Detecting malingered neurocognitive dysfunction using the reliable digit span in traumatic brain injury

Assessment of performance validity in the Stroop Color and Word Test in mild traumatic brain injury patients: a criterion-groups validation design

The current study assessed performance validity on the Stroop Color and Word Test (Stroop) in mild traumatic brain injury (TBI) using criterion-groups validation. The sample consisted of 77 patients with a reported history of mild TBI. Data from 42 moderate-severe TBI and 75 non-head-injured patients with other clinical diagnoses were also examined. TBI patients were categorized on the basis of Slick, Sherman, and Iverson (1999) criteria for malingered neurocognitive dysfunction (MND). Classification accuracy is reported for three indicators (Word, Color, and Color-Word residual raw scores) from the Stroop across a range of injury severities. With false-positive rates set at approximately 5%, sensitivity was as high as 29%. The clinical implications of these findings are discussed.

Cross-cultural effect on suboptimal effort detection: an example of the Digit Span subtest of the WAIS-III in Taiwan

Suppressed Digit Span performance has been proposed as an embedded indicator for suboptimal effort detection in neuropsychological evaluations in Western societies, particularly in the USA. However, its effectiveness in Chinese countries remains unexplored. The purposes of this study were first to explore normative Digit Span performance patterns between the Taiwan and American standardization samples, then to examine performances of patients with traumatic brain injury and with psychiatric diseases on the embedded measures (the Digit Span Scaled Score, Vocabulary minus Digit Span difference score, Reliable Digit Span, and the longest string of digits forward and backward) through retrospective data analysis. The normative Digit Span performance differs between the two cultural populations. Although litigating and nonlitigating participants perform differently on these measures, further prospective studies are needed to explore this issue with comprehensive external corroborating validity data.

Intra-individual neurocognitive variability confers risk of dependence in activities of daily living among HIV-seropositive individuals without HIV-associated neurocognitive disorders

Although HIV-associated neurocognitive disorders (HAND) are the strong predictors of everyday functioning difficulties, approximately half of all functionally impaired individuals are labeled "neurocognitively normal" according to the standard neuropsychological measures, suggesting that novel predictors of functional problems in this prevalent subgroup are needed. The present study hypothesized that increased neurocognitive intra-individual variability as indexed by dispersion would be associated with poor daily functioning among 82 persons with HIV infection who did not meet research criteria for HAND. An intra-individual standard deviation was calculated across the demographically adjusted T-scores of 13 standard neuropsychological tests to represent dispersion, and functional outcomes included self-reported declines in basic and instrumental activities of daily functioning (basic activity of daily living [BADL] and instrumental activity of daily living [IADL], respectively) and medication management. Dispersion was a significant predictor of medication adherence and dependence in both BADL and IADL, even when other known predictors of functional status (i.e., age, affective distress, and indices of disease severity) were included in the models. As a significant and unique predictor of a performance on the range of daily functioning activities, neurocognitive dispersion may be indicative of deficient cognitive control expressed as inefficient regulation of neurocognitive resources in the context of competing functional demands. As such, dispersion may have clinical utility in detecting risk for functional problems among HIV-infected individuals without HAND.

Are self-reported symptoms of executive dysfunction associated with objective executive function performance following mild to moderate traumatic brain injury?

BACKGROUND AND OBJECTIVE

We examined the relationship between self-reported pre- and post-injury changes in executive dysfunction, apathy, disinhibition, and depression, and performance on neuropsychological tests of executive function, attention/processing speed, and memory in relation to mood levels and effort test performance in individuals in the early stages of recovery from mild to moderate traumatic brain injury (TBI).

METHOD

Participants were 71 noncombat military personnel who were in a semiacute stage of recovery (<3 months post injury) from mild to moderate TBI. Pre- and post-TBI behaviors were assessed with the Frontal Systems Behavior Scale (FrSBe; Grace & Malloy, 2001 ) and correlated with levels of depressive symptoms, effort test performance, and performance on objective measures of attention, executive function, and memory.

RESULTS

Self-reported symptoms of executive dysfunction generally failed to predict performance on objective measures of executive function and memory, although they predicted poorer performance on measures of attention/processing speed. Instead, higher levels of depressive symptomatology best predicted poorer performance on measures of executive function and memory. However, the relationship between memory performance and TBI symptoms was no longer significant when effort performance was controlled.

