Malingering indexes for the Halstead Category Test

Two studies were conducted to evaluate potential malingering indexes on the Halstead Category Test. The aim of the first study was that of documenting that groups of individuals with established cognitive impairment did not score positively on the proposed indexes. Of the indexes considered, it was found that these groups made very few errors on subtests I and II of the test and improved their performance on subtest VI relative to V. Subtests I and II are very simple and both subtest V and VI involve the same principle. It was proposed that malingerers would make excessive numbers of errors on subtests I and II, and would not show improvement on subtest VI over subtest V. The second study compared the performance of patients with brain damage to students who were either trained to malinger or encouraged to perform as well as they could on the Category Test. Comparisons were made on the malingering indexes among these groups showing that mean scores of the patients with brain damage on several of the indexes did not differ from those of the students encouraged to do well, but both of these groups did significantly better than the student malingerers. A discriminant analysis of the set of malingering indexes classified 20% of the student malingerers as brain damaged, and 3.4% of the patients with brain damage as malingerers. A stepwise analysis indicated that number of errors on subtests I and II and Total Errors were particularly sensitive to malingering.