Feigned neurocognitive deficit: Taxon or dimension?

Development and application of novel performance validity metrics for computerized neurocognitive batteries

OBJECTIVES

Data from neurocognitive assessments may not be accurate in the context of factors impacting validity, such as disengagement, unmotivated responding, or intentional underperformance. Performance validity tests (PVTs) were developed to address these phenomena and assess underperformance on neurocognitive tests. However, PVTs can be burdensome, rely on cutoff scores that reduce information, do not examine potential variations in task engagement across a battery, and are typically not well-suited to acquisition of large cognitive datasets. Here we describe the development of novel performance validity measures that could address some of these limitations by leveraging psychometric concepts using data embedded within the Penn Computerized Neurocognitive Battery (PennCNB).

METHODS

We first developed these validity measures using simulations of invalid response patterns with parameters drawn from real data. Next, we examined their application in two large, independent samples: 1) children and adolescents from the Philadelphia Neurodevelopmental Cohort (n = 9498); and 2) adult servicemembers from the Marine Resiliency Study-II (n = 1444).

RESULTS

Our performance validity metrics detected patterns of invalid responding in simulated data, even at subtle levels. Furthermore, a combination of these metrics significantly predicted previously established validity rules for these tests in both developmental and adult datasets. Moreover, most clinical diagnostic groups did not show reduced validity estimates.

CONCLUSIONS

These results provide proof-of-concept evidence for multivariate, data-driven performance validity metrics. These metrics offer a novel method for determining the performance validity for individual neurocognitive tests that is scalable, applicable across different tests, less burdensome, and dimensional. However, more research is needed into their application.

Dimensions over categories: a meta-analysis of taxometric research

Taxometric procedures have been used extensively to investigate whether individual differences in personality and psychopathology are latently dimensional or categorical ('taxonic'). We report the first meta-analysis of taxometric research, examining 317 findings drawn from 183 articles that employed an index of the comparative fit of observed data to dimensional and taxonic data simulations. Findings supporting dimensional models outnumbered those supporting taxonic models five to one. There were systematic differences among 17 construct domains in support for the two models, but psychopathology was no more likely to generate taxonic findings than normal variation (i.e. individual differences in personality, response styles, gender, and sexuality). No content domain showed aggregate support for the taxonic model. Six variables - alcohol use disorder, intermittent explosive disorder, problem gambling, autism, suicide risk, and pedophilia - emerged as the most plausible taxon candidates based on a preponderance of independently replicated findings. We also compared the 317 meta-analyzed findings to 185 additional taxometric findings from 96 articles that did not employ the comparative fit index. Studies that used the index were 4.88 times more likely to generate dimensional findings than those that did not after controlling for construct domain, implying that many taxonic findings obtained before the popularization of simulation-based techniques are spurious. The meta-analytic findings support the conclusion that the great majority of psychological differences between people are latently continuous, and that psychopathology is no exception.

Concepts and controversies of malingering: A re-look

Since time immemorial, humans have tried to feign physical and mental illnesses for various reasons. This led to the development of the concept of illness deception or malingering when one tries to assume a sick role and feigns signs and symptoms to gain external incentives. The conceptual framework of malingering has undergone several changes and there is sufficient evidence to demonstrate that malingering exists. However, the diagnosis of malingering has not yet been established in the mainstream psychiatric nosological systems and still it is present in the appendices as an additional area requiring attention. This is due to the poor construct validity of the diagnosis, problems in defining malingering, problems in assessment by psychological tests and clinical assessment methodology, no well-established guidelines to detect malingering and issues related to labelling/reporting malingering. Because of several controversies in multiple domains of assessment and ethical-social issues, malingering as a distinct entity is grossly neglected. In the upcoming arena of law suits and consumer benefits suits, it is extremely important to have a better understanding of the conceptual issues related to malingering and the controversies related to it. In this review, a brief overview of evolution of concepts and controversies related to malingering is described.

Performance Validity, Neurocognitive Disorder, and Post-concussion Symptom Reporting in Service Members with a History of Mild Traumatic Brain Injury

Objective

To examine the influence of different performance validity test (PVT) cutoffs on neuropsychological performance, post-concussion symptoms, and rates of neurocognitive disorder and postconcussional syndrome following mild traumatic brain injury (MTBI) in active duty service members.

Method

Participants were 164 service members (Age: M = 28.1 years [SD = 7.3]) evaluated on average 4.1 months (SD = 5.0) following injury. Participants were divided into three mutually exclusive groups using original and alternative cutoff scores on the Test of Memory Malingering (TOMM) and the Effort Index (EI) from the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS): (a) PVT-Pass, n = 85; (b) Alternative PVT-Fail, n = 53; and (c) Original PVT-Fail, n = 26. Participants also completed the Neurobehavioral Symptom Inventory.

