Gregory Belenky

• M.D.
• Professor at Washington State University

INTRODUCTION: In commercial aviation, pilot fatigue is a major threat to safety. One key fatigue mitigation strategy on long-range (LR; 8–16 h) and ultra-long range (ULR; 16+ h on at least 10% of trips) routes is allotting in-flight rest breaks for the pilots. Since sleep is a strong predictor of performance, it is important to quantify total in-fl...

Introduction Pilots flying long range (LR; 8-16 hour) and ultra-long range (ULR; 16+ hour on 10% of trips) commercial airline routes use a variety of work/rest schedules during flights, resulting in a wide distribution of total inflight sleep time (TIFS) amounts. Since sleep is a strong predictor of performance, it is important to quantify TIFS and...

The BDNF gene contains a polymorphism (Val66Met) that influences sleep and may be associated with more flexible adaptation to circadian misalignment. Fifteen adult men (10 Val/Val homozygotes, 5 Val/Met heterozygotes) participated in a laboratory study involving two 5 d cycles of simulated night shifts. Circulating interleukin-6 (IL-6) was measured...

Introduction Safety performance indicators (SPIs) are used in aviation to determine if a trip that is non-compliant with federal regulations is safe to fly. Exemptions to regulations can be granted if a safety case demonstrates that the SPIs for an alternative means of compliance (AMOC; i.e., a trip outside regulations) are non-inferior to SPIs for...

Introduction Prior simulation and operational studies have started to address whether the number of consecutive flight segments negatively affects cognitive performance, fatigue, and sleepiness, without reaching a clear consensus. This study expands this literature by determining whether there are significant changes in cognitive performance, fatig...

Introduction Federal Aviation Administration (FAA), 2013 Federal Aviation Regulation (FAR) 14 CFR Part 117.7 allows a data collection enabled alternative to the current prescriptive regulations. Flights under this alternative approach must maintain an “equivalent level of safety” to operations within the current regulations, assessed through Safety...

Introduction The Actigraph is a wrist-worn device containing an accelerometer that can detect changes in activity to measure sleep within individuals and quantify sleep across populations. While there is some literature comparing actigraphy with other sleep scoring methods, the exact nature of data-cleaning procedures for actigraphy is not well def...

INTRODUCTION: Despite the clear need for understanding how pilot sleep affects performance during long-range (LR; 12-16h) and ultra-long-range (ULR; 16+h) flights, the scientific literature on the effects of sleep loss and circadian desynchronization on pilots' sleep in commercial aviation is sparse.METHODS: We assessed pilots' sleep timing, durati...

Introduction In commercial aviation, for augmented crews (in this study 3-pilot crews) the pilot landing the aircraft is required by the US Federal Aviation Administration to have two consecutive hours of inflight rest in the second half of the flight duty period. For 3-pilot augmented crews only the third inflight break complies with the regulatio...

In December 2014, the Federal Aviation Administration (FAA) completed a major revision of the rules and regulations governing flight and duty time in commercial aviation (Federal Aviation Regulation (FAR) Part 117). Scientists were included in the revision process and provided insights into sleep, sleep loss, the circadian rhythm, and their effects...

Introduction Ultra Long Range (ULR; 16+ hour) flights cross multiple time zones. Therefore during layover (26–40 hours), the light/dark cycle is radically out of phase relative to home base time. The question is to what degree do pilots shift or readjust their sleep/wake cycle during layover and post-flight days as measured by synchronization to ho...

Introduction The timing of shift start affects motorcoach drivers’ ratings of sleepiness. Here we compare the start of work sleepiness ratings to those made at the end of work among commercial motorcoach drivers. Methods Seventy-eight commercial motorcoach drivers were monitored for approximately one month as they completed their usual work and re...

ABSTRACT: The American Academy of Sleep Medicine and Sleep Research Society recently released a Consensus Statement regarding the recommended amount of sleep to promote optimal health in adults. This paper describes the methodology, background literature, voting process, and voting results for the consensus statement. In addition, we address import...

