAP) treatment. This was investigated by randomising subjects to either CPAP or a sub-therapeutic alternative for a six week period and then crossed-over to the alternative treatment for a further six weeks. The cardiovascular risk factors were compared following CPAP and sub-therapeutic therapy. The methodologies used to measure these cardiovascular risk factors included; blood pressure measurements, a HOMA analysis of fasting glucose and insulin values to estimate insulin resistance, a full lipid profile, a urine catecholamine analysis, and spectral analyses of baroreceptor sensitivity and heart rate variability, the latter being an indirect measure of cardiac autonomic tone. The results of these studies demonstrated that whilst OSA was independently associated with a reduced HDL cholesterol, an increased incidence of the metabolic syndrome and values of cardiac autonomic tone that have previously been demonstrated to confer an increased cardiovascular risk following myocardial infarction, only systolic, diastolic and mean arterial blood pressures were significantly reduced by CPAP. Whilst the associations of OSA with these known cardiovascular risk factors may help explain the increased cardiovascular morbidity and mortality associated with this condition, the results of the intervention study suggest that OSA clusters with the majority of these risk factors because of a common cause rather than any direct effect. Whether this common cause is a shared genetic mechanism or because subjects with OSA exhibit a sedentary lifestyle, a known risk factor for the metabolic syndrome which develops as a consequence of their daytime sleepiness, remains unclear. Further intervention using a structured physical activity programme in subjects with OSA is needed to clarify this.

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10

Melehan, Kerri Louise. "Obstructive sleep apnoea and sexual function in men". Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/11857.

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Obstructive sleep apnoea (OSA) is associated with sexual dysfunction. Untreated OSA and erectile dysfunction (ED) have both been identified as being indicative of a high risk of developing cardiovascular disease. Treatments for ED, such as testosterone supplementation or PDE-5 inhibitors, and for OSA, such as Continuous Positive Airways Pressure (CPAP) are both readily available. The effects of these treatments on the other associated conditions have not been fully assessed. The efficacy of testosterone supplementation, in untreated OSA, on sexual function and quality of life has not been investigated. PDE-5 inhibitors are an established treatment for erectile dysfunction, however, there is a paucity of information regarding their efficacy in OSA, and there is a theoretical risk of worsening of OSA with their use. CPAP, in some observational and non-treatment or alternative treatment controlled studies, has been shown to improve erection function in men with OSA, however the majority of these studies have been in men with OSA, with and without ED. Two randomised controlled trials investigating the effects of testosterone in untreated OSA (n=67), and the effects of CPAP and a PDE-5 inhibitor in men with OSA and ED using a factorial design (n=61) were performed. Sleep, sexual function and quality of life was assessed. CPAP increased the quantity of nocturnal erections and a PDE-5 inhibitor improved their quality. However, neither CPAP use, exogenous testosterone nor a PDE-5 inhibitor improved subjective erectile function in men with OSA. Post-hoc analysis showed that adherent CPAP use (>4hours per night) increased subjective erectile function and sexual desire, as well as several parameters of quality of life in men with OSA and ED. Testosterone also increased sexual desire in men with OSA.

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11

Seto, Boon Hong. "Maxillary Morphology In Patients With Obstructive Sleep Apnoea". Thesis, Faculty of Dentistry, 1996. http://hdl.handle.net/2123/5102.

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12

Shaikh, Zarrin F. "Patent foramen ovale in obstructive sleep apnoea and chronic obstructive pulmonary disease". Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/9478.

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The objective of this thesis was to determine the impact of right to left shunting (RLS) through patent foramen ovale (PFO) on oxygen saturation in obstructive sleep apnoea (OSA) and chronic obstructive pulmonary disease (COPD). The first aim was to determine the prevalence of PFO in severe OSA and whether PFO closure improves nocturnal oxygen saturation. The data showed that PFO with large shunts were more prevalent, however overall prevalence was not statistically different when compared to healthy controls. PFO closure did not reduce nocturnal desaturation. The second aim was to determine whether severe COPD patients with PaO2 ≤ 7.3kPa had a higher prevalence of PFO compared to patients with PaO2 > 8kPa, additionally to compare the prevalence of PFO in COPD with healthy controls. The data showed no difference in PFO prevalence in patients with PaO2 ≤ 7.3kPa compared to patients with PaO2 > 8kPa, however, intrapulmonary shunts were more prevalent in hypoxaemic patients. Similar to OSA, PFO with large shunts were more prevalent in severe COPD, however overall prevalence was not statistically different to healthy controls. The final aim was to determine whether patients with COPD and PFO developed RLS during exercise and whether this was associated with reduced oxygen saturation, reduced exercise endurance and increased intrathoracic pressure swings. The data showed that RLS through PFO increased from baseline during exercise and this was associated with increased swings in intrathoracic pressure. There was no difference in desaturation or exercise endurance when compared to patients with no PFO. In summary, this thesis shows that PFO with large shunts are more prevalent in both OSA and COPD. PFO closure in OSA did not reduce nocturnal desaturation. Furthermore, the presence of a PFO in COPD did not influence resting or exercise oxygen saturation despite the observed increase in RLS with exercise.

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13

Shepherd, Kelly. "Gastro-oesophageal reflux in obstructive sleep apnoea : prevalence and mechanisms". University of Western Australia. School of Anatomy and Human Biology, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0085.

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Background. Obstructive Sleep Apnoea (OSA) is associated with an increase in nocturnal gastro-oesophageal reflux (nocturnalGOR) events and symptoms, however the mechanism for this remains undefined. Treatment of OSA with continuous positive airway pressure (CPAP) has been shown to reduce nocturnalGOR in individuals with OSA however the reasons for this reduction are not clear. The combination of OSA and nocturnalGOR could be particularly problematic for individuals who have had a lung transplant in whom Bronchiolitis Obliterans Syndrome (BOS) limits survival. It is thought that GOR plays a role in the development of BOS in these individuals. Methods and Results. Five interrelated studies were undertaken. The first two studies sought to determine and compare the prevalence and risk factors of nocturnalGOR in OSA patients with the general population. To do this, a GOR questionnaire was completed by 2,042 members of the general community as part of the Busselton Health Survey and by 1,116 patients with polysomnography-diagnosed OSA. Risk of OSA in the general population was determined using a standardised sleep questionnaire. 137 of the OSA patients completed the questionnaire before and after treatment with CPAP. The prevalence of nocturnalGOR symptoms reported more than once a week (frequent symptoms) was greater in OSA patients (10.1%) than the general population (5.8%) (p<0.001), in individuals from the general population at high (11.2%) than low risk of OSA (4.5%) (p<0.001) and in patients with severe (14.7%) than mild OSA (5.2%) (p<0.001). Treatment of OSA with CPAP decreased the prevalence of frequent nocturnalGOR from 9.0% to 3.8% (p=0.04). In the general population, high risk of OSA was independently associated with a 2.4-fold increased risk of frequent ABSTRACT vi nocturnalGOR symptoms than low risk. In the OSA group, disease severity was independently associated with nocturnalGOR symptoms, with an adjusted odds ratio of 1.7 for frequent nocturnalGOR symptoms.

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14

Donoghue, Simon. "The cardiovascular consequences of obstructive sleep apnoea hypopnoea syndrome". Thesis, University of Liverpool, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269700.

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15

Butt, Mehmood Sadiq. "Micro- and macro-vascular function in obstructive sleep apnoea". Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3926/.

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Obstructive sleep apnoea (OSA) is common worldwide and is associated with cardiovascular disease. Endothelial dysfunction (ED) is regarded as a crucial step in disease development and has been demonstrated in peripheral vasculature in OSA population. However the effect of ventilatory dysfunction on myocardial perfusion is unknown. I performed comprehensive assessment of endothelial function in moderate to severe OSA subject compared with helthy and hypertensive controls, using flow mediated dilatation (FMD), laser Doppler flowmetry (LDF), flow cytometry in addition to studying vascular elastic properties. I also performed myocardial contrast echocardiography (MCE) and real time three-dimensional echocardiography (RT3DE). All these tests were repreated after 6 months of continuous positive airway pressure (CPAP) therapy. I demonstrated endothelial dysfunction in the peripheral circulation and coronary circulation as well as cardiac remodeling in OSA. However, I did not note a significant change in the indices of arterial stiffness and in the flow cytometric analysis. I noted marked improvement in the peripheral and coronary endothelial dysfunction after OSA subjects were treated with CPAP therapy for 6 months. In summary, micro- and macro-vascular dysfunction exists in otherwise healthy moderate to severe OSA subjects and improves with effective CPAP therapy. These findings may have strong clinical and prognostic implications.

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16

Glasser, Martin. "Neuroanatomical correlates of cognitive dysfunction in obstructive sleep apnoea". Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/44371.

