A parallel-group randomized controlled trial of blue light versus red light for improving sleep, fatigue, and cognition following stroke: Pilot results and recommendations for further study.

Background: Disordered sleep and fatigue are common in the acute phase of stroke and can impede recovery.

Objective: A randomized parallel group placebo-controlled pilot study compared daily morning exposure to blue light or red light (placebo) for improving daytime sleepiness, fatigue, nocturnal sleep, and cognition in patients receiving inpatient rehabilitation for acute stroke.

Methods: 43 patients with disordered sleep secondary to first episode stroke (n = 34 ischemic, n = 9 hemorrhagic; aged 66.

Effects of Sleep Deprivation on Performance during a Change Signal Task with Adaptive Dynamics.

Augmented cognition, which refers to real-time modifications to a human-system interface to improve performance and includes dynamic task environments with automated adaptations, can serve to protect against performance impairment under challenging work conditions. However, the effectiveness of augmented cognition as a countermeasure for performance impairment due to sleep loss is unknown. Here, in a controlled laboratory study, an adaptive version of a Change Signal task was administered repeatedly to healthy adults randomized to 62 h of total sleep deprivation (TSD) or a rested control condition.

Paradoxical effects from stimulus density manipulation provide new insight into the impact of sleep deprivation on PVT performance.

Study Objectives: The psychomotor vigilance test (PVT), a 10-min one-choice reaction time task with random response-stimulus intervals (RSIs) between 2 and 10 s, is highly sensitive to behavioral alertness deficits due to sleep loss. To investigate what drives the performance deficits, we conducted an in-laboratory total sleep deprivation (TSD) study and compared performance on the PVT to performance on a 10-min high-density PVT (HD-PVT) with increased stimulus density and truncated RSI range between 2 and 5 s. We hypothesized that the HD-PVT would show greater impairments from TSD than the standard PVT.

Enhancing learning and retention through the distribution of practice repetitions across multiple sessions.

The acquisition and retention of knowledge is affected by a multitude of factors including amount of practice, elapsed time since practice occurred, and the temporal distribution of practice. The third factor, temporal distribution of practice, is at the heart of research on the spacing effect. This research has consistently shown that separating practice repetitions by a delay slows acquisition but enhances retention.

Effects of heat strain on cognitive function among a sample of miners.

Heat stress is associated with workplace injuries, likely through a combination of fatigue, reduced cognitive function, and thermal discomfort. The purpose of this study was to evaluate four cognitive tasks for sensitivity to heat stress. Eight participants performed treadmill exercise followed by assessments of serial reaction time (RT), Stroop effect, verbal delayed memory, and continuous performance working memory in an environmental chamber.

Pain Catastrophizing Mediates the Relationship Between Pain Intensity and Sleep Disturbances in U.S. Veterans With Chronic Pain.

Introduction: Veterans with chronic pain frequently report comorbid disruptions in sleep and psychological dysfunction. The purpose of this study was to investigate whether psychological function variables mediate the sleep-pain relationship. Knowledge regarding such contributing factors can inform the development and optimization of treatments for sleep disturbances and pain.

Working around the Clock: Is a Person's Endogenous Circadian Timing for Optimal Neurobehavioral Functioning Inherently Task-Dependent?

Neurobehavioral task performance is modulated by the circadian and homeostatic processes of sleep/wake regulation. Biomathematical modeling of the temporal dynamics of these processes and their interaction allows for prospective prediction of performance impairment in shift-workers and provides a basis for fatigue risk management in 24/7 operations. It has been reported, however, that the impact of the circadian rhythm-and in particular its timing-is inherently task-dependent, which would have profound implications for our understanding of the temporal dynamics of neurobehavioral functioning and the accuracy of biomathematical model predictions.

Trait Interindividual Differences in the Magnitude of Subjective Sleepiness from Sleep Inertia.

In shift work settings and on-call operations, workers may be at risk of sleep inertia when called to action immediately after awakening from sleep. However, individuals may differ substantially in their susceptibility to sleep inertia. We investigated this using data from a laboratory study in which 20 healthy young adults were each exposed to 36 h of total sleep deprivation, preceded by a baseline sleep period and followed by a recovery sleep period, on three separate occasions.

Reversal learning deficits during sleep deprivation: investigating the role of information acquisition failures.

Besides degrading vigilant attention, total sleep deprivation (TSD) impairs reversal learning performance and blunts affective reactions to feedback. Whether these effects are downstream consequences of information acquisition failures from degraded vigilant attention, or distinct from degraded vigilant attention, is unclear. In well-rested individuals we simulated information acquisition failures by masking a portion of trial information in a go/no-go reversal learning task with four conditions: stimulus masking, feedback masking, alternating stimulus/feedback masking, and no-masking control.

C957T genotype modulates the time-on-task effect during total sleep deprivation.

