Verbal fluency indicators of malingering in traumatic brain injury: classification accuracy in known groups.

A known-groups design was used to determine the classification accuracy of verbal fluency variables in detecting Malingered Neurocognitive Dysfunction (MND) in traumatic brain injury (TBI). Participants were 204 TBI and 488 general clinical patients. The Slick et al. (1999) criteria were used to classify the TBI patients into non-MND and MND groups. An educationally corrected FAS Total Correct word T-score proved to be the most accurate of the several verbal fluency indicators examined. Classification accuracy of this variable at specific cutoffs is presented in a cumulative frequency table. This variable accurately differentiated non-MND from MND mild TBI patients but its accuracy was unacceptable in moderate/severe TBI. The clinical application of these findings is discussed.