The Medical Symptom Validity Test Measures Effort Not Ability in Children: A Comparison Between Mild TBI and Fetal Alcohol Spectrum Disorder Samples.

Inadequate effort during neuropsychological examination results in inaccurate representations of an individual's true abilities and difficulties. As such, performance validity tests (PVTs) are strongly recommended as standard practice during adult-based evaluations. One concern with using PVTs with children is that failure reflects immature cognitive ability rather than non-credible effort. The current study examined performance on the Medical Symptom Validity Test (MSVT) in two large pediatric clinical samples with strikingly different neuropsychological profiles: (1) mild traumatic brain injury (mTBI; n = 510) and (2) fetal alcohol spectrum disorder (FASD; n = 120). Despite higher IQ scores and reading ability, the mTBI group performed significantly worse than the FASD group on all effort indices. Sixteen percent of the mTBI group failed the MSVT, whereas only 5% of the FASD group did. Our findings support the idea that the MSVT measures effort, not ability, in most cases and help to justify incorporating PVTs into pediatric neuropsychological batteries.