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Obstructive sleep apnoea (OSA) has been reported to be associated with brain hypotrophy and cognitive dysfunction; however, whether these normalise after treatment is unclear. The overall aim of this thesis is to investigate the relationship between OSA and brain structure using FreeSurfer (a new automated technique that reliably measures brain structures). I have investigated changes in brain morphology and the newly described phenomenon in OSA of ischaemic preconditioning. Chapters 4 and 5 will also assess brain structural response to CPAP, and investigate the association between brain structure and cognitive function in OSA. Chapter 3 reports an observational study investigating brain structure. FreeSurfer analysis of magnetic resonance imaging (MRI) found OSA patients had hypertrophy in the right hippocampus (p=0.03) and right choroid plexus (p=0.02) but hypotrophy of the corpus callosum (p=0.04) compared to healthy controls. Chapter 4 reports a randomised controlled trial of CPAP in OSA. At baseline hypotrophy was seen in the corpus callosum (p=0.03) and pallidum (p=0.03) of OSA patients compared to healthy controls. Hypertrophic changes in the right thalamus were seen in the CPAP group after 1 month (p=0.06), associated with improvement in verbal memory (p=0.04). Chapter 5 reports a randomised controlled trial of CPAP in older patients with OSA. A significant decrease in left fimbria volume was seen in the CPAP group (p=0.01). A significant increase in the left presubiculum volume was seen in the best supportive care group (p=0.03). No hippocampal hypertrophy was seen in the CPAP group. In summary, young and middle-aged OSA patients had evidence of brain hypotrophy, but also areas of hypertrophy that may signify dendritic sprouting and increased connectivity as a result of ischaemic preconditioning. This allows recovery of brain hypotrophy after CPAP treatment. This was not seen in older OSA patients suggesting an age-related difference which may have implications for OSA treatment in older people.

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17

Moss, James. "Physiological effects of treatments in obstructive sleep apnoea syndrome". Thesis, Sheffield Hallam University, 2013. http://shura.shu.ac.uk/20763/.

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The original research in this thesis aimed to investigate physiological effects of different treatment approaches in obstructive sleep apnoea syndrome (OSAS). OSAS is a prevalent public health concern independently associated with increased cardiovascular risk. Specifically, study 1 examined the feasibility of conducting a pragmatic lifestyle intervention in patients reporting compliance with continuous positive airway pressure (CPAP) and collected provisional data about its efficacy, and study 2 investigated the physiological effects of low compliance to CPAP therapy in a four-arm observational study. The intervention in study 1 involved supervised exercise, dietary advice and behaviour change counselling. Primary outcome measures were recruitment, retention and compliance data and secondary outcome measures assessed anthropometrics, cardiovascular risk, quality of life and exercise capacity. Study 2 investigated macro-and microvascular function, anthropometrics, quality of life, cardiovascular risk and exercise capacity. The novel findings of this research were: 1) the lifestyle intervention was feasible to deliver; 2) the intervention improved key health outcomes such as exercise capacity (A +16%) and serum C-reactive protein (A -57%), which were maintained after 3 months of independence (A +22% and -57%, respectively); 3) self-reported CPAP compliance is an unreliable indicator of actual compliance; 4) it is difficult to recruit low-compliance patients onto research trials, and recruiting newly diagnosed patients is also difficult without interrupting the patient pathway; 5) vascular function seems impaired in low-compliance patients versus high-compliance patients, although further work is needed to confirm this. These findings contribute to the growing evidence base for the role of lifestyle intervention in OSAS, and provide provisional data on the effects of low compliance to CPAP therapy on vascular endothelial function. In summary, future research investigating pragmatic lifestyle interventions in OSAS and the physiological effects of low-compliance to CPAP is certainly warranted.

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18

Carlisle, Thomas. "Mechanisms of obstructive sleep apnoea in congestive heart failure". Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/17824.

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Approximately 50% of chronic heart failure (CHF) patients have obstructive sleep apnoea (OSA); however the mechanisms associated with OSA in CHF patients are incompletely understood. The overall aim of this thesis was to characterise upper airway phenotypes that may contribute to OSA in patients with CHF. Specifically, I sought to test the hypothesis that CHF patients with OSA have overnight rostral fluid shift. Pharyngeal phenotypes were measured non-invasively; pharyngeal calibre was measured using acoustic reflection, pharyngeal collapsibility using the passive critical closing pressure (Pcrit) technique, and changes in pharyngeal compliance during sleep using oesophageal pressure manometry combined with direct visualisation of the pharynx using bronchoscopy. Chapter 5 investigated differences in pharyngeal anatomy and morphology in healthy younger and older male volunteers using acoustic reflection, testing the hypothesis that older healthy males have similar pharyngeal dimensions to younger healthy males. The findings of this thesis showed that CHF patients with OSA have similar pharyngeal cross-sectional areas to CHF patients without OSA and healthy controls (Chapter 3). Pharyngeal collapsibility was also similar between groups (Chapter 4). CHF patients may be predisposed to pharyngeal collapse due to overnight attenuation of normal pharyngeal dilation during inspiration (Chapter 6). Finally, it was demonstrated that there may be differences in pharyngeal dimensions and morphology in older males compared to younger males (Chapter 5). The implications of the studies presented in this thesis are that fluid shift may be a contributing factor to OSA in CHF but the findings in this thesis suggest that its role is not likely to be dominant over more established mechanisms of OSA. Moreover, there may be no special features of CHF that explain the high prevalence of OSA in CHF.

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19

Bennett, Lesley Samantha. "Sleep fragmentation predictors of daytime sleepiness and health status in sleep apnoea". Thesis, University of Bristol, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299534.

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20

Rees, Karen. "Mechanisms of arousal responses from NREM sleep in patients with Obstructive Sleep Apnoea". Thesis, University of Salford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284444.

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21

Al-Abri, Mohammed A. "Studies in blood pressure and obstructive sleep apnoea/hypopnoea syndrome". Thesis, University of Edinburgh, 2007. http://hdl.handle.net/1842/24009.

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This thesis aims to explore baroreflex sensitivity (BRS) in a randomised controlled trial. The hypothesis is that BRS is impaired in sleep apnoea patients, which might be reversed with one month of CPAP therapy. The study was designed to test for BRS in newly diagnosed OSAHS patients and perform a single blinded placebo controlled crossover trial of the effect of CPAP. Twenty-nine patients were recruited with Epworth Sleepiness Scale (ESS) of more than 10 and apnoea/hypopnoea index (AHI) was more than 15. Ten healthy control subjects were also studied. The study has shown weak difference between controls and OSAHS patients in the sequential analysis measure of BRS (P=0.05) but there was no difference with other BRS variables (P>0.05). However, the study did not show any significant difference between CPAP and placebo in terms of an effect on any measure of BRS not of 24-hour blood pressure. Even a priori sub group analyses of desaturating and compliant patients (4% Desaturating Index > 10 & CPAP use > 3.9 hour/night) showed no effect of CPAP (P>0.05). Patients did improve symptomatically with CPAP (P=0.02).The main criticisms of this study are the lack of reproducibility of the BRS measuring technique. Furthermore, relatively small sample size, may perhaps, had a negative impact on the results. The new methods were investigated further by another study, looking into the reproducibility of eth technique and the principles of BRS measurement, either the sequence as well as the spectral analysis of heart rate and systolic blood pressure. This study has revealed that spontaneous methods of BRS particularly the spectral domains are quite variables over time and thus difficult to reproduce. The third study was to assess endothelial function, as part of the process of understanding the pathogenesis of development hypertension and cardiovascular diseases in OSAHS patients and the contribution of hypoxemia in these disorders. The 24 blood pressure monitoring analysis revealed that hypoxemia is a putative predictor for hypertension.

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Friberg, Danielle. "Nerve lesions in pharynx - an aetiology of obstructive sleep apnoea /". Stockholm, 1997. http://diss.kib.ki.se/1997/91-628-2721-9.

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23

Craig, Sonya Elizabeth. "Cardiovascular consequences of obstructive sleep apnoea in minimally symptomatic patients". Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708448.

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24

Ghiassi, Ramesh. "The development of pictorial tools for obstructive sleep apnoea syndrome". Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/24435.

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Introduction: Obstructive sleep apnoea syndrome (OSAS) is common but remains underdiagnosed and is linked with several disease states and increased risk of mortality. The key symptom, excessive daytime sleepiness, is commonly measured with the Epworth Sleepiness Scale which is not always easily completed by patients. The aim of this thesis is to develop pictorial material for assessing sleepiness and risk of OSAS. Methods: Health literacy was measured in a sample sleep population and the Epworth Sleepiness Scale was investigated for ease of use. Images were developed to translate the Epworth into pictures and the response to pictures of 'driving while sleepy' was investigated in detail. A new tool, the pictorial Sleepiness and Sleep Apnoea Scale, was devised by adding four sleepiness images from the pictorial Epworth to four new images representing 'risk of OSAS'. Evaluations were made in two populations of the tool's potential in predicting those at risk of OSAS. Results: Poor or impaired health literacy was found in 16% of patients attending the sleep clinic. Evaluation of the Epworth Sleepiness Scale found that a third of new patients made quantifiable errors. A preference for the pictorial Epworth Sleepiness Scale was reported by 55% of users and a kappa statistic indicated good agreement between the pictorial and traditional Epworth Sleepiness Scale. Drivers were more inclined to record feeling sleepy if the image in Q8 depicted the sleepy person in the car as a passenger. In a sleep clinic population the pictorial Sleepiness and Sleep Apnoea Scale was slightly better at predicting disease than the Epworth. In a cardiac rehabilitation clinic use of the witnessed apnoea image from the pictorial Sleepiness and Sleep Apnoea Scale, along with the Epworth Sleepiness Scale, helped to identify symptoms suggestive of sleep apnoea in a third of those screened. When investigated with a sleep study, the prevalence of sleep-disordered breathing in this patient group was 14.8%. Conclusion: Pictorial tools for patients with potential obstructive sleep apnoea syndrome have clinical value and can help bridge the gap between poor or impaired health literacy and the material we use to assess sleepiness and likelihood of obstructive sleep apnoea syndrome.