ABSTRACT: The American Academy of Sleep Medicine and Sleep Research Society recently released a Consensus Statement regarding the recommended amount of sleep to promote optimal health in adults. This paper describes the methodology, background literature, voting process, and voting results for the consensus statement. In addition, we address import...

ABSTRACT: Sleep is essential for optimal health. The American Academy of Sleep Medicine (AASM) and Sleep Research Society (SRS) developed a consensus recommendation for the amount of sleep needed to promote optimal health in adults, using a modified RAND Appropriateness Method process. The recommendation is summarized here. A manuscript detailing t...

Sleep debt and time of day/night (circadian rhythm) exert substantial effects on commercial motor vehicle (CMV) operator (e.g. truck and bus/motor coach, railroad engineer, aviation pilot) performance—and, therefore, safety. In this chapter, the influence of sleep debt and circadian effects on operator performance are described. Efficacy of various...

Sleep is essential for optimal health. The American Academy of Sleep Medicine (AASM) and Sleep Research Society (SRS) developed a consensus recommendation for the amount of sleep needed to promote optimal health in adults, using a modified RAND Appropriateness Method process. The recommendation is summarized here. A manuscript detailing the confere...

Sleep loss, adverse circadian rhythm phase, and workload interact to create fatigue. Fatigue degrades performance and well-being leading to error, incident, and accident in operational settings. An operational setting is one in which effective human performance is crucial to a successful outcome. If the human fails, the system fails. Technological...

Introduction: Flight timing is expected to influence pilot fatigue because it determines the part of the circadian body clock cycle that is traversed during a flight. However the effects of flight timing are not well-characterized because field studies typically focus on specific flights with a limited range of departure times and have small sampl...

The Karolinska Sleepiness Scale and Samn-Perelli fatigue ratings, and psychomotor vigilance task performance are proposed as measures for monitoring commercial pilot fatigue. In laboratory studies, they are sensitive to sleep/wake history and circadian phase. The present analyses examined whether they reliably reflect sleep/wake history and circadi...

Shift work is common in today's society, and is associated with negative health outcomes, and accidents and incidents. These detrimental effects can be primarily attributed to sleeping and working at an adverse circadian time. The aim of this study was to examine whether a split sleep schedule is as effective as a consolidated day shift or night sh...

Probability learning to escape from shock was investigated in 36 female albino rats. The independent variable was the intensity of shock. All Ss were run in a T-maze using a correction procedure. One side of the T, (A1), was shock-free with probability, π =.667 while the other (A2) side was shock-free with probability (1 - π) =.333. The major findi...

The objective of this research project was to determine the effectiveness, for nighttime work periods, of a restart period containing two biological nights, relative to the 34-hour restart provision in the hours of service regulations governing property-carrying Commercial Motor Vehicle drivers. A sample of 12 healthy subjects was studied in an in-...

The objective of this research project was to determine the effectiveness of the 34- hour restart provision in the Hours-of-Service regulations governing property-carrying commercial motor vehicle drivers. A sample of 27 healthy subjects was studied in an inresidence laboratory study with frequent testing of cognitive performance and driving perfor...

Physicians in training experience fatigue from sleep loss, high workload, and working at an adverse phase of the circadian rhythm, which collectively degrades task performance and the ability to learn and remember. To minimize fatigue and sustain performance, learning, and memory, humans generally need 7 to 8 hours of sleep in every 24-hour period....

This study investigated the effect of varying the events occurring between two reinforced trials on the course of learning. It was found that the effectiveness of a second reinforced trial was greater; (a) for the longer of two inter-reinforcement intervals prior to the second reinforced trial; (b) if S is not specifically tested for retention of t...

As individuals age they report increasing numbers of sleep problems (e.g., increased nighttime wakings) and this poorer sleep quality has been associated with increased risk for various medical conditions; however limited research has focused on the implications of sleep quality on everyday functioning in older adulthood. We compared three methods...

