85 research outputs found
The two-process model of sleep regulation: a reappraisal
Full text linkIn the last three decades the two-process model of sleep regulation has served as a major conceptual framework in sleep research. It has been applied widely in studies on fatigue and performance and to dissect individual differences in sleep regulation. The model posits that a homeostatic process (Process S) interacts with a process controlled by the circadian pacemaker (Process C), with time-courses derived from physiological and behavioural variables. The model simulates successfully the timing and intensity of sleep in diverse experimental protocols. Electrophysiological recordings from the suprachiasmatic nuclei (SCN) suggest that S and C interact continuously. Oscillators outside the SCN that are linked to energy metabolism are evident in SCN-lesioned arrhythmic animals subjected to restricted feeding or methamphetamine administration, as well as in human subjects during internal desynchronization. In intact animals these peripheral oscillators may dissociate from the central pacemaker rhythm. A sleep/fast and wake/feed phase segregate antagonistic anabolic and catabolic metabolic processes in peripheral tissues. A deficiency of Process S was proposed to account for both depressive sleep disturbances and the antidepressant effect of sleep deprivation. The model supported the development of novel non-pharmacological treatment paradigms in psychiatry, based on manipulating circadian phase, sleep and light exposure. In conclusion, the model remains conceptually useful for promoting the integration of sleep and circadian rhythm research. Sleep appears to have not only a short-term, use-dependent function; it also serves to enforce rest and fasting, thereby supporting the optimization of metabolic processes at the appropriate phase of the 24-h cycle
Blue blocker glasses as a countermeasure for alerting effects of evening LED - screen exposure in teenagers
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Colour vision deficiencies in Alzheimer's disease
Get PDFObjective:âvisual disorders are among the earliest symptoms of Alzheimer's disease. It is, however, still controversial as to whether Alzheimer's disease impairs colour vision. In this study, colour vision of Alzheimer's disease patients was tested using the Ishihara test and the PVâ16 choice test. The latter test, primarily designed for children, was chosen in order to avoid problems due to cognitive decline. Methods:â26 patients with mild to severe Alzheimer's disease (M:F=5:21; mean age: 80±9âyears, range: 53-95âyears) and 25 controls (M:F=5:20; mean age 80±10âyears, range: 56-100âyears) were rated after undergoing complete neuroâophthalmologic examination. Results:âthe Alzheimer's disease patients made significantly more unspecific errors in the Ishihara test (P=0.02) and in the PVâ16 choice test (P=0.0008) than the controls. No relation between test performance and severity of Alzheimer's disease was found. Conclusions:âAlzheimer's disease patients have an unspecific colour vision deficiency independent of the severity of the diseas
Subjective Mood in Young Unmedicated Depressed Women under High and Low Sleep Pressure Conditions
Get PDFDiurnal mood variations are one of the core symptoms in depression, and total sleep deprivation (SD) can induce rapid, short-lasting clinical improvement in depressed patients. Here, we investigated if differential sleep pressure conditions impact on subjective mood levels in young women with major depressive disorder (MDD) without sleep disturbances, and in healthy controls. Eight healthy and eight MDD women underwent 40-h SD (high sleep pressure) and 40-h multiple NAP (low sleep pressure) protocols under constant routine conditions during which subjective mood was assessed every 30-min. MDD women rated overall significantly worse mood than controls, with minimal values for both groups during the biological night (ca. 4 a.m.), under high and low sleep pressure conditions. During SD, nighttime mood ratings in MDD women were lower than in controls and partially recovered during the second day of SD, but never attained control levels. The degree of this diurnal time-course in mood under SD correlated positively with sleep quality in MDD women. Our data indicate that MDD women without sleep disturbances did not exhibit a SD-induced antidepressant response, suggesting that the mood enhancement response to sleep deprivation might be related to the co-existence of sleep disturbances, which is an association that remains to be fully established
Self-reported sleep disturbances in renal transplant recipients
