For those endeavoring to develop better methods of measuring/quantifying sleepiness, the "Holy Gr... more For those endeavoring to develop better methods of measuring/quantifying sleepiness, the "Holy Grail" is a measure that is maximally objective, completely unobtrusive, exquisitely sensitive, and absolutely specific (i.e., varies only as a function of sleepiness). By these criteria, physiological measures (e.g., based on brain activity such as EEG, fMRI, near-infrared spectroscopy, etc.) would appear to hold the most promise. However, from an operational standpoint, the utility of a sleepiness measure is derived not from its ability to sensitively reflect the brain's extant level of sleepiness per se, but from the implications that this level of sleepiness has for the individual's current and near-term ability to safely and efficiently perform operationally relevant tasks. Thus, an ideal operationally-relevant sleepiness measure is one that is unobtrusively embedded in the actual operational task, and allows sleepiness-related performance deficits to be distinguished from performance deficits due to other causes. Toward this end, we have developed a PVT-derived metric that incorporates the entire distribution of responses within a PVT session, and reflects changes in the pattern of performance that can be used to identify and quantify "state instability"-the putative physiological state that specifically underlies sleepiness-induced performance deficits. Citation: Balkin TJ. Behavioral biomarkers of sleepiness.
Stimulants and Sleep Loss-Bonnet et al Disclosure Statement This was not an industry supported st... more Stimulants and Sleep Loss-Bonnet et al Disclosure Statement This was not an industry supported study. Dr. Bonnet has received research support from Neurocrine, Pfizer, and Cephalon; and serves on the board or participates in speaking arrangements supported by the Sleep Medicine Educational Institute, Sanofi-Aventis, and Takeda. Dr. Dinges has received research support from Cephalon, and Mars-Masterfoods, Inc.; is a paid consultant for Pfizer, Takeda, Merck, Aventis, and Sanofi; and has received speaker honoraria from and serves on the advisory board for Cephalon. Dr. Roehrs has participated in speaking engagements supported by Sepracor; and is a consultant for Sepracor and Sanofi. Dr. Rogers has received research support from Cephalon. Drs. Balkin and Wesensten have indicated no financial conflicts of interest.
Introduction Threat-related information is preferentially processed, facilitating quick and effic... more Introduction Threat-related information is preferentially processed, facilitating quick and efficient responses. However, the impact of extended sleep deprivation on perception of and response to threatening information is not well known. Sleep loss may increase amygdalar activity and negative mood, potentially facilitating threat processing. However, it also reduces cognitive function, possibly impairing ability to respond. The present study assessed the extent to which extended sleep deprivation modulates threat processing using a threat expectation paradigm. Methods Twenty-one participants underwent one baseline night of sleep followed by 62hrs total sleep deprivation (TSD) and one recovery night of sleep (12hrs). Threat expectation task performance was assessed at baseline, at multiple time points during TSD, and following recovery sleep. To control for circadian influence, performance at three 1100 sessions (baseline, 52hrs into TSD, and recovery) were compared. The threat expe...
The EEG slow oscillation of < 1 Hertz frequency has been implicated in various sleep functions... more The EEG slow oscillation of < 1 Hertz frequency has been implicated in various sleep functions, sparking a recent interest in slow oscillation enhancement strategies. In a seminal study, Marshall et al. (2006) demonstrated that 25 minutes of a slow oscillatory form of transcranial direct current stimulation (SO-tDCS) during early nocturnal sleep improved subsequent retention of word pairs learned prior to sleep, consistent with a proposed role for the slow oscillation in sleep-related memory consolidation. Another proposed function of the slow oscillation is synaptic downscaling, hypothesized to constitute the physiological basis for satisfying the homeostatic drive for sleep, per the synaptic homeostasis hypothesis of Tononi and Cirelli. We sought to determine if SO-tDCS could enhance the restorative properties of sleep, by enhancing slow oscillation activity, during a restricted sleep opportunity by assessing performance during a subsequent period of sleep deprivation (SD). Twe...
