Neuropsychological assessment of suboptimal performance: the Word Memory Test

Abstract

Although malingering, suboptimal cognitive performance, and negative response bias represent very problematic confounds in diagnostic work with a number of neurological and some psychiatric illnesses, the evaluation of these tendencies has not yet become common practice in German-speaking countries. Only a limited number of adequately validated instruments are available. The German adaptation of the Word Memory Test (WMT), an internationally renowned test for use in the area of neurocognitive disturbances, is presented. The first study compares performance of a healthy experimental group of malingerers ( n=100) with a healthy control group after standard test instructions ( n=27). The WMT achieved a 100% correct identification of group membership. The second study was carried out with a sample of mentally retarded patients ( n=32) and showed that the WMT was likewise able to identify high performance motivation in almost all of the cases. Only one patient was incorrectly classified. These results are commensurate with the highly sensitive parameters that have been reported for the WMT in North America. With the introduction of the WMT into neuropsychological diagnostic work in Germany, it will become easier to meet quality standards that have become customary internationally.

Word Memory Test failure 23 times higher in mild brain injury than in parents seeking custody: The power of external incentives

“…(4) If their hypothesis were true, we would find fewer WMT failures in university students undergoing ADHD assessments than in children or adults with a verbal IQ below 75. On the contrary, we actually find that the university students of Sullivan [7] failed the WMT far more often than either adults or children of very low verbal intelligence (Table II) [15]. Does mild TBI really produce cognitive deficits markedly greater than those seen in mentally handicapped adults?…”

“…This is consistent with previous research demonstrating that mild mental retardation, by itself, does not impact performance on the WMT effort subtests. Brockhaus & Merten [15] reported that 31 out of 32 institutionalized but testable mentally handicapped adults in Germany were able to pass the WMT using the usual criteria (Table II), showing that low cognitive abilities, in themselves, are not necessarily associated with failure on the WMT. On the contrary, the single group in Table II with the highest levels of education and intelligence were university students, yet they had the highest WMT failure rate of all.…”

“…Given the structure of the WMT, it is very difficult for a person who is not making a full effort to produce plausible scores on all subtests. In several independent studies, the WMT was 99-100% accurate in discriminating between people asked to try their best and those who were asked to simulate memory impairment [13][14][15]. Failure on the WMT in the latter studies and the current study was defined according to the standard criteria outlined in the test manual [1], based on scoring at or below given levels on IR, DR or the consistency between the two.…”

The Relationship of IQ to Effort Test Performance

“…For this reason, different effort indices need to be emphasized, and perhaps new ones developed, for a low IQ population. In this study, the Warrington Recognition Memory Test-Words was effective at low IQ levels, and the limited data available on other forced-choice tests in low IQ groups has frequently been positive with respect to specificity (e.g., Logical Memory Rarely Missed Items Index ¼ 91%, Marshall & Happe, in press; German WMT ¼ 97%, Brockhaus & Merten, 2004; CVLT-2 Recognition ¼ 89%, Marshall & Happe, in press;TOMM ¼ 50-100%, W. R. Drwal, personal communication, August 29, 2005;Graue et al, in press;Kennedy et al, 2005;Hurley & Deal, 2006;Weinborn et al, 2003; Digit Memory Test ¼ 85%, Graue et al, in press). In addition, forced choice scores significantly below chance would not be plausible in any IQ range.…”

Malingering Intellectual Disability: The Value of Available Measures and Methods

“…With regard to the Word Memory Test (WMT), Dean et al (2008, p. 709) reported data from Brockhaus and Merten's (2004) study of 32 German adults with ID. According to Dean, Victor, Boone, and Arnold (2008), Brockhaus and Merten obtained an exceptionally high specificity rate of .97.…”