Test of Premorbid Functioning: You're Doing It Wrong, but Does It Matter?

ABSTRACT

OBJECTIVE: Clarify procedures to correctly score Test of Premorbid Functioning (TOPF) and assess the accuracy of TOPF scores in the estimation of premorbid intellectual functioning. METHOD: In this cross-sectional study, post-9/11 veterans (N = 233, 84.12% male) completed the TOPF, the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV), and performance validity measures. RESULTS: All TOPF scores were significantly correlated with WAIS-IV FSIQ scores (range r = 0.56-.73). The degree of discrepancy between TOPF scores and FSIQ varied with 10%-17% of TOPF scores deviating from FSIQ scores by one SD or more. CONCLUSIONS: Proper TOPF scoring procedures are presented. The TOPF Actual and Predicted scores were related to FSIQ. However, a higher percentage of Actual and Predicted scores were discrepant from FSIQ compared with the other three TOPF estimates, arguing against their use as independent premorbid estimates. Use of the TOPF as was designed is recommended.