More is becoming known about the importance of sleep to health, with inadequate sleep recognised as a significant public health issue. Sleep clinics have reported disproportionate numbers of Māori and Pacific peoples with more severe obstructive sleep apnoea syndrome (OSAS), raising concerns about accessibility of services and possible differences in prevalence between ethnic groups. Prevalence information on sleep disorders in Aotearoa is needed to assess its public health impact and plan for population health care needs. This thesis presents a national study examining the prevalence of OSAS symptoms and risk factors among Maori and non-Maori adults in Aotearoa. This project is also situated within the wider scope of ethnic inequalities in health between Maori and non-Maori and is concerned with making a positive contribution to Maori health and the elimination of disparities. Kaupapa Maori Research (KMR) is the underlying methodology that drives this study. As such, it assumes a Maori norm, and prioritises Maori needs. A Maori/non-Maori analytical framework is used that distinguishes Maori as tangata whenua, addresses Maori health needs as well as non-Maori, and enables the monitoring of guarantees as outlined by the Treaty of Waitangi. The goals of this thesis were to estimate the prevalence of OSAS symptoms and risk factors among Maori and non-Maori adults in New Zealand, and to examine independent predictive variables for specific OSAS symptoms. An objective was also to contribute to KMR through designing and undertaking a KMR project using a quantitative method, with the development of concepts for use in other areas of research. In April 1999, a short questionnaire was sent to a sample of 10000 New Zealands (5500 of Maori descent and 4500 non-Maori participants to enable research questions to be examined with equal statistical power for both groups. The results demonstrate that the prevalence of OSAS symptoms and risk factors, particularly among non-Maori, are comparable to other international studies, indicating that OSAS is likely to be a common problem among adults in Aotearoa. Furthermore, the results suggest that Maori are significantly more likely to suffer from OSAS than non-Maori, with higher rates of symptoms and risk factors of OSAS among both men and women. As an area of medicine that is under-serviced in Aotearoa, the results provide important information with which to plan for population needs. There are a number of health implications from this study, relating specifically to the diagnosis and management of OSAS in Aotearoa, and to Maori health and the elimination of disparities. These are multi-levelled and include health service implications across the continuum of care, from specialist sleep services to primary care; public health implications that involve preventive measures and broader determinants of health; and KMR principles that can be applied to interventions and health research in general. As a KMR project the implications and recommendations focus on Maori health research in general. As a KMR project the implications and recommendations focus on Maori health gain and addressing disparities in health. This is consistent with Maori health rights, and a population approach that considers health inequalities and the role of wider determinants of health and health services.

Clinical professionals in South Africa are generally unaware of the impact of obstructive sleep apnoea (OS A). The cost to the state of untreated apnoea may be extremely high. In primary health care encounters OSA often goes undiagnosed. The cascade of symptoms linked to OSA is profound, placing patients at risk for debilitating problems impacting on self and others. The aim of this study was to validate a questionnaire, which could be used at a primary health care level to identify patients with OSA thus cutting costs and improving efficient, effective and ethical service to patients. The Berlin Questionnaire (BQ) (Netzer et al. 1999) was administered to a clinical sample of consenting patients at a private sleep laboratory in Durban, South Africa (N = 119)(completed n = 110). Home-based sleep studies (n = 116) on a portable cardio-respiratory screening device were also obtained for objective comparison. From the results obtained in this South African sample, the BQ showed low validity and reliability (Cronbach a = 0.62 - 0.84) to individual items of the BQ. The total BQ score and high-risk symptom category analysis showed mildly significant correlations with internationally approved protocols. The BQ identified 60% of the high-risk group (AHI >5). Furthermore, risk categories were useful in predicting AHI ratings in 64% of moderate OSA cases and 25% of severe OSA cases. The BQ therefore has useful psychometric properties as an adjunct assessment tool to screen for high-risk OSA cases where resources are scant. Clinical health psychologists are in an ideal position to recognise the risk factors and symptoms of OSA. The clinical assessment and the value of the correct diagnosis will alleviate the treatment of psychological symptoms at a superficial level in primary health care facilities. / Thesis (M.Soc.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

Although a broad range of neuropsychological deficits have been reported to occur in patients with Obstructive Sleep Apnea Syndrome (OSAS), few studies have examined the executive functions in this patient group. The executive functions provide conscious control of the more basic cognitive functions and play an important role in daily living. They include capacities such as concept formation, planning, cognitive flexibility and resistance to interference. This study compared the performance of groups of moderate and severe OSAS patients with a group of unaffected individuals (N=24), on five tests of executive functioning. Two indices of sleep disordered breathing, sleep fragmentation and . hypoxemia, obtained from overnight polysomnography, were respectively used to categorise participants. ID patients with severe OSAS, executive function deficits were evident, while in those with moderate OSAS these abilities appeared largely intact. Further analyses revealed that the observed findings could not be attributed to differences in vigilance. These results suggest a discontinuity in the manifestation of executive function deficits between moderate and severe OSAS patients. There may be a threshold of OSAS severity, which if exceeded, impairments tend to occur. The magnitude of the impairment in patients with severe OSAS may be sufficient to interfere with daily cognitive functioning. Further research is needed both to replicate these findings and to establish the underlying pathogenesis of these deficits. / Thesis (M.A.)-University of Natal, Pietermaritzburg, 2001.

