Nonverbal Medical Symptom Validity Test performance of elderly healthy adults and clinical neurology patients

Abstract

The study aimed to provide independent data on the specificity of the Nonverbal Medical Symptom Validity Test (NV-MSVT; Green, 2008 ), a new test that combines conventional decision making based on cutoffs with profile analyses in order to identify invalid test performance and to reduce false positive classifications. The results of 65 bona fide neurological patients (with 21 of them meeting Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition, DSM-IV, core criteria for dementia) were compared to 50 healthy volunteers. One patient was wrongly classified as malingering, resulting in a specificity of 98.5% for neurological patients and 100% for controls. A total of 13 patients with dementia (62%), 6 patients without dementia (14%), and 1 healthy participant exhibited a dementia profile in the NV-MSVT. While these results confirm the high specificity of the NV-MSVT for the classification insufficient effort, its sensitivity has to be verified by independent research data.

Sensitivity of the Test of Memory Malingering and the Nonverbal Medical Symptom Validity Test: A Replication Study

“…The profile makes intuitive sense, in that performances on the more difficult subtests (i.e., non-forced-choice recognition and free recall trials) are much worse than performances on easier subtests (i.e., various forced-choice trials). These profiles have been observed in other samples with dementia (Henry, Merten, Wolf, & Harth, 2009;Singhal, Green, Ashay, Shankar, & Gill, 2009). Greater detail regarding the specificity of the NV-MSVT can be found elsewhere (e.g., Green, 2011).…”

“…If Criterion A and any of Criteria B1, B2, or B3 are failed, the examinee is judged to be giving poor effort. The sensitivity and specificity of these decision rules have been supported across multiple studies (Green, 2008;Green, Flaro, Brockhaus, & Montijo, 2010;Henry et al, 2009;Singhal et al, 2009).…”

“…By demonstrating these types of profiles, those individuals who failed the NV-MSVT but passed the TOMM evidenced results that are inconsistent across the various NV-MSVT subtests that differ in objective difficulty. These profiles are typical of simulators but are very infrequently seen in people with genuine memory impairment (Green, 2011(Green, , 2008Henry et al, 2009;Singhal et al, 2009). Of particular interest is what Green (2011) refers to as a ''paradoxical profile.''…”

“…The final subtest is a free recall task where the examinee is asked to recall from memory as many items from the original list of paired items as possible. The sensitivity and specificity of the NV-MSVT have been demonstrated in a variety of patient populations (Green, 2008;Henry et al, 2009;Singhal et al, 2009).…”

“…The NV-MSVT is similar to the MSVT and WMT in that the measure possesses a range of subtests that demonstrate a gradient of difficulty and these subtests allow for a profile analysis. The use of such profile analysis has been shown to achieve high sensitivity to poor effort in simulators and high specificity in people with severe impairment (Green, 2007(Green, , 2008Henry et al, 2009;Singhal et al, 2009). In the Green (2011) study, profile analysis demonstrated that for those who failed the NV-MSVT but passed the TOMM, the pattern of results better matched simulator samples rather than samples with actual severe impairment.…”