| 1. |
- Andersson, Linus, et al.
(författare)
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Chemosensory perception, symptoms and autonomic responses during chemical exposure in multiple chemical sensitivity
- 2016
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Ingår i: International Archives of Occupational and Environmental Health. - : Springer. - 0340-0131 .- 1432-1246. ; 89:1, s. 79-88
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Multiple chemical sensitivity (MCS) is a prevalent medically unexplained symptom characterized by symptom reactions to everyday chemical exposure below hygienic thresholds. The aim of this study was to investigate the expressions of hyper-reactivity in MCS during whole-body exposure to low concentrations of the odorant n-butanol.Methods: We exposed 18 participants with MCS and 18 non-ill controls to a low concentration of the odorantn-butanol using an exposure chamber. The first 10 min constituted blank exposure, after which then-butanol concentration increased and reached a plateau at 11.5 mg/m3.Results: MCS participants, compared with controls, reported greater perceived odor intensities, more unpleasantness to the exposure and increasing symptoms over time. MCS participants also expressed higher pulse rate and lower pulse rate variability than controls did. No group differences were found for breathing rate or tonic electrodermal activity responses.Conclusions: We conclude that MCS sufferers differ from healthy controls in terms of autonomic responses, symptoms and chemosensory perception during chemical exposure.
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| 2. |
- Andersson, Linus, 1979-, et al.
(författare)
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Effects of Task Demands on Olfactory, Auditory, and Visual Event-Related Potentials Suggest Similar Top-Down Modulation Across Senses
- 2018
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 43:2, s. 129-134
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Tidskriftsartikel (refereegranskat)abstract
- A widely held view is that top-down modulation of sensory information relies on an amodal control network that acts through the thalamus to regulate incoming signals. Olfaction lacks a direct thalamic projection, which suggests that it may differ from other modalities in this regard. We investigated the late positive complex (LPC) amplitudes of event-related potentials (ERP) from 28 participants, elicited by intensity-matched olfactory, auditory and visual stimuli, during a condition of focused attention, a neutral condition, and a condition in which stimuli were to be actively ignored. Amplitudes were largest during the attend condition, lowest during the ignore condition, with the neutral condition in between. A Bayesian analysis resulted in strong evidence for similar effects of task across sensory modalities. We conclude that olfaction, despite its unique neural projections, does not differ from audition and vision in terms of task-dependent neural modulation of the LPC.
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| 3. |
- Andersson, Linus, et al.
(författare)
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Short-term olfactory sensitization involves brain networks relevant for pain, and indicates chemical intolerance
- 2017
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Ingår i: International journal of hygiene and environmental health. - : Elsevier. - 1438-4639 .- 1618-131X. ; 220:2, s. 503-509
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Tidskriftsartikel (refereegranskat)abstract
- Chemical intolerance is a medically unexplained affliction that implies deleterious reactions to non-toxic everyday chemical exposure. Sensitization (i.e. increased reactivity to repeated, invariant stimulation) to odorous stimulation is an important component in theoretical explanations of chemical intolerance, but empirical evidence is scarce. We hypothesized that (1) individuals who sensitize to repeated olfactory stimulation, compared with those who habituate, would express a lower blood oxygenated level dependent (BOLD) response in key inhibitory areas such as the rACC, and higher signal in pain/saliency detection regions, as well as primary and/or secondary olfactory projection areas; and (2) olfactory sensitization, compared with habituation, would be associated with greater self-reported chemical intolerance. More-over, we assessed whether olfactory sensitization was paralleled by comparable trigeminal processing - in terms of perceptual ratings and BOLD responses. We grouped women from a previous functional magnetic imaging study based on intensity ratings of repeated amyl acetate exposure over time. Fourteen women sensitized to the exposure, 15 habituated, and 20 were considered "intermediate" (i.e. neither sensitizers nor habituaters). Olfactory sensitizers, compared with habituaters, displayed a BOLD-pattern in line with the hypothesis, and reported greater problems with odours in everyday life. They also expressed greater reactions to CO2 in terms of both perceived intensity and BOLD signal. The similarities with pain are discussed.
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| 4. |
- Dantoft, Thomas Meinertz, et al.