Results

The PVT-Pass group performed better on cognitive testing and reported fewer symptoms than the two PVT-Fail groups. The Original PVT-Fail group performed more poorly on cognitive testing and reported more symptoms than the Alternative PVT-Fail group. Both PVT-Fail groups were more likely to meet DSM-5 Category A criteria for mild and major neurocognitive disorder and symptom reporting criteria for postconcussional syndrome than the PVT-Pass group. When alternative PVT cutoffs were used instead of original PVT cutoffs, the number of participants with valid data meeting cognitive testing criteria for neurocognitive disorder or postconcussional syndrome decreased dramatically.

Conclusion

PVT performance is significantly and meaningfully related to overall neuropsychological outcome. By using only original cutoffs, clinicians and researchers may miss people with invalid performances.

You'd Better Believe It: The Conceptual and Practical Challenges of Assessing Malingering in Patients With Chronic Pain

Chronic pain is a prevalent and costly condition, with many patients receiving income support and funded treatment. Given that pain cannot be assessed objectively, patients may be suspected of exaggerating their pain and disability to receive additional funding. Although numerous methods of detecting malingering have been suggested, it is unclear whether clinicians can reliably identify malingering in patients with chronic pain. The present focus article was developed to assess the theoretical basis and empirical support for proposed methods of detecting malingering in patients with chronic pain. Five approaches were identified: the evaluation of behavioral signs, effort testing, pen and paper measures, symptom validity tests, and combined methods. An examination of the literature revealed that proposed assessment tools have little theoretical basis or empirical support in patients with chronic pain. Additionally, assessment tools are inconsistent with advances in pain science and scores or observations are likely to be influenced by the typical features of chronic pain, including fear-avoidance and central sensitization. Clinicians should be aware that as yet neither subjective clinical opinions nor clinical detection methods can reliably identify malingering in patients with chronic pain. Perspective: There is interest in the development of assessment tools to detect malingering in patients with chronic pain. An evaluation of methods reveals theoretical and empirical limitations that undermine the usefulness of these approaches. As yet, there is no reliable way for clinicians to identify malingering in patients with chronic pain.

An International Perspective on Feigned Mental Disabilities: Conceptual Issues and Continuing Controversies

In forensic contexts, an increased prevalence of feigned symptom presentations should be expected, although it will probably vary by the context and specific forensic issue. Forensic experts should examine this possibility proactively while maintaining a balanced perspective that actively considers clinical data for both feigning and genuine responding. Psychological measures and standardized methods developed for feigning and other response styles can facilitate these often complex determinations. The current article provides an international perspective on the issue of feigned mental disabilities. In particular, important conceptual issues are discussed, such as the categorical versus dimensional approaches to feigning, and the advisability of well-defined rather than single-point cut scores for accuracy in clinical decision-making. Salient problems of differential diagnosis include a spectrum from malingering and factitious disorders to somatoform and conversion disorders. In rendering these important diagnostic distinctions, the questions of motivations and intentions remain key. However, the establishment of motivation cannot be facilely assumed from the context. Instead, forensic psychologists and psychiatrists bear the professional burden of carefully evaluating motivation and recognizing the clinical reality that sometimes the motivation in especially challenging cases may not be fully determined. Copyright © 2017 John Wiley & Sons, Ltd.

Biased Symptom Reporting and Antisocial Behaviour in Forensic Samples: A Weak Link

In two studies (one with 57 forensic inpatients and one with 45 prisoners) the connection between biased symptom reporting and antisocial behaviour is explored. The findings are as follows: 1) the association between symptom over-reporting and antisocial features is a) present in self-report measures, but not in behavioural measures, and b) stronger in the punitive setting than in the therapeutic setting; and 2) participants who over-report symptoms a) are prone to attribute blame for their offence to mental disorders, and b) tend to report heightened levels of antisocial features, but the reverse is not true. The data provide little support for the inclusion of antisocial behaviour (i.e. antisocial personality disorder) as a signal of symptom over-reporting (i.e. malingering) in the Diagnostic and Statistical Manual of Mental Disorders - Fifth Edition (DSM-5). The empirical literature on symptom over-reporting and antisocial/psychopathic behaviour is discussed and it is argued that the utility of antisocial behaviour as an indicator of biased symptom reporting is unacceptably low.

The Taxonic Latent Structure and Taxometrics in Forensic Mental Health

Recently, researchers in the field of forensic mental health have attempted to address the technical, empirical question of whether important clinical problems, such as psychopathy or malingering, constitute taxa (i.e., discrete conditions). In this paper, we provide a detailed elucidation of the foundational logic of the quantitative methods employed to answer this question, focusing on the taxometric procedures developed by Paul Meehl and colleagues. We attempt to demonstrate that research on taxonicity is hampered by (a) researchers' unfamiliarity with or misunderstanding of the logic underlying latent variable technologies and (b) the fundamental incapacity of Meehlian procedures to provide a test of taxonicity. We conclude by discussing the utility of taxometric procedures to research in forensic mental health and, more broadly, in the field of applied psychological measurement.

