Comparison of time and error rates on the trail making test among patients with head injuries, experimental malingerers, patients with suspect effort on testing, and normal controls.

Clinical utility of completion time and performance errors was investigated for the Trail Making Test (TMT; Reitan, 1958). Archival neuropsychological files for patients with mild and moderate/severe head injuries, as well as patients with suspect effort on neuropsychological testing, were examined and compared to controls and experimental malingerers. Time-to-completion scores differentiated the participants who were malingering and who gave suspect effort from those patients with head injuries. There were no differences in error rates among the head-injury groups or controls for either the TMT-A or TMT-B. Errors were also not uncommon among normal controls; 12% and 35% of the controls made at least one error on TMT-A and TMT-B, respectively. However, error rates for both the suspect-effort and malingering groups were inflated on TMT-B as compared to the head-injured and control groups. Results suggest that performance errors on the TMT lack diagnostic utility for persons with head injuries, and time-to-completion is still the best indicator of neuropathology. However, performance errors, in conjunction with inflated time scores on the TMT, may be useful in the assessment of malingering.