| 1. |
- Arshamian, Artin, et al.
(författare)
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Human sickness detection is not dependent on cultural experience
- 2021
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 288:1954
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Tidskriftsartikel (refereegranskat)abstract
- Animals across phyla can detect early cues of infection in conspecifics, thereby reducing the risk of contamination. It is unknown, however, if humans can detect cues of sickness in people belonging to communities with whom they have limited or no experience. To test this, we presented Western faces photographed 2 h after the experimental induction of an acute immune response to one Western and five non-Western communities, including small-scale hunter-gatherer and large urban-dwelling communities. All communities could detect sick individuals. There were group differences in performance but Western participants, who observed faces from their own community, were not systematically better than all non-Western participants. At odds with the common belief that sickness detection of an out-group member should be biased to err on the side of caution, the majority of non-Western communities were unbiased. Our results show that subtle cues of a general immune response are recognized across cultures and may aid in detecting infectious threats.
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| 2. |
- Axelsson, John, et al.
(författare)
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Beauty sleep : experimental study on the perceived health and attractiveness of sleep deprived people
- 2010
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Ingår i: The BMJ. - : BMJ. - 1756-1833. ; 341
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Tidskriftsartikel (refereegranskat)abstract
- Our findings show that sleep deprived people appear less healthy, less attractive, and more tired compared with when they are well rested. This suggests that humans are sensitive to sleep related facial cues, with potential implications for social and clinical judgments and behaviour. Studies are warranted for understanding how these effects may affect clinical decision making and can add knowledge with direct implications in a medical context.
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| 3. |
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| 4. |
- Axelsson, John, et al.
(författare)
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Identification of acutely sick people and facial cues of sickness
- 2018
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 285:1870
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Tidskriftsartikel (refereegranskat)abstract
- Detection and avoidance of sick individuals have been proposed as essential components in a behavioural defence against disease, limiting the risk of contamination. However, almost no knowledge exists on whether humans can detect sick individuals, and if so by what cues. Here, we demonstrate that untrained people can identify sick individuals above chance level by looking at facial photos taken 2 h after injection with a bacterial stimulus inducing an immune response (2.0 ng kg-1 lipopolysaccharide) or placebo, the global sensitivity index being d' = 0.405. Signal detection analysis (receiver operating characteristic curve area) showed an area of 0.62 (95% confidence intervals 0.60-0.63). Acutely sick people were rated by naive observers as having paler lips and skin, a more swollen face, droopier corners of the mouth, more hanging eyelids, redder eyes, and less glossy and patchy skin, as well as appearing more tired. Our findings suggest that facial cues associated with the skin, mouth and eyes can aid in the detection of acutely sick and potentially contagious people.
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| 5. |
- Axelsson, John, et al.
(författare)
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Sleepiness as motivation : a potential mechanism for how sleep deprivation affects behavior
- 2020
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Ingår i: Sleep. - : Oxford University Press (OUP). - 0161-8105 .- 1550-9109. ; 43:6
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Tidskriftsartikel (refereegranskat)abstract
- STUDY OBJECTIVES: To determine how sleepiness and sleep deprivation drive the motivation to engage in different behaviors.METHODS: We studied the sleepiness of 123 participants who had been randomized to sleep deprivation or normal sleep, and their willingness to engage in a range of everyday behaviors.RESULTS: Self-reported sleepiness was a strong predictor of the motivation to engage in sleep-preparatory behaviors such as shutting one's eyes (OR=2.78, 95%CI: 2.19-3.52 for each step up on the Karolinska Sleepiness Scale) and resting (OR=3.20, CI: 2.46-4.16). Sleepiness was also related to the desire to be cared for by a loved one (OR=1.49, CI: 1.22-1.82), and preparedness to utilize monetary and energy resources to get to sleep. Conversely, increased sleepiness was associated with a decreased motivation for social and physical activities (e.g., be with friends OR=0.71, CI: 0.61-0.82; exercise OR=0.65, CI: 0.56-0.76). Sleep deprivation had similar effects as sleepiness on these behaviors. Neither sleepiness nor sleep deprivation had strong associations with hunger, thirst, or food preferences.CONCLUSIONS: Our findings indicate that sleepiness is a dynamic motivational drive that promotes sleep-preparatory behaviors and competes with other drives and desired outcomes. Consequently, sleepiness may be a central mechanism by which impaired alertness, e.g., due to insufficient sleep, contributes to poor quality of life and adverse health. We propose that sleepiness helps organize behaviors toward the specific goal of assuring sufficient sleep, in competition with other needs and incentives. A theoretical framework on sleepiness and its behavioral consequences are likely to improve our understanding of several disease mechanisms.
