Effects of coaching on detecting feigned cognitive impairment with the Category test.

In a replication and extension of previous research (Tenhula & Sweet, 1996), the current study investigated the utility of the Category Test (CT) for detecting feigned cognitive impairment. Ninety-two undergraduate participants were randomly assigned to one of three groups and administered the CT. A Coached Simulator group was instructed to simulate cognitive impairment and was provided test-taking strategies to avoid detection. An Uncoached Simulator group was simply instructed to feign impairment. A control group was instructed to perform optimally. In addition, the CT results of 30 traumatic brain injury (TBI) patients were analyzed. The results largely supported the utility of five CT malingering indicators identified by Tenhula and Sweet: (a) number of errors on subtests I and II, (b) number of errors on subtest VII, (c) total CT errors, (d) number of errors on 19 "easy" items, and (e) number of criteria exceeded. Correct Classification rates of the five indicators for Uncoached Simulators and optimal performance controls ranged from 87% to 98%. Correct Classification rates for the TBI patients ranged from 70% to 100%. In addition, significantly more Coached Simulators were misclassified as nonsimulators on four of the CT malingering indicators, relative to their Uncoached counterparts. A decision rule of > 1 error on subtests I and II was consistently the most accurate malingering indicator, regardless of degree of coaching or presence of TBI. This indicator correctly classified 76% of all simulators and 100% of the optimal performance controls and TBI patients. Implications of providing persons with test-taking strategies and the utility of these CT malingering indicators for various populations are discussed.