Get PDFAbstract Background: Poor sleep quality (SQ) and daytime sleepiness (DS) are common in renal transplant (RTx) recipients; however, related data are rare. This study describes the prevalence and frequency of self-reported sleep disturbances in RTx recipients. Methods: This cross-sectional study included 249 RTx recipients transplanted at three Swiss transplant centers. All had reported poor SQ and / or DS in a previous study. With the Survey of Sleep (SOS) self-report questionnaire, we screened for sleep and health habits, sleep history, main sleep problems and sleep-related disturbances. To determine a basis for preliminary sleep diagnoses according to the International Classification of Sleep Disorders (ICSD), 164 subjects were interviewed (48 in person, 116 via telephone and 85 refused). Descriptive statistics were used to analyze the data and to determine the frequencies and prevalences of specific sleep disorders. Results: The sample had a mean age of 59.1 ± 11.6 years (60.2% male); mean time since Tx was 11.1 ± 7.0 years. The most frequent sleep problem was difficulty staying asleep (49.4%), followed by problems falling asleep (32.1%). The most prevalent sleep disturbance was the need to urinate (62.9%), and 27% reported reduced daytime functionality. Interview data showed that most suffered from the first ICSD category: insomnias
Circadian-Related Sleep Disorders and Sleep Medication Use in the New Zealand Blind Population: An Observational Prevalence Survey
Get PDFSTUDY OBJECTIVES: To determine the prevalence of self-reported circadian-related sleep disorders, sleep medication and melatonin use in the New Zealand blind population. DESIGN: A telephone survey incorporating 62 questions on sleep habits and medication together with validated questionnaires on sleep quality, chronotype and seasonality. PARTICIPANTS: PARTICIPANTS WERE GROUPED INTO: (i) 157 with reduced conscious perception of light (RLP); (ii) 156 visually impaired with no reduction in light perception (LP) matched for age, sex and socioeconomic status, and (iii) 156 matched fully-sighted controls (FS). SLEEP HABITS AND DISTURBANCES: The incidence of sleep disorders, daytime somnolence, insomnia and sleep timing problems was significantly higher in RLP and LP compared to the FS controls (p<0.001). The RLP group had the highest incidence (55%) of sleep timing problems, and 26% showed drifting sleep patterns (vs. 4% FS). Odds ratios for unconventional sleep timing were 2.41 (RLP) and 1.63 (LP) compared to FS controls. For drifting sleep patterns, they were 7.3 (RLP) and 6.0 (LP). MEDICATION USE: Zopiclone was the most frequently prescribed sleep medication. Melatonin was used by only 4% in the RLP group and 2% in the LP group. CONCLUSIONS: Extrapolations from the current study suggest that 3,000 blind and visually impaired New Zealanders may suffer from circadian-related sleep problems, and that of these, fewer than 15% have been prescribed melatonin. This may represent a therapeutic gap in the treatment of circadian-related sleep disorders in New Zealand, findings that may generalize to other countries
Stabilising sleep for patients admitted at acute crisis to a psychiatric hospital (OWLS): An assessor-blind pilot randomised controlled trial
Get PDFBackground: When patients are admitted onto psychiatric wards, sleep problems are highly prevalent. We carried out the first trial testing a psychological sleep treatment at acute admission (Oxford Ward sLeep Solution, OWLS). Methods: This assessor-blind parallel-group pilot trial randomised patients to receive sleep treatment at acute crisis [STAC, plus standard care (SC)], or SC alone (1 : 1). STAC included cognitiveâbehavioural therapy (CBT) for insomnia, sleep monitoring and light/dark exposure for circadian entrainment, delivered over 2 weeks. Assessments took place at 0, 2, 4 and 12 weeks. Feasibility outcomes assessed recruitment, retention of participants and uptake of the therapy. Primary efficacy outcomes were the Insomnia Severity Index and WarwickâEdinburgh Mental Wellbeing Scale at week 2. Analyses were intention-to-treat, estimating treatment effect with 95% confidence intervals. Results: Between October 2015 and July 2016, 40 participants were recruited (from 43 assessed eligible). All participants offered STAC completed treatment (mean sessions received = 8.6, S.D. = 1.5). All participants completed the primary end point. Compared with SC, STAC led to large effect size (ES) reductions in insomnia at week 2 (adjusted mean difference â4.6, 95% CI â7.7 to â1.4, ES â0.9), a small improvement in psychological wellbeing (adjusted mean difference 3.7, 95% CI â2.8 to 10.1, ES 0.3) and patients were discharged 8.5 days earlier. One patient in the STAC group had an adverse event, unrelated to participation. Conclusions: In this challenging environment for research, the trial was feasible. Therapy uptake was high. STAC may be a highly effective treatment for sleep disturbance on wards with potential wider benefits on wellbeing and admission length
Stabilising sleep for patients admitted at acute crisis to a psychiatric hospital (OWLS): an assessor-blind pilot randomised controlled trial
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