This conference presentation addresses the health aspects of fatigue. The author begins by provid... more This conference presentation addresses the health aspects of fatigue. The author begins by providing an overview of fatigue and sleepiness and the current model of sleep. He then describes chronic sleep restriction and performance, sleep extension effects, and the implications for sleep models. He concludes by discussing sleep and physiology and health.
The 2014 Behavioral Health and Performance (BHP) Standing Review Panel (from here on referred to ... more The 2014 Behavioral Health and Performance (BHP) Standing Review Panel (from here on referred to as the SRP) met for a site visit in Houston, TX on December 17 18, 2014. The SRP reviewed the updated research plan for the Risk of Performance Errors Due to Fatigue Resulting from Sleep Loss, Circadian Desynchronization, Extended Wakefulness, and Work Overload (Sleep Risk) and also received a status update on the Risk of Adverse Behavioral Conditions and Psychiatric Disorders (BMed Risk) and the Risk of Performance Decrements Due to Inadequate Cooperation, Coordination, Communication, and Psychosocial Adaptation within a Team (Team Risk).
: In this work, we present a method for developing individualized biomathematical models for pred... more : In this work, we present a method for developing individualized biomathematical models for predicting cognitive performance impairment of individuals subjected to total sleep loss. The proposed method uses the two-process model of sleep regulation as the underlying parametric model, whose parameters are systematically customized for an individual by optimally combining the performance information obtained from the individual's performance measurements with a priori performance information using a Bayesian framework. As a result, the models incrementally account for an individual's uncertain initial state and unknown trait characteristics as each new performance measurement from the individual becomes available, yielding improved performance predictions. Additionally, the proposed method enables the analytical computation of statistically based measures of reliability of the model predictions in the form of prediction intervals. Results using data from subjects who particip...
Knowing how an individual responds to sleep deprivation is a requirement for developing personali... more Knowing how an individual responds to sleep deprivation is a requirement for developing personalized fatigue management strategies. Here we describe and validate the 2B-Alert App, the first mobile application that progressively learns an individual's trait-like response to sleep deprivation in real time, to generate increasingly more accurate individualized predictions of alertness. We incorporated a Bayesian learning algorithm within the validated Unified Model of Performance to automatically and gradually adapt the model parameters to an individual after each psychomotor vigilance test. We implemented the resulting model and the psychomotor vigilance test as a smartphone application (2B-Alert App), and prospectively validated its performance in a 62-hr total sleep deprivation study in which 21 participants used the app to perform psychomotor vigilance tests every 3 hr and obtain real-time individualized predictions after each test. The temporal profiles of reaction times on th...
If protein synthesis during sleep is required for sleep-dependent memory consolidation, we might ... more If protein synthesis during sleep is required for sleep-dependent memory consolidation, we might expect rates of cerebral protein synthesis (rCPS) to increase during sleep in the local brain circuits that support performance on a particular task following training on that task. To measure circuit-specific brain protein synthesis during a daytime nap opportunity, we used the L-[1-(11)C]leucine positron emission tomography (PET) method with simultaneous polysomnography. We trained subjects on the visual texture discrimination task (TDT). This was followed by a nap opportunity during the PET scan, and we retested them later in the day after the scan. The TDT is considered retinotopically specific, so we hypothesized that higher rCPS in primary visual cortex would be observed in the trained hemisphere compared to the untrained hemisphere in subjects who were randomized to a sleep condition. Our results indicate that the changes in rCPS in primary visual cortex depended on whether subjec...
To investigate the effects of caffeine on psychomotor vigilance and sleepiness during sleep restr... more To investigate the effects of caffeine on psychomotor vigilance and sleepiness during sleep restriction and following subsequent recovery sleep. Participants were N=48 healthy good sleepers. All participants underwent 5 nights of sleep satiation [time-in-bed (TIB): 10 hrs], followed by 5 nights of sleep restriction (TIB: 5 hrs), and 3 nights of recovery sleep (TIB: 8 hrs) in a sleep laboratory. Caffeine (200 mg) or placebo was administered in the form of chewing gum at 0800 and 1200 hrs each day during the sleep restriction phase. Participants completed hourly 10-min psychomotor vigilance tests (PVTs) and a modified Maintenance of Wakefulness Test approximately every 4 hours during the sleep restriction and recovery phases. Caffeine maintained objective alertness compared to placebo across the first three days of sleep restriction, but this effect was no longer evident by the fourth day. A similar pattern of results was found for MWT sleep latencies, such that those in the caffeine ...
