Performance validity and neuropsychological outcomes in litigants and disability claimants

This study examined the relationship of performance validity and neuropsychological outcomes in a sample of individuals referred for independent neuropsychological examination in the context of reported traumatic brain injury (82% mild). Archival data were examined on 175 participants aged 20 to 65 who were administered at least two performance validity measures. Participants who passed all effort measures (Pass; n=61) outperformed those who failed two or more (Fail; n=70) on the majority of tests in the neuropsychological battery. The Fail group showed a higher percentage of impaired test scores than the Pass group with impairment defined at three levels (T scores<40, 35, and 30). At the most conservative impairment cutoff (T<30), 16% of the Pass group demonstrated impaired scores on more than three measures, while 79% of the Fail group showed impaired scores on more than three measures. The number of effort measures failed correlated highly with the overall test battery mean (r=.73). On cognitive domain summary scores, effect sizes based on levels of effort (d=1.12 to 1.86) were higher than those based on injury severity (d=0.03 to 0.36).