title: Neurobehavioral effects of exposure to propionic acid revisited-Does psychosocial stress interfere with distractive effects in volunteers?
abstract: Local irritants stimulate the nervous system via chemosensory pathways that trigger cognitive distraction, subjective complaints about impaired health, and physiological defense reflexes (e.g. eye-blinks). At workplaces and in the environment chemical exposures often co-occur with psychosocial stress. This study investigated if stress modulates adverse effects of exposure to the local irritant and malodorant propionic acid (PA). Forty-eight participants were randomly assigned to an experimental (false negative feedback+salient surveillance) or control group. In a cross-over design, both groups were exposed for 4h to PA in concentrations of 0.3 and 0-20ppm (time-weighted average=10ppm). In the experimental group, the stress protocol induced moderate psychosocial stress as indicated by salivary cortisol and subjective responses. Despite concentration-dependent increases in chemosensory perceptions and symptoms, the level of exposure to PA had no impact upon the results of four out of six neurobehavioral tests. In the sustained attention test, there was a significant increase in error rates that corresponded to the exposure levels. However, a concentration-dependent impairment of spatial working memory and an adverse increase in eye-blink frequency were restricted to the control group. Stressed participants had shorter simple reaction times and high eye-blink frequency irrespective of exposure suggesting enhanced alertness. Psychosocial stress increased complaints, ocular irritation and unspecific symptoms at the end of the 0.3ppm exposure to a level that was comparable with that in the control group during exposure to 0-20ppm. Results indicate that the adverse effects of a local irritant and psychosocial stress are non-additive.
authors.affiliation: Leibniz Research Centre for Working Environment and Human Factors at TU Dortmund University, Ardeystrasse 67, 44139 Dortmund, Germany. Electronic address: pacharra@ifado.de.
authors.forename: Marlene
authors.initials: M
authors.lastname: Pacharra
authors.affiliation: Leibniz Research Centre for Working Environment and Human Factors at TU Dortmund University, Ardeystrasse 67, 44139 Dortmund, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Schäper
authors.affiliation: Leibniz Research Centre for Working Environment and Human Factors at TU Dortmund University, Ardeystrasse 67, 44139 Dortmund, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Kleinbeck
authors.affiliation: Leibniz Research Centre for Working Environment and Human Factors at TU Dortmund University, Ardeystrasse 67, 44139 Dortmund, Germany.
authors.forename: Meinolf
authors.initials: M
authors.lastname: Blaszkewicz
authors.affiliation: Leibniz Research Centre for Working Environment and Human Factors at TU Dortmund University, Ardeystrasse 67, 44139 Dortmund, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Golka
authors.affiliation: Leibniz Research Centre for Working Environment and Human Factors at TU Dortmund University, Ardeystrasse 67, 44139 Dortmund, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: van Thriel
mesh_terms: D000328:Adult; D001288:Attention / Q000187:drug effects*; D001767:Blinking / Q000187:drug effects; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D007266:Inhibition, Psychological; D008297:Male; D008570:Memory, Short-Term / Q000187:drug effects*; D009483:Neuropsychological Tests; D011422:Propionates / Q000494:pharmacology*; D011930:Reaction Time / Q000187:drug effects; D012463:Saliva / Q000737:chemistry; D012677:Sensation / Q000187:drug effects*; D013312:Stress, Physiological; D013315:Stress, Psychological / Q000209:etiology* / Q000503:physiopathology
chemical_list: D011422:Propionates; C029658:propionic acid; D006854:Hydrocortisone
keywords: Cognition; Exposure peak; Nonchemical stressor; Olfaction; Sensory irritation