This study assessed the utility of a combined field and laboratory research design for measuring the impact of consecutive night shift work on the sleepiness, vigilance, and driving performance of police patrol officers. FOR POLICE PATROL OFFICERS WORKING THEIR NORMAL NIGHT SHIFT DUTY CYCLES, SIMULATED DRIVING PERFORMANCE AND PSYCHOMOTOR VIGILANCE...

Evoked hemodynamic responses measured following sleep deprivation were larger compared baseline and recovery sleep nights. Attention differences during sleep deprivation showed larger responses in alert individuals than sleepy individuals, suggesting differences in vascular compliance.

Occupational sleep medicine is a new field within sleep medicine. Occupational sleep medicine applies (1) the science of sleep, frequently as instantiated into mathematical modeling; (2) the tactics, techniques, and procedures of sleep and performance measurement in the operational environment; and (3) the clinical practice of sleep medicine to red...

Waking neurobehavioral performance is temporally regulated by a sleep/wake homeostatic process and a circadian process in interaction with a time-on-task effect. Neurobehavioral impairment resulting from these factors is task-specific, and characterized by performance variability. Several aspects of these phenomena are not well understood, and cann...

Under simulated shift-work conditions, we investigated the efficacy of a restart break for maintaining neurobehavioral functioning across consecutive duty cycles, as a function of the circadian timing of the duty periods. As part of a 14-day experiment, subjects underwent two cycles of five simulated daytime or nighttime duty days, separated by a 3...

On 27 August 2006 at 0606 eastern daylight time (EDT) at Bluegrass Airport in Lexington, KY (LEX), the flight crew of Comair Flight 5191 inadvertently attempted to take off from a general aviation runway too short for their aircraft. The aircraft crashed killing 49 of the 50 people on board. To better understand this accident and to aid in preventi...

In recent years, theoretical models of the sleep and circadian system developed in laboratory settings have been adapted to predict fatigue and, by inference, performance. This is typically done using the timing of prior sleep and waking or working hours as the primary input and the time course of the predicted variables as the primary output. The...

Operator fatigue is a catch-all term for impairment that commonly occurs if people continue working when they have not fully recovered from the demands of prior work and other waking activities. fatigue-related impairment can accumulate across a work period where breaks are insufficient to allow short-term recovery from task demands. Fatigue-relate...

Chronic sleep deprivation is common among workers, and has been associated with negative work outcomes, including absenteeism and occupational accidents. The objective of the present study is to characterize reciprocal relationships between sleep and work. Specifically, we examined how sleep impacts work performance and how work affects sleep in in...

The time-on-task effect entails a decrement in cognitive performance across the duration of a performance task.1,2 The Psychomotor Vigilance Test (PVT)3 is sensitive to the time-on-task effect, showing a lengthening of average response time (RT) and an increase in RT variability in as little as 10 min, especially under conditions of sleep deprivati...

We studied the effects of sleep deprivation on executive functions using a task battery which included a modified Sternberg task, a probed recall task, and a phonemic verbal fluency task. These tasks were selected because they allow dissociation of some important executive processes from non-executive components of cognition. Subjects were randomiz...

There are considerable individual differences in cognitive performance deficits resulting from extended work hours and shift work schedules. Recent progress in sleep and performance research has yielded new insights into the causes and consequences of these individual differences. Neurobiological processes of sleep/wake regulation underlie trait in...

Crewmembers on ultra long-range commercial flights have the opportunity for rest and sleep in onboard areas in which the barometric pressure is 75.3 kPa (565 mmHg) or higher, equivalent to a terrestrial altitude of 2438 m (8000 ft) or lower. Sleep at higher altitudes is known to be disturbed, resulting in postsleep neurobehavioral performance decre...

Five years ago, it was first demonstrated that there are considerable, stable individual differences in performance impairment due to sleep deprivation. The discovery of this new phenotype, which has been labeled 'trototype', led to a surge of research activity aiming to identify predictors. Genes involved in the adenosinergic and circadian regulat...

