Neurobehavioral performance in human volunteers during inhalation exposure to the unpleasant local irritant cyclohexylamine

Abstract

Chemosensory active volatile organic compounds occur in the breathing air at many workplaces and it has been assumed that they are potent to impair workers' cognitive performance; however, the nature of this relationship is not understood. In the current study we investigated whether the combination of strong chemosensory potency and unpleasant odor valence is a sufficient predictor for the appearance of neurobehavioral impairment. Human volunteers were exposed to three workplace-relevant concentrations of the malodorant cyclohexylamine: 0.3 (odor control condition), 0-4 (varying condition), and 10 ppm (occupational exposure limit value, OEL, Sweden & Germany). The highest exposure evoked strong chemosensory sensations (annoyance), rather much olfactory related symptoms (bad air, stink), and increase in eye-blink frequency, which can be interpreted as indicator of trigeminal mediated adversity. Neurobehavioral performance measures (reaction times, accuracy) from three visual tasks requiring attention, motor inhibition and cognitive control did not show impairment in a consistent, dose-response related way and thus could not be related to cyclohexylamine exposure. Odorant characteristics of intensity and unpleasantness seem not sufficient to predict neurobehavioral impairment. Instead factors like participant selection bias, personality factors as well as effects related to the study design are discussed as contributing factors.