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25

Roebuck, Aoife. "Comparative analysis of polysomnographic signals for classifying obstructive sleep apnoea". Thesis, University of Oxford, 2015. http://ora.ox.ac.uk/objects/uuid:021c18bd-5422-4ebb-b770-b6627e5e705f.

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Obstructive sleep apnoea (OSA) is a common disorder involving repeated cessations of breathing due to airway collapse, causing disruption of sleep cycles. The condition is under-diagnosed and the side effects are many and varied. Currently, the ‘gold standard’ diagnostic tool for OSA is a polysomnogram (PSG) which is carried out overnight in a hospital using multiple sensors. A PSG is expensive to set-up, run and analyse, and some subjects experience different sleep patterns due to the artificial conditions of the sleep laboratory. The aim of this thesis was to find a parsimonious and easy-to-collect set of signals (from the superset of signals recorded in sleep clinics) and other related information (such as demographics), and a set of automated methods that reliably determine which subjects are suitable for standard treatments, i.e. classify subjects requiring treatment (moderate OSA, severe OSA) from those not requiring treatment (normal, snorer, mild OSA), using a smartphone. Data were collected from 1354 subjects in the home using the Grey Flash polysomnographic recording device (Stowood Scientific Instruments, Oxford, UK). Analysis of the audio signal was initially performed using standard speech processing methods, where individual events were annotated and classified. The results achieved (accuracy (Ac) = 69.6%) using this approach were lower than those required for clinical acceptance. In all subsequent work in the thesis, subjects were classified from entire recordings rather than events. Multiscale entropy (MSE) was used to identify non-linear correlations in the audio data and quantify the irregularity of the data over many time scales. The inter-snore interval (ISI) was developed, motivated by clinical intuition. MSE and ISI were then applied to both actigraphy and photoplethysomgraphy (PPG) data, and different combinations of features were analysed. The features which displayed the highest predictive accuracy were derived from the PPG signal (Ac = 89.2%). This work demonstrated that, although audio- and actigraphy-based OSA screening is possible, to achieve clinically acceptable performance PPG remains an important key factor in diagnosis.

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Faccenda, Jacqueline Frances. "Systemic blood pressure in the obstructive sleep apnoea/hypopnoea syndrome". Thesis, University of Edinburgh, 2002. http://hdl.handle.net/1842/23341.

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The purpose of this thesis was to demonstrate in a randomised controlled trial whether BP was higher in untreated OSAHS. The study was crossover in design with the patients acting as their own controls, so increasing the power of the study. Sixty-eight patients were studied with at least two major symptoms of OSAHS, and a mean AHI of 15 events/hour slept and a mean age of 49 years (27-77). Diastolic Blood Pressure (DBP) was reduced by CPAP in patients with OSAHS. These data were analysed on an intention to treat basis, including all 68 patients including poorly compliant patients. This showed a 1.5 mmHg drop in DBP (p = 0.043) with CPAP. In an a priori compliant subset (CPAP use 3.5 hours/night) DBP remained significantly lower by a magnitude of 1.9 mmHg (p = 0.042). In the other a priori subset of severely hypoxaemic patients (4% desaturation index 20/hour) there were also falls in Systolic BP (4.0 mmHg, p = 0.011), DBP (5.0 mmHg, p = 0.001) and mean arterial pressure (3.4 mmHg, P=0.023). Although all the reductions in pressures were small, data from population studies suggest such reductions may be associated with significant health benefits. In addition the effects may have been underestimated as the equipment used to measure BP may cause an arousal from sleep there by artificially elevating the night-time BP recorded. The baroreceptor function was not different between the two treatments. The urinary microalbumin was abnormal in 35% of the patient group, the reasons for this needs further investigation. The benefits found in quality of life confirmed previous studies although this is the first randomised controlled trial to show benefits in the Functional Outcomes of Sleep Questionnaire. The lack of improvement in the neuropsychological testing may reflect the tests used. The CPAP compliance on this study was less than ideal, but similar to those in other prospective studies.

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27

JOFFE, David. "OBSTRUCTIVE SLEEP APNOEA: THE GENESIS OF DAYTIME SOMNOLENCE AND COGNITIVE IMPAIRMENT - AROUSALS, HYPOXIA AND CIRCADIAN RHYTHM". Thesis, The University of Sydney, 1997. http://hdl.handle.net/2123/382.

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Obstructive Sleep Apnoea (OSA) is a disease characterised by repetitive upper airway obstructions which are manifest by desaturation and arousal from sleep. It has been known for many years that this interruption to the normal architecture of sleep may present to the clinician as excessive daytime somnolence often with a complaint of difficulties with concentration and short term memory. Previous work had demonstrated a relationship between variables of cognitive dysfunction in patients with obstructive sleep apnoea, however, little was known about which components of the syndrome contributed to this outcome and whether specific clinical thresholds of sleep disordered breathing could be defined for the development of cognitive dysfunction. In the context of this body of work cognitive dysfunction is defined as: a level of cognitive performance below normal derived values for a given cognitive test, when the subjects performance is controlled for age, sex and level of education.

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28

JOFFE, David. "OBSTRUCTIVE SLEEP APNOEA: THE GENESIS OF DAYTIME SOMNOLENCE AND COGNITIVE IMPAIRMENT - AROUSALS, HYPOXIA AND CIRCADIAN RHYTHM". University of Sydney, Respiratory Medicine, Royal North Shore Hospital, 1997. http://hdl.handle.net/2123/382.

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Obstructive Sleep Apnoea (OSA) is a disease characterised by repetitive upper airway obstructions which are manifest by desaturation and arousal from sleep. It has been known for many years that this interruption to the normal architecture of sleep may present to the clinician as excessive daytime somnolence often with a complaint of difficulties with concentration and short term memory. Previous work had demonstrated a relationship between variables of cognitive dysfunction in patients with obstructive sleep apnoea, however, little was known about which components of the syndrome contributed to this outcome and whether specific clinical thresholds of sleep disordered breathing could be defined for the development of cognitive dysfunction. In the context of this body of work cognitive dysfunction is defined as: a level of cognitive performance below normal derived values for a given cognitive test, when the subjects performance is controlled for age, sex and level of education.

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29

Earing, C. M. N. "Factors associated with the severity of Apnoea Hypopnoea Index (AHI) in Obstructive Sleep Apnoea (OSA)". Thesis, Bangor University, 2015. https://research.bangor.ac.uk/portal/en/theses/factors-associated-with-the-severity-of-apnoea-hypopnoea-index-ahi-in-obstructive-sleep-apnoea-osa(67d4be66-a209-4034-a7c1-916e6d86fd35).html.

