Acute exposure to 50Â ppm toluene does not increase sleepiness

The Pupillographic Sleepiness Test (PST) is a new neurophysiological method to assess sleepiness. In an exposure study to a constant exposure level of 50 ppm toluene on 20 healthy men, our aim was to find out, if increased sleepiness could be seen with PST. PST was performed before and after 4.5 h of exposure. General complaints were assessed with the Swedish Performance Evaluation System (SPES) self-assessment questionnaire, once before and during exposure. Values obtained during exposure were related to pre-exposure values. Parametric cross-over analysis of logarithmic Pupillary Unrest Index (PUI) values did not show an effect of toluene exposure. In a nonparametric cross-over analysis of SPES-scores a significant increase of the scores of unpleasant smell and irritation to the throat, but not of tiredness was found. In conclusion, acute exposure to 50 ppm toluene, corresponding to the German threshold limit value, did not increase sleepiness.