CONCLUSIONS

Our findings suggest that, among individuals in early recovery from mild to moderate TBI, self-reported depressive symptoms, rather than patients' cognitive complaints, are associated with objective executive function. However, self-reported cognitive complaints may be associated with objectively measured inattention and slow processing speed.

The Repeatable Battery for the Assessment of Neuropsychological Status effort scale

The measurement of effort is now considered to be an important component of neuropsychological assessment. In addition to stand-alone measures, built-in, or embedded measures of effort have been derived for a limited number of standard neurocognitive tests. The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) is a widely used brief battery, employed as a core diagnostic tool in dementia and as a neurocognitive screening battery or tracking/outcome measure in a variety of other disorders. An effort index (EI) for the RBANS has been published previously (Silverberg, N. D., Wertheimer, J. C., & Fichtenberg, N. L. 2007. An EI for the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Clinical Neuropsychology, 21 (5), 841-854), but it has been reported to result in high false positive rates when applied to patients with "true" amnesia (e.g., Alzheimer's disease). We created a new effort scale (ES) for the RBANS based on the observation of patterns of free recall and recognition performance in amnesia versus inadequate effort. The RBANS ES was validated on a sample of patients with amnestic disorders and a sample of mild traumatic brain injury participants who failed a separate measure of effort. The sensitivity and specificity of the new ES was compared with the previously published EI. Receiver-operating characteristic analyses demonstrated much better sensitivity and specificity of the ES, with a marked reduction in false positive errors. Application and limitations of the RBANS ES, including indications for its use, are discussed.

Reliable Digit Span

Reliable Digit Span (RDS) is a heavily researched symptom validity test with a recent literature review yielding more than 20 studies ranging in dates from 1994 to 2011. Unfortunately, limitations within some of the research minimize clinical generalizability. This systematic review and cross-validation study was conducted to address these limitations, thus increasing the measure’s clinical utility. Sensitivity and specificity rates were calculated for the ≤6 and ≤7 cutoffs when data were globally combined and divided by clinical groups. The cross-validation of specific diagnostic groups was consistent with the data reported in the literature. Overall, caution should be used when utilizing the ≤7 cutoff in all clinical groups and when utilizing the ≤6 cutoff in the following groups: cerebrovascular accident, severe memory disorders, mental retardation, borderline intellectual functioning, and English as a second language. Additional limitations and cautions are provided.

Examining Unusual Digit Span Performance in a Population of Postsecondary Students Assessed for Academic Difficulties

Methods of identifying poor test-related motivation using the Wechsler Adult Intelligence Scale Digit Span subtest are based on identification of performance patterns that are implausible if the test taker is investing full effort. No studies to date, however, have examined the specificity of such measures, particularly when evaluating persons with either known or suspected learning or attention disorders. This study investigated performance of academically challenged students on three measures embedded in the Wechsler Adult Intelligence Scale—III, namely, low Digit Span, high Vocabulary-Digit span (Voc-DS), and low Reliable Digit Span scores. Evaluating subjects believed to be investing full effort in testing, it was found that both Digit Span and Reliable Digit Span had high specificity, although both showed relatively lower sensitivity. In contrast, VOC-DS was especially weak in both sensitivity and specificity, with an apparent false positive rate of 28%. Use of VOC-DS is therefore not appropriate for those with a history of learning or attention problems.

Executive dysfunction in traumatic brain injury: the effects of injury severity and effort on the Wisconsin Card Sorting Test

This study examined the persistent effects of traumatic brain injury (TBI) on Wisconsin Card Sorting Test (WCST) performance. Since poor effort can contaminate results in populations with incentive to perform poorly, performance validity was explicitly assessed and controlled for using multiple well-validated cognitive malingering indicators. Participants were 109 patients with mild TBI and 67 patients with moderate-to-severe TBI seen for neuropsychological evaluation at least one year post injury. Patients with diffuse neurological impairment and healthy controls were included for comparison. Results suggested a dose-response effect of TBI severity on WCST performance in patients providing good effort; the mild TBI group did not differ from controls while increased levels of impairment were observed in the moderate-to-severe TBI group. Effort during testing had a larger impact on WCST performance than mild or moderate-to-severe TBI. Clinical implications of these findings are discussed.

