Cognitive tests: Interpretation for neurotoxicity? (Workshop summary)

The appropriate use and interpretation of cognitive tests presents importan t challenges to the toxicologist and to the risk assessor. For example, int elligence cannot be measured directly; rather intelligence is quantified in directly by scoring responses (i.e., behaviors) to specific situations (pro blems), This workshop, "Cognitive Tests: Interpretation for Neurotoxicity?" provided an overview on the types of cognitive tests available and describ ed approaches by which the validity of such tests can be assessed. Unlike m any tools available to the toxicologist, cognitive tests have a particular advantage. Being noninvasive and species-neutral, the same test can be perf ormed in different mammalian species. This enhances one's ability to assess the validity of test results. Criteria for test validity include comparabl e responses across species as well as similar disruption by the same neurot oxicant across species, Test batteries, such as the Operant Test Battery, h ave indicated remarkable similarity between monkeys and children with respe ct to performance of certain tasks involving, for example, short-term memor y. Still, there is a need for caution in interpretation of such tests, In p articular, cognitive tests, especially when performed in humans, are subjec t to confounding by a range of factors, including age, gender, and, in part icular, education. Moreover, the ability of such tests to reflect intellige nce must be considered. Certain aspects of intelligence, such as the abilit y to plan or carry out specific tasks, are not well reflected by many of th e standard tests of cognition. Nonetheless, although still under developmen t, cognitive tests do hold promise for reliably predicting neurotoxicity in humans.