| 1. |
- Hansson, Lina S., 1986-, et al.
(författare)
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Pointing out sickness : Detection of sickness from gait patterns
- 2021
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Ingår i: Brain, behavior, and immunity. - : Elsevier BV. - 0889-1591 .- 1090-2139. ; 98, s. 21-21
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background: The ability to detect sick individuals is crucial for survival, by allowing avoidance of contagion. We have shown that humans can detect sick individuals from facial cues and body odors, but perception of these cues requires close proximity to the infectious person. Given that gait patterns can be detected from a distance and are altered during sickness, it would be beneficial to detect sickness from biological motion. Methods: We collected videos and point-light displays of walking individuals who were either made sick experimentally with an injection of lipopolysaccharide, or who were healthy (placebo). In study 1, 106 naive subjects watched these displays and rated them as coming from someone sick or healthy. In study 2, 106 other subjects rated health, sadness and tiredness of the displays on a VAS scale. Results: In Study 1, the sensitivity was 59% for videos and 57% for point-light displays, while the specificity was 74% for videos and 61% for point-light displays. Additional results will be presented at the conference. Conclusion: This study will indicate if sickness can be detected from gait patterns, possibly adding to immune defensive behaviors by facilitating avoidance of contagious peers.
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| 2. |
- Hansson, Lina S., 1986-, et al.
(författare)
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The walking sick : what predicts the detection of walking sick individuals?
- 2022
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Ingår i: Brain, behavior, and immunity. - : Elsevier. - 0889-1591 .- 1090-2139. ; 106, s. 36-36
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Methods: In two studies, raters watched video recordings and point-light displays (i.e. dots depicting the body joints) of walking individuals who were either experimentally sick (after injection with lipopolysaccharide at 2.0 ng/kg bw) or healthy (after a placebo injection). In study 1, 106 raters classified each walking individual as either sick or healthy. In study 2, 106 other raters graded health of the stimuli on a visual analogue scale. We assessed the predicting effect on sickness detection (study 1) and apparent health (study 2) of walking parameters (objective measures of stride length, width, time, as well as knee angle, arm angle, and head angle) and well-known sickness responses (Sickness Questionnaire score, pain intensity, body temperature, and interleukin-6 concentration).Results: In study 1, shorter steps was the only predictor of the detection of sick individuals from video recordings (β=0.712(0.257), p=0.02). In the point-light displays, slower, wider, stiffer and shorter steps, all predicted a better sickness detection (β=0.0003(0.0001)-0.415(0.126), p<0.05).In study 2, lipopolysaccharide-induced slower, shorter and stiffer steps (B=5.214(1.888)-6.385(2.083), p<0.01), as well as higher interleukin-6 concentrations (B=0.051(0.020), p=0.01), predicted worse health ratings of sick individuals in the video recordings. In the point-light displays, lipopolysaccharide-induced slower, shorter and stiffer steps, and more head tilting, predicted worse health ratings of sick individuals (B=4.185(1.892)-6.701(2.092), p<0.05).Conclusions: The results imply that specific changes in walking parameters may aid in sickness detection, possibly regulating approach-avoidance behaviors towards sick peers.
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| 3. |
- Balter, Leonie J. T., et al.
