0000000000172163
AUTHOR
Omer Van Den Bergh
Symptoms and the body: Taking the inferential leap
The relationship between the conscious experience of physical symptoms and indicators of objective physiological dysfunction is highly variable and depends on characteristics of the person, the context and their interaction. This relationship often breaks down entirely in the case of "medically unexplained" or functional somatic symptoms, violating the basic assumption in medicine that physical symptoms have physiological causes. In this paper, we describe the prevailing theoretical approach to this problem and review the evidence pertaining to it. We then use the framework of predictive coding to propose a new and more comprehensive model of the body-symptom relationship that integrates ex…
Prospective study of nocebo effects related to symptoms of idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF).
The exact causes of Idiopathic Environmental Intolerance Attributed to Electromagnetic Fields (IEI-EMF, i.e., experience of somatic symptoms attributed to low-level electromagnetic fields) are still unknown. Psychological causation such as nocebo effects seem plausible. This study aimed to experimentally induce a nocebo effect for somatic symptom perception and examined whether it was reproducible after one week. We also examined whether these effects were associated with increased sympathetic activity and whether interoceptive accuracy (IAcc) moderated these relationships. Participants were recruited from the general population and instructed that electromagnetic exposure can enhance somat…
Supplemental Material, JEP059716_supplement - Sensory and affective components of symptom perception: A psychometric approach
Supplemental Material, JEP059716_supplement for Sensory and affective components of symptom perception: A psychometric approach by Marta Walentynowicz, Michael Witthöft, Filip Raes, Ilse Van Diest, and Omer Van den Bergh in Journal of Experimental Psychopathology
Sensory and affective components of symptom perception: A psychometric approach
Psychological accounts of symptom perception put forward that symptom experiences consist of sensory-perceptual and affective-motivational components. This division is also suggested by psychometric studies investigating the latent structure of symptom reporting. To corroborate the view that the general and symptom-specific factors of a bifactor model represent affective and sensory components, respectively, we performed bifactor models applying confirmatory factor analytic approaches to the Patient Health Questionnaire-15 and the Checklist for Symptoms in Daily Life completed by 1053 undergraduate students. Additionally, we explored the association of latent factors with negative affectivi…
Idiopathic Environmental Intolerance: A Treatment Model
Idiopathic environmental intolerance (IEI) refers to a health condition characterized by the presence of multiple symptoms in different organ systems in response to a variety of environmental cues, such as chemical exposures, electromagnetic radiation, infrasound from windmill farms, (parts of) buildings, foods, etc. Typically, the symptoms arise in response to triggers and at dosages that do not cause symptoms in the majority of people, and no clear link with any physiological dysfunction can be found. The condition varies in a dimensional way from very mild, for which no medical help is sought, to very disabling, compromising normal life. The condition is controversial, but several indica…
Are media reports able to cause somatic symptoms attributed to WiFi radiation? An experimental test of the negative expectation hypothesis
People suffering from idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF) experience numerous non-specific symptoms that they attribute to EMF. The cause of this condition remains vague and evidence shows that psychological rather than bioelectromagnetic mechanisms are at work. We hypothesized a role of media reports in the etiology of IEI-EMF and investigated how somatosensory perception is affected. 65 healthy participants were instructed that EMF exposure can lead to enhanced somatosensory perception. Participants were randomly assigned to watch either a television report on adverse health effects of EMF or a neutral report. During the following experiment…
“Symptoms associated with environmental factors” (SAEF) – Towards a paradigm shift regarding “idiopathic environmental intolerance” and related phenomena
Health conditions characterized by symptoms associated with chemical, physical and biological environmental factors unrelated to objectifiable pathophysiological mechanisms are often labelled by the general term “idiopathic environmental intolerances”. More specific, exposure-related terms are also used, e.g. “multiple chemical sensitivities”, “electromagnetic hypersensitivity” and “candidiasis hypersensitivity”. The prevalence of the conditions varies from a few up to more than 50%, depending on definitions and populations. Based on evolving knowledge within this field, we provide arguments for a paradigm shift from terms focusing on exposure and intolerance/(hyper-)sensitivity towards a t…
Idiopathic Environmental Intolerance: A Comprehensive Model
Idiopathic environmental intolerance refers to a group of poorly understood health conditions characterized by heterogeneous somatic symptoms that occur in response to environmental triggers, but for which no physiological causes can be found. We focus on three varieties, namely symptoms attributed to (a) chemical substances, (b) electromagnetic fields, and (c) infrasound and vibroacoustic sources. As no clear link with organ pathology or dysfunction has been established so far, we review critical evidence about alternative causal mechanisms as a platform for a novel unifying model of these conditions. There is consistent evidence that expectancy and nocebo mechanisms are critically involve…
Somatic Symptom Perception From a Predictive Processing Perspective: An Empirical Test Using the Thermal Grill Illusion.
OBJECTIVE In a predictive processing perspective, symptom perceptions result from an integration of preexisting information in memory with sensory input. Physical symptoms can therefore reflect the relative predominance of either sensory input or preexisting information. In this study, we used the thermal grill illusion (TGI), which applies interlaced warm and cool temperatures to the skin to create a paradoxical heat-pain experience. Assuming that the TGI compared with single-temperature stimulation relies more importantly on an active integration process of the brain to create this paradoxical sensation, we tested the hypothesis whether a manipulation of the expectations during TGI would …