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International Archives of Occupational and Environmental Health
Published in: International Archives of Occupational and Environmental Health 3/2004

01-04-2004 | Original Article

Perceived relation between odors and a negative event determines learning of symptoms in response to chemicals

Authors: Stephan Devriese, Winnie Winters, Ilse Van Diest, Steven De Peuter, Gerrit Vos, Karel Van de Woestijne, Omer Van den Bergh

Published in: International Archives of Occupational and Environmental Health | Issue 3/2004

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Abstract

Background

We investigated the effects of worrying information about chemical pollution on subjective symptoms in response to an odor that was previously associated with symptom episodes.

Methods

Ammonia and butyric acid in harmless concentrations were used as odor cues, and 10% CO2-enriched air was used to induce symptoms. One of two odors was consistently mixed with CO2-enriched air while the other odor was presented in room air during 80 s breathing trials (three trials of each). Next, information framing the experiment in the context of possible health-damaging effects of chemical pollution of our environment was presented to half the participants, whereas no information was given to the other half. Finally, both odor cues were presented with room air. Symptom scores were used as the dependent variable.

Results

Unexpectedly, participants reported more symptoms in response to the odor previously presented with air than to the odor previously presented with CO2-enriched air. Post-hoc analyses suggested a crucial role for perceived rather than actual contingencies between odor and symptom episodes. Information manipulation had no effect.

Conclusions

Believing that a specific odor cue was associated with a symptom episode was more important than the actual association in order to provoke symptoms in response to harmless odor cues.
Footnotes
1
In psychological terms, this procedures is equivalent to a revaluation paradigm: after an association between a cue (or conditioned stimulus) and a negative event (or an unconditioned stimulus, US) has been established, the administration of a modified US (e.g. stronger) may increase or decrease the value of the US. Next, its effects on the response to the cue are tested (see for example Hosoba et al. 2001).
 
2
We administered ammonia at this increased rate to equate the subjective appraisal of this odor with the other odor. The rate was determined in a pilot study for a previous experiment (Winters et al. 2001).
 
3
Order balanced presentation was as follows: the six trials of two different types (cue and non-cue odor) had the restriction that no more than two consecutive trials could be of the same type (which ruled out the possibility of there being three consecutive cue odor trials or three consecutive non-cue odor trials). This gave a total of 14 possible orders of presentation. Participants were randomly assigned to an order presentation.
 
4
The unequal N HSD is a modification of the Tukey HSD test. Because no clear-cut rules exist for an adequate error term in post-hoc tests for pairwise comparisons of means in interactions between within-subjects and between-subjects variables, we opted for a pooled within-between error term (Winer et al. 1991).
 
5
Because the variances were not homogeneous between cells for the cue odor test trials (Levene’s F(1,50)=5.54, p<0.05) or for the cue odor test trials (Levene’s F(1,50)=16.01, p<0.01), we performed a Box–Cox transformation (reciprocal) to stabilize the variances (Box and Cox 1964)
 
Literature
Box G, Cox D (1964) An analysis of transformations. J R Stat Soc 26:211–253
Devriese S, Winters W, Nemery B, Veulemans H, Eelen P, Van den Bergh O (2000) Generalisation in a differential odour conditioning paradigm in a model for multiple chemical sensitivity. Psychosom Med 62:751–759PubMed
Graveling R, Pilkington A, George J, Butler M, Tannahill S (1999) A review of multiple chemical sensitivity. Occup Environ Med 56:73–85PubMed
Hosoba T, Iwanaga M, Seiwa H (2001) The effect of UCS inflation and deflation procedures on ‘fear’ conditioning. 465–475
Miller C (2001) The compelling anomaly of chemical intolerance. Ann N Y Acad Sci 933:1–23PubMed
Ross P (2000) Chemical sensitivity and fatigue syndromes from hypoxia/hypercapnia. Med Hypotheses 54:734–738CrossRefPubMed
Sorg BA (1999) Multiple chemical sensitivity: potential role for neural sensitization. Crit Rev Neurobiol 13:283–316PubMed
Sorg BA, Tschirgi M, Swindell S, Chen L, Fang J (2001) Repeated formaldehyde effects in an animal model for multiple chemical sensitivity. Ann N Y Acad Sci 933:57–67PubMed
Van den Bergh O, Devriese S, Winters W, Veulemans H, Nemery B, Eelen P, Van de Woestijne K (2001) Acquiring symptoms in response to odors: a learning perspective on multiple chemical sensitivity. Ann N Y Acad Sci 933:278–290PubMed
Watson D, Pennebaker J (1989) Health complaints, stress, and distress: exploring the central role of negative affectivity. Psychol Rev 96:234–254PubMed
Winer B, Brown D, Michels K (1991) Statistical principles in experimental design McGraw-Hill 3 edition
Winters W (2002) Acquisition phenomena in a learning model of multiple chemical sensitivity. Ph.D. thesis, Katholieke Universiteit Leuven, Leuven, Belgium
Winters W, Devriese S, Eelen P, Veulemans H, Nemery B, Van den Bergh O (2001) Symptom learning in response to odors in a single odor respiratory learning paradigm. Ann N Y Acad Sci 933:315–318PubMed
Winters W, Devriese S, Van Diest I, Nemery B, Veulemans H, Eelen P, Van deWoestijne K, Van den Bergh O (2003) Media warnings about environmental pollution facilitate the acquisition of symptoms in response to chemical substances. Psychosom Med 65:332–338CrossRefPubMed
Metadata
Title
Perceived relation between odors and a negative event determines learning of symptoms in response to chemicals
Authors
Stephan Devriese
Winnie Winters
Ilse Van Diest
Steven De Peuter
Gerrit Vos
Karel Van de Woestijne
Omer Van den Bergh
Publication date
01-04-2004
Publisher
Springer-Verlag
Published in
International Archives of Occupational and Environmental Health / Issue 3/2004
Print ISSN: 0340-0131
Electronic ISSN: 1432-1246
DOI
https://doi.org/10.1007/s00420-003-0488-8

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