(författare)
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Chemical Intolerance
- 2015
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Ingår i: Current Rheumatology Reviews. - : Bentham Science. - 1573-3971 .- 1875-6360. ; 11:2, s. 167-184
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Tidskriftsartikel (refereegranskat)abstract
- Chemical intolerance (CI) is a term used to describe a condition in which the sufferer experiences a complex array of recurrent unspecific symptoms attributed to low-level chemical exposure that most people regard as unproblematic. Severe CI constitutes the distinguishing feature of multiple chemical sensitivity (MCS). The symptoms reported by CI subjects are manifold, involving symptoms from multiple organs systems. In severe cases of CI, the condition can cause considerable life-style limitations with severe social, occupational and economic consequences. As no diagnostic tools for CI are available, the presence of the condition can only be established in accordance to criteria definitions. Numerous modes of action have been suggested to explain CI, with the most commonly discussed theories involving the immune system, central nervous system, olfactory and respiratory systems as well as altered metabolic capacity, behavioral conditioning and emotional regulation. However, in spite of more than 50 years of research, there is still a great deal of uncertainties regarding the event(s) and underlying mechanism( s) behind symptom elicitation. As a result, patients are often misdiagnosed or offered health care solutions with limited or no effect, and they experience being met with mistrust and doubt by health care professionals, the social care system and by friends and relatives. Evidence-based treatment options are currently unavailable, however, a person-centered care model based on a multidisciplinary treatment approach and individualized care plans have shown promising results. With this in mind, further research studies and health care solutions should be based on a multifactorial and interdisciplinary approach.
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| 5. |
- Dantoft, Thomas M., et al.
(författare)
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Gene expression profiling in persons with multiple chemical sensitivity before and after a controlled n-butanol exposure session
- 2017
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Ingår i: BMJ Open. - : BMJ. - 2044-6055. ; 7:2
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To investigate the pathophysiological pathways leading to symptoms elicitation in multiple chemical sensitivity (MCS) by comparing gene expression in MCS participants and healthy controls before and after a chemical exposure optimised to cause symptoms among MCS participants.The first hypothesis was that unexposed and symptom-free MCS participants have similar gene expression patterns to controls and a second hypothesis that MCS participants can be separated from controls based on differential gene expression upon a controlled n-butanol exposure.DESIGN: Participants were exposed to 3.7 ppm n-butanol while seated in a windowed exposure chamber for 60 min. A total of 26 genes involved in biochemical pathways found in the literature have been proposed to play a role in the pathogenesis of MCS and other functional somatic syndromes were selected. Expression levels were compared between MCS and controls before, within 15 min after being exposed to and 4 hours after the exposure.SETTINGS: Participants suffering from MCS and healthy controls were recruited through advertisement at public places and in a local newspaper.PARTICIPANTS: 36 participants who considered themselves sensitive were prescreened for eligibility. 18 sensitive persons fulfilling the criteria for MCS were enrolled together with 18 healthy controls.OUTCOME MEASURES: 17 genes showed sufficient transcriptional level for analysis. Group comparisons were conducted for each gene at the 3 times points and for the computed area under the curve (AUC) expression levels.RESULTS: MCS participants and controls displayed similar gene expression levels both at baseline and after the exposure and the computed AUC values were likewise comparable between the 2 groups. The intragroup variation in expression levels among MCS participants was noticeably greater than the controls.CONCLUSIONS: MCS participants and controls have similar gene expression levels at baseline and it was not possible to separate MCS participants from controls based on gene expression measured after the exposure.
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| 6. |
- Johansson, Amanda, et al.
(författare)
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Symptoms, personality traits, and stress in people with mobile phone-related symptoms and electromagnetic hypersensitivity
- 2010
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Ingår i: Journal of Psychosomatic Research. - : Elsevier. - 0022-3999 .- 1879-1360. ; 68:1, s. 37-45
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Tidskriftsartikel (refereegranskat)abstract
- Some people report symptoms that they associate with electromagnetic field (EMF) exposure. These symptoms may be related to specific EMF sources or to electrical equipment in general (perceived electromagnetic hypersensitivity, EHS). Research and clinical observations suggest a difference between mobile phone (MP)-related symptoms and EHS with respect to symptom prevalence, psychological factors, and health prognosis. This study assessed prevalence of EMF-related and EMF-nonrelated symptoms, anxiety, depression, somatization, exhaustion, and stress in people with MP-related symptoms or EHS versus a population-based sample and a control sample without EMF-related symptoms.
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| 7. |
- Lind, Nina, 1989-, et al.
(författare)
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Comorbidity and multimorbidity of asthma and allergy and intolerance to chemicals and certain buildings
- 2017
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Ingår i: Journal of Occupational and Environmental Medicine. - 1076-2752 .- 1536-5948. ; 59:1, s. 80-84
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: We tested the hypothesis of high comorbidity between asthma/allergy and chemical intolerance (CI) and between asthma/allergy and building intolerance (BI), and high multimorbidity between asthma/allergy, CI, and BI.Methods: Population-based questionnaire data were used from 530 participants with asthma/allergy (allergic asthma, nonallergic asthma, allergic rhinitis, and/or atopic dermatitis), 414 with self-reported and 112 with physician-diagnosed CI, and 165 with self-reported and 47 with physician-diagnosed BI. Separate reference groups were formed for each of the five case groups.Results: Adjusted odds ratios varied from 4.6 to 13.1 for comorbidity, and from 6.6 to 46.4 for multimorbidity.Conclusion: The large comorbidity and multimorbidity between asthma/allergy, CI, and BI evokes the question as to whether there are similarities in underlying mechanisms between these conditions.
