Laboratory and field studies have consistantly shown that sleep loss negatively impacts on neurobehavioural performance and alertness. Moreover, recent research suggests that the detrimental effects of sleep loss are qualitatively and quantitatively similar to the effects of alcohol intoxication. Despite this, sleepiness-related performance impairment has not been subject to the strict levels of regulatory intervention that govern alcohol consumption when driving and/or at work. It has been proposed that this failure to address the occupational, health and safety impact of sleep loss, and the subsequent lack of legislation to manage and control sleepiness in a manner commensurate with the associated statistical risks, may in part, reflect a failure to provide policy makers with a readily understood index of the relative risk associated with sleep loss. Therefore the aim of the studies in this thesis was to assess and quantify the effects of sleep loss on a range of measures, including neurobehavioural performance, sleepiness, and daytime sleep quality and quantity.

Throughout public discourse, sleep, despite being a physiological function and an important facet of an individual's health, is frequently utilized as a rhetorical device to comment on an individual's productivity within society. As Antje Richter (2003:34) explains, to consider someone early to rise yet late to bed is less a comment on their sleeping behavior and more an assessment of their dedication to their business. Too often productivity is conveyed as existing in the absence of sleep, an idea that has contributed to the association of sleep with laziness (Yi 2003:60) and a general misuse of time (Richter 2003:36). The purpose of this study is to explore the relationship between sleep and personal perspectives of productivity within a college population. Utilizing in depth, ethnographic semi-structured interviews, and working with 25 college students from the University of Central Florida, it was found that the standards and expectations students have internalized regarding their productivity are influencing the way in which they are practicing in their daily sleeping behaviors and ultimately influencing the amount of sleep they get each night.

Previous research has shown that insufficient sleep at night and daytime sleepiness contributes to psychological distress, cognitive deficiencies and poor academic performance. The current study examines the effect of nighttime sleep extension on sleep, psychological health, academic performance and cognitive functioning in a sample of adolescents with complaints of daytime sleepiness and insufficient nighttime sleep.Participants were 56 adolescents (34 females) aged 14 - 18 (Mean age = 16.46). Participants were given daily sleep diaries and actiwatch during an initial interview. Sleepiness, psychological, academic and cognitive assessments were completed after one week of sleep data collection. The participants were randomly assigned to either extend their sleep for at least 60 minutes on three consecutive school nights or continue with their normal sleep schedule. After the sleep extension the same battery of tasks were completed. Baseline and post-intervention sleep, psychological, academic and cognitive data included daily sleep diaries, the Pediatric Daytime Sleepiness Scale (PDSS), State Trait Anxiety Scale - Short (STAI-S), AIMS reading comprehension and mathematic questions, digit span, verbal fluency, trail making and go/no go inhibition.Nineteen of those assigned to extend their sleep succeeded (M = 80.35 min.). Repeated measures ANOVAs were performed on sleep, psychological well being, academics and cognitive assessments to evaluate the sleep extension intervention. Interactions for the sleep variables found that Sleep Extenders decreased difficulty in waking in the morning and daytime sleepiness, increased time in bed, total sleep time and sleep efficiency more than Non-Sleep Extenders, (all p < .05). No differences were found for the STAI-S or the academic questions. All participants improved on the forward digit span (p < .05); however, t-tests showed that only the Sleep Extenders improved on the backward digit span (p < .05). All participants performed worse on the verbal fluency task, (p < .01). Everyone improved on trail making part A (p < .01), however, only Sleep Extenders improved on trail making part B, (p < .01).Even small increases in the duration of nighttime sleep can improve sleep variables, reduce daytime sleepiness, and produce improvement on measures of cognitive ability requiring mental control and flexibility in adolescents.