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| 6. |
- Balter, Leonie J. T., et al.
(författare)
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Experimental Sleep Deprivation Results in Diminished Perceptual Stability Independently of Psychosis Proneness
- 2022
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Ingår i: Brain Sciences. - : MDPI AG. - 2076-3425. ; 12:10
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Tidskriftsartikel (refereegranskat)abstract
- Psychotic disorders as well as psychosis proneness in the general population have been associated with perceptual instability, suggesting weakened predictive processing. Sleep disturbances play a prominent role in psychosis and schizophrenia, but it is unclear whether perceptual stability diminishes with sleep deprivation, and whether the effects of sleep deprivation differ as a function of psychosis proneness. In the current study, we aimed to clarify this matter. In this preregistered study, 146 participants successfully completed an intermittent version of the random dot kinematogram (RDK) task and the 21-item Peters Delusion Inventory (PDI-21) to assess perceptual stability and psychosis proneness, respectively. Participants were randomized to sleep either as normal (8 to 9 h in bed) (n = 72; Mage = 24.7, SD = 6.2, 41 women) or to stay awake through the night (n = 74; Mage = 24.8, SD = 5.1, 44 women). Sleep deprivation resulted in diminished perceptual stability, as well as in decreases in perceptual stability over the course of the task. However, we did not observe any association between perceptual stability and PDI-21 scores, nor a tendency for individuals with higher PDI-21 scores to be more vulnerable to sleep-deprivation-induced decreases in perceptual stability. The present study suggests a compromised predictive processing system in the brain after sleep deprivation, but variation in psychosis trait is not related to greater vulnerability to sleep deprivation in our dataset. Further studies in risk groups and patients with psychosis are needed to evaluate whether sleep loss plays a role in the occurrence of objectively measured perceptual-related clinical symptoms.
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| 7. |
- Balter, Leonie J. T., et al.
(författare)
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Intelligence predicts better cognitive performance after normal sleep but larger vulnerability to sleep deprivation
- 2023
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Ingår i: Journal of Sleep Research. - : John Wiley & Sons. - 0962-1105 .- 1365-2869. ; 32:4
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Tidskriftsartikel (refereegranskat)abstract
- Fluid intelligence is seen as a beneficial attribute, protecting against stress and ill-health. Whether intelligence provides resilience to the cognitive effects of insufficient sleep was tested in the current pre-registered experimental study. Participants (N = 182) completed the Raven's test (measuring fluid intelligence) and a normal night of sleep or a night of total sleep deprivation. Sleepiness and four cognitive tests were completed at 22:30 hours (baseline), and the following day after sleep manipulation. At baseline, higher fluid intelligence was associated with faster and more accurate arithmetic calculations, and better episodic memory, but not with spatial working memory, simple attention or sleepiness. Those with higher fluid intelligence were more, not less, impacted by sleep deprivation, evident for arithmetic ability, episodic memory and spatial working memory. We need to establish a more nuanced picture of the benefits of intelligence, where intelligence is not related to cognitive advantages in all situations.
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| 8. |
- Balter, Leonie J. T., et al.
(författare)
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Sickness and sleep health predict frustration and affective responses to a frustrating trigger
- 2021
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1, s. 1542-
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Tidskriftsartikel (refereegranskat)abstract
- Fluctuations in health and sleep are common, but we know surprisingly little about how these daily life stressors affect one's level of frustration and sensitivity to becoming frustrated. In this pre-registered study, 517 participants (Mage = 30.4, SD = 10.4) reported their current sickness symptoms, health status, sleepiness, and sleep duration and quality the previous night. They also rated their general frustration and mood before and after a mild frustration-eliciting task. In the task, participants were instructed to copy geometric shapes onto a piece of paper, without lifting the pen from the paper. Participants were given three minutes to copy the eight shapes, but in order to induce frustration half of them were unsolvable. The study was subsequently repeated in an independent sample (N = 113). Frustration increased in response to the task; however, those with the worst sickness symptoms or sleep health reduced or did not change their frustration levels. Instead, across both studies, frustration was already high at baseline for these individuals. These findings indicate that being sick or having poor sleep is related to high general frustration, but resilience to further frustration due to mild frustrating situations.