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Obstructive sleep apnoea (OSA) is the most prevalent sleep disorder, characterised by repetitive episodes of complete or partial obstructions of the upper airway during sleep. These apnoeic related events have been associated with intermittent hypoventilation, hypoxemia, hypercapnia, recurrent arousals in sleep and the activation of the sympathetic nervous system. Questions arise over the feasibility of a risk factor intervention strategy in reducing the incidence of mild to moderate OSA. Currently the only adequately supported intervention is weight loss. The long term objective of this thesis will be to guide the design of future interventions which are focussed on the specific symptomatology of OSA. The general theme of this thesis is to identify which physiological factors most strongly contribute to the pathogenesis of OSA. A particular interest is first given to the potential effects of the exposure to intermittent hypercapnia and hypoxia during sleep, while newly developed techniques for assessment of chemosensitivity towards carbon dioxide (CO2) and oxygen (O2) was piloted in scuba divers and controls. Following this, the implications of the baroreflex-chemoreflex interactions are assessed before reviewing inflammatory markers present within the patients with OSA. Finally, with the understanding that the occlusive airway and subsequent apnoeas associated with OSA may lead to increased inspiratory efforts whereby the inspiratory muscles are overloaded during sleep, alongside the environment of nocturnal bouts of hypoxia and hypercapnia and systemic inflammation, the prevalence of inspiratory muscle fatigue in OSA is also investigated. The general introduction (Chapter 1) provides the background information and proposes the aims of the research presented in the thesis. Following this, the first study (Chapter 2) investigates the ventilatory response to CO2 amongst scuba divers using a novel methodology. Different populations have displayed altered ventilatory responses to CO2; scuba divers are an example in a healthy population. Investigating scuba divers enabled us to develop and test methodology designed to assess the relative contribution of adaptations to the peripheral and/or central chemoreceptors to their ventilatory response to CO2. Their ventilatory response was also compared to the patients with OSA in chapter 3. The same methodology was then applied in the first OSA Study (Chapter 3) to assess the ventilatory response amongst patients with OSA with the theory that the exposure to intermittent hypercapnia and hypoxia during apnoeic related events may cause a similar modification in the ventilatory response seen in scuba divers. The third study (Chapter 4) assessed the implications of baroreflex sensitivity on the severity of OSA and the ventilatory response to CO2 observed in the third chapter, to increase our understanding of the strength of the baroreflex-chemoreceptor interaction previously reported in the research literature. To increase our knowledge of the inflammatory processes involved in the pathogenesis of OSA, the forth study (Chapter 5) investigates cytokines related to obesity through the quantification of adiponectin, c-reactive protein, leptin and the endocannabinoids (2-arachidonoylglycerol and arachidonoylethanolamide) on the severity of OSA. The endocannabinoids have been shown to mediate anti-inflammatory properties in addition to playing a significant role in the regulation of energy metabolism within adipose tissue. The final study (Chapter 6) assesses the neuromuscular properties of the breathing apparatus with particular interest in studying the fatigability of the inspiratory muscles. This chapter involves the development of an entirely novel protocol which is designed to elicit inspiratory muscle fatigue through submaximal loading. The final chapter (Chapter 7) integrates the findings of all the studies to propose a novel regression model which can be designed to predict the severity of OSA from the physiological processes investigated.

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Ratnavadivel, Rajeev y rajeev ratnavadivel@health sa gov au. "The Importance of Non-Anatomical Factors in the Pathogenesis of Obstructive Sleep Apnoea". Flinders University. Medicine, 2009. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20090901.162141.

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Obstructive sleep apnoea (OSA) is a common condition characterized by recurrent complete and partial upper airway obstruction. OSA sufferers have been shown to have a significantly smaller upper airway lumen compared to non-OSA sufferers. However, non-anatomical factors of sleep stage, arousability and neuromechanical responses to airway occlusion and chemosensitivity are likely to play a significant part in influencing OSA severity across the night. An exploration of these non-anatomical factors forms the basis for the experiments in this thesis. In the first experimental chapter presented in this thesis, a detailed retrospective epoch by epoch analysis of nocturnal polysomnography in 253 patients referred to a clinical sleep service was performed to examine differences in sleep apnoea severity and arousal indices across the different stages of sleep, while controlling for posture. Both patients with and without OSA demonstrated significant reductions in respiratory and arousal event frequencies from stage 1 to 4 with intermediate frequencies in REM sleep. Lateral posture was also associated with significant improvements in OSA and arousal frequencies, with an effect size comparable to that of sleep stage. The majority of patients showed significant reductions in OSA severity during slow wave sleep. In non-REM sleep, there was a strong correlation between OSA severity and arousal frequency. These results confirm in a large group of patients, a strong sleep stage dependence of both OSA and arousal frequencies. The second study in this thesis explores the development of a CO2 stabilising or clamp device to enable the provision of positive airway pressure, and by proportional rebreathing, the maintenance of relatively constant end-tidal CO2 despite significant hyperventilation. Healthy volunteers performed brief periods of significant voluntary hyperventilation at 2 levels of CPAP with the rebreathing function off and with active CO2 clamping in randomized order. Compared to CPAP alone, the device substantially attenuated hypocapnia associated with hyperventilation. The third study of the thesis was designed to investigate if increasing and stabilizing end-tidal CO2 could improve obstructive breathing patterns during sleep. 10 patients with severe OSA underwent rapid CPAP dialdown from therapeutic to a sub-therapeutic level to experimentally induce acute, partial upper airway obstruction over 2 minute periods repeated throughout the night. The CO2 clamp device developed and validated in Study 2 was used to determine whether during periods of partial upper airway obstruction with severe flow limitation, (1) increased end-tidal CO2 resulted in improved airflow and ventilation and (2) clamping end-tidal CO2 lessened post-arousal ventilatory undershoot. Three conditions were studied in random order: no clamping of CO2, clamping of end-tidal CO2 3-4 mmHg above eucapnic levels during the pre-dialdown baseline period only, and clamping of CO2 above eucapnia during both baseline and dialdown periods. Elevated CO2 in the baseline period alone or in the baseline and dialdown periods together resulted in significantly higher peak inspiratory flows and ventilation compared to the no clamp condition. Breath-by-breath analysis immediately pre- and post-arousal showed higher end-tidal CO2 despite hyperventilation immediately post-arousal and attenuation of ventilatory undershoot in CO2 versus non-CO2 clamped conditions. These results support that modulation of ventilatory drive by changes in pre- and post-arousal CO2 are likely to importantly influence upper airway and ventilatory stability in OSA. The fourth study was designed to explore several possible pathophysiological mechanisms whereby obstructive sleep apnoea is improved in stages 3 & 4 (slow wave) versus stage 2 sleep. 10 patients with severe OSA who demonstrated significant reductions in OSA frequency during slow wave sleep on diagnostic investigation were studied. Patients underwent rapid dialdowns from therapeutic CPAP to 3 different pre-determined sub-therapeutic pressures to induce partial airway obstruction and complete airway occlusions in a randomised sequence during the night in both stage 2 and slow wave sleep. Partial airway obstructions and complete occlusions were maintained until arousal occurred or until 2 minutes had elapsed, whichever came first. After airway occlusions, time to arousal, peak pre-arousal negative epiglottic pressure and the rate of ventilatory drive augmentation were significantly greater, suggesting a higher arousal threshold and ventilatory responsiveness to respiratory stimuli during slow wave compared to stage 2 sleep. Post dialdowns, the likelihood of arousal was lower with less severe dialdowns and in slow wave compared to stage 2 sleep. Respiratory drive measured by epiglottic pressure progressively increased post-dialdown, but did not translate into increases in peak flow or ventilation pre-arousal and was not different between sleep stages. These data suggest that while arousal time and propensity following respiratory challenge are altered by sleep depth, there is little evidence to support that upper airway and ventilatory compensation responses to respiratory load are fundamentally improved in slow wave compared to stage 2 sleep. In summary, sleep stage, arousal threshold and chemical drive appear to strongly influence upper airway and ventilatory stability in OSA and are suggestive of important non-anatomical pathogenic mechanisms in OSA.

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Islam, Shofiq. "Maxillo-facial surgical considerations in the management of obstructive sleep apnoea". Thesis, University of Leicester, 2016. http://hdl.handle.net/2381/37932.

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Obstructive sleep apnoea (OSA) represents an important public health issue affecting approximately 4% of the UK population. Maxillo-mandibular advancement (MMA) can be considered the most successful surgical procedure for the treatment of OSA. Despite the evidence of the efficacy of MMA, there have been no previously published studies from the UK in this area. This research was designed to investigate several key aspects relevant to the application of MMA in OSA. The results from these studies shed light on both the effectiveness and role of maxillofacial orthognathic procedures in the treatment of selected patients with OSA who require alternative treatment options to first-line therapies. The potential applications of technical modifications to maxillofacial procedures in order to improve outcome is also discussed. The research addresses the important consideration of optimising patient selection for MMA procedures through the utilisation of clinical tools, as well as considering important individual patient factors. In particular, these studies have demonstrated that the Malampatti airway classification does not have a predictive role in outcome following MMA, in contrast to other surgical modalities used to treat OSA. The Kushida morphometric model which incorporates cranio-facial dysmorphism, does not appear to correlate with surgical outcomes, but in spite of this, it retains a diagnostic value to maxillofacial surgeons treating OSA patients. These research findings have shown that baseline OSA severity as well as duration of continuous positive airway pressure (CPAP) use prior to MMA surgery, would appear to significantly correlate with a reduction in subjective outcome measures, however, this association was not seen with objective outcome measures. The lack of consistent correlation between these outcome variables perhaps highlights a complexity that has not been reflected in previously published surgical literature. The important surgical consideration of patient acceptance of a permanently altered facial profile was investigated, with the findings demonstrating that the majority of patients subjectively rated their postoperative facial appearance positively following MMA. This was found to be independent of overall surgical outcome. Additionally, we examined cardiovascular risk factor modification after MMA demonstrating that this surgery has a potent beneficial effect on blood pressure reduction, particularly in those with established hypertension. This body of research significantly contributes to the evidence base in support of this branch of maxillofacial surgery which is currently not widely practiced in the UK. The research demonstrates that surgery can be safely and efficaciously applied to treat selected patients with MMA procedures as an alternative treatment modality in OSA, when other first-line treatments are not tolerated or successful.

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32

Seetho, Ian. "The assessment and characterisation of obstructive sleep apnoea in severe obesity". Thesis, University of Liverpool, 2015. http://livrepository.liverpool.ac.uk/2017419/.