Substantial evidence suggests that brain regions that have been disproportionately used during waking will require a greater intensity and/or duration of subsequent sleep. For example, rats use their whiskers in the dark and their eyes during the light, and this is manifested as a greater magnitude of electroencephalogram (EEG) slow-wave activity i...

A new algorithm is introduced to efficiently estimate confidence intervals for Bayesian model predictions based on multidimensional parameter space. The algorithm locates the boundary of the smallest confidence region in the multidimensional probability density function (pdf) for the model predictions by approximating a one-dimensional slice throug...

Sleep is vital to cognitive performance, productivity, health and well-being. Earlier theories of sleep presumed that it occurred at the level of the whole organism and that it was governed by central control mechanisms. However, evidence now indicates that sleep might be regulated at a more local level in the brain: it seems to be a fundamental pr...

The two-process model of sleep regulation makes accurate predictions of sleep timing and duration for a variety of experimental sleep deprivation and nap sleep scenarios. Upon extending its application to waking neurobehavioral performance, however, the model fails to predict the effects of chronic sleep restriction. Here we show that the two-proce...

: Clinical observations suggest that endogenous opioids and their receptors may be involved in affective disorders. We theorized that these endogenously activated opioid systems may play a therapeutic role in the antidepressant effects known to result from electroconvulsive therapy (ECT). In an initial test of this pypothesis, we subjected rats to...

The Sleep and Performance Research Center (SPRC) at Washington State University will conduct laboratory and field studies of sleep loss and performance in normal humans. These studies will provide the scientific basis for the effective management of sleep to sustain performance in the operational environment, including all 24x7 operations, extended...

In a 2001 report the Committee on Military Nutrition Research (CMNR) stated that military personnel are often placed in unique situations in which extended alertness is required. This is most evident in situations involving sentry duty, radar monitoring, communications, long-range air support missions, and logistical supply requirements as well as...

When used to counteract the effects of sleep deprivation, multiple doses of caffeine are typically ingested across an extended period of time. The goal of this study was to determine the optimal dose of caffeine for sustaining performance during sleep loss with administration of multiple doses. There were 48 subjects (28 men, 20 women) who were ran...

Oculomotor responses related to the pupil light reflex (PLR) and saccadic velocity may be sensitive to the effects of sleepiness and therefore could be used to evaluate an individual's fitness for duty. There were 12 normal subjects who completed an 8-d study. They were allowed 8 h in bed on the first three nights, 4 h in bed on the fourth night, a...

Network-centric warfare is the basis of doctrine and operations for the U.S. Army, Navy, and Air Force. Fundamental to network-centric warfare is the availability of accurate, detailed, real-time information at all levels of command and control. Network-centric operations and the associated self-synchronization put a premium on the performance of i...

This field-portable reaction time test and analysis software run on devices using the Palm operating system. It is designed to emulate a test and commercial device widely used in sleep deprivation, shift work, fatigue, and stimulant drug research but provides additional capabilities. Experimental comparisons with the standard commercial device in a...

Caffeine is widely used to reverse alertness and performance decrements. However, caffeine's effects on subsequent recovery sleep and post-recovery performance are not well documented and, therefore, were evaluated. Six habitually low (LC: < or = 100 mg x d(-1)) and three habitually high (HC: > or = 400 mg x d(-1)) caffeine users completed a random...

Pharmacologic enhancement of daytime sleep may help sustain optimal cognitive performance. At effective doses, zolpidem induces sleep but also impairs performance. Combining melatonin with low-dose zolpidem may promote daytime sleep without exacerbating performance impairments seen with high-dose zolpidem alone. Following an 8-hour undisturbed nigh...

The purpose of this study was to examine the effects of caffeine (CAF) on physical, vigilance, and marksmanship tasks in soldiers during a sustained 55-h field exercise. There were 30 soldiers (23.6 +/- 4.5 yr, 81.8 +/- 10.3 kg) who were divided into a placebo (PLAC) and a CAF group. After a period of restricted sleep of 3 h during the first night,...