Embedded symptom validity tests and overall neuropsychological test performance.

A sample of 314 consecutive clinical and forensic referrals with mild traumatic brain injury was evaluated using the Meyers Neuropsychological Battery (MNB). A comparison was made of the test performance and performance on the embedded Symptom Validity Tests (SVTs) with a control for multicolinearity utilized. Using the nine embedded SVTs in the MNB, the incidence of poor effort fell at 26% of the total sample. Involvement in litigation was related to more failures on the individual SVTs. The correlation between failed effort measures and the Overall Test Battery Mean (OTBM) was consistently negative, regardless of litigation status, in that more failures were associated with lower OTBM scores. The correlation between the number of SVTs failed and the OTBM was -.77. Our results are similar to those presented by Green, Rohling, Lees-Haley, and Allen (2001); who reported a .73 correlation with the failure on the Word Memory Test and performance on the OTBM. The results of the current study also indicate that 50% of the variance in neuropsychological testing can be accounted by failures on internal SVTs.