Investigation of biases in the general public in evaluating mild head injury using neuropsychological and CT scan results: forensic implications.

The purpose of this study was to determine how the general public considers neuropsychological (NP) vs. CT scan data in assessing the effects of a possible mild traumatic brain injury (MTBI). Ten scenarios depicting an MTBI from a motor vehicle accident were presented to community volunteer participants. Case scenarios differed with regard to diagnostic information presented (i.e., all combinations of normal, abnormal, or absent NP and CT results were provided). The number of participants ranged from 31 to 42 across the 10 cases and there were no age or educational differences among the groups. Participants rated the likelihood of symptoms being attributable to brain damage from the accident on a 7-point Likert-type scale. Scenarios with positive NP or CT results were rated as more likely to have sustained brain damage than when NP/CT results were negative. However, when NP and CT data were contradictory (i.e., one positive and the other negative), there were no differences in the ratings of the participants. Thus, members of the general public did not demonstrate any preconceived bias about the validity of NP vs. CT results in MTBI. Women were more likely than men to attribute symptoms to brain damage from the motor vehicle accident, as did participants with a history of TBI. Forensic implications are discussed.