(författare)
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Lipopolysaccharide-induced changes in the kynurenine pathway and symptoms of sickness behavior in humans
- 2023
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Ingår i: Psychoneuroendocrinology. - 0306-4530 .- 1873-3360. ; 153
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Tidskriftsartikel (refereegranskat)abstract
- Metabolites of the kynurenine pathway are hypothesized to be implicated in inflammation-associated depression, but there is a lack of experimental studies in humans assessing the kinetics of kynurenine metabolites in relation to experimentally-induced sickness. The aim of the present study was to assess changes in the kynurenine pathway and to explore its relation to symptoms of sickness behavior during an acute experimental immune challenge.This double-blind placebo-controlled randomized cross-over study included 22 healthy human participants (n = 21 both sessions, Mage = 23.4, SD = 3.6, nine women) who received an intravenous injection of 2.0 ng/kg lipopolysaccharide (LPS) and saline (placebo) on two different occasions in a randomized order. Blood samples (0 h, 1 h, 1.5 h, 2 h, 3 h, 4 h, 5 h, 7 h post-injection) were analyzed for kynurenine metabolites and inflammatory cytokines. The intensity of symptoms of sickness behavior was assessed using the 10-item Sickness Questionnaire at 0 h, 1.5 h, 3 h, 5 h, and 7 h post-injection.LPS induced significantly lower concentrations of plasma tryptophan (at 2 h, 4 h, 5 h, and 7 h post-injection), kynurenine (at 2 h, 3 h, 4 h, and 5 h post-injection), nicotinamide (at 4 h, 5 h, and 7 h post-injection), and higher levels for quinolinic acid at 5 h post-injection as compared to placebo. LPS did not affect kynurenic acid, 3-hydroxykynurenine, and picolinic acid. The development of the sickness symptoms was largely similar across items, with the highest levels around 1.5–3 h post-injection. Changes in plasma levels of kynurenine metabolites seem to coincide rather than precede or follow changes in subjective sickness. Exploratory analyses indicate that higher Sickness Questionnaire total scores at 1.5–5 h post-injection were correlated with lower kynurenic acid and nicotinamide levels.These results lend further support for LPS-induced changes in the kynurenine pathway, but may not, as interpreted from blood levels, causally link to LPS-induced acute symptoms of sickness behavior. Future research may consider a larger sample to further scrutinize the role of the kynurenine pathway in the sickness response.
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| 4. |
- Gordon, Amy R., et al.
(författare)
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Human scent as a first-line defense against disease
- 2023
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Ingår i: Scientific Reports. - 2045-2322. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Individuals may have a different body odor, when they are sick compared to healthy. In the non-human animal literature, olfactory cues have been shown to predict avoidance of sick individuals. We tested whether the mere experimental activation of the innate immune system in healthy human individuals can make an individuals' body odor be perceived as more aversive (intense, unpleasant, and disgusting). Following an endotoxin injection (lipopolysaccharide; 0.6 ng/kg) that creates a transient systemic inflammation, individuals smelled more unpleasant compared to a placebo group (saline injection). Behavioral and chemical analyses of the body odor samples suggest that the volatile components of samples from sick individuals changed qualitatively rather than quantitatively. Our findings support the hypothesis that odor cues of inflammation in axillary sweat are detectable just a few hours after experimental activation of the innate immune system. As such, they may trigger behavioral avoidance, hence constituting a first line of defense against pathogens of infected conspecifics.
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| 5. |
- Juran, Stephanie Anja, et al.
(författare)
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Disgusting odors trigger the oral immune system
- 2023
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Ingår i: Evolution, Medicine, and Public Health. - : Oxford University Press. - 2050-6201. ; 11:1, s. 8-17
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Tidskriftsartikel (refereegranskat)abstract
- Recent research has characterized the behavioral defense against disease. In particular the detection of sickness cues, the adaptive reactions (e.g. avoidance) to these cues and the mediating role of disgust have been the focus. A presumably important but less investigated part of a behavioral defense is the immune system response of the observer of sickness cues. Odors are intimately connected to disease and disgust, and research has shown how olfaction conveys sickness cues in both animals and humans. This study aims to test whether odorous sickness cues (i.e. disgusting odors) can trigger a preparatory immune response in humans. We show that subjective and objective disgust measures, as well as TNFα levels in saliva increased immediately after exposure to disgusting odors in a sample of 36 individuals. Altogether, these results suggest a collaboration between behavioral mechanisms of pathogen avoidance in olfaction, mediated by the emotion of disgust, and mechanisms of pathogen elimination facilitated by inflammatory mediators.Disgusting stimuli are associated with an increased risk of infection. We here test whether disgusting odors, can trigger an immune response in the oral cavity. The results indicate an increase level of TNFα in the saliva. This supports that disease cues can trigger a preparatory response in the oral cavity.
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| 6. |
- Lasselin, Julie, 1986-, et al.
