Detecting the malingering of cognitive deficits: an update

The False Recognition Test, a new tool for the assessment of false memories, with normative data from an Italian sample

INTRODUCTION

False memory can be defined as remembering something that did not happen. To a certain extent it is a normal phenomenon, but its occurrence seems to increase in healthy and pathological aging, possibly providing relevant clues on some clinical conditions in the spectrum of dementia. We adapted a well-established Deed-Roediger-McDermott paradigm, frequently used in experimental contexts, to devise a new neuropsychological assessment tool, the False Recognition Test (FRT), that can investigate classical facets of episodic memory performance (i.e. free recall and recognition), and assess proneness to produce semantically related and non-semantic false memories. Here we describe the FRT and provide normative data and correction grids to consider the possible effects of age, gender, and education on the FRT scores.

METHOD

Two-hundred and thirty-two Italian healthy individuals (99 male) aged 18-91 years, with different educational levels (from primary to university) underwent the FRT, together with validated tests for cognitive screening and episodic memory assessment and one scale for depression.

RESULTS

Multiple linear regression analysis revealed that age and education significantly influenced performance on FRT. From the derived linear equations, we provide correction grids for the raw scores of the FRT, and equivalent scores estimated using a nonparametric method. Correlational analysis showed significant associations between FRT subscores and cognitive, executive and memory functions, and depression.

CONCLUSION

The FRT may constitute a useful instrument for both clinical and research purposes.

Cognitive Underperformance in a Mixed Neuropsychiatric Sample at Diagnostic Evaluation of Adult ADHD

(1) Background: The clinical assessment of attention-deficit/hyperactivity disorder (ADHD) in adulthood is known to show non-trivial base rates of noncredible performance and requires thorough validity assessment. (2) Objectives: The present study estimated base rates of noncredible performance in clinical evaluations of adult ADHD on one or more of 17 embedded validity indicators (EVIs). This study further examines the effect of the order of test administration on EVI failure rates, the association between cognitive underperformance and symptom overreporting, and the prediction of cognitive underperformance by clinical information. (3) Methods: A mixed neuropsychiatric sample (N = 464, ADHD = 227) completed a comprehensive neuropsychological assessment battery on the Vienna Test System (VTS; CFADHD). Test performance allows the computation of 17 embedded performance validity indicators (PVTs) derived from eight different neuropsychological tests. Further, all participants completed several self- and other-report symptom rating scales assessing depressive symptoms and cognitive functioning. The Conners' Adult ADHD Rating Scale and the Beck Depression Inventory-II were administered to derive embedded symptom validity measures (SVTs). (4) Results and conclusion: Noncredible performance occurs in a sizeable proportion of about 10% up to 30% of individuals throughout the entire battery. Tests for attention and concentration appear to be the most adequate and sensitive for detecting underperformance. Cognitive underperformance represents a coherent construct and seems dissociable from symptom overreporting. These results emphasize the importance of performing multiple PVTs, at different time points, and promote more accurate calculation of the positive and negative predictive values of a given validity measure for noncredible performance during clinical assessments. Future studies should further examine whether and how the present results stand in other clinical populations, by implementing rigorous reference standards of noncredible performance, characterizing those failing PVT assessments, and differentiating between underlying motivations.

Validation of the Coin in Hand-Extended Version Among Older Adults With and Without Dementia

OBJECTIVE

The current study aimed to validate the Performance Validity Test Coin in Hand-Extended Version (CIH-EV) in groups of healthy older adults and older adults with dementia.

METHOD

Using an analog simulation paradigm, the healthy control group and the clinical group were instructed to perform to the best of their ability, whereas the feigning older adults were instructed to simulate a memory deficit to obtain allowance, financial aid, or early retirement.

RESULTS

Results showed that the control and clinical groups performed more optimally than the feigning group, although the clinical group had superior response times. The CIH-EV was insensitive to sociodemographic variables and neurocognitive functioning in all groups, demonstrated good convergent validity with other performance validity measures, and showed a reduced rate of false positives.

