Validity of a computer-assisted neurobehavioral test battery in toxicant encephalopathy

The computer-assisted Neurobehavioral Evaluation System 2 (NES2) test battery provides an efficient method of measuring neurobehavioral effects in epidemiological studies, and a newer computer-assisted battery, NES3, has been developed to assist in neuropsychological assessment. This study assesses the validity of some NES2 and NES3 tests in patients diagnosed with toxicant encephalopathy (TE) following exposure to lead or to mixed solvents. This information can be used to improve the interpretation of NES test results in research studies and clinical evaluations examining central nervous system function. Performance on a battery of computer-assisted tests, consisting of several NES2 and NES3 tasks, by persons diagnosed with TE was compared to that of control subjects to determine if performance differences reflected a priori hypothesized brain-behavior relationships. Performance on the NES2 and NES3 tests was also correlated with performance on analogous standard neuropsychological tests. Significant performance differences between the patient cases and controls were observed in most of the predicted domains on the NES tests. Overall, moderate correlations were obtained between standard neuropsychological tests and NES2 and NES3 tests from the same functional domains. The results suggest that a test battery composed of NES2 and NES3 tests can identify clinically significant performance deficits in solvent-exposed patients who have been diagnosed with TE using traditional clinical neuropsychological test methods. The results with lead-exposed TE patients are less robust. Possible explanations for these differences are discussed.