MMPI-2 interpretation and closed-head trauma: cross-validation of a correction factor

A substantial body of research suggests that the MMPI-2 contains a number of items that are sensitive to closed-head trauma (CHT) and other neurologic conditions. A correction procedure was recommended by Gass (1991) using an index consisting of 14 neurologically sensitive items that were extracted from a predominantly male veteran sample of CHT patients. The generalizability of these correction items was assessed in the present study by investigating the MMPI-2 scoring characteristics of an outpatient referral sample of 54 CHT patients (28 male, 26 female) who had sustained recent and mild head trauma. Their frequency of endorsement of MMPI-2 was contrasted with that of the MMPI-2 normative sample (N = 2,600). Chi-square analyses identified the 15 MMPI-2 items that best differentiated this CHT sample from normal subjects. The results indicate that: (a) unlike those in an inpatient psychiatric sample (n = 524), the MMPI-2 items that best distinguished the CHT Ss from normals consisted of neurologic symptom content; (b) of these 15 items, 10 were included in the 14-item correction (Gass, 1991); and (c) 13 of the 14 correction items effectively discriminated the cross-validation sample of CHT Ss from normals. These findings offer empirical support for the application of the MMPI-2 correction with patients who have mild and recent head trauma.