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Background: Obstructive Sleep Apnoea (OSA) is associated with cardiovascular disease. The current evidence regarding the effects of OSA in individuals with severe obesity is limited and has hitherto been largely unexplored. With the growing population of diabetes and obesity globally, the identification of severely obese individuals who have OSA is important given the risk of adverse outcomes associated with OSA. In this regard, the use of urinary proteomic (urinary peptide) profiling as a potential tool to characterise adult severely obese patients for the diagnostic assessment of OSA remains to be investigated. Aims: The aims of the studies described in this thesis were to (1) investigate the effects of OSA in severe obesity in relation to measures related to cardiovascular risk, specifically, arterial stiffness and serum urate; (2) assess current clinical practice of OSA assessment; and (3) explore the use of urinary proteomics in characterising subjects with severe obesity and OSA. Methods: In the arterial stiffness, urate and urinary proteomic studies, patients with severe obesity, were assessed at baseline and at follow-up. Anthropometric, respiratory and cardio-metabolic parameters were measured. All subjects had overnight polysomnography. Subjects with OSA were initially naive to OSA treatment at baseline were subsequently offered CPAP. For the arterial stiffness studies, pulse wave analysis (PWA) was performed. In the urate studies, serum urate measurements were taken to identify associations between OSA and urate at baseline; and CPAP with change in urate at follow-up. OSA assessment in diabetes clinical practice was explored by a national survey in relation to the International Diabetes Federation (IDF) guidance. In the urinary proteomics studies, urine samples were analysed by capillary electrophoresis-mass spectrometry (CE-MS) at baseline and at follow-up. Results: Severely obese patients with OSA had increased arterial stiffness. Although sleepiness and blood pressure improved with CPAP in severe obesity, CPAP alone was not sufficient to modify PWA measures to levels comparable with non-OSA patients. In the urate study, serum urate was associated with OSA in severely obese females and there was a trend for reduced urate levels in CPAP-treated patients. The questionnaire study revealed a disappointing low awareness of the IDF statements and of the perceived importance of assessing for OSA in type 2 diabetes. The urinary proteomic studies identified trends in the urinary peptide profiles suggesting that there may be inherent differences between OSA and non-OSA patients, even following a period of effective CPAP treatment. The identified peptide panel included collagens, cadherin and fibrinogen subtypes. Conclusions: The theme that links the studies in this thesis has been the importance of OSA in relation to cardiovascular risk. Severely obese patients with OSA have increased arterial stiffness that may increase cardiovascular risk. Likewise, in severely obese individuals with OSA who have hyperuricaemia or recurrent gout, there may be a need to consider OSA assessment as elevated urate levels are associated with increased cardiovascular risk. From the questionnaire study, it is clear that more work needs to be done to raise awareness about OSA assessment in diabetes teams as obesity is a risk factor for type 2 diabetes. Urinary proteomic CE-MS profiling has provided novel insights into the urinary proteome in OSA, with and without CPAP. Although there is insufficient evidence to support its use for OSA diagnosis, the urinary peptides identified may be linked with mechanisms underlying cardiovascular disease in OSA and may be associated with treatment effects of CPAP on OSA progression that influences expression of urinary peptides.

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33

Gederi, Elnaz. "Video and audio analysis for the detection of obstructive sleep apnoea". Thesis, University of Oxford, 2017. http://ora.ox.ac.uk/objects/uuid:73387396-d1ba-4a22-9e7a-e84e0c951cfc.

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Obstructive sleep apnoea (OSA) is a common sleep disorder characterised by serious sleep fragmentation due to repeated breathing pauses (OSA events) followed by brief awakenings. OSA is under-diagnosed with many consequences that may be life threatening. The standard screening test, polysomnography (PSG), requires an overnight stay in a clinic and the attachment of several on-body sensors which may be uncomfortable for some patients. Large-scale screening for OSA is limited to the availability of equipment and sleep specialists. The manual review of hours of PSG recordings is also cumbersome and costly. The increasing prevalence of OSA and the long waiting times for screening and treatment highlights a need for contactless home monitoring solutions. The research presented in this thesis aims to (i) investigate whether automatic processing of video recordings of sleep can be used to differentiate patients with OSA who more urgently require treatment and are more likely to respond to the treatment, and (ii) investigate the possibility of deriving respiratory information (respiratory signal, respiratory rate) from video recordings of sleep and scoring individual OSA events using the derived respiratory information. This thesis presents the analysis of PSG recordings from 259 patients with suspected OSA and 30 normal volunteers. First, PSG video recordings are used to identify moderate-to-severe OSA patients based on the pattern of their overnight gross-body movements. Then, PSG audio recordings are used to improve the identification of moderate-to-severe OSA patients based on their pattern of snoring, cessation of snoring, and choking sounds. Using the features derived from patients' gross-body movements and audio recordings, moderate-to-severe OSA patients are differentiated from mild-to-no OSA patients with an accuracy of 85.5%, sensitivity of 76.4%, and specificity of 91.1%. Next, a respiratory signal (VDR signal) is derived from the subtle respiratory movements in the PSG video recordings. Patients' respiratory rate (RR) per minute is estimated from the VDR signals. The mean absolute error for the derived RR is 0.82 breaths per minute (bpm) for mild-to-no OSA patients and 0.98 bpm for moderate-to-severe OSA patients. Finally, individual OSA events were scored in the VDR signals and an OSA severity index was calculated. The scored OSA events had an F₁score of 76.0%, sensitivity of 81.0%, and positive predictive value of 73.8% when compared to the reference OSA events.

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Serinel, Yasmina. "Novel Methods for Treating and Assessing Hypertension in Obstructive Sleep Apnoea". Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/20445.

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In this thesis, the primary motivation was to develop a strategy to help improve the treatment of hypertension in patients with obstructive sleep apnoea (OSA), and to discover new biomarkers of risk that can be used for future prognostication and for therapeutic interventions. A central theme throughout is the emphasis on analysing and targeting the 24 hour blood pressure profile of patients with OSA, given our newer understanding that nocturnal blood pressure is the strongest predictor of cardiovascular mortality. Chapter 1 is a comprehensive literature review covering blood pressure physiology, the pathophysiology of hypertension and arterial stiffness both in non-OSA and OSA populations and treatment strategies including chronotherapy. In chapter 2 we explore the use of chronotherapy, or the altered timing of once-daily medication administration, in a randomised double blinded placebo controlled trial, in an effort to improve the blood pressure control of patients with OSA. In chapter 3, we explored 24 hour arterial haemodynamics in patients with OSA as a novel biomarker for future risk stratification and therapeutic interventions with the use of state-of-the-art technology. In the final chapter we summarise the key findings of our studies and briefly discuss future directions.

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Revol, Bruno. "Pharmacoépidémiologie des apnées du sommeil Impact of concomitant medications on obstructive sleep apnoea Drugs and obstructive sleep apnoeas Diagnosis and management of central sleep apnea syndrome Baclofen and sleep apnoea syndrome: analysis of VigiBase® the WHO pharmacovigilance database Gabapentinoids and sleep apnea syndrome: a safety signal from the WHO pharmacovigilance database Valproic acid and sleep apnea: a disproportionality signal from the WHO pharmacovigilance database Ticagrelor and Central Sleep Apnea What is the best treatment strategy for obstructive sleep apnoea-related hypertension? Who may benefit from diuretics in OSA? A propensity score-matched observational study". Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALV026.

