Performance validity in older adults: Observed versus predicted false positive rates in relation to number of tests administered

Identifying Factors that Increase False-Positive Rates on Embedded Performance Validity Testing in ADHD Evaluations

OBJECTIVE

This study investigated why certain embedded performance validity indicators (EVIs) are prone to higher false-positive rates (FPRs) in attention-deficit/hyperactivity disorder (ADHD) evaluations. The first aim was to establish the relationship between FPRs and 15 EVIs derived from six cognitive tests when used independently and together among adults with ADHD who have valid test performance. The second aim was to determine which specific EVIs increase the FPRs in this population.

METHOD

Participants were 517 adult ADHD referrals with valid neurocognitive test performance as determined by multiple performance validity tests and established empirical criteria. FPRs were defined by the proportion of participants who scored below an empirically established EVI cutoff with ≥0.90 specificity.

RESULTS

EVIs derived from two of the six tests exhibited unacceptably high FPRs (>10%) when used independently, but the total FPR decreased to 8.1% when the EVIs were aggregated. Several EVIs within a sustained attention test were associated with FPRs around 11%. EVIs that did not include demographically adjusted cutoffs, specifically for race, were associated with higher FPRs around 14%. Conversely, FPRs did not significantly differ based on whether EVIs included timed versus untimed, verbal versus nonverbal, or graphomotor versus non-graphomotor components, nor whether they had raw versus standardized cut scores.

CONCLUSIONS

Findings suggest that practitioners should consider both the type of test from which an EVI is derived and the aggregate number of EVIs employed to minimize the FPRs in ADHD evaluations. Findings also indicate that more nuanced approaches to validity test selection and development are needed.

Racial differences in positive findings on embedded performance validity tests

INTRODUCTION

Embedded performance validity tests (PVTs) may show increased positive findings in racially diverse examinees. This study examined positive findings in an older adult sample of African American (AA) and European American (EA) individuals recruited as part of a study on aging and cognition.

METHOD

The project involved secondary analysis of deidentified National Alzheimer's Coordinating Center data (N = 22,688). Exclusion criteria included diagnosis of dementia (n = 5,550), mild cognitive impairment (MCI; n = 5,160), impaired but not MCI (n = 1,126), other race (n = 864), and abnormal Mini Mental State Examination (MMSE < 25; n = 135). The initial sample included 9,853 participants (16.4% AA). Propensity score matching matched AA and EA participants on age, education, sex, and MMSE score. The final sample included 3,024 individuals with 50% of participants identifying as AA. Premorbid ability estimates were calculated based on demographics. Failure rates on five raw score and six age-adjusted scaled score PVTs were examined by race.

RESULTS

Age, education, sex, MMSE, and premorbid ability estimate were not significantly different by race. Thirteen percent of AA and 3.8% of EA participants failed two or more raw score PVTs (p < .0001). On age-adjusted PVTs, 20.6% of AA and 5.9% of EA participants failed two or more (p < .0001).

CONCLUSIONS

PVT failure rates were significantly higher among AA participants. Findings indicate a need for cautious interpretation of embedded PVTs with underrepresented groups. Adjustments to embedded PVT cutoffs may need to be considered to improve diagnostic accuracy.

Just the Tip of the Iceberg: a Brief Report of the Tip-of-the-Tongue Score as an Embedded Validity Indicator for the Children's Auditory and Visual Naming Tests

OBJECTIVE

Explore the tip-of-the-tongue (TOT) scores from the Children's Auditory and Visual Naming Tests (cANT, cVNT) as embedded validity indicators (EVIs).

METHOD

A retrospective design of 98 consecutively referred youth aged 6-15 years (M = 11.28, SD = 2.80) that completed neuropsychological evaluation at a tertiary-care academic medical center.

RESULTS

Invalid performance (i.e., ≥2 failed PVTs) occurred in 12.2% of the sample, with base rates of failure on individual PVTs ranging from 1.0% to 30.6%. Area under the curve (AUC) showed statistical significance for the auditory (AUC = 0.811, p = .004) but not the visual TOT. Logistic regression indicated the combination of both TOT scores with other PVTs increased correct identification of invalid performance to 85.7% versus 75% without TOT scores.

CONCLUSION

The utility of the TOT as a language-based EVI is one of many potential advantages of the cANT and cVNT compared to other confrontation naming tests. To confirm this, future studies with more diverse populations are warranted.

Determining whether false positive rates increase with performance validity test battery expansion

OBJECTIVE

Performance validity test (PVT) misclassification is an important concern for neuropsychologists. The present study determined whether expanding PVT analysis from 4-PVTs to 8-PVTs could lead to elevated rates of false positive performance validity misclassifications.

