Human Neurobehavioral Effects of Long-Term Exposure to Styrene: A Meta-Analysis

Many reports in the literature suggest that long-term exposure to styrene may exert a variety of effects on the nervous system, including increased choice reaction time and decreased performance of color discrimination and color arrangement tasks. Sufficient information exists to perform a meta-analysis of these observations quantifying the relationships between exposure (estimated from biomarkers) and effects on two measures of central nervous system function: reaction time and color vision. To perform the meta-analysis, we pooled data into a single database for each end point. End-point data were transformed to a common metric of effect magnitude (percentage of baseline). We estimated styrene concentration from biomarkers of exposure and fitted linear least-squares equations to the pooled data to produce dose–effect relationships. Statistically significant relationships were demonstrated between cumulative styrene exposure and increased choice reaction time as well as increased color confusion index. Eight work-years of exposure to 20 ppm styrene was estimated to produce a 6.5% increase in choice reaction time, which has been shown to significantly increase the probability of automobile accidents. The same exposure history was predicted to increase the color confusion index as much as 1.7 additional years of age in men

Olfaction: anatomy, physiology and behavior

The anatomy, physiology and function of the olfactory system are reviewed, as are the normal effects of olfactory stimulation. It is speculated that olfaction may have important but unobtrusive effects on human behavior

A hybrid system for computer analysis of EEG data

In the past few years the field of neuropsychology has begun to make use of some mathematical methods of wave analysis developed for use in information theory and signal processing systems. The present study relates these information theory concepts to regression analysis, expands upon the concepts, discusses a hardware computer system for the realization of the mathematical methods and presents a few examples of some data analysis. The first chapter discusses some basic time function terms in the framework of statistics as well as engineering, making relations between the two. This done, the Fourier wave analysis method is derived from the least squares regression model. Various innovations and extensions of Fourier analysis are discussed. Chapter two discusses the design of a general purpose hybrid computer. The design philosophy is presented, the hardware capability discussed and programming methods are introduced. Much basic hardware theory is presented. Chapter three is an extension of chapter two in the sense that it covers the basic programs to date. Some mathematical model innovations and interpretations are also discussed here. Chapter four is a discussion of the results of the analysis of some EEG data from the olfactory bulb and amygdala of three cats. The emphasis here is upon the analysis methods and the conclusions which may be drawn from them. Comparisons were made between EEG traces under different odor stimulation conditions. No significant differences across odors were found. The relationships between the two central nervous system structures were also discussed in an information theory framework. Chapter five discusses the implications of this work for future research.Psychology, Department o

_113N5_Science_517-589

Many reports in the literature suggest that long-term exposure to styrene may exert a variety of effects on the nervous system, including increased choice reaction time and decreased performance of color discrimination and color arrangement tasks. Sufficient information exists to perform a meta-analysis of these observations quantifying the relationships between exposure (estimated from biomarkers) and effects on two measures of central nervous system function: reaction time and color vision. To perform the meta-analysis, we pooled data into a single database for each end point. End-point data were transformed to a common metric of effect magnitude (percentage of baseline). We estimated styrene concentration from biomarkers of exposure and fitted linear leastsquares equations to the pooled data to produce dose-effect relationships. Statistically significant relationships were demonstrated between cumulative styrene exposure and increased choice reaction time as well as increased color confusion index. Eight work-years of exposure to 20 ppm styrene was estimated to produce a 6.5% increase in choice reaction time, which has been shown to significantly increase the probability of automobile accidents. The same exposure history was predicted to increase the color confusion index as much as 1.7 additional years of age in men

Human Neurobehavioral Effects of Long-Term Exposure to Styrene: A Meta-Analysis-3

<p><b>Copyright information:</b></p><p>Taken from "Human Neurobehavioral Effects of Long-Term Exposure to Styrene: A Meta-Analysis"</p><p>Environmental Health Perspectives 2005;113(5):532-538.</p><p>Published online 27 Jan 2005</p><p>PMCID:PMC1257543.</p><p>This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI.</p