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Avant leur mise sur le marché, l'évaluation clinique des médicaments repose sur des essais contrôlés randomisés. Bien qu'ils représentent la méthode de référence, leurs résultats sont nécessairement limités aux patients inclus dans ces essais. De plus, ils sont d’abord conçus pour mesurer l'efficacité des traitements, avant d’évaluer leurs effets indésirables. Concernant le syndrome d'apnées du sommeil (SAS), alors que de nombreux essais médicamenteux ont été menés, la plupart des résultats sont de faible niveau de preuve, voire contradictoires. Outre la durée et les effectifs limités de ces essais, une explication est que le SAS est une pathologie hétérogène en termes de symptômes et de physiopathologie, incluant divers "phénotypes" de patients. Des données de vie réelle sont donc nécessaires pour définir quels médicaments pourraient améliorer le SAS ou les comorbidités associées et quels patients pourraient en bénéficier. Au contraire, les cliniciens doivent être avertis que certains médicaments peuvent induire ou aggraver le SAS.La pharmacoépidémiologie fait désormais partie de toute enquête de pharmacovigilance, car elle permet une approche à la fois descriptive et comparative des notifications spontanées. Des associations entre l'exposition à un ou plusieurs médicaments et l'apparition d'effets indésirables peuvent ainsi être recherchées. Comme pour toutes les études observationnelles, la principale difficulté consiste à contrôler les facteurs de confusion. L'un des modèles couramment utilisés est l'analyse cas/non-cas, qui étudie la disproportionnalité entre le nombre d’effets indésirables rapportés avec le médicament d’intérêt, par rapport aux effets notifiés pour les autres médicaments. Nous avons ainsi montré des associations significatives entre l'utilisation de baclofène, des gabapentinoïdes ou de l'acide valproïque et la survenue de SAS dans la base de pharmacovigilance de l'OMS, suggérant le rôle du système GABAergique dans la pathogenèse des apnées centrales d’origine médicamenteuse. Un signal de disproportionnalité a également été observé pour le ticagrélor, reposant sur un mécanisme d'action différent.Les analyses pharmacoépidémiologiques permettent également d'étudier le bénéfice des médicaments en vie réelle. Le score de propension est utilisé pour minimiser les biais de sélection et recréer des conditions de comparabilité proches de celles des essais randomisés. À l'aide de ces méthodes statistiques, nous avons évalué l'intérêt potentiel de cibler le système rénine-angiotensine pour la prise en charge de l'hypertension artérielle chez les patients atteints d’apnées obstructives, en particulier avec l’utilisation des sartans. Chez ces mêmes patients apnéiques et hypertendus, nos travaux suggèrent que les diurétiques pourraient diminuer la sévérité des apnées, notamment en cas de surpoids ou d’obésité modérée. Des études prospectives sont désormais nécessaires afin de confirmer ces résultats, car les données de vie réelle ne peuvent se substituer aux essais cliniques contrôlés
The clinical evaluation of drugs before approval is based on randomized controlled trials. Although they are considered as the gold standard for testing drugs, their results are necessarily limited to patients included in the trials. Moreover, almost all clinical trials are primarily designed to assess the efficacy of a treatment, so safety is only a secondary concern. Regarding sleep apnea syndrome (SAS), while many drug trials have been conducted, most of the results are weak or even contradictory. In addition to limited trial duration and population size, one explanation is that the sleep apnea population is highly heterogeneous with respect to symptoms and physiological traits linked to disease pathogenesis, giving various patient “phenotypes”. Real-life data are therefore needed to define which drugs could improve SAS or associated comorbidities and who might benefit from them. On the contrary, clinicians need to be aware that some drugs may induce or worsen sleep apnea.Pharmacoepidemiology is now part of any pharmacovigilance survey, as it provides both descriptive and comparative approaches of spontaneous reports. Associations between the exposure to one or more drugs and the occurrence of adverse effects can thus be sought. As for all observational studies, the major difficulty is to control for confounding factors. One of the study designs commonly used, is the case/non-case analysis, which investigates disproportionality between the numbers of adverse drug reactions reported with the drug of interest compared to the number reported with all other drugs. In this way, we showed significant associations between the use of baclofen, gabapentinoids or valproic acid and the reporting of SAS in the WHO drug adverse event database, suggesting a role of the GABAergic system in the pathogenesis of drug-induced central sleep apnea. A disproportionality signal was also found for ticagrelor, based on a different mechanism of action.Pharmacoepidemiological analyses also make it possible to study the benefit of drugs in real-life. Propensity scores are used to minimize selection bias, leading to a comparability between the exposure groups close to that observed in randomized trials. Using these statistical methods, we have investigated the potential value of targeting the renin-angiotensin system for the management of hypertension in obstructive sleep apnea (OSA) patients, especially the use of sartans. For hypertensive apneic patients, our work suggests that diuretics could decrease the severity of OSA, particularly in the overweight or moderately obese. Prospective studies are now needed to confirm these findings, because real-life data cannot be a substitute for controlled clinical trials

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36

Johnston, Christopher David. "Sleep-disordered breathing : a cephalometric and clinical study". Thesis, Queen's University Belfast, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313925.

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37

Wakwella, Ajith S. "Processing of snore related sounds for the diagnosis of obstructive sleep apnoea (OSA) /". [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18755.pdf.

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38

Cross, Nathan. "Obstructive sleep apnoea in older adults: Predictors of cognitive decline and neurodegeneration". Thesis, The University of Sydney, 2017. http://hdl.handle.net/2123/17763.

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There is growing evidence that sleep disturbances share associations with neurodegeneration, and poor sleep is emerging as an independent risk factor for dementia. As a common sleep disorder, obstructive sleep apnea (OSA) has been connected to compromised cognition, brain integrity and an increased risk for dementia. However, there is a need to clarify these relationships in older adults and understand the mechanisms underpinning the link between OSA and cognitive decline. The aims of this thesis were: 1) to characterise and quantitatively analyse the relationship between OSA and cognitive function in older adults, 2) to determine whether any changes in neural oscillations during sleep or brain grey matter thickness and volume, might be associated with OSA and related to makers of cognitive decline (e.g. memory) in a sample of older adults at-risk for dementia. At-risk adults were diagnosed as health-seeking older adults (>50 years) with subjective or objective cognitive impairment. Neural oscillations were recorded using electroencephalography and brain grey matter thickness and volume were measured using magnetic resonance imaging. These findings showed that the presence of OSA in at-risk older adults is related to a marked reduction in specific neural oscillations (sleep spindles), key aspects of sleep microarchitecture that are integrally linked with memory consolidation. Furthermore, OSA-related oxygen desaturation was associated with decreased cortical thickness in both the left and right temporal lobes, while sleep disturbance was related to increased cortical thickness in in frontal, central and occipital regions of the right cortex. This work has provided evidence that OSA is related to features which may contribute to early-stage neurodegeneration and cognitive decline, which are important in identifying critical periods for intervention. Given that effective treatment exists for OSA, efforts to increase OSA screening in older adults are now warranted.

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39

Desai, Anup Vijayendra. "Obstructive sleep apnoea and driver performance: prevalence, correlates and implications for driver fatigue". University of Sydney. Medicine, 2003. http://hdl.handle.net/2123/589.

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Obstructive sleep apnoea (OSA) is characterised by repetitive reductions or pauses in breathing during sleep due to upper airway narrowing or closure. Due to disruption to normal sleep patterns, many patients with OSA suffer from increased daytime sleepiness. Epidemiological studies have established a link between OSA and driver fatigue and accidents, generally showing a two to seven times increased risk of road traffic accidents in non-commercial drivers with OSA. There is emerging evidence that commercial drivers have a higher prevalence of OSA than the general population, being predominately male, middle-aged and overweight, three important risk factors for OSA. However, little is known about the relationship between OSA and driver sleepiness in commercial drivers, whether road accidents are increased in commercial drivers with OSA, and whether OSA interacts with other fatigue promoting factors, such as sleep deprivation, to further escalate road accident risk. One thousand randomly selected commercial drivers were surveyed in the field. In addition, 61 randomly selected NSW commercial drivers had in hospital sleep studies and daytime performance testing, including a PC based driving simulator task. The prevalence of OSA, defined as Respiratory Disturbance Index (RDI) < 10, was approximately 50% in NSW commercial drivers. Approximately one quarter of the drivers reported pathological daytime sleepiness, and 12-14% had both OSA and pathological daytime sleepiness. A diagnosis of OSA was the most important factor predicting excessive daytime sleepiness in these drivers: OSA was more important than 15 other work-related, lifestyle and medical factors that could be expected to promote, or be associated with, daytime sleepiness. Drivers with sleep apnoea syndrome (both OSA and pathological daytime sleepiness) had an increased driving accident risk, using driving simulator and daytime performance testing as proxy measures for accident risk. These results demonstrate the importance of OSA as a cause of driver fatigue in commercial drivers and suggest that all commercial drivers should be screened for the presence of sleep apnoea syndrome in order to potentially reduce road accident risk through treatment. A separate, but related body of work examined the combined effects of mild OSA and other fatigue promoting factors (sleep deprivation and circadian influences) on driving performance. Twenty nine subjects, consisting of a group with mild OSA and a group of non-OSA controls, were tested on several occasions throughout the night and day using an intensive performance battery, under both baseline conditions and after a period of 36 hours of total sleep deprivation. The results suggest that drivers with mild OSA are not different to the control group in their response to sleep deprivation or time of day influences. However, the subjects with mild OSA were less aware of their impairment due to sleep deprivation, which is of concern if drivers with OSA are relying on their subjective awareness of fatigue to make decisions about when to stop driving. A final perspective on OSA and driver fatigue is provided through a clinical case series of seven fall-asleep fatality associated MVA�s associated with unrecognised or under-treated sleep disorders. As well as demonstrating the day to day potential for devastating road accidents due, at least in part, to un-recognised or untreated sleep disorders, these cases also serve to highlight some of the current medico-legal controversies and difficulties in this area of driver fatigue. In conclusion, this body of work has provided novel information about the epidemiology and implications of OSA in commercial drivers, and about how OSA interacts with other fatigue promoting factors. Finally, it has explored some of the medico-legal issues that relate to sleep disorders and driver fatigue. As well as providing much needed information in the area of driver fatigue, at the same time this work raises many more questions and suggests areas of future research. For instance, such research should examine the relationship between objective accident rates and OSA/sleep apnoea syndrome in commercial drivers, the interaction between mild sleep apnoea syndrome and other fatigue risk factors, and driver perception of sleepiness prior to sleep onset in drivers with sleep disorders.

