Physiological synchrony in electrodermal activity predicts decreased vigilant attention induced by sleep deprivation

Introduction: When multiple individuals are presented with narrative movie oraudio clips, their electrodermal activity (EDA) and heart rate show significantsimilarities. Higher levels of such inter-subject physiological synchrony are relatedwith higher levels of attention toward the narrative, as for instance expressedby more correctly answered questions about the narrative. We here investigatewhether physiological synchrony in EDA and heart rate during watching ofmovie clips predicts performance on a subsequent vigilant attention task amongparticipants exposed to a night of total sleep deprivation.Methods: We recorded EDA and heart rate of 54 participants during a nightof total sleep deprivation. Every hour from 22:00 to 07:00 participants watcheda 10-min movie clip during which we computed inter-subject physiologicalsynchrony. Afterwards, they answered questions about the movie and performedthe psychomotor vigilance task (PVT) to capture attentional performance.Results: We replicated findings that inter-subject correlations in EDA and heartrate predicted the number of correct answers on questions about the movieclips. Furthermore, we found that inter-subject correlations in EDA, but not inheart rate, predicted PVT performance. Individuals’ mean EDA and heart rate alsopredicted their PVT performance. For EDA, inter-subject correlations explainedmore variance of PVT performance than individuals’ mean EDA.Discussion: Together, these findings confirm the association betweenphysiological synchrony and attention. Physiological synchrony in EDA doesnot only capture the attentional processing during the time that it is determined,but also proves valuable for capturing more general changes in the attentionalstate of monitored individuals.<br/

Understanding the combined effects of sleep deprivation and acute social stress on cognitive performance using a comprehensive approach

Background: Sleep deprivation (SD) and acute social stress are common, often unavoidable, and frequently co-occurring stressors in high-risk professions. Both stressors are known to acutely induce inflammatory responses and an increasing body of literature suggests this may lead to cognitive impairment. This study examined the combined effects of total SD and acute social stress on cognitive performance and took a comprehensive approach to explore their (shared) underlying mechanism leading to cognitive decline. Method: We recorded cognitive performance on a response inhibition task and a multitask and monitored a range of inflammatory, psychophysiological and self-reported markers in 101 participants, both before and after one night of either sleep (control group: N = 48) or SD (N = 53), and both before and after a social stressor (Trier Social Stress Test). Results: SD decreased cognitive performance. The social stress test also results in cognitive performance decline in the control group on the response inhibition task, but improved rather than decreased performance of sleep deprived participants on both tasks. The subjective ratings of mental effort also reflect this antagonistic interaction, indicating that the social stressor when sleep-deprived also reduced mental effort. In the inflammatory and physiological measures, this pattern was only reflected by IL-22 in blood. SD reduced blood IL-22 concentrations, and the social stress reduced IL-22 in the control group as well, but not in sleep-deprived participants. There were no interactive effects of SD and social stress on any other inflammatory or psychophysiological measures. The effects of the social stress test on autonomic measures and subjective results suggest that increased arousal may have benefited sleep-deprived participants’ cognitive performance. Discussion: SD generally decreased cognitive performance and increased required mental effort. By contrast, the isolated effects of a social stressor were not generic, showing a positive effect on cognitive performance when sleep deprived. Our study is the first that studied combined effects of sleep deprivation and acute social stress on cognitive performance and inflammatory markers. It provides a comprehensive overview of effects of these stressors on a range of variables. We did not show unequivocal evidence of an underlying physiological mechanism explaining changes in performance due to (the combination of) sleep deprivation and social stress, but consider IL-22 as a possible cytokine involved in this mechanism and certainly worth following up on in future research.</p

Understanding the effects of sleep deprivation and acute social stress on cognitive performance using a comprehensive approach

Different professionals (e.g. in the military) have to perform cognitive challenging tasks in multi-stressor environments. However, our understanding how combined stressors interact and affect cognitive performance is limited (Van Dongen &amp; Belenky, 2009). This study examined how sleep deprivation (SD) and acute social stress affect cognitive performance in isolation and in combination, and used a comprehensive approach to find evidence for a (shared) mechanism. Recent research suggests that SD leads to higher amounts of proinflammatory markers (i.e. cytokines) in the blood, which assumedly contribute to a decline in cognitive performance (Irwin, 2019; Shields et al., 2017). In addition, acute social stressors have also been shown to elicit an immune response, as reflected by circulating cytokines in blood (Marsland et al., 2017; Prather et al., 2014). These findings suggest that different stressors may affect cognitive performance through an effect on the immune system. We therefore hypothesize that individuals showing a high proinflammatory response to a combination of two stressors (SD and acute social stress) are more vulnerable to cognitive decline compared to individuals showing a lower proinflammatory response. To test this hypothesis, we measured not only cognitive performance, but also the physiological response and biochemical determinants of metabolism and inflammation at baseline and after SD, but also in response to an acute social stressor (Tkacheenko &amp; Dinges, 2018)

