The prevalence of cognitive malingering in persons reporting exposure to occupational and environmental substances

ObjectiveDirectly estimate the prevalence of cognitive malingering in persons claiming exposure to occupational and environmental substances.MethodsRetrospective review of 128 neuropsychological cases with financial incentive. Estimates were based on two methods: (1) clinical identification using the Slick, Sherman and Iverson criteria for malingered neurocognitive dysfunction (MND), and (2) statistical modeling based on patient performance on several individual psychometric indicators of malingering.ResultsThe prevalence based on the clinical method was 40%. The statistically based estimates ranged from 30% to more than 45% depending on model parameters. Different incentive parameters may influence prevalence.ConclusionsCognitive malingering in toxic exposure is common and must be adequately addressed in the clinical neuropsychological assessment of toxic exposure and in research on its neurocognitive effects or findings will likely over-estimate the degree of cognitive impairment and related disability.