Using the Wechsler Memory Scale-III to Detect Malingering in Mild Traumatic Brain Injury

This study examined the classification accuracy of the WMS-III primary indices in the detection of Malingered Neurocognitive Dysfunction (MND) in Traumatic Brain Injury (TBI) using a known-groups design. Sensitivity, specificity, and positive predictive power are presented for a range of index scores comparing mild TBI non-malingering (n = 34) and mild TBI malingering (n = 31) groups. A moderate/severe TBI non-malingering (n = 28) and general clinical group (n = 93) are presented to examine specificity in these samples. In mild TBI, sensitivities for the primary indices ranged from 26% to 68% at 97% specificity. Three systems used to combine all eight index scores were also examined and all achieved at least 58% sensitivity at 97% specificity in mild TBI. Specificity was generally lower in the moderate/severe TBI and clinical comparison groups. This study indicates that the WMS-III primary indices can accurately identify malingered neurocognitive dysfunction in mild TBI when used as part of a comprehensive classification system.

Classification Accuracy of MMPI-2 Validity Scales in the Detection of Pain-Related Malingering

The purpose of this study was to determine the accuracy of Minnesota Multiphasic Personality Inventory 2nd edition (MMPI-2; Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) validity indicators in the detection of malingering in clinical patients with chronic pain using a hybrid clinical-known groups/simulator design. The sample consisted of patients without financial incentive ( n = 23), nonmalingering patients with financial incentive ( n = 34), patients definitively determined to be malingering based on published criteria ( n = 32), and college students asked to simulate pain-related disability ( n = 26). The MMPI-2 validity scales differentiated malingerers from nonmalingerers with a high degree of accuracy. Hypochondriasis and Hysteria were also effective. For all variables except Scale L, more extreme scores were associated with higher specificity. This study demonstrates that the MMPI-2 is capable of differentiating intentional exaggeration from the effects on symptom report of chronic pain, genuine psychological disturbance, and concurrent stress associated with pursuing a claim in a medico-legal context.

Validity Testing in Dually Diagnosed Post-Traumatic Stress Disorder and Mild Closed Head Injury

Prospects for the coexistence of post-traumatic stress syndrome (PTSS) and mild traumatic brain injury (mTBI) rely exclusively on subjective evidence, increasing the risk of response bias in a compensatable social context. Using a priori specificities derived from genuine brain disorder groups, we examined validity failure rates in three domains (symptom, cognitive, motor) in 799 persons reporting persistent subjective disability long after mild neurological injury. Validity tests included the Test of Memory Malingering, MMPI-2 Fake Bad Scale, and Infrequency (F) scales, reliable digit span, and Halstead-Reitan finger tapping. Analyses showed invalidity signs in large excess of actuarial expectations, with rising invalidity risk conditional on post-traumatic complexity; the highest failure rates were produced by the 95 persons reporting both neurogenic amnesia and re-experiencing symptoms. We propose an "over-endorsement continuum" hypothesis: The more complex the post-traumatic presentation after mild neurological injury, the stronger the association with response bias. Late-appearing dual diagnosis is a litigation phenomenon so intertwined with secondary gain as to be a byproduct of it.

Distinguishing between Neuropsychological Malingering and Exaggerated Psychiatric Symptoms in a Neuropsychological Setting

It is unclear whether symptom validity test (SVT) failure in neuropsychological and psychiatric domains overlaps. Records of 105 patients referred for neuropsychological evaluation, who completed the Test of Memory Malingering (TOMM), Reliable Digit Span (RDS), and Millon Clinical Multiaxial Inventory-III (MCMI-III), were examined. TOMM and RDS scores were uncorrelated with MCMI-III symptom validity indices and factor analysis revealed two distinct factors for neuropsychological and psychiatric SVTs. Only 3.5% of the sample failed SVTs in both domains, 22.6% solely failed the neuropsychological SVT, and 6.1% solely failed the psychiatric SVT. The results support a dissociation between neuropsychological malingering and exaggeration of psychiatric symptoms in a neuropsychological setting.

