Exposure of Humans to a Volatile Organic Mixture. I. Behavioral Assessment

Abstract

Exposure to a low-level mixture of volatile organic compounds, typical of those found in new buildings, has been reported to impair neurobehavioral function in persons who have experienced sick building syndrome (SBS). Sixty-six healthy young males who had no history of chemical sensitivity were exposed for 2.75 h to a complex mixture of volatile organic compounds at 0 and 25 mg/m3. Even though subjects reported more fatigue and more mental confusion following exposure to volatile organic compounds than to clean air, performance on 13 neurobehavioral tests was not affected. Practice or learning effects were observed if administration of many behavioral tests were repeated. Further studies are needed to clarify the relationship of exposure to volatile organic chemicals, neurobehavioral performance, and subject characteristics, e.g., age, gender, and chemical sensitivity.

Neuropsychological approaches for the detection and evaluation of toxic symptoms.

“…These will require a better understanding of the behavior of neuropsychological tests under repeated measures conditions. Otto et al (4) found significant practice effects for several of the tests on the NES battery. To avoid ceiling effects on these tests after repeated administration, he suggested that test parameters be altered to make the tasks more difficult and better suited to repeated measures design (4).…”

“…Otto et al (4) found significant practice effects for several of the tests on the NES battery. To avoid ceiling effects on these tests after repeated administration, he suggested that test parameters be altered to make the tasks more difficult and better suited to repeated measures design (4). Similarly, increasing demands are being made for neuropsychological methods to assess subtle effects in acute and unusually low-exposure circumstances.…”

“…As has been suggested by other investigators, one method for detecting effects at lower exposure levels is to vary parameters within the performance test to increase its sensitivity to effects (4,63). Documentation of the effects of varied test parameters has been the subject of much attention within the experimental literature (e.g., signal-detection paradigms) and virtually no systematic attention within the neuropsychological literature or in the literature investigating the behavioral effects of neurotoxicants.…”

“…Kjaergaard et al (58) also found impaired digit span performance in SBS-sensitive subjects but not among non-SBS subjects with exposure at 25 mg/m3 VOC mixture, which is roughly equivalent to 7 ppm toluene. Otto et al (4) suggested that differential effects may be due to differential sensitivity of the subject groups as well as relative insensitivity of many of the current neurobehavioral methods.…”

“…By 1990 approximately 250 different tests had been used to evaluate the effects of neurotoxicants on behavior (1). Numerous articles have been written in which the range of functions assessed and the specific tests used to assess those functions are reviewed (1)(2)(3)(4)(5). Tests applied to evaluate symptoms among humans derive from two different psychological approaches: traditional neuropsychological testing to diagnose brain dysfunction and experimental cognitive psychology.…”