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| 8. |
- Meinertz Dantoft, Thomas, et al.
(författare)
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Inflammatory mediator profiling of n-butanol exposed upper airways in individuals with multiple chemical sensitivity
- 2015
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:11
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Multiple Chemical Sensitivity (MCS) is a chronic condition characterized by reports of recurrent symptoms in response to low level exposure to various chemical substances. Recent findings suggests that dysregulation of the immune system may play a role in MCS pathophysiology.OBJECTIVES: The aim of this study was to examine baseline and low dose n-butanol-induced upper airway inflammatory response profiles in MCS subjects versus healthy controls.METHOD: Eighteen participants with MCS and 18 age- and sex-matched healthy controls were enrolled in the study. Epithelial lining fluid was collected from the nasal cavity at three time points: baseline, within 15 minutes after being exposed to 3.7 ppm n-butanol in an exposure chamber and four hours after exposure termination. A total of 19 cytokines and chemokines were quantified. Furthermore, at baseline and during the exposure session, participants rated the perceived intensity, valence and levels of symptoms and autonomic recordings were obtained.RESULTS: The physiological and psychophysical measurements during the n-butanol exposure session verified a specific response in MCS individuals only. However, MCS subjects and healthy controls displayed similar upper airway inflammatory mediator profiles (P>0.05) at baseline. Likewise, direct comparison of mediator levels in the MCS group and controls after n-butanol exposure revealed no significant group differences.CONCLUSION: We demonstrate no abnormal upper airway inflammatory mediator levels in MCS subjects before or after a symptom-eliciting exposure to low dose n-butanol, implying that upper airways of MCS subjects are functionally intact at the level of cytokine and chemokine production and secretory capacity. This suggests that previous findings of increased cytokine plasma levels in MCS are unlikely to be caused by systemic priming via excessive upper airway inflammatory processes.
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| 9. |
- Nordin, Steven, et al.
(författare)
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Effects of negative affectivity and odor valence on chemosensory and symptom perception and perceived ability to focus on a cognitive task
- 2017
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Ingår i: Perception. - : SAGE Publications. - 0301-0066 .- 1468-4233. ; 46:3-4, s. 431-446
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Tidskriftsartikel (refereegranskat)abstract
- The aim was to gain understanding for the impact of negative affectivity (NA) and odor valanceon perceptual aspects during low-level odorous exposure. Fifty-five young adults who were eitherrelatively low or high in NA (anxiety, depression, and somatization) were randomized forexposure to either limonene (pleasant odor) or pyridine (unpleasant odor). In an exposurechamber, they took part in baseline, blank and stable exposure sessions, during which theyrated odor intensity, impact on ability to focus on an imagined cognitive task, and intensity ofsymptoms. The results showed higher ratings of negative impact on ability to focus duringexposure to the unpleasant odor compared with the pleasant odor, and an association betweenNA and symptom intensity, with 18% of the variance in symptom intensity explainedby somatization. The association between NA and symptom intensity was found to be drivenby the factor sex. These results imply (a) that prior findings of odorous exposure that interferenegatively with work performance may be due to impact of an unpleasant odor on ability to focuson cognitive tasks and (b) that there are associations between NA, sex, and symptoms that maypartly be referred to attentiveness to and interpretation of bodily sensations.
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| 10. |
- Paulin, Johan, et al.
(författare)
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Characteristics of hyperacusis in the general population
- 2016
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Ingår i: Noise & Health. - : Medknow Publications. - 1463-1741 .- 1998-4030. ; 18:83, s. 178-184
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Tidskriftsartikel (refereegranskat)abstract
- There is a need for better understanding of various characteristics in hyperacusis in the general population. The objectives of the present study were to investigate individuals in the general population with hyperacusis regarding demographics, lifestyle, perceived general health and hearing ability, hyperacusis-specific characteristics and behavior, and comorbidity. Using data from a large-scale population-based questionnaire study, we investigated individuals with physician-diagnosed (n=66) and self-reported (n=313) hyperacusis in comparison to individuals without hyperacusis (n=2995). High age, female sex, and high education were associated with hyperacusis, and that trying to avoid sound sources, being able to affect the sound environment, and having sough medical attention were common reactions and behaviors. Posttraumatic stress disorder, chronic fatigue syndrome, generalized anxiety disorder, depression, exhaustion, fibromyalgia, irritable bowel syndrome, migraine, hearing impairment, tinnitus, and back/joint/muscle disorders were comorbid with hyperacusis. The results provide ground for future study of these characteristic features being risk factors for development of hyperacusis and/or consequences of hyperacusis.
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