An effort index for the Repeatable Battery For The Assessment Of Neuropsychological Status (RBANS)

The present study aimed to develop an internal validity indicator for a brief general purpose screening battery, the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Two subtests of the RBANS were predicted to be relatively resilient to cognitive dysfunction on the basis of previous research. An Effort Index (EI) was created by combining them via a scaling system. The frequency of EI scores was first examined in a heterogenous clinical sample. A subsequent validation study showed good discriminability. In conclusion, the EI appears to be useful for detecting insufficient effort on a screening battery.

The Performance of Individuals with Mental Retardation on Cognitive Tests Assessing Effort and Motivation

The purpose of this study was to determine which tests of effort and motivation would be appropriate for use with patients with mental retardation when feigning of cognitive deficits is suspected. The seven measures evaluated included the WMS-III Rarely Missed Index Test, forced-choice recognition portion of the California Verbal Learning Test-II, Reliable Digit Span test, Rey 15-Item Test, Rey Dot Counting Test, the Rey 15-Item Test with Recognition Trial, and the Vocabulary (V)-Digit Span (DS) difference score. Results indicated that the forced-choice portion of the CVLT-II, the V-DS difference score, and the Rarely Missed Index Test from the WMS-III might be appropriate for use with this population with passing rates of 89%, 98%, and 91% respectively.

On the limits of effort testing: Symptom validity tests and severity of neurocognitive symptoms in nonlitigant patients

Modern symptom validity tests (SVTs) use empirical cutoffs for decision making. However, limits to the applicability of these cutoffs may arise when severe cognitive symptoms are present. The purpose of the studies presented here was to explore these limits of applicability. In Experiment 1, a group of 24 bona fide neurological patients without clinically obvious cognitive symptoms was compared to a group of 24 patients with rather severe symptoms. A comprehensive test battery was employed, which included four SVTs (the Test of Memory Malingering, TOMM, the Word Memory Test, WMT, the Bremer Symptomvalidierung, BSV, and the Amsterdam Short-Term Memory Test, ASTM). In Experiment 2, a group of 20 patients with mild Alzheimer's disease was compared to 14 healthy controls. Results of both studies showed that cognitive impairment may significantly interfere with SVT performance. Correlation analyses revealed dissimilar relationships between SVTs and neuropsychological test measures. Whereas TOMM and WMT correlated mainly with tests of declarative memory, the BSV correlated with tests of attention, and ASTM correlated with tests of working memory. Intercorrelations between symptom validity measures were relatively low. The published cutoffs of the TOMM would be suitable for estimating effort in patients with Mini-Mental State Examination scores of 24 or above. More research will be necessary to investigate how performance in SVTs is related to cognitive functioning in populations of severely impaired patients.

Test of Memory Malingering (Tomm) Trial 1 as a Screening Measure for Insufficient Effort

The identification of insufficient effort is critical to neuropsychological evaluation, and several existing instruments assess effort on neuropsychological tasks. Yet instruments designed to detect insufficient effort are underutilized in standard neuropsychological assessments, perhaps in part because they typically require significant administration time and are, therefore, not ideally suited to screening contexts. The Test of Memory Malingering (TOMM) is a commonly administered, well-validated symptom validity test. This study evaluates the utility of TOMM Trial 1 as a relatively brief screening measure of insufficient effort. Results suggest that TOMM Trial 1 demonstrates high diagnostic accuracy and is a viable option for screening insufficient effort. Diagnostic accuracy estimates are presented for a range of base rates. The need for more comprehensive SVT assessment in most clinical and forensic situation is discussed.

The Booklet Category Test and Malingering in Traumatic Brain Injury: Classification Accuracy in Known Groups

A known-groups design was used to determine the classification accuracy of 12 Booklet Category Test variables in the detection of malingered neurocognitive dysfunction (MND) in traumatic brain injury (TBI). Participants were 206 TBI and 60 general clinical patients seen for neuropsychological evaluation. Slick, Sherman, and Iverson's (1999) criteria were used to classify the TBI patients into non-malingering, suspect, and MND groups. Classification accuracy of the BCT depended on the specific variable and injury severity examined, with some scores detecting more than 40% of malingerers with false positive error rates of 10% or less. However, the BCT variables are often influenced by cognitive ability as well as malingering, so caution is indicated in applying the BCT to the diagnosis of malingering. Application of these data in clinical practice is discussed.