(författare)
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Inflammation-related gait- Analysis of biological motion using the Microsoft® Kinect® during experimentally-induced sickness
- 2017
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Ingår i: Brain, behavior, and immunity. - : Elsevier BV. - 0889-1591 .- 1090-2139. ; 66
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Tidskriftsartikel (refereegranskat)abstract
- Biological motion is a powerful communication cue and we have recently shown that sickness can be detected from gait pattern. However, it is unclear which gait characteristics are modulated by health status and whether change in gait pattern relates to inflammation and to the degree of sickness. The current study aimed at answering these questions by assessing biological motion characteristics in 19 individuals during experimentally-induced sickness, obtained by intravenous injection of lipopolysaccharide (2 ng/kg bw), and after placebo administration. Joint 3-D coordinates were recorded using the Microsoft® Kinect® during a walking paradigm and a mobility test (time-up-and-go test). Results indicate that gait during experimentally-induced sickness is characterized by slower and shorter strides, resulting in slower walking speed, as well as a slower time to stand up from a chair. In addition, sick subjects appear to swing their arms and to lift their legs less than when healthy, as reflected by smaller elbow angle during arm extension and larger knee angle during leg flexion compared to the placebo condition. Alterations in the overall gait pattern during experimentally-induced sickness was associated with interleukin-6 peak concentrations and a trend was observed with sickness symptoms. Altogether, these findings suggest that gait pattern might signal sickness/inflammatory status and could be used as an objective assessment of sickness, as well as to determine evolution of health status in individuals over time.
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| 7. |
- Tognetti, Arnaud, et al.
(författare)
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Discriminating between sick and healthy faces based on early sickness cues : an exploratory analysis of sex differences
- 2023
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Ingår i: Evolution, Medicine, and Public Health. - : Oxford University Press. - 2050-6201. ; 11:1, s. 386-396
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Tidskriftsartikel (refereegranskat)abstract
- Background and objectives: It has been argued that sex and disease-related traits should influence how observers respond to sensory sickness cues. In fact, there is evidence that humans can detect sensory cues related to infection in others, but lack of power from earlier studies prevents any firm conclusion regarding whether perception of sickness cues is associated with sex and disease-related personality traits. Here, we tested whether women (relative to men), individuals with poorer self-reported health, and who are more sensitive to disgust, vulnerable to disease, and concerned about their health, overestimate the presence of, and/or are better at detecting sickness cues.Methodology: In a large online study, 343 women and 340 men were instructed to identify the sick faces from a series of sick and healthy photographs of volunteers with an induced acute experimental inflammation. Participants also completed several disease-related questionnaires.Results: While both men and women could discriminate between sick and healthy individuals above chance level, exploratory analyses revealed that women outperformed men in accuracy and speed of discrimination. Furthermore, we demonstrated that higher disgust sensitivity to body odors is associated with a more liberal decision criterion for categorizing faces as sick.Conclusion: Our findings give strong support for the human ability to discriminate between sick and healthy individuals based on early facial cues of sickness and suggest that women are significantly, although only slightly, better at this task. If this finding is replicated, future studies should determine whether women’s better performance is related to increased avoidance of sick individuals.
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| 8. |
- Tognetti, Arnaud, et al.
