Correlates of invalid neuropsychological test performance after traumatic brain injury

Primary objective: To investigate external correlates of invalid test performance after traumatic brain injury, as assessed by the California Verbal Learning Test - Second Edition (CVLT-II) and Word Memory Test (WMT).

Research design: Consecutive 2-year series of rehabilitation referrals with a diagnosis of traumatic brain injury (n = 87).

Methods and procedures: Logistic regression analysis was used to determine which demographic and neurological variables best differentiated those with vs. without actuarial CVLT-II or WMT evidence for invalid responding.

Main outcomes and results: Twenty-one participants (about 24%) performed in the invalid range. The combination of a premorbid psychiatric history with minimal or no coma was associated with an approximately four-fold increase in the likelihood of invalid performance.

Conclusions: Premorbid psychosocial complicating factors constitute a significant threat to validity of neuropsychological test results after (especially mild) traumatic brain injury. At the same time, care should be taken to not routinely assume that all persons with mild traumatic brain injury and premorbid psychiatric histories are simply malingering. The WMT appears to be a promising instrument for the purpose of identifying those cases where neuropsychological test results are confounded by factors not directly related to acquired cerebral impairment.