Circadian Phase and Phase Angle Disorders in Primary Insomnia.

Objectives: We aimed to identify the prevalence of circadian phase and phase angle abnormalities in patients with insomnia.

Methods: We conducted a cross-sectional, multicenter study at three sleep laboratories in the United States and Australia. Patients with insomnia and healthy control participants completed a sleep log for 7 days.

Neurobehavioral performance impairment in insomnia: relationships with self-reported sleep and daytime functioning.

Study Objectives: Despite the high prevalence of insomnia, daytime consequences of the disorder are poorly characterized. This study aimed to identify neurobehavioral impairments associated with insomnia, and to investigate relationships between these impairments and subjective ratings of sleep and daytime dysfunction.

Design: Cross-sectional, multicenter study.

Improved neurobehavioral performance during the wake maintenance zone.

Study Objectives: Although impairment of daytime functioning is a symptom of many sleep disorders, there are limited data on their nature for some patient groups. The role of the circadian system on impaired functioning, specifically the wake maintenance zone (WMZ)-a ∼3-h window of reduced sleep propensity that occurs shortly before the onset of melatonin synthesis-has received little attention. The study examined the influence of the WMZ on neurobehavioral performance under normal conditions and following sleep deprivation.

Fatigue and sleep disturbance following traumatic brain injury--their nature, causes, and potential treatments.

Background: Although fatigue and sleep disturbance are commonly reported following traumatic brain injury (TBI), understanding of their nature and treatment remains limited.

Objectives: This article reviews a series of investigations of the nature and causes of fatigue and sleep disturbance following TBI.

Methods: A large cohort of community-based patients with TBI, recruited from a TBI rehabilitation program, completed measures of subjective fatigue and sleep disturbances, as well as attentional measures.

Sleep disturbance and melatonin levels following traumatic brain injury.

Objectives: Sleep disturbances commonly follow traumatic brain injury (TBI) and contribute to ongoing disability. However, there are no conclusive findings regarding specific changes to sleep quality and sleep architecture measured using polysomnography. Possible causes of the sleep disturbances include disruption of circadian regulation of sleep-wakefulness, psychological distress, and a neuronal response to injury.