Classification Accuracy of the Test of Memory Malingering in Traumatic Brain Injury: Results of a Known-Groups Analysis

This study used a known-groups design to determine the classification accuracy of the Test of Memory Malingering (Tombaugh, 1996, 1997) in detecting cognitive malingering in traumatic brain injury (TBI). Forty-one of 161 TBI patients met Slick, Sherman, and Iverson (1999) criteria for Malingered Neurocognitive Dysfunction. Twenty-two no-incentive memory disorder patients were also included. The original cutoffs (<45) for Trial 2 and Retention demonstrated excellent specificity (less than a 5% false positive error rate) and impressive sensitivity (greater than 45%). However, these cutoffs are actually conservative in the context of mild TBI. Over 90% of the non-MND mild TBI sample scored 48 or higher on the Retention Trial and none scored less than 46 while 60% of the MND patients claiming mild TBI were detected at those levels. Trial 1 also demonstrated excellent classification accuracy. Application of these data to clinical practice is discussed.

Detecting Feigned Impairment with the Digit Span and Vocabulary Subtests of the Wechsler Adult Intelligence Scale—Third Edition

The WAIS-III Digit Span and Vocabulary subtests were investigated as indicators of feigned cognitive impairment. Participants included 64 undergraduates randomly assigned to control, symptom-coached, or test-coached groups. Six previously researched validity indicators were examined. We hypothesized that symptom-coached participants would perform worse relative to test-coached simulators. Analyses determined both simulator groups performed lower than controls on all indicators except Vocabulary. Symptom-coached participants, however, did not differ from test-coached participants on any indicator. Classification accuracies for these six indicators ranged from 42 to 78%. While the WAIS-III validity indicators hold some promise, they should not be employed as independent measures.

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.

Compensation and Malingering in Traumatic Brain Injury: A Dose-Response Relationship?

The purpose of this study was to determine if there is a dose-response relationship between potential monetary compensation and failure on psychological indicators of malingering in traumatic brain injury. 332 traumatic brain injury patients were divided into three groups based on incentive to perform poorly on neuropsychological testing: no incentive; limited incentive as provided by State law; high incentive as provided by Federal law. The rate of failure on five well-validated malingering indicators across these groups was examined. Cases handled under Federal workers compensation laws showed considerably higher rates of failure and diagnosable malingering than cases handled under State law. The findings indicate that monetary compensation associated with workers compensation claims is a major motive for exaggeration and malingering of problems attributed to work-related brain injuries. The clinician's index of suspicion regarding exaggeration and malingering of symptoms and deficits should be much higher in the context of Federal workers compensation claims, particularly in patients who have suffered only mild traumatic brain injury.

Sensitivity and Specificity of MMPI-2 Validity Scales and Indicators to Malingered Neurocognitive Dysfunction in Traumatic Brain Injury

The present study used a known-groups design to determine the classification accuracy of 10 MMPI-2 validity scales and indicators in the detection of cognitive malingering in traumatic brain injury. Participants were 259 traumatic brain injury and 133 general clinical patients seen for neuropsychological evaluation. The TBI patients were subdivided into groups based on a comprehensive examination of effort following Slick, Sherman, and Iverson's (1999) criteria. More extreme scores demonstrated excellent specificity; often impressive sensitivity was seen even while maintaining a low false positive error rate. Specificity was good even in stroke, memory disorder, and psychiatric patients without incentive. The results of this study are presented in frequency tables that can be easily referenced in clinical practice.

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.

Sensitivity and Specificity of Various Digit Span Scores in the Detection of Suspect Effort

Digit Span Age-Corrected Scaled Score (ACSS) and Reliable Digit Span (RDS) have been suggested as effective in assessing credibility. The purpose of this study was to confirm the efficacy of suggested cutoffs for ACSS and RDS and to explore the utility of other Digit Span variables in a large sample (N = 66) of "real-world" > or = suspect effort patients versus clinic patients with no motive to feign (N = 56) and controls (N = 32). With specificity at > or = 90%, sensitivity of ACSS increased from 32% to 42% when a < or = 5 cutoff was used instead of the recommended < or = 4. The RDS recommended cutoff of < or = 7 resulted in a sensitivity of 62% but with an unacceptably high false positive rate (23%); dropping the cutoff to < or = 6 raised the specificity to 93% but sensitivity fell to 45%. Cutoffs for other Digit Span scores did not exceed 45% sensitivity with the exception of 50% sensitivity (11% false positive rate) for average time per digit for all attempted items > 1.0 second. A criterion of ACSS < or = 5 or RDS < or = 6 was associated with 51% sensitivity (91% specificity) while RDS < or = 6 or longest string with at least one item correct < or = 4 was associated with 54% sensitivity (88% specificity). While only moderately sensitive, Digit Span scores, including new time variables, may have a unique and effective role in the detection of suspect effort.