Existing mathematical models for predicting neurobehavioural performance are not suited for mobil... more Existing mathematical models for predicting neurobehavioural performance are not suited for mobile computing platforms because they cannot adapt model parameters automatically in real time to reflect individual differences in the effects of sleep loss. We used an extended Kalman filter to develop a computationally efficient algorithm that continually adapts the parameters of the recently developed Unified Model of Performance (UMP) to an individual. The algorithm accomplishes this in real time as new performance data for the individual become available. We assessed the algorithm's performance by simulating real-time model individualization for 18 subjects subjected to 64 h of total sleep deprivation (TSD) and 7 days of chronic sleep restriction (CSR) with 3 h of time in bed per night, using psychomotor vigilance task (PVT) data collected every 2 h during wakefulness. This UMP individualization process produced parameter estimates that progressively approached the solution produc...
Computational tools that predict the effects of daily sleep/wake amounts on neurobehavioral perfo... more Computational tools that predict the effects of daily sleep/wake amounts on neurobehavioral performance are critical components of fatigue management systems, allowing for the identification of periods during which individuals are at increased risk for performance errors. However, none of the existing computational tools is publicly available, and the commercially available tools do not account for the beneficial effects of caffeine on performance, limiting their practical utility. Here, we introduce 2B-Alert Web, an open-access tool for predicting neurobehavioral performance, which accounts for the effects of sleep/wake schedules, time of day, and caffeine consumption, while incorporating the latest scientific findings in sleep restriction, sleep extension, and recovery sleep. We combined our validated Unified Model of Performance and our validated caffeine model to form a single, integrated modeling framework instantiated as a Web-enabled tool. 2B-Alert Web allows users to input d...
Existing mathematical models of neurobehavioral performance cannot predict the beneficial effects... more Existing mathematical models of neurobehavioral performance cannot predict the beneficial effects of caffeine across the spectrum of sleep loss conditions, limiting their practical utility. Here, we closed this research gap by integrating a model of caffeine effects with the recently validated Unified Model of Performance (UMP) into a single, unified modeling framework. We then assessed the accuracy of this new UMP in predicting performance across multiple studies. We hypothesized that the pharmacodynamics of caffeine vary similarly during both wakefulness and sleep, and that caffeine has a multiplicative effect on performance. Accordingly, to represent the effects of caffeine in the UMP, we multiplied a dose-dependent caffeine factor (which accounts for the pharmacokinetics and pharmacodynamics of caffeine) to the performance estimated in the absence of caffeine. We assessed the UMP predictions in 14 distinct laboratory- and field-study conditions, including 7 different sleep-loss ...
Aviation Space and Environmental Medicine, May 1, 2007
Biomedical devices allow investigators to collect long-term repeated measures data to study adapt... more Biomedical devices allow investigators to collect long-term repeated measures data to study adaptation. We examined 26 d of actigraph sleep data and tested for individual differences in sleep patterns prior to, during, and after a transition of sleeping in garrison to sleeping in a field exercise setting. In addition, we examined whether the individual difference variable of participant age (a continuous variable ranging from 19-29 yr) was related to sleep patterns. Actigraph data was obtained from 77 cadets participating in a month-long military training program. At day 17, participants transitioned from sleeping in garrison to sleeping in a field exercise setting. A discontinuous growth model tested for individual differences in 1) overall sleep time, 2) garrison sleep slope, 3) the transition, and 4) the sleep slope during the field exercise setting. Individuals varied significantly in their overall sleep time, pattern of sleep in garrison, and the degree to which sleep decreased at the transition. The decline in sleep at the transition was related to participant age such that increases in age were associated with larger declines in sleep minutes. Individuals display significant variability in sleep patterns that can be detected using discontinuous growth models. The individual difference variable of participant age explains some of this variability. Much of the variability, however, remains unexplained. Future work will benefit from using discontinuous growth models to identify and model individual difference variables such as age when examining response patterns and transitions in data collected in applied field settings.