A descriptive study of patients' perceptions to sleep in a general practice was undertaken. The aim of the study was to describe the perceptions about sleep in the adult patient in a general practice environment. This included descriptions of demographic data, patient’s perceptions and expectations of sleep and their perceived seriousness and prevalence of sleep disorders. Differences in perceptions about sleep and sleep hygiene between patients with and without a sleep problem were also determined. A self-administered questionnaire with an accompanying subject information sheet was used for the research. The questionnaire was given to adult (over 18 years of age) patients,with prior informed consent, attending the author's practice in Port Elizabeth (Eastern Cape, South Africa), for completion in the waiting room. A sample of 400 patients was used. Simple descriptive statistics were used to discuss three main areas of the study: 1) demographics, 2) perceived prevalence and seriousness of sleep disorders and 3) perceptions of sleep hygiene. Analysis of the results revealed a population that was predominantly White (78.9% White,11.2% Coloured, 8.1% Black)), young (67.7% were less than 40 years of age),with equal male and female ratios, well-educated (69.5% passed Metric) and with a current job (over 90% were employed). Despite such a young population the incidence of self-reported sleep problems was markedly high and were of long duration (25.8% of patients had some sort of sleep disorder, while 23.5% admitted having a sleep problem) and compared favourably with overseas statistics. Long-term sleep problems were more common in the population studied. Males had more long-term sleep-problems than females. Black patients slept for more longer periods, woke up more often without going back to sleep and perceived their sleep problem as more serious than White, Coloured and Indian patients. Patients with a higher level of education were less likely to; have a sleep problem,feel worried about their sleep, see someone professional about their sleep and suffer from any medical or psychological condition than those with a lower level of education. Patients who perceived they had a sleep problem were; more worried about their sleep, suffering from more medical or psychological conditions, taking more medication to sleep, more sleepier during the day, not falling asleep easily, not waking up feeling refreshed, waking up too early, v/aking up and going back to sleep with more difficulty, consulting someone regarding their sleep more and were consulting someone professional regarding their sleep problem more than patients without a sleep problem. Underreporting of patients’ sleep problems to health professionals was encountered. Only 10 out of the 26 sleep hygiene questions were statistically significant. Perceptions of sleep hygiene did not correlate with having a sleep problem. People who had a sleep problem probably knew about correct sleeping hygiene, but were either not implementing it, or had some external factor accounting for their poor sleep. Certain inferences were made from this study highlighting important patient perceptions regarding the concept of sleep in general. These may be used as recommendations for family physicians to assist in management of patients complaining of sleep problems.

