Despite the prevalence of sleep complaints among psychiatric patients, few questionnaires have been specifically designed to measure sleep quality in clinical populations. The Pittsburgh Sleep Quality Index (PSQI) is a self-rated questionnaire which assesses sleep quality and disturbances over a 1-month time interval. Nineteen individual items generate seven "component" scores: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction. The sum of scores for these seven components yields one global score. Clinical and clinimetric properties of the PSQI were assessed over an 18-month period with "good" sleepers (healthy subjects, n = 52) and "poor" sleepers (depressed patients, n = 54; sleep-disorder patients, n = 62). Acceptable measures of internal homogeneity, consistency (test-retest reliability), and validity were obtained. A global PSQI score greater than 5 yielded a diagnostic sensitivity of 89.6% and specificity of 86.5% (kappa = 0.75, p less than 0.001) in distinguishing good and poor sleepers. The clinimetric and clinical properties of the PSQI suggest its utility both in psychiatric clinical practice and research activities.

The Pittsburgh Sleep Quality Index: A new instrument for psychiatric practice and research.

Background Limited data have suggested that sleep-disordered breathing, a condition of repeated episodes of apnea and hypopnea during sleep, is prevalent among adults. Data from the Wisconsin Sleep Cohort Study, a longitudinal study of the natural history of cardiopulmonary disorders of sleep, were used to estimate the prevalence of undiagnosed sleep-disordered breathing among adults and address its importance to the public health. Methods A random sample of 602 employed men and women 30 to 60 years old were studied by overnight polysomnography to determine the frequency of episodes of apnea and hypopnea per hour of sleep (the apnea-hypopnea score). We measured the age- and sex-specific prevalence of sleep-disordered breathing in this group using three cutoff points for the apnea-hypopnea score (≥ 5, ≥ 10, and ≥ 15); we used logistic regression to investigate risk factors. Results The estimated prevalence of sleep-disordered breathing, defined as an apnea-hypopnea score of 5 or higher, was 9 percent for w...

The Occurrence of Sleep-Disordered Breathing among Middle-Aged Adults

Background Sleep-disordered breathing is prevalent in the general population and has been linked to chronically elevated blood pressure in cross-sectional epidemiologic studies. We performed a prospective, population-based study of the association between objectively measured sleep-disordered breathing and hypertension (defined as a laboratory-measured blood pressure of at least 140/90 mm Hg or the use of antihypertensive medications). Methods We analyzed data on sleep-disordered breathing, blood pressure, habitus, and health history at base line and after four years of follow-up in 709 participants of the Wisconsin Sleep Cohort Study (and after eight years of follow-up in the case of 184 of these participants). Participants were assessed overnight by 18-channel polysomnography for sleep-disordered breathing, as defined by the apnea–hypopnea index (the number of episodes of apnea and hypopnea per hour of sleep). The odds ratios for the presence of hypertension at the four-year follow-up study according to...

https://www.nejm.org/doi/pdf/10.1056/NEJM200005113421901

Prospective study of the association between sleep-disordered breathing and hypertension.

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(05)71141-7.pdf

Long-term cardiovascular outcomes in men with obstructive sleep apnoea-hypopnoea with or without treatment with continuous positive airway pressure: an observational study

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(99)01376-8.pdf

Impact of sleep debt on metabolic and endocrine function

A manual of standardized terminology, techniques and scoring system for sleep stages of human subjects

A manual of Standardized Terminology

The issue of whether sleep is physiologically necessary has been unresolved because experiments that reported deleterious effects of sleep deprivation did not control for the stimuli used to prevent sleep. In this experiment, however, experimental and control rats received the same relatively mild physical stimuli, but stimulus presentations were timed to reduce sleep severely in experimental rats but not in controls. Experimental rats suffered severe pathology and death; control rats did not.

https://science.sciencemag.org/content/sci/221/4606/182.full.pdf

Physiological correlates of prolonged sleep deprivation in rats

The results of a series of studies on total and selective sleep deprivation in the rat are integrated and discussed. These studies showed that total sleep deprivation, paradoxical sleep deprivation, and disruption and/or deprivation of non-rapid eye movement (NREM) sleep produced a reliable syndrome that included death, debilitated appearance, skin lesions, increased food intake, weight loss, increased energy expenditure, decreased body temperature during the late stages of deprivation, increased plasma norepinephrine, and decreased plasma thyroxine. The significance of this syndrome for the function of sleep is not entirely clear, but several changes suggested that sleep may be necessary for effective thermoregulation.

/pdf/sleep-deprivation-in-the-rat-x-integration-and-discussion-of-3q00uqbaae.pdf

Sleep deprivation in the rat: X. Integration and discussion of the findings.

Ten rats were subjected to total sleep deprivation (TSD) by the disk apparatus. All TSD rats died or were sacrificed when death seemed imminent within 11-32 days. No anatomical cause of death was identified. All TSD rats showed a debilitated appearance, lesions on their tails and paws, and weight loss in spite of increased food intake. Their yoked control (TSC) rats remained healthy. Since dehydration was ruled out and several measures indicated accelerated use rather than failure to absorb nutrients, the food-weight changes in TSD rats were attributed to increased energy expenditure (EE). The measurement of EE, based upon caloric value of food, weight, and wastes, indicated that all TSD rats increased EE, with mean levels reaching more than twice baseline values.

Allan Rechtschaffen

Papers

A manual of standardized terminology, techniques and scoring system for sleep stages of human subjects

A manual of Standardized Terminology

Physiological correlates of prolonged sleep deprivation in rats

Sleep deprivation in the rat: X. Integration and discussion of the findings.

Sleep deprivation in the rat. III: Total sleep deprivation