Sleep, vigilance, and thermosensitivity

The regulation of sleep and wakefulness is well modeled with two underlying processes: a circadian and a homeostatic one. So far, the parameters and mechanisms of additional sleep-permissive and wake-promoting conditions have been largely overlooked. The present overview focuses on one of these conditions: the effect of skin temperature on the onset and maintenance of sleep, and alertness. Skin temperature is quite well suited to provide the brain with information on sleep-permissive and wake-promoting conditions because it changes with most if not all of them. Skin temperature changes with environmental heat and cold, but also with posture, environmental light, danger, nutritional status, pain, and stress. Its effect on the brain may thus moderate the efficacy by which the clock and homeostat manage to initiate or maintain sleep or wakefulness. The review provides a brief overview of the neuroanatomical pathways and physiological mechanisms by which skin temperature can affect the regulation of sleep and vigilance. In addition, current pitfalls and possibilities of practical applications for sleep enhancement are discussed, including the recent finding of impaired thermal comfort perception in insomniacs

Prevention of depression and sleep disturbances in elderly with memory-problems by activation of the biological clock with light - a randomized clinical trial

<p>Abstract</p> <p>Background</p> <p>Depression frequently occurs in the elderly and in patients suffering from dementia. Its cause is largely unknown, but several studies point to a possible contribution of circadian rhythm disturbances. Post-mortem studies on aging, dementia and depression show impaired functioning of the suprachiasmatic nucleus (SCN) which is thought to be involved in the increased prevalence of day-night rhythm perturbations in these conditions. Bright light enhances neuronal activity in the SCN. Bright light therapy has beneficial effects on rhythms and mood in institutionalized moderate to advanced demented elderly. In spite of the fact that this is a potentially safe and inexpensive treatment option, no previous clinical trial evaluated the use of long-term daily light therapy to prevent worsening of sleep-wake rhythms and depressive symptoms in early to moderately demented home-dwelling elderly.</p> <p>Methods/Design</p> <p>This study investigates whether long-term daily bright light prevents worsening of sleep-wake rhythms and depressive symptoms in elderly people with memory complaints. Patients with early Alzheimer's Disease (AD), Mild Cognitive Impairment (MCI) and Subjective Memory Complaints (SMC), between the ages of 50 and 75, are included in a randomized double-blind placebo-controlled trial. For the duration of two years, patients are exposed to ~10,000 lux in the active condition or ~300 lux in the placebo condition, daily, for two half-hour sessions at fixed times in the morning and evening. Neuropsychological, behavioral, physiological and endocrine measures are assessed at baseline and follow-up every five to six months.</p> <p>Discussion</p> <p>If bright light therapy attenuates the worsening of sleep-wake rhythms and depressive symptoms, it will provide a measure that is easy to implement in the homes of elderly people with memory complaints, to complement treatments with cholinesterase inhibitors, sleep medication or anti-depressants or as a stand-alone treatment.</p> <p>Trial registration</p> <p>ISRCTN29863753</p

Violência física e fatores associados: estudo de base populacional no sul do Brasil Violencia física y factores asociados: estudio de base poblacional en el sur de Brasil Physical violence and associated factors: a population-based study in Southern Brazil

OBJETIVO: Estimar a prevalência de violência física e sua associação com aspectos sociodemográficos, eventos estressantes e utilização de serviços de saúde por problemas emocionais. MÉTODOS: Estudo transversal de base populacional realizado em amostra de 1.954 sujeitos com 14 anos ou mais, residentes em Canoas, RS, 2002-2003. A amostragem por conglomerados seguiu sistemática pré-estabelecida. Os dados foram coletados em visitas domiciliares com questionário semi-estruturado e confidencial. Foram realizadas as análises: bivariada, por meio de regressão logística multinomial e multivariada, por regressão politômica, categorizando o desfecho por faixa etária. RESULTADOS: Foi encontrada prevalência de 9,7% (IC 95%: 8,37;11,03) e associação com: sexo feminino a partir dos 20 anos de idade (OR=2,74; IC 95%: 1,52;4,94), maior escolaridade (p<0,03), maior vivência de eventos estressantes com 20 anos ou mais (OR=6,61; IC 95%: 2,71;16,1) e consulta por problemas emocionais a partir dos 10 anos de idade (p>0,001). CONCLUSÕES: A prevalência da violência física na população foi significativa, com conseqüências emocionais e impacto nos serviços de saúde, requerendo capacitação dos profissionais da área.<br>OBJETIVO: Estimar la prevalencia de violencia física y sua asociacion con aspectos sociodemográfcos, eventos estresantes y utilizacion de servicios de salud por problemas emocionales. MÉTODOS: Estudio transversal de base poblacional realizado en muestra de 1.954 sujetos con 14 anos o mas, residentes en Canoas, sur de Brasil, 2002-2003. La muestra por conglomerados siguio sistemática pré-estabelecida. Los datos fueron tomados en visitas domiciliarias con cuestionário semi-estructurado y confidencial. Fueron realizadas las analisis: bivariada, por meio de regresión logística multinomial y multivariada, por regresión politómica, según grupo etario. RESULTADOS: Fue encontrada prevalencia de 9,7% (IC 95%: 8,37;11,03) y asociación con: sexo feminino a partir dos 20 anos de edad (OR=2,74; IC 95%: 1,52;4,94), mayor escolaridade (p<0,03), mas vivencia de eventos estresantes con 20 anos o mas (OR=6,61; IC 95%: 2,71;16,1) y consulta por problemas emocionales a partir de los 10 anos de edad (p>0,001). CONCLUSÕES: La prevalencia de la violencia física en la poblacion fue significativa, con consecuencias emocionales e impacto en los servicios de salud, requiriendo capacitación de los profesionales del área.<br>OBJECTIVE: To estimate the prevalence of physical violence and its association with sociodemographic aspects, stressful life events, and the use of health services due to emotional problems. METHODS: A cross-sectional population-based study was conducted with a sample of 1,954 14-year-old or older inhabitants of the city of Canoas (Southern Brazil). They were selected by means of conglomerate sampling according to a pre-established system. Data were obtained in visits to households by means of a confidential semi-structured questionnaire. A bivariate analysis was carried out through multinomial logistic regression, and the multivariate analysis by polytomous logistic regression, categorizing the outcome by age group. RESULTS: The findings show a prevalence of 9.7% (CI 95%: 8.37;11.03) and association with: women 20 years old and older (OR=2.74; CI 95%: 1.52;4.94); higher schooling rate (p<0.03); higher experience of stressful life events at 20 years of age or more (OR=6.61; CI 95%: 2.71;16.1); and doctors' appointments due to emotional problems as of 10 years of age (p>0.001). CONCLUSIONS: The prevalence of physical violence in the population was significant, resulting in important emotional consequences and impact on health services, requiring capacity building of the professionals in the field