METHOD

Retrospective analysis of 443 patients who underwent a fixed neuropsychological test battery in a mixed clinical and forensic setting. Rates of failing two PVTs were compared to those predicted by Monte Carlo simulations when PVT analysis extended from 4-PVTs to 8-PVTs. Indeterminate performers (IDT; n = 42; those who failed two PVTs only after PVT analysis extended from 4-PVTs to 8-PVTs) were compared to a PVT-Fail group (n = 148; those who failed two PVTs in the 4-PVT battery or failed >2 PVTs).

RESULTS

Rate of failing two PVTs remained stable when PVT analysis extended from 4- to 8-PVTs (12.9 to 11.9%) and was significantly lower than those predicted by Monte Carlo simulations. Compared to PVT-Fail, the IDT group was significantly younger, had stronger neuropsychological test performance, and demonstrated comparable rates of forensic referral and conditions with known neurocognitive sequelae (e.g. stroke, moderate-to-severe TBI).

CONCLUSIONS

Monte Carlo simulations significantly overestimated rates of individuals failing two PVTs as PVT battery length doubled. IDT did not differ from PVT-Fail across variables with known PVT effects (e.g. age, referral context, neurologic diagnoses), lowering concern that this group is comprised entirely of false-positive PVT classifications. More research is needed to determine the effect of PVT battery length on validity classification accuracy.

Comparing embedded performance validity indicators within the WAIS-IV Letter-Number sequencing subtest to Reliable Digit Span among adults referred for evaluation of attention-deficit/hyperactivity disorder

Objectives: This study investigated the Wechsler Adult Intelligence Scale-Fourth Edition Letter-Number Sequencing (LNS) subtest as an embedded performance validity indicator among adults undergoing an attention-deficit/hyperactivity disorder (ADHD) evaluation, and its potential incremental value over Reliable Digit Span (RDS). Method: This cross-sectional study comprised 543 adults who underwent neuropsychological evaluation for ADHD. Patients were divided into valid (n = 480) and invalid (n = 63) groups based on multiple criterion performance validity tests. Results: LNS total raw scores, age-corrected scaled scores, and age- and education-corrected T-scores demonstrated excellent classification accuracy (area under the curve of .84, .83, and .82, respectively). The optimal cutoff for LNS raw score (≤16), age-corrected scaled score (≤7), and age- and education-corrected T-score (≤36) yielded .51 sensitivity and .94 specificity. Slightly lower sensitivity (.40) and higher specificity (.98) was associated with a more conservative T-score cutoff of ≤33. Multivariate models incorporating both LNS and RDS improved classification accuracy (area under the curve of .86), and LNS scores explained a significant but modest proportion of variance in validity status above and beyond RDS. Chaining LNS T-score of ≤33 with RDS cutoff of ≤7 increased sensitivity to .69 while maintaining ≥.90 specificity. Conclusions: Findings provide preliminary evidence for the criterion and construct validity of LNS as an embedded validity indicator in ADHD evaluations. Practitioners are encouraged to use LNS T-score cutoff of ≤33 or ≤36 to assess the validity of obtained test data. Employing either of these LNS cutoffs with RDS may enhance the detection of invalid performance.

CVLT-II short form forced choice recognition in a clinical dementia sample: Cautions for performance validity assessment

Performance validity tests are susceptible to false positives from genuine cognitive impairment (e.g., dementia); this has not been explored with the short form of the California Verbal Learning Test II (CVLT-II-SF). In a memory clinic sample, we examined whether CVLT-II-SF Forced Choice Recognition (FCR) scores differed across diagnostic groups, and how the severity of impairment [Clinical Dementia Rating Sum of Boxes (CDR-SOB) or Mini-Mental State Examination (MMSE)] modulated test performance. Three diagnostic groups were identified: subjective cognitive impairment (SCI; n = 85), amnestic mild cognitive impairment (a-MCI; n = 17), and dementia due to Alzheimer's Disease (AD; n = 50). Significant group differences in FCR were observed using one-way ANOVA; post-hoc analysis indicated the AD group performed significantly worse than the other groups. Using multiple regression, FCR performance was modeled as a function of the diagnostic group, severity (MMSE or CDR-SOB), and their interaction. Results yielded significant main effects for MMSE and diagnostic group, with a significant interaction. CDR-SOB analyses were non-significant. Increases in impairment disproportionately impacted FCR performance for persons with AD, adding caution to research-based cutoffs for performance validity in dementia. Caution is warranted when assessing performance validity in dementia populations. Future research should examine whether CVLT-II-SF-FCR is appropriately specific for best-practice testing batteries for dementia.