Http Dx Doi Org 10 2466 29 22 25 Pms 116 1 280 293, May 10, 2013
Naps are an effective strategy for maintaining alertness and cognitive performance; however, upon... more Naps are an effective strategy for maintaining alertness and cognitive performance; however, upon abrupt wakening from naps, sleep inertia (temporary performance degradation) may ensue. In the present study, attenuation of post-nap sleep inertia was attempted by administration of caffeine gum. Using a double-blind, placebo-controlled crossover design, 15 healthy, non-smoking adults were awakened at 1 hr. and again at 6 hr. after lights out (0100 and 0600, respectively) and were immediately administered a gum pellet containing 100 mg of caffeine or placebo. A 5-min. psychomotor vigilance task was administered at 0 min., 6 min., 12 min., and 18 min. post-awakening. At 0100, response speed with caffeine was significantly better at 12 min. and 18 min. post-awakening compared to placebo; at 0600, caffeine's effects were evident at 18 min. post-awakening. Caffeinated gum is a viable means of rapidly attenuating sleep inertia, suggesting that the adenosine receptor system is involved in sleep maintenance. It is well documented that sleep sustains aspects of cognition critical for optimal mental performance (
The study objective was to determine whether sleep extension (a) improves alertness and performan... more The study objective was to determine whether sleep extension (a) improves alertness and performance during subsequent sleep restriction and (b) mediates the rate at which alertness and performance are restored by post- restriction recovery sleep. Twenty-four healthy adult participants (ages 18-39) were randomly assigned to an Extended (10 hours time in bed (TIB)) or Habitual (mean (SD) = 7.09 (0.7))
For those endeavoring to develop better methods of measuring/quantifying sleepiness, the "Holy Gr... more For those endeavoring to develop better methods of measuring/quantifying sleepiness, the "Holy Grail" is a measure that is maximally objective, completely unobtrusive, exquisitely sensitive, and absolutely specific (i.e., varies only as a function of sleepiness). By these criteria, physiological measures (e.g., based on brain activity such as EEG, fMRI, near-infrared spectroscopy, etc.) would appear to hold the most promise. However, from an operational standpoint, the utility of a sleepiness measure is derived not from its ability to sensitively reflect the brain's extant level of sleepiness per se, but from the implications that this level of sleepiness has for the individual's current and near-term ability to safely and efficiently perform operationally relevant tasks. Thus, an ideal operationally-relevant sleepiness measure is one that is unobtrusively embedded in the actual operational task, and allows sleepiness-related performance deficits to be distinguished from performance deficits due to other causes. Toward this end, we have developed a PVT-derived metric that incorporates the entire distribution of responses within a PVT session, and reflects changes in the pattern of performance that can be used to identify and quantify "state instability"-the putative physiological state that specifically underlies sleepiness-induced performance deficits. Citation: Balkin TJ. Behavioral biomarkers of sleepiness.
Stimulants and Sleep Loss-Bonnet et al Disclosure Statement This was not an industry supported st... more Stimulants and Sleep Loss-Bonnet et al Disclosure Statement This was not an industry supported study. Dr. Bonnet has received research support from Neurocrine, Pfizer, and Cephalon; and serves on the board or participates in speaking arrangements supported by the Sleep Medicine Educational Institute, Sanofi-Aventis, and Takeda. Dr. Dinges has received research support from Cephalon, and Mars-Masterfoods, Inc.; is a paid consultant for Pfizer, Takeda, Merck, Aventis, and Sanofi; and has received speaker honoraria from and serves on the advisory board for Cephalon. Dr. Roehrs has participated in speaking engagements supported by Sepracor; and is a consultant for Sepracor and Sanofi. Dr. Rogers has received research support from Cephalon. Drs. Balkin and Wesensten have indicated no financial conflicts of interest.