CONCLUSIONS

This study corroborates the CIH-EV's effectiveness in detecting the simulation of cognitive deficits in healthy older adults and older adults with dementia.

A comparison of the self-report patterns of analog versus real-world malingerers of attention deficit hyperactivity disorder

Much of what we know about malingering of attention deficit hyperactivity disorder (ADHD) has been learned from the performance of analog malingerers, typically first-year psychology students given credit for study participation. It is not clear, however, whether their performance is similar to that found in actual clinical settings. Indeed, past research suggests that analog malingerers may overexaggerate deficits relative to real-world malingerers, making them easier to identify in controlled studies. The purpose of the current study was, therefore, to compare the performance of analog malingers to post-secondary students strongly suspected of malingering ADHD on a self-report measure of ADHD symptoms. Their scores were, in turn, compared to those returned by students with genuine ADHD and clinical controls. Results demonstrated that, apart from analog subjects overexaggerating symptoms of hyperactivity, few differences exist between the scores returned by analog malingerers relative to clinical malingerers. While newly devised symptom validity measures show promise in identifying malingered ADHD, neither the analog nor the clinical malingers consistently failed these symptom validity scales. Furthermore, a good portion in both malingering groups failed to endorse high levels of ADHD symptoms in general. Clinical implications are discussed.

Discriminating malingered attention Deficit Hyperactivity Disorder from genuine symptom reporting using novel Personality Assessment Inventory validity measures

It is now widely understood that ADHD can be feigned easily and convincingly. Despite this, almost no methods exist to assist clinicians in identifying when such behavior occurs. Recently, new validity indicators specific to feigned ADHD were reported for the Personality Assessment Inventory (PAI). Derived from a logistic regression, these algorithms are said to have excellent specificity and good sensitivity in identifying feigned ADHD. However, these authors compared those with genuine ADHD only to nonclinical undergraduate students (asked to respond honestly or asked to simulate ADHD); no criterion group of definite malingerers was included. We therefore investigated these new validity indicators with 331 postsecondary students who underwent assessment for possible ADHD and compared scores of those who were eventually diagnosed with ADHD (n = 111) to those who were not [Clinical controls (66), Definite malingerers (36); No diagnosis (117)]. The two proposed PAI algorithms were found to have poor positive predictive value (.19 and .17). Self-report validity measures from the Connors' Adult Attention Rating Scale, and the Negative Impression Management scale on the PAI returned more positive results. Overall, more research is needed to better identify noncredible ADHD presentation, as the PAI-based methods proposed by Aita et al. appear inadequate as symptom validity measures.

Detecting memory performance validity with DETECTS: A computerized performance validity test

Evaluating performance validity is essential in neuropsychological and forensic assessments. Nonetheless, most psychological assessment tests are unable to detect performance validity and other methods must be used for this purpose. A new Performance Validity Test (DETECTS - Memory Performance Validity Test) was developed with several characteristics that enhance test utility. Moreover, precise response time measurement was added to DETECTS. Two groups of participants (normative and simulator group) completed DETECTS and three memory tests from the Wechsler Memory Scale III. Simulators achieved considerably lower scores (hits) and higher response times in DETECTS compared with the normative group. All participants in the normative group were classified correctly and no simulator was classified as having legitimate memory deficits. Thus, DETECTS seems to be a valuable computerized Performance Validity Test with reduced application time and effective cut-off scores as well as high sensitivity, specificity, and positive and negative predictive power values. Lastly, response time may be a very useful measure for detecting memory malingering.

