Should the retention trial of the Test of Memory Malingering be optional? A reply

Archives of Clinical Neuropsychology 22 (2007) 87–89 Commentary Should the retention trial of the Test of Memory Malingering be optional? A reply Randee L. Booksh ∗ , Melissa J. Aubert, Susan R. Andrews Neuropsychological Services for Children and Adults, LLC, 2626 N. Arnoult Road, Suite 220, Metairie, LA 70002, United States Accepted 2 November 2006 Keywords: Malingering; Test of Memory Malingering; Effort testing Greve and Bianchini (2006) have posed the question, “Should the Retention trial of the Test of Memory Malingering be optional?” The answer to this question is important given the finding by Slick, Tan, Strauss, and Hultsch (2004) that the Test of Memory Malingering (TOMM; Tombaugh, 1996) is one of the most commonly used malingering tests among surveyed psychologists. Greve and Bianchini (2006) suggest the Retention Trial should always be administered, based on their finding that 3% of their sample of 300 patients with traumatic brain injury or chronic pain obtained a score below 45 on the Retention Trial of the TOMM, after obtaining passing scores (45 or greater) on Trial 2. The authors suggest that administering the Retention trial “detected” this minority of malingerers that would have otherwise not been identified (Greve & Bianchini, 2006). It is reported in the TOMM manual that 3.1% of the cognitively impaired group, not involved in litigation or considered “at risk” for malingering, scored below 45 on the Retention Trial (Tombaugh, 1996). This raises the possibility that the probable malingerers in Greve and Bianchini’s study scored below 45 on the Retention Trial for reasons other than frank malingering. Greve and Bianchini (2006) suggest always administering the Retention trial even though their data do not significantly differ from the statistics published in the manual. It appears that Greve and Bianchini (2006) may simply prefer a more conservative criterion rule. In their article, Greve and Bianchini (2006) report that they administer the Retention trial of the TOMM (Tombaugh, 1996) in “standard fashion” to all patients. The authors also repeatedly refer to an “early termination criteria,” implying that all three trials of the TOMM are supposed to be administered to all individuals and that one is remiss if they do not do so. However, according to the TOMM manual, the Retention Trial is an optional test that need be administered only if the score of Trial 2 is less than 45 (Tombaugh, 1996, p. 18). In addition, Greve and Bianchini (2006) report that they use standard scoring and stated that their scoring is “consistent with the manual”. Further, they state that scores of 45 or higher on Trial 2 and the Retention trial were considered passing while scores below 45 on either Trial 2 or on the Retention trial are suggestive of malingering. Although the manual states that any score lower than 45 on Trial 2 or on the Retention Trial should raise concerns that ∗ Corresponding author. Tel.: +1 504 831 0109; fax: +1 504 834 8802. E-mail address: (R.L. Booksh). 0887-6177/$ – see front matter © 2006 National Academy of Neuropsychology. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.acn.2006.11.002 88 R.L. Booksh et al. / Archives of Clinical Neuropsychology 22 (2007) 87–89 the individual is not putting forth maximum effort, it also states that this decision rule uses the score on Trial 2 as its point of reference, not the Retention Trial (Tombaugh, 1996, p. 19–22). Greve and Bianchini (2006) imply that always administering the Retention Trial of the TOMM may increase its sensitivity. Recent work by O’Bryant and Lucas (2006) shows the TOMM has a very high positive predictive value (.98), when compared with the Word Memory Test (as a gold standard) and an acceptable negative predictive value (.78). As Mossman (2003) points out in his discussion of cognitive malingering and test accuracy, when establishing a cutoff score to distinguish positive from negative results, malingering tests are often treated as if they are binary, when there is a range of outcomes. This point highlights the importance of considering the distance between the patients’ individual scores from the cutoff. When using a cutoff score, the TOMM results in two overlapping distributions, and trade offs occur between sensitivity and specificity. When considering the diagnostic accuracy of an instrument, the base rate of malingering in the given population must also be considered. Mittenberg, Patton, Canyock, and Condit (2002) found that reported base rates of malingering in personal injury were related to the proportion of plaintiff versus defense referrals. At least one study has shown that a lower cutoff score is appropriate when working with a population that has a higher base rate of malingering (Weinborn, Orr, Woods, Conover, & Felix, 2003). It appears that different cutoff scores may be appropriate for different populations. Administration time also appears to factor strongly in psychologists’ decisions on which malingering instruments to use, and may effect patient performance as well. Slick et al. (2004) conducted a survey of experts’ practices, and reported a significant minority of psychologists (about 21%) do not routinely use any specialized technique for detecting malingering in litigant assessment. The authors found the Rey 15-Item test and the TOMM were the most frequently used measures (Slick et al., 2004). This appears due to the ease of administration and the brief administration time of these measures. Increasing the administration time of the TOMM is not likely to improve the frequency of its use and does not appear to increase its usefulness in detecting malingering. In fact, two recent publications (Gavett et al., 2005; Horner, Bedwell, & Duong, 2006) suggest that even briefer administrations of the TOMM, using only Trial 1, may be appropriate in some instances and that lowering the criterion score still provides acceptable positive and negative predictive value for the TOMM. A score as low as 36 on Trial 1 indicated a 99% likelihood that the TOMM would be passed in the study by Horner et al. (2006). Using an abbreviated form may improve psychologists’ likelihood of adhering to the recommendation by Slick, Sherman, and Iverson (1999) to use at least two well-validated measures for detecting suboptimal effort in any standard assessment of litigants. No specific guideline has been offered with regard to the maximum number of malingering tests that should be given or the appropriateness of a battery exclusively designed to detect malingering. Greve and Bianchini (2006) report that it is the standard practice of their clinic to always administer the TOMM Retention Trial regardless of outcome on Trial 2, in addition to at least one other symptom validity test, usually the Portland Digit Recognition Test. The authors also report using the malingering indices on the MMPI-2 and stated that some subjects were also given the Word Memory Test. It is possib (...truncated)