Saint, David AlbertPamula, YvonneCoussens, Scott Wade2016-10-052016-10-052015http://hdl.handle.net/2440/101558An examination of the nature of sleep fragmentation in children with upper airway obstruction. Introduction – Sleep related upper airway obstruction (UAO) in children disrupts breathing in sleep, resulting in sleep fragmentation and subsequent neurocognitive and behavioural deficits. Unfortunately the nature of this fragmentation in children is poorly understood and a universally accepted, clinically valid, measure of sleep fragmentation has been elusive. This limits our ability to accurately determine and measure the consequences of sleep fragmentation on a child’s development due to UAO, as well as the success of any treatment administered. General Aims - The aim of the current study was to (i) examine the nature of sleep fragmentation in children with upper airway obstruction and (ii) to develop a new sleep fragmentation index for use in paediatric clinical populations with upper airway obstruction. When this study began no such index existed that was widely accepted and utilized. A range of sleep fragmentation measures already trialed in children with upper airway obstruction were reviewed to identify problems and limitations with current and previous methods of measuring sleep fragmentation in these children. An attempt was also made to identify other possible additional factors that mediate sleep fragmentation so as to develop a workable and generally applicable sleep fragmentation index for children with upper airway obstruction. Methods – We performed a series of analyses on sleep and neurocognitive data from children with upper airway obstruction to identify and quantify neural activity associated with sleep fragmentation. We then used these measures and other mediating factors to create a composite measure of sleep fragmentation in children. Results – We found that children with upper airway obstruction had characteristically altered neural activity as measured by electroencephalogram (e.g. changes in sleep spindle density, decreased alpha and sigma power around spontaneous arousals from sleep). They also had an altered movement distribution in sleep (increased exponential distribution coefficient when sleep runs between movements are modeled on a survival curve), when compared to normal controls. The studies also demonstrated the potential ability of a composite measure of such sleep fragmentation markers and mediating vulnerability factors to more accurately and usefully quantify the negative impacts of upper airway obstruction. Conclusions - Sleep fragmentation is a significant consequence of UAO in children, however the current measure of UAO severity is insufficient for determining the overall impact on a child’s development. As this study demonstrates, the impact of sleep fragmentation is dependent on a complicated set of variables including: age, health factors (e.g. BMI), exposure time, disease severity (e.g. AHI), genetics, trait-like factors, social factors (e.g. SES) and family history. The arousals, or disruptions to sleep, are also altered in children with UAO compared to normal controls. We therefore propose a composite measure of these important factors as a more accurate tool for determining the impact of sleep fragmentation and overall severity of UAO in children.childrenupper airways obstructionsleep fragmentationarousalsTheses