Thesis (Ph. D.)--Washington State University, May 2010. / Title from PDF title page (viewed on June 11, 2010). "College of Nursing." Includes bibliographical references (p. 70-83).

Thesis (Ph. D.)--West Virginia University, 2010. / Title from document title page. Document formatted into pages; contains xii, 125 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 66-77).

Thesis (Ph.D.)--OGI School of Science & Engineering at OHSU, Aug. 2006. / Includes bibliographical references (leaves 125-133).

No description available.

Self-report retrospective estimates of sleep behaviors are not as accurate as prospective estimates from sleep diaries, but are more practical for epidemiological studies. Therefore, it is important to evaluate the validity of retrospective measures and improve upon them. The current study compared sleep diaries to two self-report retrospective measures of sleep, the commonly used Pittsburgh Sleep Quality Index (PSQI) and a newly developed sleep questionnaire (SQ), which assessed weekday and weekend sleep separately. It was hypothesized that the new measure would be more accurate than the PSQI because it accounts for variability in sleep throughout the week. The relative accuracy of the PSQI and SQ in obtaining estimates of total sleep time (TST), sleep efficiency (SE), and sleep onset latency (SOL) was examined by comparing their mean differences from, and correlations with, estimates obtained by the sleep diaries. Correlations of the PSQI and SQ with the sleep diaries were moderate, with the SQ having significantly stronger correlations on the parameters of TST, SE, and sleep quality ratings. The SQ also had significantly smaller mean differences from sleep diaries on SOL and SE. The overall pattern of results indicated that the SQ performs better than the PSQI when compared to sleep diaries.

Childhood OSA is increasingly recognized to be associated with a variety of complications including neurocognitive and cardiovascular diseases. The intermediate link between OSA and end organ damage has been suggested to be inflammation, and both local airway and systemic inflammation have been described in adults with OSA. A non-invasive technique of sputum induction was utilised to show that children with OSA also have airway inflammation, as characterized by a significant increase in neutrophils, and the severity of OSA also correlated significantly with the degree of neutrophilic inflammation (Chapter 7). This finding may lead to research on the use of anti-inflammatory therapeutic agents or antibiotics for the treatment of childhood OSA. Another marker of inflammation, C-reactive protein (CRP) was measured in a cohort of children with OSA before and after treatment (Chapter 8). Children with OSA had higher CRP levels compared to their non-OSA counterparts, and the raised CRP decreased significantly following treatment suggesting that the inflammatory response is potentially reversible. The cardiovascular risk factors of insulin levels and blood pressure (BP) were evaluated and children with OSA had higher serum insulin and greater systolic and diastolic BP compared to healthy controls (Chapters 9 and 10). These findings suggest that children with OSA may be at risk of developing metabolic syndrome and its devastating consequence. (Abstract shortened by UMI.) / The original research studies undertaken were based on nocturnal sleep examinations to explore childhood OSA in two main aspects, namely its assessment, and a better understanding of its complications in children. The gold standard for diagnosing OSA is overnight polysomnography (PSG), which is an expensive investigation that is not routinely available at all public hospitals in Hong Kong. Alternative valid assessment tools for OSA that are more cost-effective are needed. The feasibility of using radiographic techniques to assess severity of OSA was explored, and the size of the upper airway, as reflected by the tonsillar pharyngeal (TP) ratio obtained from lateral neck radiograph, correlated well with the severity of OSA (Chapter 4). A defined TP cutoff could accurately predict moderate-to-severe OSA with high sensitivity and specificity. This method could be used in clinical practice to prioritize patients with suspected OSA for further evaluation. A locally applicable questionnaire scale was examined for its validity and accuracy in diagnosing children with OSA (Chapter 5). The presence of three symptoms (snoring, mouth breathing and nocturnal sweating) was found to have high predictive value in correctly identifying children with the condition. The question of whether a single night PSG study is adequate in diagnosing OSA was examined together with the assessment for the presence of night-to-night variability in PSG and respiratory parameters in childhood sleep (Chapter 6). Forty-four obese children and 43 age and sex-matched healthy controls underwent two consecutive nights PSG examination. Although a first night effect was clearly documented, a single night PSG study would have correctly identified over 80% of children with OSA. This finding has significant resource implications. / Albert Martin Li. / Adviser: Tony Nelson. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3420. / Thesis (M.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves xxxv-lxxx). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English only. / School code: 1307.

Thesis (Ph. D.)--University of Sydney, 2008. / Title from title screen (viewed Mar. 12, 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Discipline of Medicine, Faculty of Medicine. Degree awarded 2008; thesis submitted 2007. Includes bibliography. Also issued in print.

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.

Why do we need to sleep? Not only is getting enough sleep important for our overall health and well-being, it is perhaps of utmost importance for normal brain functioning. Scientific findings derived from studying sleep deprivation suggests that sleep also plays an important role in our emotional functioning, which has led researchers to propose a causal and intimate relationship between sleep and emotional brain functioning. Without sleep it seems as our emotional processing become impaired in various ways. Along with advances in cognitive neuroscience, it is now possible to characterize mechanisms underlying emotional brain processes. In pursuit of the possible functions of sleep, researchers have also proposed that rapid eye movement sleep, might support a process of affective brain homeostasis and recalibration that optimally prepares the organism for next-day social and emotional functioning. This thesis reviews current behavioral and neurophysiological evidence focused on the relationship between sleep and emotional brain functioning, and the role of rapid eye movement sleep in emotional processing.

Numerous studies have shown the relationship between sleep and overall health. A common measure of sleep is sleep quality which has been shown to be influenced by a variety of factors such as physical activity, diet, stress, social engagement, cognitive stimulating, and sleep hygiene behaviors. Data was analyzed from a previous study to determine whether trying to change one’s sleep would improve sleep quality and if this was more effective than physical exercise. A group of 104 individuals, randomized to the treatment group, were asked to log their daily activities, via smartphone app, within these six behavioral domains for six months. Behavioral change scores were computed as the difference between six-month behavioral level and baseline behavioral level, for each of the six domains. Factor analysis that revealed that two latent factors explained the majority of the variance in behavioral change, with a "Physical Body Related behavior change” factor ("Physical") and a "Mental/Emotional" behavior change factor ("Mental"). In linear regression models, Physical significantly predicted sleep quality improvement over the six months (p=.029), but Mental did not (p=.606). In the middle aged adults in this study, the behavioral change pattern of increasing diet quality and physical activity, significantly predicted improvements in sleep quality. While efforts to improve one's cognitive and emotional well-being were not found to predict to sleep improvement, they still may be important for cognitive health overall. This information can prove useful as different interventions and programs are implemented to improve sleep in the population.