Human performance during exposure to toluene

Abstract

Purpose: The purpose of this research was to examine the effects of inhalation of toluene on respiratory function and neuropsychological performance of humans.

Methods: We exposed six healthy adults to 100 ppm toluene or air (control) for 6 h, in a double-blind, randomized fashion, with exposures separated by at least 14 d and including 30 min of exercise at a level that quadrupled minute ventilation. Blood and exhaled air toluene levels were measured before, during, immediately, and 1 and 2 h post-exposure. Lung function was measured before and immediately after exposure. Three repetitions of two computerized neuropsychological tests were performed, including a brief standard neuropsychological battery (ANAM) and a 1-h complex performance test (SYNWORK). Statistical analysis of the psychological data was conducted as a repeated measures ANOVA.

Findings: Following exercise, the mean blood and exhaled air toluene levels averaged 1.5 micrograms and 28 ppm, respectively. Lung function was unchanged post-exposure. On the SYNWORK test, the Composite score obtained over time during toluene exposure was lower than that during room air (F = 29.20, p = 0.005), with the score from the final hour reduced by 10%. On standard neuropsychological tests, latency but not accuracy proved the sensitive measure for five of the seven subtests presented.

Conclusions: Performance of complex tests and response time to simple brief tests can be disrupted by toluene inhalation at 100 ppm. Differences in performance between air and toluene conditions were greatest after exercise, indicating that physical activity may enhance the response to volatile organic solvents.