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  1. Acquisition and extinction of somatic symptoms in response to odours : a pavlovian paradigm relevant to multiple chemical sensitivity.

    Article - En anglais

    Objectives-Multiple chemical sensitivity is a poorly understood syndrome in which various symptoms are triggered by chemically unrelated, but often odorous substances, at doses below those known to be harmful.

    This study focuses on the process of pavlovian acquisition and extinction of somatic symptoms triggered by odours.

    Methods-Diluted ammonia and butyric acid were odorous conditioned stimuli (CS).

    The unconditioned stimulus (US) was 7.4% CO2 enriched air.

    One odour (CS+) was presented together with the US for 2 minutes (CS+trial), and the other odour (CS-) was presented with air (CS-trial).

    Three CS+and three CS-exposures were run in a semi-randomised order ; this as the acquisition (conditioning) phase.

    To test the effect of the conditioning, each subject then had one CS+only-that is, CS+without CO2-and one CS-test exposure.

    Next, half the subjects (n=32) received five additional CS+only exposures (extinction group), while the other half received five exposures to breathing air (wait group).

    Finally, all subjects got one CS+only test exposure to test the effect of the extinction.

    Ventilatory responses were measured during and somatic symptoms after each exposure.


    More symptoms were reported upon exposure to CS+only than to CS-odours, regardless of the odour type.

    Altered respiratory rate was only found when ammonia was CS+Five extinction trials were sufficient to reduce the level of acquired symptoms. (...)

    Mots-clés Pascal : Exposition, Médecine travail, Sensibilité chimique multiple, Odeur, Inhalation, Homme, Individu sain, Conditionnement classique, Toxicité, Symptomatologie, Extinction, Fonction respiratoire, Ammoniac, Butyrique acide

    Mots-clés Pascal anglais : Exposure, Occupational medicine, Multiple chemical sensitivity, Odor, Inhalation, Human, Healthy subject, Classical conditioning, Toxicity, Symptomatology, Extinction, Lung function, Ammonia, Butyric acid

    Logo du centre Notice produite par :
    Inist-CNRS - Institut de l'Information Scientifique et Technique

    Cote : 99-0236115

    Code Inist : 002B03L06. Création : 16/11/1999.