Effort in acute traumatic brain injury: considering more than pass/fail

PURPOSE/OBJECTIVE

Performance validity is often conceptualized as a dichotomous process. Effort likely lies on a continuum, however, and psychologists' tendency to rely on pass/fail descriptors of one's effort may not be the only approach. The current study aims to show that when performance validity is considered on a continuum, it may provide clinical information related to cognitive functioning.

RESEARCH METHOD/DESIGN

Forty-four patients with moderate or severe traumatic brain injury were evaluated with the Repeatable Battery for the Assessment of Neuropsychological Status upon their emergence from posttraumatic amnesia. From this data, previously developed effort index scores and "other cognitive functions" index scores were calculated.

RESULTS

Performance on the effort index significantly accounted for the patients' performance on a cognitive composite score after considering education and severity of injury.

CONCLUSIONS/IMPLICATIONS

Findings suggest that more in-depth analysis of validity test performance is beneficial to gauge a patient's level of effort and is important to consider when interpreting results and in treatment planning.

Factitious disorders and malingering: challenges for clinical assessment and management

Compared with other psychiatric disorders, diagnosis of factitious disorders is rare, with identification largely dependent on the systematic collection of relevant information, including a detailed chronology and scrutiny of the patient's medical record. Management of such disorders ideally requires a team-based approach and close involvement of the primary care doctor. As deception is a key defining component of factitious disorders, diagnosis has important implications for young children, particularly when identified in women and health-care workers. Malingering is considered to be rare in clinical practice, whereas simulation of symptoms, motivated by financial rewards, is regarded as more common in medicolegal settings. Although psychometric investigations (eg, symptom validity testing) can inform the detection of illness deception, such tests need support from converging evidence sources, including detailed interview assessments, medical notes, and relevant non-medical investigations. A key challenge in any discussion of abnormal health-care-seeking behaviour is the extent to which a person's reported symptoms are considered to be a product of choice, or psychopathology beyond volitional control, or perhaps both. Clinical skills alone are not typically sufficient for diagnosis or to detect malingering. Medical education needs to provide doctors with the conceptual, developmental, and management frameworks to understand and deal with patients whose symptoms appear to be simulated. Central to the understanding of factitious disorders and malingering are the explanatory models and beliefs used to provide meaning for both patients and doctors. Future progress in management will benefit from an increased appreciation of the contribution of non-medical factors and a greater awareness of the conceptual and clinical findings from social neuroscience, occupational health, and clinical psychology.

Die differentielle Validität neuropsychologischer Testverfahren zum Nachweis nicht-authentischer Störungen

Ziel dieser Studie ist es, die Eignung unterschiedlicher neuropsychologischer Verfahren zur Diagnostik von nicht-authentischen Störungen zu ermitteln. Darüber hinaus soll untersucht werden, ob Beschwerdenvalidierungstests (BVT) eine höhere Validität gegenüber anderen neuropsychologischen Verfahren zum Nachweis von nicht authentischen Störungen aufweisen. Dazu wurden 59 Probanden untersucht, die zwischen 2003 bis 2013 forensisch-neuropsychologisch begutachtet wurden. Sie wurden hinsichtlich ihrer Authentizität ihrer neuropsychologischen Beschwerden beurteilt. Neben neuropsychologischen Tests wurden auch BVT eingesetzt. Es zeigte sich, dass die BVT hoch signifikant mit der gutachterlichen Gesamtbeurteilung korrelieren. Zwischen den neuropsychologischen Standardverfahren und der gutachterlichen Gesamtbeurteilung konnten keine signifikanten Zusammenhänge nachgewiesen werden. Es sind demnach nur diejenigen Verfahren, die speziell für den Nachweis von nicht-authentischen Störungen entwickelt worden, dazu geeignet, die Authentizität der Beschwerdenschilderung zu messen.

Categories versus dimensions in personality and psychopathology: a quantitative review of taxometric research

Taxometric research methods were developed by Paul Meehl and colleagues to distinguish between categorical and dimensional models of latent variables. We have conducted a comprehensive review of published taxometric research that included 177 articles, 311 distinct findings and a combined sample of 533 377 participants. Multilevel logistic regression analyses have examined the methodological and substantive variables associated with taxonic (categorical) findings. Although 38.9% of findings were taxonic, these findings were much less frequent in more recent and methodologically stronger studies, and in those reporting comparative fit indices based on simulated comparison data. When these and other possible confounds were statistically controlled, the true prevalence of taxonic findings was estimated at 14%. The domains of normal personality, mood disorders, anxiety disorders, eating disorders, externalizing disorders, and personality disorders (PDs) other than schizotypal yielded little persuasive evidence of taxa. Promising but still not definitive evidence of psychological taxa was confined to the domains of schizotypy, substance use disorders and autism. This review indicates that most latent variables of interest to psychiatrists and personality and clinical psychologists are dimensional, and that many influential taxonic findings of early taxometric research are likely to be spurious.