(författare)
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Humans can detect axillary odor cues of an acute respiratory infection in others
- 2023
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Ingår i: Evolution medicine and public health. - 2050-6201. ; 11:1, s. 219-228
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Tidskriftsartikel (refereegranskat)abstract
- Background and objectives Body odor conveys information about health status to conspecifics and influences approach-avoidance behaviors in animals. Experiments that induce sickness in otherwise healthy individuals suggest that humans too can detect sensory cues to infection in others. Here, we investigated whether individuals could detect through smell a naturally occurring acute respiratory infection in others and whether sickness severity, measured via body temperature and sickness symptoms, was associated with the accuracy of detection. Methodology Body odor samples were collected from 20 donors, once while healthy and once while sick with an acute respiratory infection. Using a double-blind, two-alternative forced-choice method, 80 raters were instructed to identify the sick body odor from paired sick and healthy samples (i.e. 20 pairs). Results Sickness detection was significantly above chance, although the magnitude of the effect was low (56.7%). Raters' sex and disgust sensitivity were not associated with the accuracy of sickness detection. However, we find some indication that greater change in donor body temperature, but not sickness symptoms, between sick and healthy conditions improved sickness detection accuracy. Conclusion and implications Our findings suggest that humans can detect individuals with an acute respiratory infection through smell, albeit only slightly better than chance. Humans, similar to other animals, are likely able to use sickness odor cues to guide adaptive behaviors that decrease the risk of contagion, such as social avoidance. Further studies should determine how well humans can detect specific infections through body odor, such as Covid-19, and how multisensory cues to infection are used simultaneously. Lay Summary Researchers suggest humans evolved the ability to detect sickness in others, facilitating behavioral responses to reduce contagion risk, such as the avoidance of sick individuals. Our study suggests that humans can distinguish healthy from sick individuals with a naturally occurring respiratory infection by smelling body odors, but with limited accuracy.
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| 9. |
- Tognetti, Arnaud, et al.
(författare)
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Olfactory Cues of Naturally Occurring Systemic Inflammation : A Pilot Study of Seasonal Allergy
- 2023
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Ingår i: Neuroimmunomodulation. - : S. Karger. - 1021-7401 .- 1423-0216. ; 30:1, s. 338-345
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: In an attempt to avoid contact with infectious individuals, humans likely respond to generalized rather than specific markers of disease. Humans may thus perceive a noninfectious individual as socially less attractive if they look (e.g., have facial discolouration), move (e.g., have a slower walking pace), or sound (e.g., sneeze) sick. This pilot study tested whether humans are averse to the body odour of noninfectious individuals with a low-grade systemic inflammation. Methods: We collected the axillary body odour of individuals with severe seasonal allergy (N = 14) and healthy controls (N = 10) during and outside the allergy season and measured serum levels of two inflammatory cytokines (tumour necrosis factor-α and interleukin-5). Independent participants (N = 67) then sampled and rated these odours on intensity and pleasantness. Results: While individuals with seasonal allergy had nominally more unpleasant and intense body odours during the allergy season, relative to outside the allergy season and to healthy controls, these effects were not significant. When examining immune markers, the change in perceived pleasantness of an individual’s body odour (from out-to-inside pollen season) was significantly related to the change in their interleukin-5 levels but not to tumour necrosis factor-α. Discussion: Our findings tentatively suggest that the human olfactory system could be sensitive to inflammation as present in a noncommunicable condition. Larger replications are required to determine the role of olfaction in the perception of infectious and noninfectious (e.g., chronic diseases) conditions.
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| 10. |
- Andreasson, Anna, 1980-, et al.
(författare)
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Assessing sickness behavior in the French : Validation of the French translation of the sickness questionnaire (SicknessQ) in a non-clinical French population
- 2023
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Ingår i: Brain, Behavior, & Immunity - Health. - 2666-3546. ; 34
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Tidskriftsartikel (refereegranskat)abstract
- The Sickness Questionnaire (SicknessQ) is a questionnaire developed to assess symptoms of sickness behavior, including somatic, behavioral, and affective dimensions. To promote cross-cultural assessments of sickness behavior, we aim to expand the use of this questionnaire to other populations and languages. The aim of the present study was to evaluate the French translation of SicknessQ in a French-speaking general population during the COVID-19 pandemic. One hundred and thirty-nine individuals completed the SicknessQ online, along with the construct criteria measures of self-rated health, state anxiety (STAI-S), and depressive symptoms (PHQ-9). The principal component analyses revealed two components: the first component included seven items concerning mood, motivation and experiences of fatigue and pain; the second component included three items concerning somatic sickness symptoms. Higher scores on the total scale and the two component subscales were associated with poorer self-rated health and higher STAI-S and PHQ-9 scores. Since the associations with construct criteria variables were relatively similar between the single- and the two-dimensional solutions, both the total scale and the subscales of the two components of the French SicknessQ can be used in future studies to measure sickness behavior in French-speaking populations.
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