Ross Pigeau

Modafinil, d‐amphetamine and placebo during 64 hours of sustained mental work. I. Effects on mood, fatigue, cognitive performance and body temperature

SUMMARY  Modafinil is an alerting substance that is considered safer than amphetamine with fewer side effects. Although modafinil has been used successfully to treat narcolepsy, relatively little is known about its ability to ameliorate fatigue and declines in mental performance due to sleep deprivation (SD) in a normal population. Forty‐one military subjects received either 300 mg of modafinil, 20 mg of d‐amphetamine, or placebo on 3 separate occasions during 64 hours of continuous cognitive work and sleep loss. Three drug treatments were given: at 23.30 hours and 05.30 hours during the first and second SD nights, respectively, and once at 15.30 hours during the third day of continuous work. Subjective estimates of mood, fatigue and sleepiness, as well as objective measures of reaction time, logical reasoning and short‐term memory clearly showed better performance with both modafinil and amphetamine relative to placebo. Both modafinil and amphetamine maintained or increased body temperature compared to the natural circadian cycle observed in the placebo group. Also, from subject debriefs at the end of the study, modafinil elicited fewer side‐effects than amphetamine, although more than the placebo group. Modafinil appears to be a good alternative to amphetamine for counteracting the debilitating mood and cognitive effects of sleep loss during sustained operations.

Self-monitoring cognitive performance during sleep deprivation: effects of modafinil, d-amphetamine and placebo

Self‐monitoring refers to the ability to assess accurately ones own performance in a specific environment. The present study investigated the effects of the stimulating drugs modafinil (300 mg) and d‐amphetamine (20 mg) on the ability to self‐monitor cognitive performance during 64 h of sleep deprivation (SD) and sustained mental work. Two cognitive tasks were investigated: a visual (perceptual) judgment task and a complex mental addition task. Subjects in the placebo condition displayed marked circadian and SD effects on cognitive task performance but their self‐monitoring was substantively undisturbed by SD. Subjects performing under the influence of d‐amphetamine likewise displayed highly proficient self‐monitoring throughout the SD period. In contrast, modafinil had a disruptive effect on self‐monitoring, inducing a reliable «overconfidence» effect (i.e. an overestimation of actual cognitive performance), which was particularly marked 2–4 h post‐dose. Although modafinil has proven to be a safe and effective countermeasure to the effects of extensive SD on cognitive task performance, we encourage a more comprehensive understanding of the relation between its subjective and performance enhancing effects before the drug is recommended as a viable fatigue countermeasure.

Redefining Command and Control

Human creativity, initiative, resolve, problem solving, leadership, and trust play crucial roles in military operations. For command and control (C2) to be effective in the full range of missions that modern militaries encounter, it is essential that it be human-centred. We have previously argued that C2’s human component has been chronically under-emphasized and under-researched (Pigeau & McCann, 1995). The military has gotten swept away all too easily by the allure of technology (for example, battlefield digitization): as a result, C2has become obscured in conceptualizations of rigid structure and process. We have also argued that existing definitions of command and control have provided little guidance either to the military or to industry for allocating the scarce resources necessary for supporting command (Pigeau & McCann, 1995). To redress this problem, McCann and Pigeau (1996) offered a new definition of C2, one that “emphasizes the critical role of Command [that is, human will] while acknowledging the necessary contribution of Control [that is, technology]” (p. 533). In this chapter, we will explore this new definition’s implications, and we will demonstrate its explanatory power for elucidating C2organizational structures and leadership.

On the ability to self-monitor cognitive performance during sleep deprivation: a calibration study

SUMMARY  The antagonistic effects of extensive sleep deprivation (SD) on human cognitive performance are well documented. However, one aspect of human performance that has not been investigated with respect to its susceptibility to SD is the ‘metacognitive’ ability to self‐monitor overt performance. In the present study, 16 male subjects participated in an experiment requiring sustained cognitive work during a three day period. One of the cognitive tasks required the mental addition of rapidly presented numbers. On each trial, subjects reported the sum and then provided a subjective confidence rating to indicate the degree of certainty in their response. As expected, performance on the sequential addition task deteriorated with increasing fatigue and returned to baseline following a recovery sleep. However, calibration analyses, which quantify a number of properties of the relationship between subjective and overt performance, revealed that the correlation between confidence and performance (calibration), the ability to differentiate correct from incorrect judgments (resolution), and validity of subjective ‘certainty’, were all unaffected by SD. Hence, in the absence of external feedback from the environment, people have access to fairly reliable internal feedback about their performance during periods of sustained and vigilant cognitive activity.

Effects of Sleep Loss on Team Decision Making: Motivational Loss or Motivational Gain?:

Objective: To examine the effects of 30 hr of sleep loss and continuous cognitive work on performance in a distributed team decision-making environment. Background: To date, only a few studies have examined the effect of sleep loss on distributed team performance, and only one other to our knowledge has examined the relationship between sleep loss and social-motivational aspects of teams (Hoeksema-van Orden, Gaillard, & Buunk, 1998). Method: Sixteen teams participated; each comprised 4 members. Three team members made threat assessments on a military surveillance task and then forwarded their judgments electronically to a team leader, who made a final assessment on behalf of the team. Results: Sleep loss had an antagonistic effect on team decision-making accuracy and decision time. However, the performance loss associated with fatigue attributable to sleep loss was mediated by being part of a team, as compared with performing the same task individually — that is, we found evidence of a “motivational gain” effect in these sleepy teams. We compare these results with those of Hoeksema-van Orden et al. (1998), who found clear evidence of a “social loafing” effect in sleepy teams. Conclusion: The divergent results are discussed in the context of the collective effort model (Karau & Williams, 1993) and are attributable in part to a difference between independent and interdependent team tasks. Application: The issues and findings have implications for a wide range of distributed, collaborative work environments, such as military network-enabled operations.

