Malingering and other validity considerations in the neuropsychological evaluation of mild head injury.

Eight malingerers (MPs) were identified via significantly below-chance symptom validity testing (SVT) within a sample of 106 consecutive admissions for neuropsychological evaluation. The resulting incidence of 7.5% is seen as a minimal estimate of malingering within the sample. Eight individuals who "passed" SVT but produced neuropsychological data of questionable validity were also identified (QVs). MPs and QVs were compared with matched controls on 14 measures that have been previously suggested as indicators of invalid neuropsychological data. MPs and QVs differed from controls on General Neuropsychological Deficit Scale, Fingertip Number Writing, and Digit Span. CVLT Recognition, Finger Agnosia, and Speech Perception differed for one of the target groups versus controls and had trends toward significance in the other group. However, many of the previously suggested invalidity signs were rare or absent. Reliance on these measures could result in overconfidence in the validity of neuropsychological data.