Exploring Children's Induced Defensiveness to the Tell Me a Story Test (TEMAS)

This study examined the effect of inducing a defensive attitude (fake good) in children on their responses to the Tell Me a Story test (TEMAS; Costantino, Malgady, & Rogler, 1988 ). Different story elicitation procedures were employed to explore their efficacy for inducing a defensive response style in children. Eighty-four Italian children aged 8 to 10 years old completed the TEMAS and the L scale of the Behavioral Assessment Scale for Children-2 (BASC-2; Reynolds & Kamphaus, 2004 ), which were used to detect the adoption of a defensive attitude. Children completed the tests under 1 of 3 conditions: (a) honest condition, (b) fake good with verbal instructions, and (c) fake good with verbal instructions and visual stimuli illustrating what was verbally explained. Using simultaneous verbal instructions and visual stimuli facilitated children's understanding of the researcher's instructions compared to using verbal stimuli alone. Results showed that children instructed to fake good used less time to tell stories and tended to modify the simpler and more face valid aspects of their stories. Still, 29 out of 47 children failed to fake good on the BASC-2 L scale. More complex TEMAS variables showed no significant difference between story elicitation conditions.

Indicators of suboptimal performance embedded in the Wechsler Memory Scale-Fourth Edition (WMS-IV)

INTRODUCTION

Recognition and visual working memory tasks from the Wechsler Memory Scale-Fourth Edition (WMS-IV) have previously been documented as useful indicators for suboptimal performance. The present study examined the clinical utility of the Dutch version of the WMS-IV (WMS-IV-NL) for the identification of suboptimal performance using an analogue study design.

METHOD

The patient group consisted of 59 mixed-etiology patients; the experimental malingerers were 50 healthy individuals who were asked to simulate cognitive impairment as a result of a traumatic brain injury; the last group consisted of 50 healthy controls who were instructed to put forth full effort.

RESULTS

Experimental malingerers performed significantly lower on all WMS-IV-NL tasks than did the patients and healthy controls. A binary logistic regression analysis was performed on the experimental malingerers and the patients. The first model contained the visual working memory subtests (Spatial Addition and Symbol Span) and the recognition tasks of the following subtests: Logical Memory, Verbal Paired Associates, Designs, Visual Reproduction. The results showed an overall classification rate of 78.4%, and only Spatial Addition explained a significant amount of variation (p < .001). Subsequent logistic regression analysis and receiver operating characteristic (ROC) analysis supported the discriminatory power of the subtest Spatial Addition. A scaled score cutoff of <4 produced 93% specificity and 52% sensitivity for detection of suboptimal performance.

CONCLUSION

The WMS-IV-NL Spatial Addition subtest may provide clinically useful information for the detection of suboptimal performance.

The malingering factor

The influence of malingering and suboptimal performance on neuropsychological tests has become a major interest of clinical neuropsychologists. Methods to detect malingering have focused on specialized tests or embedded patterns associated with malingering present in the conventional neuropsychology tests. There are two stages to the study of their validity. The first stage involves whether the method can discriminate malingering subjects from those who are not malingering. In the second stage, they must be examined for their relationship to the conventional tests used to establish impairment and disability. Constantinou, Bauer, Ashendorf, Fisher, and McCaffrey (2005. Is poor performance on recognition memory effort measures indicative of generalized poor performance on neuropsychological tests? Archives of Clinical Neuropsychology, 20, 191-198.) conducted the only study in which correlations are presented between a commonly used symptom validity test, the Test of Memory Malingering (TOMM) and the subtests of the Wechsler Adult Intelligence Scale-Revised (WAIS-R). A factor analysis was conducted using these correlations. It revealed a clear malingering factor that explained significant variance in the TOMM and the WAIS-R subtests. The relationship of malingering with cognitive tests is complex: some tests are sensitive to malingering and others are not. Factor analysis can summarize the magnitude of variance associated with each test and reveal the patterns of inter-relationships between malingering and clinical tests. The analysis also suggested that malingering assessment methods could be improved by the addition of timing the responses.