Effects of heat load and hypobaric hypoxia on cognitive performance:a combined stressor approach

This study investigates how cognitive performance is affected by the combination of two stressors that are operationally relevant for helicopter pilots: heat load and hypobaric hypoxia. Fifteen participants were exposed to (1) no stressors, (2) heat load, (3) hypobaric hypoxia, and (4) combined heat load and hypobaric hypoxia. Hypobaric hypoxia (13,000 ft) was achieved in a hypobaric chamber. Heat load was induced by increasing ambient temperature to ∼28 °C. Cognitive performance was measured using two multitasks, and a vigilance task. Subjective and physiological data (oxygen saturation, heart rate, core- and skin temperature) were also collected. Mainly heat load caused cognitive performance decline. This can be explained by high subjective heat load and increased skin temperature, which takes away cognitive resources from the tasks. Only the arithmetic subtask was sensitive to hypobaric hypoxia, whereby hypobaric hypoxia caused a further performance decline in addition to the decline caused by heat load. Practitioner summary: Little is known about how multiple environmental stressors interact. This study investigates the combined effects of heat load and hypobaric hypoxia on cognitive performance. An additive effect of heat load and hypobaric hypoxia was found on a arithmetic task, which may be attributed to independent underlying mechanisms.</p

Cognitive task performance under (combined) conditions of a metabolic and sensory stressor

Effects of stressors on cognitive task performance have primarily been studied in isolation, and little is known about the combined effects of two or more stressors. This study examined how a metabolic stressor (skipping breakfast) and a sensory stressor (noise) affect cognitive task performance in isolation and combined. In addition to performance, we collected physiological and subjective data to get insight in the underlying mechanisms. Twenty participants came to the lab twice, once after skipping breakfast, and once after a standardized breakfast. They performed runs of the 2-back task and the International Shopping List Task, which were alternately presented with and without noise. During the 2-back task, electrocardiography (ECG), electrodermal activity (EDA), and electroencephalography (EEG) were recorded. Subjective ratings on effort and stress were also collected. No interaction effects between the two stressors on cognitive performance were found. Skipping breakfast did not cause hypoglycemia, but resulted in subjective discomfort and a lower state of arousal (as indicated by lower heart rate and EDA). These may underly the trend for more missed responses on the 2-back task after breakfast skipping. Noise appeared to generate arousal and increased attention (reflected in higher EDA and P300) in accordance with higher experienced load and stress. This is consistent with less missed 2-back responses in noise conditions. The results indicate that individuals spent extra effort to maintain task performance in the presence of noise. We propose to use a model that, besides additional effort, takes the effect of stressors on performance into account

Effects of modafinil and caffeine on night-time vigilance of air force crewmembers: A randomized controlled trial

BACKGROUND: Fatigue remains an important factor in major aviation accidents. Stimulants may counteract fatigue's adverse effects, with modafinil as a promising alternative to caffeine. However, the effect of a single dose of modafinil after a limited period of sleep deprivation remains unknown. AIMS: This study aims to determine the effect of 200 mg modafinil on vigilance during a limited period of sleep deprivation compared to 300 mg caffeine and placebo. METHODS: Thirty-two volunteers of the Royal Netherlands Air Force (RNLAF) were double-blindly administered modafinil, caffeine, and placebo on three non-consecutive trial days after being awake for median 17 h. Afterwards, subjects completed six series of the Vigilance and Tracking test (VigTrack), psychomotor vigilance task (PVT), and Stanford Sleepiness Scale (SSS), yielding six primary endpoints. RESULTS: This study revealed statistically significant effects of caffeine and modafinil compared with placebo on all endpoints, except for VigTrack mean tracking error. PVT results were less impaired 2 h after administration, followed by VigTrack parameters and SSS scores 2 h thereafter. Compared with caffeine, modafinil significantly improved PVT and SSS scores at 8 h after administration. CONCLUSIONS: The present study demonstrates that 200 mg modafinil and 300 mg caffeine significantly decrease the effects of a limited period of sleep deprivation on vigilance compared with placebo. Although PVT parameters already improved 2 h after administration, the most notable effects occurred 2-4 h later. Modafinil seems to be effective longer than caffeine, which is consistent with its longer half-life

