Effects of Coaching on Detecting Feigned Cognitive Impairment with the Category Test

Abstract

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.

Malingering Indexes for the Halstead Category Test

“…On subtests I and II, the student controls made an average of less than 1 error, the brain-damaged group made an average of 1.2 errors, and the student malingering group made an average of 4.9 errors. These results are consistent with findings in the literature (e.g., Tenhula and Sweet, 1996;DiCarlo et al, 2000) suggesting that indeed, the HCT indexes perhaps most sensitive to malingering are errors on subtests I and II. However, it should be noted that participants in the current study were not coached as to HCT structure and content.…”

“…With regard to performance on subtests I and II, it has been suggested by several researchers that making more than one error on the first two subtests may be the single best predictor of malingering on the HCT, as even patients with severe brain injury rarely miss any of these items (e.g., DiCarlo et al, 2000;Tenhula & Sweet, 1996;Reitan & Wolfson, 1993). The current data are largely consistent with this suggestion but also indicate that a slightly greater percentage of errors are made on subtest II than subtest I and that a more liberal cut-off or two or more errors would misclassify substantially fewer individuals as malingering.…”

Limited Predictive Accuracy of the Booklet Category Test in a Criminal Forensic Sample

“…A cutoff of > 1 on Subtests I and II demonstrated the highest overall classification rate of 71% with 95% specificity and 49% sensitivity. This comparatively stronger performance of > 1 errors on Subtests I and II was consistent with previous studies by DiCarlo et al (2000), Forrest et al (2004), Tenhula and Sweet (1996), and Sweet and Nelson (2007). While an AUC of .72 signifies only acceptable discrimination (Hosmer & Lemeshow, 2000), a positive finding on this index resulted in a PPV of more than .90 at the expected base rate of exaggeration among this population (Ardolf et al, 2007).…”

“…The ''difficult items'' index was found to have the least effectiveness in the detection of malingering (Tenhula & Sweet). DiCarlo, Gfeller, and Oliveri (2000) conducted an extension and replication of Tenhula and Sweet's (1996) research. The study found malingering simulation groups scored lower than traumatic brain injury (TBI) and control groups.…”

The Rey AVLT Serial Position Effect: A Useful Indicator of Symptom Exaggeration?

“…The SPE was examined in four groups: normal controls (NC), symptom-coached simulators (SC), test-coached simulators (TC), and a group of unequivocal moderate to severe subacute traumatic brain injury patients (TBI). TC simulators have been shown to engage in more sophisticated malingering compared to SC simulators (DiCarlo, Gfeller, & Oliveri, 2000). The present investigation extends previous research on the SPE on the RAVLT (e.g., Bernard, 1991;Suhr, 2002;and Sullivan et al, 2002) by varying the coaching paradigm across sophisticated malingering groups, by using more stringent criteria to define suppression of the primacy effect (described above), and by investigating the diagnostic utility (i.e., documenting the classification accuracy statistics) of the SPE (i.e., suppression of the primacy effect) in predicting poor effort.…”