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40

Desai, Anup Vijayendra. "Obstructive sleep apnoea and driver performance: prevalence, correlates and implications for driver fatigue". Thesis, The University of Sydney, 2002. http://hdl.handle.net/2123/589.

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Obstructive sleep apnoea (OSA) is characterised by repetitive reductions or pauses in breathing during sleep due to upper airway narrowing or closure. Due to disruption to normal sleep patterns, many patients with OSA suffer from increased daytime sleepiness. Epidemiological studies have established a link between OSA and driver fatigue and accidents, generally showing a two to seven times increased risk of road traffic accidents in non-commercial drivers with OSA. There is emerging evidence that commercial drivers have a higher prevalence of OSA than the general population, being predominately male, middle-aged and overweight, three important risk factors for OSA. However, little is known about the relationship between OSA and driver sleepiness in commercial drivers, whether road accidents are increased in commercial drivers with OSA, and whether OSA interacts with other fatigue promoting factors, such as sleep deprivation, to further escalate road accident risk. One thousand randomly selected commercial drivers were surveyed in the field. In addition, 61 randomly selected NSW commercial drivers had in hospital sleep studies and daytime performance testing, including a PC based driving simulator task. The prevalence of OSA, defined as Respiratory Disturbance Index (RDI) < 10, was approximately 50% in NSW commercial drivers. Approximately one quarter of the drivers reported pathological daytime sleepiness, and 12-14% had both OSA and pathological daytime sleepiness. A diagnosis of OSA was the most important factor predicting excessive daytime sleepiness in these drivers: OSA was more important than 15 other work-related, lifestyle and medical factors that could be expected to promote, or be associated with, daytime sleepiness. Drivers with sleep apnoea syndrome (both OSA and pathological daytime sleepiness) had an increased driving accident risk, using driving simulator and daytime performance testing as proxy measures for accident risk. These results demonstrate the importance of OSA as a cause of driver fatigue in commercial drivers and suggest that all commercial drivers should be screened for the presence of sleep apnoea syndrome in order to potentially reduce road accident risk through treatment. A separate, but related body of work examined the combined effects of mild OSA and other fatigue promoting factors (sleep deprivation and circadian influences) on driving performance. Twenty nine subjects, consisting of a group with mild OSA and a group of non-OSA controls, were tested on several occasions throughout the night and day using an intensive performance battery, under both baseline conditions and after a period of 36 hours of total sleep deprivation. The results suggest that drivers with mild OSA are not different to the control group in their response to sleep deprivation or time of day influences. However, the subjects with mild OSA were less aware of their impairment due to sleep deprivation, which is of concern if drivers with OSA are relying on their subjective awareness of fatigue to make decisions about when to stop driving. A final perspective on OSA and driver fatigue is provided through a clinical case series of seven fall-asleep fatality associated MVA�s associated with unrecognised or under-treated sleep disorders. As well as demonstrating the day to day potential for devastating road accidents due, at least in part, to un-recognised or untreated sleep disorders, these cases also serve to highlight some of the current medico-legal controversies and difficulties in this area of driver fatigue. In conclusion, this body of work has provided novel information about the epidemiology and implications of OSA in commercial drivers, and about how OSA interacts with other fatigue promoting factors. Finally, it has explored some of the medico-legal issues that relate to sleep disorders and driver fatigue. As well as providing much needed information in the area of driver fatigue, at the same time this work raises many more questions and suggests areas of future research. For instance, such research should examine the relationship between objective accident rates and OSA/sleep apnoea syndrome in commercial drivers, the interaction between mild sleep apnoea syndrome and other fatigue risk factors, and driver perception of sleepiness prior to sleep onset in drivers with sleep disorders.

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41

Mehta, Atul S. "Treatment of snoring and obstructive sleep apnoea using a mandibular advancement splint". Master's thesis, Faculty of Dentistry, 1998. http://hdl.handle.net/2123/4904.

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This work was digitised and made available on open access by the University of Sydney, Faculty of Dentistry and Sydney eScholarship . It may only be used for the purposes of research and study. Where possible, the Faculty will try to notify the author of this work. If you have any inquiries or issues regarding this work being made available please contact the Sydney eScholarship Repository Coordinator - ses@library.usyd.edu.au

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42

Lai, Yuen-kwan Agnes y 賴婉君. "Continuous positive airway pressure education on adherence in adults with obstructive sleep apnoea". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/198849.

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Poor adherence to continuous positive airway pressure (CPAP) treatment in patients with obstructive sleep apnoea (OSA) limits its therapeutic effectiveness and has a major impact on clinical outcomes. Effective education programme is important to enhance CPAP use. However, existing education programmes are either manpower or resource demanding and may not be feasible in clinical practice. Moreover, the Self-Efficacy Measure for Sleep Apnoea (SEMSA) has been widely adopted for assessing adherence-related cognitions on CPAP therapy in OSA patients, but it was not available for Chinese. The aims of this thesis are: (i) to perform linguistic and psychometric evaluation of a Chinese version of SEMSA (SEMSA-C); (ii) to examine the efficacy of brief motivational enhancement education programme in addition to standard care versus standard care only on improving adherence to CPAP treatment in patients with OSA. The SEMSA-C was obtained after the standard forward-backward translation process. A randomised controlled trial was then conducted on newly diagnosed OSA patients. Patients in the control group received standard care (SC) comprising advice on the importance of CPAP therapy and its care while those in the intervention group received SC plus motivational enhancement education programme (ME). ME focused to enhance subjects’ knowledge, motivation and self-efficacy to use CPAP, comprising one 45-minute session on the day after CPAP titration and one 10-minute telephone follow-up shortly after commencing CPAP treatment. Epworth Sleepiness Scale (ESS), SEMSA-C, and quality of life were assessed. CPAP usage data were downloaded at the completion of this 3-month study. The primary outcome was the CPAP adherence. Furthermore, 21 patients were randomly sampled at baseline and completed the SEMSA-C at one week. 100 patients (Men : Women, 84 : 16) with OSA indicated for CPAP treatment were recruited, with an average age of 52±10 years, and apnoea hypopnoea index (AHI) of 36.2±22 events/hour. Factor analysis of SEMSA-C identified three factors: risk perception, outcome expectancies and treatment self-efficacy. Their corresponding internal consistency was high with Cronbach’s alpha >0.88, which were larger than all correlations between subscales (Range: 0.14 to 0.58). The correlations between items and their hypothesized subscale (Range: 0.58 to 0.85) were generally higher than the correlations between items and their competing subscales (Range: -0.10 to 0.58). One-week test-retest intra-class correlation ranged from 0.70 to 0.82. CPAP adherence was associated with outcome expectancies and treatment self-efficacy at 3-month assessment. Furthermore, SEMSA-C demonstrated an improvement in self-efficacy (standardised response mean = 0.33, p = .044) but no significant changes were observed in the other two factors, after CPAP use. The 100 patients were followed for 3 months. The interventional effects maintained during the 3-month study period. There were a better CPAP use [higher daily CPAP usage of 2 hours/day (Cohen d = 1.33, p < .001), four-fold the number of subjects using CPAP for ≥ 70% of days with ≥ 4 hours per day (p < 0.001)], and greater improvements in ESS by 2.2 (p = 0.001) and treatment self-efficacy by 0.2 (p = 0.012) in the intervention group, relative to the control group. The traditional Chinese SEMSA-C possesses satisfactory psychometric properties. It is a reliable and responsive instrument to measure perceived risks, outcome expectancies and treatment self-efficacy in Chinese patients with OSA. Moreover, the newly developed brief motivational enhancement education programme in addition to standard care is effective in improving adherence to CPAP treatment, treatment self-efficacy and daytime sleepiness.
published_or_final_version
Nursing Studies
Doctoral
Doctor of Nursing

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43

Zamora, Mayela E. "The study of the sleep and vigilance electroencephalogram using neural network methods". Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365699.

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44

Wools, Christine. "Characterising sleep and fatigue in patients with primary mitochondrial disease". Thesis, University of Sydney, 2020. https://hdl.handle.net/2123/23037.

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Fatigue is common in primary mitochondrial disease (PMD). The pathophysiology of fatigue in PMD is likely multifactorial and may include sleep pathology. Methods Patients with PMD were assessed with inpatient polysomnography and validated measures of fatigue (Fatigue Severity Scale and Fatigue Impact Scale), muscle fatigability (Five Times Sit to Stand Test), disease severity (Newcastle Mitochondrial Disease Adult Scale), sleep propensity (Epworth Sleepiness Scale), sleep quality (Pittsburgh Sleep Quality Index) and depression (Beck Depression Inventory II). Results Fifteen participants completed inpatient polysomnography. Obstructive sleep apnoea (OSA) was common (53%), although mostly mild in severity. There was a trend toward OSA associating with myopathy (p=0.119) and increasing age (p = 0.15). The Epworth Sleepiness Scale showed potential as a screening tool for OSA in PMD (p=0.119). 81% and 69% of patients showed fatigue on the Fatigue Severity Scale and Fatigue Impact Scale, respectively. The average Five Times Sit-To-Stand time in PMD (14.1 seconds) was almost double the community norm (7.6 seconds; p=0.02). However, neither fatigue or muscle fatigability associated with OSA. Beck Depression Inventory II scores correlated with the Fatigue Severity (rs=0.592, p=0.016) and Fatigue Impact (rp=0.629, p=0.009) Scales, with mean scores being significantly higher if fatigue was present on both scales (p=0.05 and 0.004, respectively), suggesting an association between fatigue and depression. Conclusion Fatigue was common in PMD, but not associated with sleep disorder in this study. Muscle fatiguability was also present. OSA was common, although mostly mild in severity. Furthermore, patients reporting fatigue tended to have depressive features. This study suggests that optimal treatment of fatigue in PMD may be multimodal, but requires further study.