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| 9. |
- Esfahani, Mahdad Jafarzadeh, et al.
(författare)
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Validation of the sleep EEG headband ZMax
- 2023
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Ingår i: bioRxiv. - : Cold Spring Harbor Laboratory Press (CSHL). - 2692-8205.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Polysomnography (PSG) is the gold standard for recording sleep. However, the standard PSG systems are bulky, expensive, and often confined to lab environments. These systems are also time-consuming in electrode placement and sleep scoring. Such limitations render standard PSG systems less suitable for large-scale or longitudinal studies of sleep. Recent advances in electronics and artificial intelligence enabled ‘wearable’ PSG systems. Here, we present a study aimed at validating the performance of ZMax, a widely-used wearable PSG that includes frontal electroencephalography (EEG) and actigraphy but no submental electromyography (EMG). We analyzed 135 nights with simultaneous ZMax and standard PSG recordings amounting to over 900 hours from four different datasets, and evaluated the performance of the headband’s proprietary automatic sleep scoring (ZLab) alongside our open-source algorithm (DreamentoScorer) in comparison with human sleep scoring. ZLab and DreamentoScorer compared to human scorers with moderate and substantial agreement and Cohen’s kappa scores of 59.61% and 72.18%, respectively. We further analyzed the competence of these algorithms in determining sleep assessment metrics, as well as shedding more lights on the bandpower computation, and morphological analysis of sleep microstructural features between ZMax and standard PSG. Relative bandpower computed by ZMax implied an error of 5.5% (delta), 4.5% (theta), 1.6% (alpha), 0.5% (sigma), 0.8% (beta), and 0.2% (gamma), compared to standard PSG. In addition, the microstructural features detected in ZMax did not represent exactly the same characteristics as in standard PSG. Besides similarities and discrepancies between ZMax and standard PSG, we measured and discussed the technology acceptance rate, feasibility of data collection with ZMax, and highlighted essential factors for utilizing ZMax as a reliable tool for both monitoring and modulating sleep.
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| 10. |
- Floros, Orestis, et al.
(författare)
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Vulnerability in Executive Functions to Sleep Deprivation Is Predicted by Subclinical Attention-Deficit/Hyperactivity Disorder Symptoms
- 2021
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Ingår i: Biological Psychiatry. - : Elsevier. - 2451-9022 .- 2451-9030. ; 6:3, s. 290-298
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Tidskriftsartikel (refereegranskat)abstract
- Background: Sleep loss results in state instability of cognitive functioning. It is not known whether this effect is more expressed when there is an increased cognitive demand. Moreover, while vulnerability to sleep loss varies substantially among individuals, it is not known why some people are more affected than others. We hypothesized that top-down regulation was specifically affected by sleep loss and that subclinical inattention and emotional instability traits, related to attention-deficit/hyperactivity disorder symptoms, predict this vulnerability in executive function and emotion regulation, respectively.Methods: Healthy subjects (ages 17–45 years) rated trait inattention and emotional instability before being randomized to either a night of normal sleep (n = 86) or total sleep deprivation (n = 87). Thereafter, they performed a neutral and emotional computerized Stroop task, involving words and faces. Performance was characterized primarily by cognitive conflict reaction time and reaction time variability (RTV), mirroring conflict cost in top-down regulation.Results: Sleep loss led to increased cognitive conflict RTV. Moreover, a higher level of inattention predicted increased cognitive conflict RTV in the neutral Stroop task after sleep deprivation (r = .30, p = .0055) but not after normal sleep (r = .055, p = .65; interaction effect β = 6.19, p = .065). This association remained after controlling for cognitive conflict reaction time and emotional instability, suggesting domain specificity. Correspondingly, emotional instability predicted cognitive conflict RTV for the emotional Stroop task only after sleep deprivation, although this effect was nonsignificant after correcting for multiple comparisons.Conclusions: Our findings suggest that sleep deprivation affects cognitive conflict variability and that less stable performance in executive functioning may surface after sleep loss in vulnerable individuals characterized by subclinical symptoms of inattention.
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