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.

Sleep related breathing disorders in childhood are increasingly recognised as contributors to morbidity as well as suboptimal physical, mental and social development. The associated cost in social and economic terms is clearly significant. Detection and diagnosis of such disorders can be costly and technically difficult. Multi-parameter monitoring like polysomnography is expensive and inappropriate for mass screening or investigations remote from tertiary centres. A simple and non-invasive cardiovascular approach termed pulse transit time (PTT) is useful in determining the status of upper airways during sleep. This approach employs the measurement of the time delay in the arterial pulse pressure wave from the aortic valve of the heart to a peripheral site. PTT has shown promise to provide quantify inspiratory effort in adults with sleep disordered breathing (SDB) and can then be an effective monitoring tool in children. Initial investigations explore the parameters that can confound the PTT measurements of a child. This work provides an estimate of the expected PTT ranges from infancy to childhood. Thereafter, overnight PTT recordings were performed in conjunction with PSG studies to corroborate evidence for its capability in paediatric respiratory studies. The results show that PTT has the ability to identify abnormal respiratory events during sleep. Furthermore, the use of PTT can differentiate the nature of respiratory events as obstructive or central. Technological considerations to improve the robustness of PTT measure to be used not only in cardiorespiratory but also cardiovascular studies on children were also illustrated. Preliminary findings obtained here suggest that the properties of PTT show promise as a predictor for obstructive sleep apnoea. There is a need to bridge the gap of providing quality SDB diagnosis and yet accommodating requirements for a robust screening measure. PTT has demonstrated its suitability and utility as a measure to play a role in the investigation and monitoring of treatment in this area.

Thesis (Ph. D.)--University of Washington, 1989. / Vita. Includes bibliographical references (leaves [62]-66).

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.

Thesis--Auburn University, 2009. / Abstract. Vita. Includes bibliographical references (p. 82-93).

Thesis (Ph.D.)--University of Wollongong, 2008. / Typescript. Includes bibliographical references: leaf 106-126.

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 83-99).

Thesis (M.S.)--University of Michigan, 1977.

Thesis (M.S.)--University of Michigan, 1980.

Thesis (M.S.)--Oregon State University, 2004. / Includes bibliographical references. Also available online (PDF file) by a subscription to the set or by purchasing the individual file.