Heart rate activation during spontaneous arousals from sleep: effect of sleep deprivation

OBJECTIVE Arousal (AR) from sleep is associated with an autonomic reflex activation raising blood pressure and heart rate (HR). Recent studies indicate that sleep deprivation may affect the autonomic system, contributing to high vascular risk. Since in sleep disorders a sleep fragmentation and a partial sleep deprivation occurs, it could be suggested that the cardiovascular effects observed at AR from sleep might be physiologically affected when associated with sleep deprivation. The aim of the study was to examine the effect of sleep deprivation on cardiac arousal response in healthy subjects. METHODS Seven healthy male subjects participated in a 64 h sleep deprivation protocol. Arousals were classified into four groups, i.e. >3<6 s, >6<10 s, >10<15 s and >15 s, according to their duration. Pre-AR HR values were measured during 10 beats preceding the AR onset, and the event-related HR fluctuations were calculated during the 20 beats following AR onset. As an index of cardiac activation, the ratio of highest HR in the post-AR period over the lowest recorded before AR (HR ratio) was calculated. RESULTS For AR lasting less than 10 s, the occurrence of AR induces typical HR oscillations in a bimodal pattern, tachycardia followed by bradycardia. For AR lasting more than 10 s, i.e. awakenings, the pattern was unimodal with a more marked and sustained HR rise. The HR response was consistently similar across nights, during NREM and REM sleep, without difference between conditions. CONCLUSIONS Overall, total sleep deprivation appeared to have no substantial effect on cardiac response to spontaneous arousals and awakenings from sleep in healthy subjects. Further studies are needed to clarify the role of chronic sleep deprivation on cardiovascular risk in patients with sleep disorders. SIGNIFICANCE In healthy subjects acute prolonged sleep deprivation does not affect the cardiac response to arousal.

The Human in Command

The impetus for this book is simple: to outline, discuss, and emphasize the uniquely human dimension of military command.

Time of night and first night effects on arousal response in healthy adults

OBJECTIVE Several factors, such as homeostatic and circadian influences, may affect the density of cortical and subcortical arousals (AR). The purpose of this study was to examine the time-of-night and the first night effect on AR response. METHODS AR were classified into microarousals (MA), phases of transitory activation (PAT), delta (D-burst) and K-complex burst (K-burst). The AR density and duration was analyzed during two consecutive nights with the analysis of sleep stage and sleep cycle in thirty-six healthy subjects. RESULTS D- and K-burst showed a trend toward progressive decline across sleep cycles (p<0.0001). While MA rate was unaffected throughout sleep cycles, PAT index increased across the night (p=0.002). The density and duration of each group of AR exhibited reproducibility without significant differences between nights. An individual inter-night variability in AR density was found independently of night and sleep structure. CONCLUSIONS While homeostatic and circadian influences affect nighttime subcortical and MA responses, a wakefulness drive modulates the occurrence of AR with movements. Although the pattern of AR responses was highly reliable from the first to second night, the substantial inter-individual variability suggests the existence of an individual susceptibility. SIGNIFICANCE The first night effect on arousal response is affected by individual susceptibility and circadian and homeostatic influences.

Research Challenges for the Human in Command

As the chapters in this book attest, command is a rich and intricate tapestry of concepts, skills, and behaviour, demanding that military personnel of all ranks invent novel solutions to unique problems, often under extremely stressful environmental, physical, and emotional conditions. Time and again, the authors in this book have intimated (and indeed often stated) that the human alone shoulders the responsibility for achieving the mission: it is the commander’s duty to conceive new tactics, to negotiate with belligerents, to manage resources, to monitor morale, to decide, to motivate, to reflect, to act—in short, to creatively express his or her will in the accomplishment of the mission.3 Although technology—the modern siren that promises Western society speeed,efficiency, and force multillication—can certainly facilitate command, technology can also hinder it. Technology can encourage unrealistic expectations, spawn unforeseen consequences, or simply fail to work. Effective command and control (C2) depends on human command, not technological control.

The effects of formal order and spatial content on reasoning in three dimensions

This study investigates the effects of formal order and spatial content on reasoning in three dimensions in view of the Formal Rules theory and the Mental Models theory of spatial reasoning. Twenty-six subjects solved 144 spatial deductive problems that varied by the formal order of the entities (referential order, referential continuity) and the spatial content (dimension, orientation, and direction). There were two dependant variables: the correct responses and their response times. The number of mental models and the formal derivations underlying the deductions allowed comparison of opposite predictions made by the Formal Rules theory and the Mental Models theory of spatial reasoning. The results overwhelmingly supported the Mental Models theorys predictions. The effects of referentialorder showedthatproblems yielding twopossiblemental models were significantly more difficult than problems based on one mental model, although the former problems involved a shorter formal derivation than the latter. The...