VALIDITY OF NEUROPSYCHOLOGICAL TEST-RESULTS IN DISABILITY EVALUATIONS

A group of 50 disability claimants referred by the Social Security Adm inistration for neuropsychological screening were administered a 36-it em, forced-choice, digit-recognition method of detecting malingering t o assess effort and motivation to perform well. This abbreviated form of the 1989 Hiscock and Hiscock Forced-choice Procedure has been shown to be quite easy even for individuals with severe organic brain dysfu nction. A perfect performance of 36 correct on this digit-recognition task is obtained by most individuals with moderate to severe brain dam age. A performance of less than 90% correct is due more likely to poor effort or even malingering rather than brain damage. In this sample, 18% (n = 9) obtained scores of less than 90% correct, i.e., < 33, whic h calls into question the reliability and validity of test data obtain ed. An additional 20% (n = 10) obtained intermediate scores of 33 to 3 5 correct. These intermediate scores are more difficult to interpret a lthough at least some proportion of those scores reflects poor motivat ion. The results over-all indicate that nearly one-fifth of potential disability claimants produced invalid and uninterpretable neuropsychol ogical test protocols and an additional one-fifth obtained protocols t hat should be well scrutinized for evidence of poor effort as well. Ne uropsychologists conducting disability evaluations are urged to use me asures designed specifically to assess effort and motivation.