Standalone Performance Validity Tests May Be Differentially Related to Measures of Working Memory, Processing Speed, and Verbal Memory in Patients With Multiple Sclerosis

Cognitive functioning may account for minimal levels (i.e., 5%-14%) of variance of performance validity test (PVT) scores in clinical examinees. The present study extended this research twofold: (a) by determining the variance cognitive functioning explains within three distinct PVTs (b) in a sample of patients with multiple sclerosis (pwMS). Seventy-five pwMS (Mage = 48.50, 70.6% female, 80.9% White) completed the Victoria Symptom Validity Test (VSVT), Word Choice Test (WCT), Dot Counting Test (DCT), and three objective measures of working memory, processing speed, and verbal memory as part of clinical neuropsychological assessment. Regression analyses in credible groups (ns ranged from 54 to 63) indicated that cognitive functioning explained 24% to 38% of the variance in logarithmically transformed PVT variables. Variance from cognitive testing differed across PVTs: verbal memory significantly influenced both VSVT and WCT scores; working memory influenced VSVT and DCT scores; and processing speed influenced DCT scores. The WCT appeared least related to cognitive functioning of the included PVTs. Alternative plausible explanations, including the apparent domain/modality specificity hypothesis of PVTs versus the potential sensitivity of these PVTs to neurocognitive dysfunction in pwMS were discussed. Continued psychometric investigations into factors affecting performance validity, especially in multiple sclerosis, are warranted.

Multivariate examination of embedded indicators of performance validity for ADHD evaluations: A targeted approach

This study investigated the individual and combined utility of 10 embedded validity indicators (EVIs) within executive functioning, attention/working memory, and processing speed measures in 585 adults referred for an attention-deficit/hyperactivity disorder (ADHD) evaluation. Participants were categorized into invalid and valid performance groups as determined by scores from empirical performance validity indicators. Analyses revealed that all of the EVIs could meaningfully discriminate invalid from valid performers (AUCs = .69-.78), with high specificity (≥90%) but low sensitivity (19%-51%). However, none of them explained more than 20% of the variance in validity status. Combining any of these 10 EVIs into a multivariate model significantly improved classification accuracy, explaining up to 36% of the variance in validity status. Integrating six EVIs from the Stroop Color and Word Test, Trail Making Test, Verbal Fluency Test, and Wechsler Adult Intelligence Scale-Fourth Edition was as efficacious (AUC = .86) as using all 10 EVIs together. Failing any two of these six EVIs or any three of the 10 EVIs yielded clinically acceptable specificity (≥90%) with moderate sensitivity (60%). Findings support the use of multivariate models to improve the identification of performance invalidity in ADHD evaluations, but chaining multiple EVIs may only be helpful to an extent.

Specificity of Embedded Performance Validity Tests in Elderly Veterans with Mild and Major Neurocognitive Disorder

OBJECTIVE

This study explored the specificity of four embedded performance validity tests (PVTs) derived from common neuropsychological tasks in a sample of older veterans with verified cognitive decline and whose performance was deemed valid by licensed psychologists.

METHOD

Participants were 180 veterans who underwent comprehensive neuropsychological evaluation, were determined to have valid performance following profile analysis/conceptualization, and were diagnosed with mild neurocognitive disorder (i.e., MCI; n = 64) or major neurocognitive disorder (i.e., Dementia; n = 116). All participants completed at least one of four embedded PVTs: Reliable Digit Span (RDS), California Verbal Learning Test-2nd ed. Short Form (CVLT-II SF) Forced choice, Trails B:A, and Delis-Kaplan Executive Function System (DKEFS) Letter and Category Fluency.

RESULTS

Adequate specificity (i.e., ≥90%) was achieved at modified cut-scores for all embedded PVTs across MCI and Dementia groups. Trails B:A demonstrated near perfect specificity at its traditional cut-score (Trails B:A < 1.5). RDS ≤ 5 and CVLT-II SF Forced Choice ≤7 led to <10% false positive classification errors across MCI and dementia groups. DKEFS Letter and Category Fluency achieved 90% specificity at extremely low normative cut-scores.

CONCLUSIONS

RDS, Trails B:A, and CVLT-II SF Forced Choice reflect promising embedded PVTs in the context of dementia evaluations. DKEFS Letter and Category Fluency appear too sensitive to genuine neurocognitive decline and, therefore, are inappropriate PVTs in adults with MCI or dementia. Additional research into embedded PVT sensitivity (via known-groups or analogue designs) in MCI and dementia is needed.

OUP accepted manuscript

OBJECTIVE

Individuals with early-onset dysexecutive Alzheimer's disease (dAD) have high rates of failed performance validity testing (PVT), which can lead to symptom misinterpretation and misdiagnosis.