The detection of malingering in memory performance: The sensitivity and specificity of four measures in a UK population

OBJECTIVES

To investigate the validity of a clinical neuropsychological battery for the detection of malingering on tests of memory.

METHODS

A simulated scenario design was developed to investigate the effectiveness of a battery of four neuropsychological tests in the detection of malingering; the Coin in the Hand Test (CIH), Autobiographical Memory Index (AMI), Rey I 5-Item Test (RIT),and the Wechsler Mental Control Test (MCT). The performances of patients with an acquired brain injury (N = 40) were compared with two groups of controls instructed either to simulate a head injury performance (N = 40) or do their best (N = 40).

RESULTS

The CIH and MCT demonstrated good validity and displayed high sensitivity and specificity. The RIT and the AMI was relatively poor in distinguishing between simulators and patients.

CONCLUSIONS

The sensitivity and specificity of all four tests to the detection of malingering has been assessed. Two of the tests the CIH and MCT would be useful as a quick and accurate screening tool for detecting malingering.

Deterring malingered psychopathology: The effect of warning simulating malingerers

The utility of a warning to deter malingering on measures of personality and psychopathology was examined. Sixty-seven first year psychology students were randomly assigned to one of three conditions: unwarned malingerers, warned malingerers, and controls. Participants in the two malingering groups were given a financial incentive to simulate believable psychological impairment. Warned malingerers received an additional warning that the tests could detect malingering and that detection would result in loss of course credit. Controls received standardized test instructions. It was hypothesized that the malingering incentive would be sufficient to induce malingering, but that a deterrence theory warning would have a subsequent deterrent effect. Between-groups analyses indicated that the warning used in this study significantly altered test performance on the Personality Assessment Inventory (PAI) and revised Symptom Checklist 90 (SCL-90-R). Warned malingerers scored significantly lower (faked less) than unwarned malingerers on the majority of the psychopathology scales and frequently approximated control group performances. These results support the effectiveness of a warning to complement existing malingering detection methods.

Classification Accuracy of the Portland Digit Recognition Test in Traumatic Brain Injury: Results of a Known-Groups Analysis

The present study used a known-groups design to examine the accuracy of the Portland Digit Recognition Test (PDRT) in the detection of malingering in traumatic brain injury (TBI). Data were derived from 262 TBI patients who were classified as not malingering, possibly malingering, and malingering based on the Slick, Sherman, and Iverson (1999) criteria. The original PDRT cutoffs detected between 20 and 50% of malingering TBI patients with a false positive error rate of 5% or less. When the false positive error rate was held at 5%, across all item sets, sensitivity was as high as 70%. The results show that the original PDRT cutoffs are conservative and that higher scores detect more MND patients without causing the false positive error rate to become unacceptably high. Clinical application and future research needs are discussed.

A Review of Internet Sites Regarding Independent Medical Examinations: Implications for Clinical Neuropsychological Practitioners

Malingering research typically uses analog simulation design or differential prevalence design among "real" patients. Both have been criticized for methodological limitations in external and internal validity, respectively. Samples of simulated malingerers were compared to suspected malingerers to examine generalizability of analog findings. Overall results support the use of simulation designs. Furthermore, it was demonstrated that stringent selection of suspected malingerers maintains internal validity of the differential prevalence design. A second focus, to determine if demographic matching of simulated malingerers is necessary, showed that matching on age and race is not necessary.

Detection of feigned recognition memory impairment using the old/new effect of the event-related potential

Twenty-four undergraduate university students with no known neurological disorders completed the Recognition Memory Test (Warrington, A., 1984. Recognition Memory Test manual. Windsor, Berkshire: NFER-Nelson.) while event-related potentials (ERPs) were recorded. Twelve subjects were instructed to feign a recognition memory deficit (malingering group), while the remainder served as controls. The malingerers performed poorly on the test compared to the control group. The 'old/new effect', an ERP measure thought to reflect recognition memory processes, did not differ between the groups, indicating recognition of previously learned material in the malingering group despite poor test performance. The study also revealed a second, early, old/new effect, maximal at left frontal sites in the malingering relative to the control group, suggesting task-related processing differences between the two groups. These effects appear to be of potential value in the detection of malingering of cognitive impairment in the clinical situation.