Introduction Threat-related information is preferentially processed, facilitating quick and effic... more Introduction Threat-related information is preferentially processed, facilitating quick and efficient responses. However, the impact of extended sleep deprivation on perception of and response to threatening information is not well known. Sleep loss may increase amygdalar activity and negative mood, potentially facilitating threat processing. However, it also reduces cognitive function, possibly impairing ability to respond. The present study assessed the extent to which extended sleep deprivation modulates threat processing using a threat expectation paradigm. Methods Twenty-one participants underwent one baseline night of sleep followed by 62hrs total sleep deprivation (TSD) and one recovery night of sleep (12hrs). Threat expectation task performance was assessed at baseline, at multiple time points during TSD, and following recovery sleep. To control for circadian influence, performance at three 1100 sessions (baseline, 52hrs into TSD, and recovery) were compared. The threat expe...
The EEG slow oscillation of < 1 Hertz frequency has been implicated in various sleep functions... more The EEG slow oscillation of < 1 Hertz frequency has been implicated in various sleep functions, sparking a recent interest in slow oscillation enhancement strategies. In a seminal study, Marshall et al. (2006) demonstrated that 25 minutes of a slow oscillatory form of transcranial direct current stimulation (SO-tDCS) during early nocturnal sleep improved subsequent retention of word pairs learned prior to sleep, consistent with a proposed role for the slow oscillation in sleep-related memory consolidation. Another proposed function of the slow oscillation is synaptic downscaling, hypothesized to constitute the physiological basis for satisfying the homeostatic drive for sleep, per the synaptic homeostasis hypothesis of Tononi and Cirelli. We sought to determine if SO-tDCS could enhance the restorative properties of sleep, by enhancing slow oscillation activity, during a restricted sleep opportunity by assessing performance during a subsequent period of sleep deprivation (SD). Twe...
This conference presentation addresses the health aspects of fatigue. The author begins by provid... more This conference presentation addresses the health aspects of fatigue. The author begins by providing an overview of fatigue and sleepiness and the current model of sleep. He then describes chronic sleep restriction and performance, sleep extension effects, and the implications for sleep models. He concludes by discussing sleep and physiology and health.
The 2014 Behavioral Health and Performance (BHP) Standing Review Panel (from here on referred to ... more The 2014 Behavioral Health and Performance (BHP) Standing Review Panel (from here on referred to as the SRP) met for a site visit in Houston, TX on December 17 18, 2014. The SRP reviewed the updated research plan for the Risk of Performance Errors Due to Fatigue Resulting from Sleep Loss, Circadian Desynchronization, Extended Wakefulness, and Work Overload (Sleep Risk) and also received a status update on the Risk of Adverse Behavioral Conditions and Psychiatric Disorders (BMed Risk) and the Risk of Performance Decrements Due to Inadequate Cooperation, Coordination, Communication, and Psychosocial Adaptation within a Team (Team Risk).
: In this work, we present a method for developing individualized biomathematical models for pred... more : In this work, we present a method for developing individualized biomathematical models for predicting cognitive performance impairment of individuals subjected to total sleep loss. The proposed method uses the two-process model of sleep regulation as the underlying parametric model, whose parameters are systematically customized for an individual by optimally combining the performance information obtained from the individual's performance measurements with a priori performance information using a Bayesian framework. As a result, the models incrementally account for an individual's uncertain initial state and unknown trait characteristics as each new performance measurement from the individual becomes available, yielding improved performance predictions. Additionally, the proposed method enables the analytical computation of statistically based measures of reliability of the model predictions in the form of prediction intervals. Results using data from subjects who particip...
