Malingering and mild brain injury: how low is too low

The purpose of this study was to investigate potential validity markers for 4 commonly used neuropsychological tests. Participants were divided into 5 groups: moderate/severe brain injury (n = 27), mild brain injury--nonlitigating (n = 35), normal controls (n = 30), mild brain injury--litigating (n = 49), and malingering "actors" (n = 20). Participants completed a flexible neuropsychological battery that included the 4 tests of interest (Judgment of Line Orientation, Token Test, Dichotic Listening, and 20-item forced choice). Results demonstrated cutoff levels on all 4 tests below which people with mild brain injury would not be expected to fall. The fact that some litigants, but no nonlitigants, fell below these cutoff levels suggests these tests and their cutoff levels may be used appropriately as internal validity markers. There was 100% specificity and 95% sensitivity found when all 4 tests were used together (1-test criteria) to separate litigants, nonlitigants, and actors. It is suggested that further examination of these tests and other neuropsychological tests, be completed so that, eventually, all neuropsychological tests will have internal validity markers.