Doctor of Philosophy(PhD) / Several studies have documented the direct effect of macronutrient intake on sleep. A general picture that has emerged indicates that a low carbohydrate diet with a total energy between 13-47% and high fat content with a total energy between 47-77% shows increases in slow wave sleep and may decrease rapid-eye movement sleep. However, previous studies investigating the association between carbohydrate meals and sleep have not explored the effects of the glycemic index (GI) of carbohydrate on sleep. This thesis investigated the affect of GI on the sleep pattern. In a cross-over, repeated measures design, we explored both the effect of GI and the timing of these meals on sleep in good sleepers. The effects of high and low GI carbohydrate-based meals given 4 h before the subjects’ usual bedtime on their sleep quality were examined in Chapter 3. Also evaluated was the effect of high GI meal timing (4 h vs. 1 h) on sleep. Twelve healthy men (18-35y, BMI 18.5-25 kgm-2) were administered a standard, isocaloric meal of low GI = 50 or high GI=109 in a cross-over and counter balanced manner, 4 h before their usual bedtime. On another occasion, the high GI meal was given 1 h before bedtime. Following the high or the low GI meal, participants underwent a familiarization sleep night followed by three polysomnographic test nights. The subjects’ blood and urine were collected for glucose and 6-sulfatoxymelatonin analysis respectively. Significant differences were found between the area under the curve (AUC) for blood glucose responses following the high GI meal compared to the responses for the low GI meal. It was shown that a carbohydrate-based high GI meal resulted in a significant shortening of sleep onset latency (SOL) in normal sleepers compared to a low GI meal (P = 0.009), and was most effective when consumed 4 h before bedtime (P = 0.01). There were no significant changes in other sleep indices. The Atkins’ Diet is a popular dietary therapy that promotes weight loss. This restricted carbohydrate diet with high fat and high protein content has not been evaluated for its effects on sleep, or systematically documented for its effects on mood, fatigue or sleepiness. The short term effect of the Atkins’ diet over 48 h on the sleep quality of healthy, non-obese males to a Control mixed diet was compared in Chapter 4. This study employed a repeated measure design where fourteen healthy, non-obese, good sleepers were given isocaloric diets and matching evening test meals (4 h before usual bedtime), which were either mixed (15% protein, 25% fat, 60% carbohydrate) or Atkins’ (38% protein, 61% fat, <1% carbohydrate). After a familiarization night with polysomnography, further polysomnographic testing was then performed on the Control night, 4 h after the first Atkins’ test meal (Atkins Acute) and 48 h (Atkins Ketosis) following commencement of the Atkins’ diet. Objective sleep was recorded using Compumedics S-series Sleep system; Compumedics Ltd, Melbourne, Australia. Urine ketone level was monitored before the evening test meals and at bedtime on the Control night, during the Atkins Acute and Ketosis phase. Blood glucose level was measured before the evening test meal until 120 min following the meal. Significant differences were found for the AUC for the blood glucose between the Control night and the Atkins Acute and Atkins Ketosis phase (P < 0.001). Participants developed mild hypoglycemia and ketosis 48 h following the Atkins’ diet. A significant reduction in the proportion of rapid eye movement (%REM) sleep to total sleep time (TST) was observed following the Atkins’ Acute and Atkins’ Ketosis phase compared to the Control (P = 0.006 and 0.05 respectively). The percentage of slow wave sleep (%SWS) to TST significantly increased for both the Atkins’ Acute and Ketosis phase compared to the Control meal (P = 0.02 for both phases). The sleep changes may be linked to the energy metabolism of fat of the Atkins’ diet. The effects of the Atkins’ diet compared to a Control mixed diet on sleepiness, mood, fatigue and dream recall were also investigated (Chapter 5). Participants’ overall daytime mood, fatigue intensity, sleepiness and other symptoms were assessed using a visual analogue scale before the evening test meals. The number of subjects with dream recalls was recorded on awakening after each polysomnographic night. The daytime symptoms of fatigue, sleepiness and depressed mood were significantly increased following the Atkins’ diet compared to the Control diet. A greater proportion of subjects reported dreams 48 h after the Atkins’ diet compared to either the Atkins’ Acute phase or the Control condition. Our findings suggest that mild hypoglycemia resulting from the diet may mediate the subjective responses of daytime sleepiness, depressed mood and intense fatigue. The increased proportion of subjects with dream recall may be related to an increased transient arousals from sleep during which dreams are usually consolidated into memory. The finding that “high-glycemic-index carbohydrate meals shorten sleep onset” may be relevant to persons with sleep disturbance. These meals may facilitate sleep transition for those with sleep initiation problems. The effect of the Atkins’ diet in SWS promotion and increasing feelings of fatigue and suppressing mood in the short-term may be relevant for patients with sleep apnoea (obesity), who experience low proportion of SWS and significant somnolence. Further studies to explore these effects on a longer term in this group would be worthwhile.

