The use of neurobehavioural test batteries for research, diagnosis and screening: methodological aspects.

In recent years neurobehavioural tests have been used increasingly in occupational and environmental settings to identify changes in cognitive functioning associated with exposure to neurotoxicants. Applications in cross-sectional research studies, involving the comparison of the performance of exposed and control groups, are relatively well established. However, the use of such methods requires attention to a variety of methodological issues including aspects of study design such as sample size, the selection of appropriate controls, the separation of acute and chronic effects and control or adjustment for numerous potential influences on performance. Studies requiring repeated testing, such as longitudinal investigations or studies of acute effects require attention to learning and practice effects and diurnal rhythms. The validity of adapting existing test batteries for use as diagnostic or screening instruments is questionable. Well-developed techniques exist for diagnosis but this requires lengthy and skilled test administration and interpretation and cannot be accomplished using research batteries. Existing tests may, in the future, be used for screening, but a number of problems will need to be addressed before they can be successfully applied in this context.