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45

Desai, Anup. "Obstructive sleep apnoea and driver performance prevalence, correlates, and implications for driver fatigue /". Connect to full text, 2002. http://hdl.handle.net/2123/589.

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Thesis (Ph. D.)--University of Sydney, 2003.
Includes tables and questionnaires. Title from title screen (viewed Apr. 29, 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Faculty of Medicine. Degree awarded 2003; thesis submitted 2002. Includes bibliography. Also available in print form.

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46

Wåhlin, Larsson Britta. "Skeletal muscle in Restless legs syndrome (RLS) and Obstructive sleep apnoea syndrome (OSAS)". Doctoral thesis, Örebro universitet, Hälsoakademin, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-6245.

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Restless legs syndrome (RLS) and Obstructive sleep apnoea syndrome (OSAS) are two sleep disorders that affect daily life with symptoms such as sleepiness and fatigue. It was therefore hypothesised that the skeletal muscle could be affected as symptoms from skeletal muscle are common. The overall aim of the thesis was to investigate aerobic capacity and structure of skeletal muscle in patients with OSAS and RLS and an age matched control group to provide information regarding the underlying mechanisms. The specific aims were to investigate muscle fibre composition, capillary network, capillary proliferation and sings of local inflammation in musculus tibialis anterior of RLS and OSAS.OSAS and RLS patients had a significantly lower predicted VO2 max expressed in ml/min/kg compared with the control group and in the OSAS group apnoes-hyponea index (AHI) was inversely correlated to maximal oxygen uptake Fibre type composition and muscle fibre cross sectional area in the tibialis anterior muscle was equal in all groups with a predominant proportion of slow type I fibres and a smaller fibre area in slow type I fibres compared to fast type II fibres. The distribution of fast fibres (I/IIA, IIA) did not differ except for the group IIX and IIA/IIX where OSAS and RLS had a significantly higher percentage. OSAS patients had a significantly higher number of capillaries per fibre (CAF) for slow type I fibres and CAF per fibre area (CAFA) for fast type II fibres. CFPE- index (capillary to fibre perimeter exchange) and LC/PF-index (length of capillary/perimeter of fibre) were higher in both patient groups. Vascular endothelial growth factor (VEGF) and proliferating endothelial cells were analysed by double-immunofluorescence staining and were presented to a greater extent in the patient groups compared with the healthy controls. Based on normal amounts of T-cells and macrophages in the histological picture it was also demonstrated that local inflammation was not present in the tibialis anterior muscle of RLS and OSAS whish was also supported by the absence of expression of major histocompatibility complex class I molecules (MHC class I) on the surface of the tibialis anterior muscle fibres.In conclusion, the low predicted VO2 max together with higher percentage of type IIX and IIA/IIX muscle fibres indicates a low central capacity in the patient groups. The increased capillary network and the absence of inflammation indicate the occurrence of local hypoxia in tibialis anterior muscle in patients OSAS and RLS.

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47

Wåhlin, Larsson Britta. "Skeletal muscle in Restless legs syndrome (RLS) and Obstructive sleep apnoea syndrome (OSAS) /". Örebro : Örebro University, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-6245.

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48

Turnbull, Christopher David. "CPAP withdrawal as a model of the cardiovascular effects of obstructive sleep apnoea". Thesis, University of Oxford, 2018. http://ora.ox.ac.uk/objects/uuid:015bc59d-568b-4d49-b51b-192f4800a84a.

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Obstructive sleep apnoea (OSA) is associated with cardiovascular disease and hypertension. The underlying causes of cardiovascular disease and hypertension in OSA are not fully understood. Potential causes for cardiovascular disease and hypertension in OSA include; intermittent hypoxia, arousal mediated sympathetic activation, oxidative stress, endothelial dysfunction, and systemic inflammation. Continuous positive airway pressure (CPAP) is the standard treatment for OSA and CPAP withdrawal is used to model the consequences of OSA. In the CPAP withdrawal model patients with known OSA are withdrawn from their usual CPAP treatment and randomised to intervention or control for two weeks. Utilising a CPAP withdrawal model, I examined the effects of supplemental oxygen versus air (sham) during CPAP withdrawal on several outcomes, including; morning blood pressure, intermittent hypoxia, markers of arousal, and daytime sleepiness. In addition, I examined the effects of the return of OSA following CPAP withdrawal on several biomarkers. Supplemental oxygen virtually abolished the rise in morning blood pressure seen following CPAP withdrawal. Supplemental oxygen markedly attenuated intermittent hypoxia, whilst having little effect on markers of arousal, and no effect on daytime sleepiness. This suggests that intermittent hypoxia is the dominant cause of morning increases in blood pressure in OSA. Following CPAP withdrawal there was a small unexpected reduction in adrenomedullin, which is a potent vasodilator and may contribute to the blood pressure rise with CPAP withdrawal.

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49

Lam, Aaron. "Characterising obstructive sleep apnoea in memory clinics: hypoxemia, memory, and structural brain changes". Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/28504.

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Dementia is characterised by the progressive deterioration of cognitive function, leading to an impairment in activities of everyday life. Between 40-50% of dementia risk can be attributed to modifiable risk factors, warranting early intervention approaches for dementia prevention. Obstructive sleep apnoea (OSA) in midlife is associated with a 26% increased risk of dementia longitudinally. However, there is limited knowledge regarding these inter-relationships in older adults ‘at-risk’ for dementia. It is important to understand the links between OSA and neurodegeneration in these older samples, since this is a critical window for secondary prevention strategies. The current thesis aims to provide new knowledge regarding the inter-relationships between OSA and cognitive impairment in older adults seeking within a specialist memory clinic. The first study demonstrates that greater OSA severity is linked to poorer sleep-dependent memory performance in older adults with subjective memory complaints. The second study shows the importance of intermittent hypoxemia during REM sleep on daytime memory performance in older adults with mild cognitive impairment. The third study assessed tract-specific white matter alterations in older adults at-risk of dementia with OSA compared to without OSA. The final study examines the rates of OSA in a memory clinic using a variety of methods including self-report, sleep study, and pulse oximetry. Overall, although older people may attend memory clinics for cognitive concerns, the findings of this thesis show that memory performance is linked to sleep micro-architecture, hypoxia and to neuroimaging markers. Screening older people within the memory clinic for OSA may be, particularly if treatment for OSA in such groups can slow cognitive decline or prevent dementia.

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50

Mohammadieh, Anna Mary. "Enhancing the Diagnosis and Management of Obstructive Sleep Apnoea in Atrial Fibrillation Patients". Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/29879.

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Background: Atrial fibrillation (AF), is the most common sustained cardiac arrhythmia, and significantly increases the risk of stroke and cardiovascular mortality. It is strongly associated with obstructive sleep apnoea (OSA). Aims: 1. Examine the epidemiology of OSA in a hospital cohort with AF. 2. Compare the diagnostic accuracy of clinical screening tools for OSA in patients with AF. 3. Compare cardiac autonomic function in AF patients with and without OSA. 4. Conduct a pilot study of mandibular advancement splint (MAS) therapy for OSA in AF patients. Methods: 107 AF patients were recruited. The diagnostic accuracy of screening tools including a level 3 (portable) sleep study device as compared to polysomnography in AF patients was assessed. Cardiac autonomic function as a potential mechanistic link between OSA and AF was assessed using Heart Rate Variability (HRV). A pilot study of OSA treatment in AF patients using MAS therapy was conducted. Results: 62.6% of patients were newly diagnosed with OSA. Patients with moderate to severe OSA showed an increased BMI, neck circumference and Mallampati score, but were not significantly different in terms of daytime somnolence. Oxygen desaturation index (ODI) derived from a Level 3 portable sleep study device performed best for the diagnosis of moderate to severe and severe OSA, with excellent diagnostic accuracy (AUC 0.899, 95% CI 0.838 – 0.960 and AUC 0.925, 95% CI 0.859 – 0.991 respectively). We found a chronic increase in parasympathetic nervous activity in paroxysmal AF patients with OSA. MAS therapy showed high rates of acceptance, compliance and efficacy in AF patients. Conclusions: This thesis contributes to our understanding of the association between AF and OSA across a spectrum of

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