BACKGROUND Disturbances in rest-activity rhythm are prominent and disabling symptoms in Alzheimer's disease (AD). Nighttime sleep is severely fragmented and daytime activity is disrupted by multiple napping episodes. In most institutional environments, light levels are very low and may not be sufficient to enable the circadian clock to entrain to the 24-hour day. The purpose of this randomized,...

Patients with dementia have been shown to have disturbed sleep/wake rhythms. There is evidence of impairment in endogenous generation of rhythms and deficient environmental cues in this population. This study sought to examine patterns of rest/activity rhythms as they relate to dementia severity. Three days of actigraphy were collected from 150 nursing-home patients with dementia and used to co...

STUDY OBJECTIVES Individual sleep timing differs and is governed partly by circadian oscillators, which may be assessed by hormonal markers, or by clock gene expression. Clock gene expression oscillates in peripheral tissues, including leukocytes. The study objective was to determine whether the endogenous phase of these rhythms, assessed in the absence of the sleep-wake and light-dark cycle, c...

Background APPswe/PS1dE9 mice reproduce features of amyloid β (Aβ) pathology and neuronal dysfunction as reflected in electrophysiological recordings hyperexcitability. This leads to changes sleep-wake-rhythm, downstream affecting brain clearance functionality. Our objective is investigate the effect circadian rhythm Aβ on efficacy mice. Method First, we examined wide distribution an intrahippo...

Objective: To describe the physiologic and behavioral characteristics of circadian rhythm sleep disorders (CRSDs) following minor traumatic brain injury (mTBI) in patients complaining insomnia. Methods: Forty two with insomnia complaints mTBI were screened. Those suspected having CRSD underwent actigraphy, saliva melatonin oral temperature measurement, polysomnography. All also fille...

This is the first study to examine effective doses of controlled-release (CR) melatonin in children with chronic sleep wake cycle disorders. All 42 subjects had severe neurodevelopmental difficulties. Initially, a randomized double-blinded cross-over design was used in 16 children, comparing the effectiveness of fast-release (FR) and CR melatonin. In the remainder of the patients, the CR melato...

Hummingbirds are specialized hoverers for which the vortex wake has been described as a series of single vortex rings shed primarily during the downstroke. Recent findings in bats and birds, as well as in a recent study on Anna's hummingbirds, suggest that each wing may shed a discrete vortex ring, yielding a bilaterally paired wake. Here, we describe the presence of two discrete rings in the w...

Despite advances in the treatment of bipolar disorder, a significant proportion of patients experience disabling symptoms between episodes, and relapse rates are high. These circumstances suggest that there is a critical need to achieve a mechanistic understanding of triggers of relapse and to target them with specific, empirically derived treatments. Sleep disturbances are among the most promi...