Total sleep deprivation (TSD) and time-on-task (TOT), especially in combination, increase cognitive instability and cause performance impairment. There are large inter-individual differences in TSD and TOT effects which, in part, have a genetic basis. Here, we show that the dopamine receptor D C957T genetic polymorphism predicts the magnitude of the TOT effect on a psychomotor vigilance test (PVT) during 38 h of TSD.

New insights into the cognitive effects of sleep deprivation by decomposition of a cognitive throughput task.

Study Objectives: A cognitive throughput task known as the Digit Symbol Substitution Test (DSST) (or Symbol Digit Modalities Test) has been used as an assay of general cognitive slowing during sleep deprivation. Here, the effects of total sleep deprivation (TSD) on specific cognitive processes involved in DSST performance, including visual search, spatial memory, paired-associate learning, and motor response, were investigated through targeted task manipulations.

Methods: A total of 12 DSST variants, designed to manipulate the use of specific cognitive processes, were implemented in two laboratory-based TSD studies with N = 59 and N = 26 subjects, respectively.

Sleep deprivation, vigilant attention, and brain function: a review.

Vigilant attention is a major component of a wide range of cognitive performance tasks. Vigilant attention is impaired by sleep deprivation and restored after rest breaks and (more enduringly) after sleep. The temporal dynamics of vigilant attention deficits across hours and days are driven by physiologic, sleep regulatory processes-a sleep homeostatic process and a circadian process.

Working Time Society consensus statements: Prescriptive rule sets and risk management-based approaches for the management of fatigue-related risk in working time arrangements.

Traditionally, working time arrangements to limit fatigue-related risk have taken a prescriptive approach, which sets maximum shift durations in order to prevent excessive buildup of fatigue (and the associated increased risk) within shifts and sets minimum break durations to allow adequate time for rest and recovery within and/or between shifts. Prescriptive rule sets can be successful when, from a fatigue-related risk standpoint, they classify safe work hours as permitted and unsafe work hours as not permitted. However, prescriptive rule sets ignore important aspects of the biological factors (such as the interaction between circadian and homeostatic processes) that drive fatigue, which are critical modulators of the relationship between work hours and fatigue-related risk.

Sleep Deprivation Diminishes Attentional Control Effectiveness and Impairs Flexible Adaptation to Changing Conditions.

Insufficient sleep is a global public health problem resulting in catastrophic accidents, increased mortality, and hundreds of billions of dollars in lost productivity. Yet the effect of sleep deprivation (SD) on decision making and performance is often underestimated by fatigued individuals and is only beginning to be understood by scientists. The deleterious impact of SD is frequently attributed to lapses in vigilant attention, but this account fails to explain many SD-related problems, such as loss of situational awareness and perseveration.

Shift Work: Disrupted Circadian Rhythms and Sleep-Implications for Health and Well-Being.

Purpose Of Review: Our 24/7 society is dependent on shift work, despite mounting evidence for negative health outcomes from sleep displacement due to shift work. This paper reviews short- and long-term health consequences of sleep displacement and circadian misalignment due to shift work.

Recent Findings: We focus on four broad health domains: metabolic health; risk of cancer; cardiovascular health; and mental health.

Effects of a 12-week physical activities programme on sleep in female university students.

Lack of sleep is known to negatively affect adolescent's health and the links between regular physical activity and sleep are unclear.This pilot study investigated whether the regular practice of physical activities among sedentary female students would improve their sleep. Nineteen female students, identified as sedentary and having poor subjective sleep quality were assigned in two groups to a 12-week university physical activities programme in accordance with the recommendations of World Health Organisation (N = 10) or to a control condition (N = 9).

P2X7 receptors in body temperature, locomotor activity, and brain mRNA and lncRNA responses to sleep deprivation.

The ionotropic purine type 2X7 receptor (P2X7R) is a nonspecific cation channel implicated in sleep regulation and brain cytokine release. Many endogenous rhythms covary with sleep, including locomotor activity and core body temperature. Furthermore, brain-hypothalamic cytokines and purines play a role in the regulation of these physiological parameters as well as sleep.

Fatiguing effect of multiple take-offs and landings in regional airline operations.

Fatigue is a risk factor for flight performance and safety in commercial aviation. In US commercial aviation, to help to curb fatigue, the maximum duration of flight duty periods is regulated based on the scheduled start time and the number of flight segments to be flown. There is scientific support for regulating maximum duty duration based on scheduled start time; fatigue is well established to be modulated by circadian rhythms.

Validation of a portable, touch-screen psychomotor vigilance test.

Introduction: The Psychomotor Vigilance Test (PVT) measures effects of fatigue from sleep loss and circadian misalignment on sustained vigilance performance. To promote PVT use in field environments, a 5-min PVT version has been implemented on a personal digital assistant (PDA) with a touch screen. The present laboratory study was conducted to validate this PVT against a standard 10-min laptop PVT across 38 h of total sleep deprivation (TSD).