Content removed due to copyright restrictions: Marshall, N. S., Neill, A. M., Campbell, A. J., & Sheppard, D. S. (2005). Randomised controlled crossover trial of humidified continuous positive airway pressure in mild obstructive sleep apnoea. Thorax, 60(5), 427-432. Marshall, N. S., Gander, P. H., & Neill, A. M. (2003). Obstructive sleep apnoea and risk of motor vehicle accident: A perspective. New Zealand Medical Journal, 116(1176) / The practice of sleep medicine is expanding and evolving rapidly, often ahead of the evidence base to support clinical practice. Obstructive Sleep Disordered Breathing (SDB) is a condition characterised by repetitive airway collapse causing harmful intermittent blood oxygen desaturations and fragmented sleep. When combined with daytime sleepiness it is known as Obstructive Sleep Apnoea Syndrome (OSAS). Continuous Positive Airway Pressure (CPAP) eliminates SDB by pneumatically splinting open the airway with positive air pressure applied through the nose and/or mouth. CPAP effectively reduces daytime sleepiness in patients with severe OSAS. However, doubt remains as to the effectiveness of CPAP in the majority of patients with mild-moderate OSAS. The effects of CPAP were compared to a placebo CPAP during a three week crossover Randomised Controlled Trial (RCT) that included 31 mild-moderate OSAS patients. CPAP effectively eliminated SDB (when worn) and moderately improved subjective sleepiness. But. it did not improve objective wakefulness, mood, psychomotor function, or quality of life. Patients who were extremely sleepy at baseline tended to gain the most placebo adjusted benefit from treatment. A systematic review and meta-analysis aimed to gather and objectively combine all relevant RCT studies to find our whether CPAP reduced sleepiness in patients with mild-moderate OSAS. Seven trials were combined and showed that both subjective sleepiness and objective wakefulness were slightly improved by CPAP therapy. Objective sleepiness was not improved by CPAP. It is not clear from these two studies that treating mild-moderate OSAS with CPAP is an effective use of resources. CPAP effectiveness might be limited by sub-optimal compliance. C-Flex aims to improve compliance by modulating pressure during exhalation. C-Flex was compared to CPAP during a pilot RCT that included 19 patients with severe OSAS. C-Flex was associated with a non-significant increase in compliance of 1.7 hours/night compared to CPAP. However, this increase in compliance was not associated with better daytime patient outcomes. Further experiments are proposed as a result of our pilot RCT. This thesis helps expand evidence-based sleep medicine. Practitioners need to be vigilant, ensuring that treatments are effective in the patients groups in which they are being used (clinical drift), and that new treatments are not adopted without superiority over existing treatments (technological drift).

Content removed due to copyright restrictions: Marshall, N. S., Neill, A. M., Campbell, A. J., & Sheppard, D. S. (2005). Randomised controlled crossover trial of humidified continuous positive airway pressure in mild obstructive sleep apnoea. Thorax, 60(5), 427-432. Marshall, N. S., Gander, P. H., & Neill, A. M. (2003). Obstructive sleep apnoea and risk of motor vehicle accident: A perspective. New Zealand Medical Journal, 116(1176) / The practice of sleep medicine is expanding and evolving rapidly, often ahead of the evidence base to support clinical practice. Obstructive Sleep Disordered Breathing (SDB) is a condition characterised by repetitive airway collapse causing harmful intermittent blood oxygen desaturations and fragmented sleep. When combined with daytime sleepiness it is known as Obstructive Sleep Apnoea Syndrome (OSAS). Continuous Positive Airway Pressure (CPAP) eliminates SDB by pneumatically splinting open the airway with positive air pressure applied through the nose and/or mouth. CPAP effectively reduces daytime sleepiness in patients with severe OSAS. However, doubt remains as to the effectiveness of CPAP in the majority of patients with mild-moderate OSAS. The effects of CPAP were compared to a placebo CPAP during a three week crossover Randomised Controlled Trial (RCT) that included 31 mild-moderate OSAS patients. CPAP effectively eliminated SDB (when worn) and moderately improved subjective sleepiness. But. it did not improve objective wakefulness, mood, psychomotor function, or quality of life. Patients who were extremely sleepy at baseline tended to gain the most placebo adjusted benefit from treatment. A systematic review and meta-analysis aimed to gather and objectively combine all relevant RCT studies to find our whether CPAP reduced sleepiness in patients with mild-moderate OSAS. Seven trials were combined and showed that both subjective sleepiness and objective wakefulness were slightly improved by CPAP therapy. Objective sleepiness was not improved by CPAP. It is not clear from these two studies that treating mild-moderate OSAS with CPAP is an effective use of resources. CPAP effectiveness might be limited by sub-optimal compliance. C-Flex aims to improve compliance by modulating pressure during exhalation. C-Flex was compared to CPAP during a pilot RCT that included 19 patients with severe OSAS. C-Flex was associated with a non-significant increase in compliance of 1.7 hours/night compared to CPAP. However, this increase in compliance was not associated with better daytime patient outcomes. Further experiments are proposed as a result of our pilot RCT. This thesis helps expand evidence-based sleep medicine. Practitioners need to be vigilant, ensuring that treatments are effective in the patients groups in which they are being used (clinical drift), and that new treatments are not adopted without superiority over existing treatments (technological drift).