Since studies have revealed sleeping quality is highly related to our health conditions, sleep-medicine has attracted more and more attention in recent years. Sleep staging is one of the most important elements of sleep-medicine. Traditionally, it¡¦s done by observing the information form of EEG, EOG and EMG signals. But this is almost not possible to achieve at home. Automatic detection of REM sleep is the main goal of this study. Via comparing the classification performances of different combinations of EEG, EOG and EMG signals, this study also tries to simplify the number of signal channels. By using features extracted from EEG, EOG and EMG signals, the back-propagation neural networks are used to distinguish REM and NREM sleep. By refining the outputs of the neural networks, this study extensively test the efficacy of the proposed approach by using databases from two different sleep centers. This work also investigates the influences of the number of signal channels, REM sleep ratio, AHI, and age on classification results. Data acquired from the sleep centers of China Medical University Hospital (CMUH) and Sheng-Mei Hospital are arranged in ten different groups. For our largest datasets, which consists of 1318 subjects from CMUH, the results show that the proposed method achieves 95.5% epoch-to-epoch agreement with Cohen's Kappa 0.833, sensitivity 85.9% and specificity 97.3%. The generalization accuracy is 94.1% with Cohen's Kappa 0.782, sensitivity 78.5% and specificity 97.3%.

Objective: To investigate the association of sleep duration with cognitive function in adults. Methods and Results: Relevant studies were searched through PubMed, ScienceDirect and Google Scholar using keywords of ((“cognitive” OR “cognition” OR “memory impairment”) AND (“sleep duration” OR “sleep hours” OR “sleep time”)). Studies on the association of sleep duration with cognitive function as measured by various cognitive assessment tools in adults aged 18+ years were included. The initiate search generates 415 articles, after excluding studies that were duplicates, not published in English journals and not conducted in adults, giving 10 to be included in this systematic review. These studies were conducted in 6 countries (US, China, France, Spain, England, and Finland) and most of them were cross-sectional studies (7 cross-sectional studies and 3 prospective studies). Most of the studies showed that participants with either long sleep duration (≥ 9 h per day) or short sleep duration (≤ 6 h per day) had higher risks of cognitive impairment than participants with sleep hours of about 7 hour per day. One study showed that short, but not long sleep duration was associated with poor cognitive function while four studies showed that only long sleep duration was associated with poor cognitive function. Some sleep-related factors such as sleep disorder breathing, excessive daytime sleepiness, sleep quality and sleep cycle may partly explain the association of sleep duration with cognitive functions. Conclusion: Most of the earlier studies consistently showed that both long (≥ 9 h per day) and short (≤ 6 h per day) sleep duration were associated with poor cognitive function. These findings provide evidence support for further intervention studies to examine the potential beneficial effect of normalizing sleep duration in preventing cognitive decline. / published_or_final_version / Public Health / Master / Master of Public Health

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The Ontario Ministry of Education’s guidelines for full-day kindergarten do not specifically mention naptime (Ontario Ministry of Education, 2010). This study sought to address the issue of naptime in full-day kindergarten. Focus groups and interviews were conducted to understand the perspectives of eighteen parent and teacher participants. Seven of the participants were kindergarten teachers, nine were parents. Two participants qualified to be both teacher and parent. The main findings from this study demonstrated that parents and teachers considered the following to be advantages of naptime: (1) a nap allows a break that enables students to focus on afternoon learning, (2) a nap allows the behaviour of children to improve (3) some children are young and require a nap, (4) teachers use naptime to complete preparation for the next lesson, and (5) since school is a long day for children, a nap is required to ensure students will remain awake in the afternoon. The disadvantages of kindergarten naptime were identified as: (1) an afternoon nap is not useful for all students, (2) it takes away from time devoted to academics, (3) it negatively affects bedtimes and, (4) managing naptime is problematic. Additionally, more appealing alternatives to a naptime session were suggested: (1) Down Time which refers to activities that are quiet without any expectation that children will sleep, (2) Rest Time which includes an option to sleep or participate in quiet, individual activities, and (3) Quiet Time which is a period of time dedicated to quiet, individual activities without any intention of sleeping. It was suggested that only Junior Kindergarten students need a chance to nap, since it will help them focus in the afternoon. A synthesis of my findings suggests that a 30-minute rest time could be incorporated in the full-day Junior Kindergarten, but not Senior Kindergarten, program at the midday point. / Thesis (Master, Education) -- Queen's University, 2014-05-27 14:50:50.525

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