Knowing how an individual responds to sleep deprivation is a requirement for developing personali... more Knowing how an individual responds to sleep deprivation is a requirement for developing personalized fatigue management strategies. Here we describe and validate the 2B-Alert App, the first mobile application that progressively learns an individual's trait-like response to sleep deprivation in real time, to generate increasingly more accurate individualized predictions of alertness. We incorporated a Bayesian learning algorithm within the validated Unified Model of Performance to automatically and gradually adapt the model parameters to an individual after each psychomotor vigilance test. We implemented the resulting model and the psychomotor vigilance test as a smartphone application (2B-Alert App), and prospectively validated its performance in a 62-hr total sleep deprivation study in which 21 participants used the app to perform psychomotor vigilance tests every 3 hr and obtain real-time individualized predictions after each test. The temporal profiles of reaction times on th...
If protein synthesis during sleep is required for sleep-dependent memory consolidation, we might ... more If protein synthesis during sleep is required for sleep-dependent memory consolidation, we might expect rates of cerebral protein synthesis (rCPS) to increase during sleep in the local brain circuits that support performance on a particular task following training on that task. To measure circuit-specific brain protein synthesis during a daytime nap opportunity, we used the L-[1-(11)C]leucine positron emission tomography (PET) method with simultaneous polysomnography. We trained subjects on the visual texture discrimination task (TDT). This was followed by a nap opportunity during the PET scan, and we retested them later in the day after the scan. The TDT is considered retinotopically specific, so we hypothesized that higher rCPS in primary visual cortex would be observed in the trained hemisphere compared to the untrained hemisphere in subjects who were randomized to a sleep condition. Our results indicate that the changes in rCPS in primary visual cortex depended on whether subjec...
To investigate the effects of caffeine on psychomotor vigilance and sleepiness during sleep restr... more To investigate the effects of caffeine on psychomotor vigilance and sleepiness during sleep restriction and following subsequent recovery sleep. Participants were N=48 healthy good sleepers. All participants underwent 5 nights of sleep satiation [time-in-bed (TIB): 10 hrs], followed by 5 nights of sleep restriction (TIB: 5 hrs), and 3 nights of recovery sleep (TIB: 8 hrs) in a sleep laboratory. Caffeine (200 mg) or placebo was administered in the form of chewing gum at 0800 and 1200 hrs each day during the sleep restriction phase. Participants completed hourly 10-min psychomotor vigilance tests (PVTs) and a modified Maintenance of Wakefulness Test approximately every 4 hours during the sleep restriction and recovery phases. Caffeine maintained objective alertness compared to placebo across the first three days of sleep restriction, but this effect was no longer evident by the fourth day. A similar pattern of results was found for MWT sleep latencies, such that those in the caffeine ...
Existing mathematical models for predicting neurobehavioural performance are not suited for mobil... more Existing mathematical models for predicting neurobehavioural performance are not suited for mobile computing platforms because they cannot adapt model parameters automatically in real time to reflect individual differences in the effects of sleep loss. We used an extended Kalman filter to develop a computationally efficient algorithm that continually adapts the parameters of the recently developed Unified Model of Performance (UMP) to an individual. The algorithm accomplishes this in real time as new performance data for the individual become available. We assessed the algorithm's performance by simulating real-time model individualization for 18 subjects subjected to 64 h of total sleep deprivation (TSD) and 7 days of chronic sleep restriction (CSR) with 3 h of time in bed per night, using psychomotor vigilance task (PVT) data collected every 2 h during wakefulness. This UMP individualization process produced parameter estimates that progressively approached the solution produc...
Computational tools that predict the effects of daily sleep/wake amounts on neurobehavioral perfo... more Computational tools that predict the effects of daily sleep/wake amounts on neurobehavioral performance are critical components of fatigue management systems, allowing for the identification of periods during which individuals are at increased risk for performance errors. However, none of the existing computational tools is publicly available, and the commercially available tools do not account for the beneficial effects of caffeine on performance, limiting their practical utility. Here, we introduce 2B-Alert Web, an open-access tool for predicting neurobehavioral performance, which accounts for the effects of sleep/wake schedules, time of day, and caffeine consumption, while incorporating the latest scientific findings in sleep restriction, sleep extension, and recovery sleep. We combined our validated Unified Model of Performance and our validated caffeine model to form a single, integrated modeling framework instantiated as a Web-enabled tool. 2B-Alert Web allows users to input d...