Traumatic brain injury assessed with olfactory event-related brain potentials

Olfactory event-related potentials (OERPs) were evaluated to develop an objective, quantitative assessment of sensory and cognitive olfactory loss following traumatic brain injury (TBI). Subjects included 25 TBI patients and 25 age/gender-matched healthy controls. Following standard clinical evaluation of smell function, TBI patients were divided into three groups: 12 anosmics (loss of smell), 6 hyposmics (reduced smell), and 7 normosmics (normal smell). Cognitive ability was assessed using the Trail Making Test (A and B). OERPs were recorded monopolarly from midline electrode sites using an amyl acetate stimulus with a 60-second interstimulus interval; subjects estimated the magnitude of each odor stimulus. Anosmic TBI patients were also tested with OERPs using ammonia to ensure trigeminal nerve function. Amyl acetate OERPs demonstrated that the sensory N1 and P2 amplitudes and the cognitive P3 amplitudes were absent in the anosmic TBI patients and greatly reduced in the hyposmic and normosmic TBI patients compared to healthy controls. The trigeminal OERPs from the anosmic TBI patients were within normal limits, indicating that the primary olfactory deficits were objectively measured with OERPs. The relationship between the OERPs and neuropsychologic test performance supports the cognitive loss associated with TBI. The present study lends support to the utility of OERPs as an objective tool for measuring sensory and cognitive loss after traumatic brain injury.

Cognitive complaints in patients after whiplash injury: the impact of malingering

OBJECTIVES

The validity of memory and concentration complaints that are often reported after a whiplash trauma is controversial. The prevalence of malingering or underperformance in post-whiplash patients, and its impact on their cognitive test results were studied.

METHODS

The Amsterdam short term memory (ASTM) test, a recently developed malingering test, was used as well as a series of conventional memory and concentration tests. The study sample was a highly selected group of patients, who were examined either as part of a litigation procedure (n=36) or in the normal routine of an outpatient clinic (n=72).

RESULTS

The prevalence of underperformance, as defined by a positive score on the malingering test, was 61% (95% CI: 45-77) in the context of litigation, and 29% (95% CI: 18-40) in the outpatient clinic (p=0.003). Furthermore, the scores on the memory and concentration test of malingering post-whiplash patients (n=43) and non-malingering post-whiplash patients (n=65) were compared with the scores of patients with closed head injury (n=20) and normal controls (n=46). The malingering post-whiplash patients scored as low as the patients with closed head injury on most tests.

CONCLUSIONS

The prevalence of malingering or cognitive underperformance in late post-whiplash patients is substantial, particularly in litigation contexts. It is not warranted to explain the mild cognitive disorders of whiplash patients in terms of brain damage, as some authors have done. The cognitive complaints of non-malingering post-whiplash patients are more likely a result of chronic pain, chronic fatigue, or depression.

Practical guidelines in the use of symptom validity and other psychological tests to measure malingering and symptom exaggeration in traumatic brain injury cases

The detection of malingering or symptom exaggeration has become an essential component in forensic neuropsychological evaluations, particularly in cases involving personal injury claims. Symptom Validity Tests refer to those measures that can be utilized to detect test performance that is so poor that it is below the level of probability, often times even among brain-damaged populations. This article outlines legal standards for expert testimony in regard to forensic neuropsychological personal injury evaluations. The article provides an outline of specific Symptom Validity Tests and Indicators, and reviews literature supporting test sensitivity and validity. In addition, the use of symptom checklists and questionnaires is discussed, as well as the appropriate use of Symptom Validity Tests and Indicators to establish the presence or absence of malingering or symptom exaggeration.