Examining false positives on the Word Memory Test in adults with mild traumatic brain injury

Brain Inj. 2009 Aug;23(9):741-50.

Green P, Flaro L, Courtney J.

PRIMARY OBJECTIVE: Many adults with mild traumatic brain injury (MTBI) fail effort tests, indicating poor effort and invalid test results. However, two studies have suggested a high rate of false positives on the Word Memory Test (WMT) in adults with MTBI. This study examines the question of false positives in adults with MTBI who failed the effort subtests of the WMT.

RESEARCH DESIGN: A modified and shortened version of the WMT, the Medical Symptom Validity Test (MSVT) was given to adults with MTBI, some of whom failed the WMT. It was also given to samples of schoolchildren in grades two and above, to several hundred children with developmental disabilities and to healthy adults.

OUTCOMES AND RESULTS: Failures on the MSVT were far more frequent in adults with MTBI than in second grade children or in children with developmental disabilities. Adults with MTBI who failed the WMT scored much lower on the MSVT effort subtests than children with a mean FSIQ of 63 and much lower than children with impaired memory.

CONCLUSIONS: Comparison with developmentally disabled children on the MSVT suggests that the adults with MTBI who failed the WMT were not making an effort to do well on either the WMT or the MSVT. Their results were invalid. False positives on the WMT in adults with mild TBI are very rare.