No Effects of Successful Bidirectional SMR Feedback Training on Objective and Subjective Sleep in Healthy Subjects

There is a growing interest in the application of psychophysiological signals in more applied settings. Unidirectional sensory motor rhythm-training (SMR) has demonstrated consistent effects on sleep. In this study the main aim was to analyze to what extent participants could gain voluntary control over sleep-related parameters and secondarily to assess possible influences of this training on sleep metrics. Bidirectional training of SMR as well as heart rate variability (HRV) was used to assess the feasibility of training these parameters as possible brain computer interfaces (BCI) signals, and assess effects normally associated with unidirectional SMR training such as the influence on objective and subjective sleep parameters. Participants (n = 26) received between 11 and 21 training sessions during 7 weeks in which they received feedback on their personalized threshold for either SMR or HRV activity, for both up- and down regulation. During a pre- and post-test a sleep log was kept and participants used a wrist actigraph. Participants were asked to take an afternoon nap on the first day at the testing facility. During napping, sleep spindles were assessed as well as self-reported sleep measures of the nap. Although the training demonstrated successful learning to increase and decrease SMR and HRV activity, no effects were found of bidirectional training on sleep spindles, actigraphy, sleep diaries, and self-reported sleep quality. As such it is concluded that bidirectional SMR and HRV training can be safely used as a BCI and participants were able to improve their control over physiological signals with bidirectional training, whereas the application of bidirectional SMR and HRV training did not lead to significant changes of sleep quality in this healthy population

sj-docx-2-jop-10.1177_02698811221142568 – Supplemental material for Effects of modafinil and caffeine on night-time vigilance of air force crewmembers: A randomized controlled trial

Supplemental material, sj-docx-2-jop-10.1177_02698811221142568 for Effects of modafinil and caffeine on night-time vigilance of air force crewmembers: A randomized controlled trial by Yara Q. Wingelaar-Jagt, Charelle Bottenheft, Wim J. Riedel and Johannes G. Ramaekers in Journal of Psychopharmacology</p

sj-doc-1-jop-10.1177_02698811221142568 – Supplemental material for Effects of modafinil and caffeine on night-time vigilance of air force crewmembers: A randomized controlled trial

Supplemental material, sj-doc-1-jop-10.1177_02698811221142568 for Effects of modafinil and caffeine on night-time vigilance of air force crewmembers: A randomized controlled trial by Yara Q. Wingelaar-Jagt, Charelle Bottenheft, Wim J. Riedel and Johannes G. Ramaekers in Journal of Psychopharmacology</p

No Effects of Successful Bidirectional SMR Feedback Training on Objective and Subjective Sleep in Healthy Subjects

There is a growing interest in the application of psychophysiological signals in more applied settings. Unidirectional sensory motor rhythm-training (SMR) has demonstrated consistent effects on sleep. In this study the main aim was to analyze to what extent participants could gain voluntary control over sleep-related parameters and secondarily to assess possible influences of this training on sleep metrics. Bidirectional training of SMR as well as heart rate variability (HRV) was used to assess the feasibility of training these parameters as possible brain computer interfaces (BCI) signals, and assess effects normally associated with unidirectional SMR training such as the influence on objective and subjective sleep parameters. Participants (n = 26) received between 11 and 21 training sessions during 7 weeks in which they received feedback on their personalized threshold for either SMR or HRV activity, for both up- and down regulation. During a pre- and post-test a sleep log was kept and participants used a wrist actigraph. Participants were asked to take an afternoon nap on the first day at the testing facility. During napping, sleep spindles were assessed as well as self-reported sleep measures of the nap. Although the training demonstrated successful learning to increase and decrease SMR and HRV activity, no effects were found of bidirectional training on sleep spindles, actigraphy, sleep diaries, and self-reported sleep quality. As such it is concluded that bidirectional SMR and HRV training can be safely used as a BCI and participants were able to improve their control over physiological signals with bidirectional training, whereas the application of bidirectional SMR and HRV training did not lead to significant changes of sleep quality in this healthy population