Existing mathematical models of neurobehavioral performance cannot predict the beneficial effects... more Existing mathematical models of neurobehavioral performance cannot predict the beneficial effects of caffeine across the spectrum of sleep loss conditions, limiting their practical utility. Here, we closed this research gap by integrating a model of caffeine effects with the recently validated Unified Model of Performance (UMP) into a single, unified modeling framework. We then assessed the accuracy of this new UMP in predicting performance across multiple studies. We hypothesized that the pharmacodynamics of caffeine vary similarly during both wakefulness and sleep, and that caffeine has a multiplicative effect on performance. Accordingly, to represent the effects of caffeine in the UMP, we multiplied a dose-dependent caffeine factor (which accounts for the pharmacokinetics and pharmacodynamics of caffeine) to the performance estimated in the absence of caffeine. We assessed the UMP predictions in 14 distinct laboratory- and field-study conditions, including 7 different sleep-loss ...
Aviation Space and Environmental Medicine, May 1, 2007
Biomedical devices allow investigators to collect long-term repeated measures data to study adapt... more Biomedical devices allow investigators to collect long-term repeated measures data to study adaptation. We examined 26 d of actigraph sleep data and tested for individual differences in sleep patterns prior to, during, and after a transition of sleeping in garrison to sleeping in a field exercise setting. In addition, we examined whether the individual difference variable of participant age (a continuous variable ranging from 19-29 yr) was related to sleep patterns. Actigraph data was obtained from 77 cadets participating in a month-long military training program. At day 17, participants transitioned from sleeping in garrison to sleeping in a field exercise setting. A discontinuous growth model tested for individual differences in 1) overall sleep time, 2) garrison sleep slope, 3) the transition, and 4) the sleep slope during the field exercise setting. Individuals varied significantly in their overall sleep time, pattern of sleep in garrison, and the degree to which sleep decreased at the transition. The decline in sleep at the transition was related to participant age such that increases in age were associated with larger declines in sleep minutes. Individuals display significant variability in sleep patterns that can be detected using discontinuous growth models. The individual difference variable of participant age explains some of this variability. Much of the variability, however, remains unexplained. Future work will benefit from using discontinuous growth models to identify and model individual difference variables such as age when examining response patterns and transitions in data collected in applied field settings.
Http Dx Doi Org 10 2466 29 22 25 Pms 116 1 280 293, May 10, 2013
Naps are an effective strategy for maintaining alertness and cognitive performance; however, upon... more Naps are an effective strategy for maintaining alertness and cognitive performance; however, upon abrupt wakening from naps, sleep inertia (temporary performance degradation) may ensue. In the present study, attenuation of post-nap sleep inertia was attempted by administration of caffeine gum. Using a double-blind, placebo-controlled crossover design, 15 healthy, non-smoking adults were awakened at 1 hr. and again at 6 hr. after lights out (0100 and 0600, respectively) and were immediately administered a gum pellet containing 100 mg of caffeine or placebo. A 5-min. psychomotor vigilance task was administered at 0 min., 6 min., 12 min., and 18 min. post-awakening. At 0100, response speed with caffeine was significantly better at 12 min. and 18 min. post-awakening compared to placebo; at 0600, caffeine's effects were evident at 18 min. post-awakening. Caffeinated gum is a viable means of rapidly attenuating sleep inertia, suggesting that the adenosine receptor system is involved in sleep maintenance. It is well documented that sleep sustains aspects of cognition critical for optimal mental performance (
The study objective was to determine whether sleep extension (a) improves alertness and performan... more The study objective was to determine whether sleep extension (a) improves alertness and performance during subsequent sleep restriction and (b) mediates the rate at which alertness and performance are restored by post- restriction recovery sleep. Twenty-four healthy adult participants (ages 18-39) were randomly assigned to an Extended (10 hours time in bed (TIB)) or Habitual (mean (SD) = 7.09 (0.7))
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