Neuropsychological changes following electrical injury

The clinical presentation of electrical injury commonly involves physical, cognitive, and emotional complaints. Neuropsychological studies, including case reports, have indicated that electrical injury (EI) survivors may experience a broad range of impaired neuropsychological functions, although this has not been clarified through controlled investigation. In this study, we describe the neuropsychological test findings in a series of 29 EI patients carefully screened and matched to a group of 29 demographically similar healthy electricians. Participants were matched by their estimated premorbid intellectual ability. Multivariate analysis of variance was used to assess group differences in the following neuropsychological domains: attention and mental speed, working memory, verbal memory, visual memory, and motor skills. EI patients performed significantly worse on composite measures of attention/mental speed and motor skills, which could not be explained by demographic differences, injury parameters, litigation status, or mood disturbance. Results suggest that cognitive changes do occur in patients suffering from electrical injury.

Pain, malingering and the WAIS-III Working Memory Index

BACKGROUND CONTEXT

Pain patients often report cognitive symptoms, and many will include them in their claims of disability. There is empirical evidence that patients with pain do experience problems on attention-demanding cognitive tasks, but the results are mixed and the potential impact of exaggeration in the context of pain-related litigation has not been addressed.

PURPOSE

1) Examine the impact of pain and malingering on attention; 2) determine if the Working Memory Index (WMI) of the Wechsler Adult Intelligence Scale-3 (WAIS-III) can reliably detect malingering.

STUDY DESIGN/SETTING

Study 1: simulator design; Study 2: clinical known-groups design.

PATIENT SAMPLE

Study 1 used healthy college students; Study 2 used chronic pain patients and neurological patients.

OUTCOME MEASURES

The WMI and its constituent subtests.

METHODS

Study 1: College students were administered the WMI under three conditions: standard administration, with cold-pressor induced pain, or with instructions to simulate impairment due to pain. Study 2: Known-groups design in which the WMI was examined in non-malingering and definite malingering chronic pain patients, non-malingering moderate-severe traumatic brain injury, and memory disorder patients seen for routine psychological evaluation. Malingering was operationalized using published criteria.

RESULTS

There were no group differences in WMI or its subtests among non-malingering groups, but some individual clinical patients with pain did score at a level suggestive of attentional impairment. The lowest scores were found in the simulated malingering college students and definite malingering clinical pain groups, in which about half scored worse than 95% of the non-malingering clinical patients.

CONCLUSIONS

This study demonstrated that even when controlling for exaggeration some pain patients do exhibit problems with attentional function. However, significant impairment in WMI performance (eg, index score<or=70), particularly in the absence of brain dysfunction, cannot reasonably be attributed to the effects of either acute or chronic pain, even at moderate to severe levels, and likely reflects intentional exaggeration.

Malingered Neurocognitive Dysfunction in Neurotoxic Exposure: An Application of the Slick Criteria

Toxic torts are increasing across the country and often the results of the neuropsychological evaluation are crucial for defining damages. Therefore, the accurate differentiation of those damaged by toxic exposure from those exaggerating or fabricating deficits is important. However, there is little research on malingering in this context. Presented are four patients claiming cognitive deficits after apparent occupational neurotoxic exposure who were diagnosed as malingering using the Slick, Sherman, and Iverson criteria. The goals of this article were to (1) illustrate the application of the Slick Criteria; (2) discuss current knowledge about the neurological and neurocognitive effects of toxic substances and its impact on clinical decision-making; (3) discuss the application of the Slick Criteria, specifically, and malingering research, generally, to toxic exposure cases; and (4) propose a paradigm in which medical, toxicological and neuropsychology professionals coordinately evaluate cases of alleged neurotoxic chemical exposure.