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EVALUATION AND INTERPRETATION OF NEURODEVELOPMENTAL ENDPOINTS FOR HUMAN HEALTH RISK ASSESSMENT -- POSITIVE CONTROL STUDIES, NORMAL VARIABILITY AND STATISTICAL ISSUES.
CROFTON, K. M., K. RAFFAELE, R. HOLSON, V. C. MOSER, J. FOSS, S. HANCOCK, AND J. W. FITZPATRICK. EVALUATION AND INTERPRETATION OF NEURODEVELOPMENTAL ENDPOINTS FOR HUMAN HEALTH RISK ASSESSMENT -- POSITIVE CONTROL STUDIES, NORMAL VARIABILITY AND STATISTICAL ISSUES. Presented at Society of Toxicology, Charlotte, NC, March 25 - 29, 2007.
ILSI Research Foundation/Risk Science Institute convened an expert working group to assess the lessons learned from the implementation of the EPA Developmental Neurotoxicity (DNT) Guideline and provide guidance for future use. The group prepared manuscripts in five areas: public health protection, use of positive controls, understanding normal variability, appropriate statistical techniques, and data interpretation. This poster will present the results from the positive control, variability, and statistical reports. Positive control data are instrumental in evaluating laboratory proficiency in detecting chemical-induced changes in measured endpoints. This review is a practical guide for the selection, use, and interpretation of positive control studies in DNT. To evaluate data quality and interpret results of treatment, normal levels of variability in measured parameters must be understood. This report presents a framework for investigators and regulators to use in comparing achieved versus expected levels of variability in DNT study data, as well as a discussion of factors contributing to inappropriate levels of variability. Appropriate statistical analyses of the behavioral data collected in DNT studies are imperative, including attention to within-litter correlations, gender and repeated testing as factors, and approaches specific for the different data types. This report presents a discussion of statistical approaches and makes general recommendations. This work is supported by EPA Cooperative Agreements X-82916701 (OPPT) and R-83049601 (OPP) and the ILSI/RF Risk Science Institute. This abstract does not necessarily represent EPA policy.