Neurotoxicology is the science that investigates the relationship between exposures to chemical or physical agents and adverse effects in the nervous system. Behavioral Neurotoxicology is the branch of the science that employs neurobehavioral test methods. The test methods to study human subjects in this research are typically drawn from experimental or clinical psychology including neuropsychology, neurology, or related fields (the methods are extensively detailed in Anger, 1990 and 2003).
Neurotoxicology research using animal subjects has been carried on for at least a century. Behavioral neurotoxicology in human subjects began in the middle of the twentieth century. Formalized experimental research on human subjects in laboratory exposure chambers began in the 1950s when Beard and Wertheim began their work on the effects of carbon monoxide (Beard, 1974). Hanninen initiated field studies in 1966, of workers exposed occupationally to carbon disulfide. The history of this field and the early findings are described in Anger and Johnson (1985). Current data and research strategies are found in many sources, including Anger et al. (1998 and 1999). Detailed information on dealing with issues of human subject variability as it relates to this field can be found in Eckerman et al. (1998). Descriptions of computerized testing systems for field research with humans are found in Anger et al. (1996 and 2003).
Designing Research Projects
Human neurobehavioral research or clinical evaluations of populations exposed to chemicals must be carefully planned, and research must additionally be carefully structured. Planning begins with selecting an hypothesis to be tested. The first step is to design the study and to select a battery of tests to administer to the study Participants. Proven tests should always form the core of the battery. Proven tests may be drawn from consensus batteries such as the World Health Organization-recommended Neurobehavioral Core Test Battery (NCTB) or the Adult Environmental Neurobehavioral Test Battery (AENTB). Selection of primary measures allows the formulation of power analyses to assist in the selection of appropriate tests and determine the number of Participants to be tested to achieve a credible result. Computerized neurobehavioral testing batteries such as the Neurobehavioral Evaluation System (NES2), Swedish Performance Evaluation System (SPES), and Behavioral Assessment and Research System (BARS) add consistency to the tests, and psychological tests and other questionnaires can be administered with the computerized Health Screening System (HSS). Development and implementation of testing protocols, piloting to achieve optimal tests parameters, conduct of the study, quality assurance, data management and steps in analysis are described. This process is described in detail in Anger et al., 1999.
References
Anger WK. Neurobehavioural tests and systems to assess neurotoxic exposures in the workplace and community [invited]. Occupational and Environmental Medicine, 2003, 60: 531-538.
Anger WK, Rohlman DS, Storzbach D. Neurobehavioral Testing in Humans (11.7.1-11.7.17) . Current Protocols in Toxicology (M Maines, L Costa, IG Sipes, S Sasse, DJ Reed, eds). John Wiley & Sons, New York, 1999.
Anger WK, Storzbach D, Amler RW, Sizemore OJ. Human behavioral neurotoxicology: Workplace and community assessments (pp. 709-731). In: Environmental and Occupational Medicine (third edition) (W Rom, Ed.) Lippencott-Raven Publishers, Philadelphia. 1998.
Eckerman DA, Glowa JR, Anger WK. Human variability in response to chemical exposures. In: Measures, Modeling and Risk Assessment (DA Neumann, CA Kimmel, Eds.). CRC Press (ILSI Press), 1998.
Anger WK, Otto DA; Letz R (editors). Symposium on Computerized Behavioral Testing of Humans in Neurotoxicology Research. Dedicated Issue of Neurotoxicology and Teratology, 1996; 18: 347-518.
Anger WK. Worksite behavioral research: Results, sensitive methods, test batteries, and the transition from laboratory data to human health. NeuroToxicology, 1990, 11:629-720.
Anger WK, Johnson BL. Chemicals affecting behavior (pp. 51-148). In: Neurotoxicology of Industrial and Commercial Chemicals (J O’Donoghue, Ed.) Boca Raton, FL: CRC Press, 1985.
Beard RR. Early development of behavioral toxicology in the U.S. In: Xintaras C, Johnson BL, de Groot I, eds. Behavioral Toxicology: Early Detection of Occupational Hazards. Washington, DC: U.S. Government Printing Office: DHEW publication [NIOSH] # 74-126; 1974:427-431.
Hanninen H. Psychological tests in the diagnosis of carbon disulfide poisoning. Work, Environment, Health. 1966;2:16-20.