METHOD

The aim of this retrospective study is to evaluate rates of failure on a common PVT, the test of memory malingering (TOMM), in a sample of clinical patients with biomarker-confirmed early-onset dAD who completed neuropsychological testing.

RESULTS

We identified seventeen patients with an average age of symptom onset at 52.25 years old. Nearly fifty percent of patients performed below recommended cut-offs on Trials 1 and 2 of the TOMM. Four of six patients who completed outside neuropsychological testing were misdiagnosed with alternative etiologies to explain their symptomatology, with two of these patients' performances deemed unreliable based on the TOMM.

CONCLUSIONS

Low scores on the TOMM should be interpreted in light of contextual and optimally biological information and do not necessarily rule out a neurodegenerative etiology.

Considerations regarding noncredible performance in the neuropsychological assessment of patients with multiple sclerosis: A case series

Determining the validity of data during clinical neuropsychological assessment is crucial for proper interpretation, and extensive literature has emphasized myriad methods of doing so in diverse samples. However, little research has considered noncredible presentation in persons with multiple sclerosis (pwMS). PwMS often experience one or more factors known to impact validity of data, including major neurocognitive impairment, psychological distress/psychogenic interference, and secondary gain. This case series aimed to illustrate the potential relationships between these factors and performance validity testing in pwMS. Six cases from an IRB-approved database containing pwMS referred for neuropsychological assessment at a large, academic medical center involving at least one of the above-stated factors were identified. Backgrounds, neuropsychological test data, and clinical considerations for each were reviewed. Interestingly, no pwMS diagnosed with major neurocognitive impairment was found to have noncredible performance, nor was any patient with noncredible performance in the absence of notable psychological distress. Given the variability of noncredible performance and multiplicity of factors affecting performance validity in pwMS, clinicians are strongly encouraged to consider psychometrically appropriate methods for evaluating validity of cognitive data in pwMS. Additional research aiming to elucidate base rates of, mechanisms begetting, and methods for assessing noncredible performance in pwMS is imperative.

Performance validity assessment using response time on the Warrington Recognition Memory Test

OBJECTIVE

The present study tested the incremental utility of response time (RT) on the Warrington Recognition Memory Test - Words (RMT-W) in classifying bona fide versus feigned TBI.

METHOD

Participants were 173 adults: 55 with moderate to severe TBI, 69 healthy comparisons (HC) instructed to perform their best, and 49 healthy adults coached to simulate TBI (SIM). Participants completed a computerized version of the RMT-W in the context of a comprehensive neuropsychological battery. Groups were compared on RT indices including mean RT (overall, correct trials, incorrect trials) and variability, as well as the traditional RMT-W accuracy score.

RESULTS

Several RT indices differed significantly across groups, although RMT-W accuracy predicted group membership more strongly than any individual RT index. SIM showed longer average RT than both TBI and HC. RT variability and RT for incorrect trials distinguished SIM-HC but not SIM-TBI comparisons. In general, results for SIM-TBI comparisons were weaker than SIM-HC results. For SIM-HC comparisons, classification accuracy was excellent for all multivariable models incorporating RMT-W accuracy with one of the RT indices. For SIM-TBI comparisons, classification accuracies for multivariable models ranged from acceptable to excellent discriminability. In addition to mean RT and RT on correct trials, the ratio of RT on correct items to incorrect items showed incremental predictive value to accuracy.

CONCLUSION

Findings support the growing body of research supporting the value of combining RT with PVTs in discriminating between verified and feigned TBI. The diagnostic accuracy of the RMT-W can be improved by incorporating RT.

The Impact of Learning and Memory on Performance Validity Tests in a Mixed Clinical Pediatric Population

OBJECTIVE

This study examined the degree to which verbal and visuospatial memory abilities influence performance validity test (PVT) performance in a mixed clinical pediatric sample.

METHOD

Data from 252 consecutive clinical pediatric cases (Mage=11.23 years, SD=4.02; 61.9% male) seen for outpatient neuropsychological assessment were collected. Measures of learning and memory (e.g., The California Verbal Learning Test-Children's Version; Child and Adolescent Memory Profile [ChAMP]), performance validity (Test of Memory Malingering Trial 1 [TOMM T1]; Wechsler Intelligence Scale for Children-Fifth Edition [WISC-V] or Wechsler Adult Intelligence Scale-Fourth Edition Digit Span indices; ChAMP Overall Validity Index), and intellectual abilities (e.g., WISC-V) were included.

RESULTS

Learning/memory abilities were not significantly correlated with TOMM T1 and accounted for relatively little variance in overall TOMM T1 performance (i.e., ≤6%). Conversely, ChAMP Validity Index scores were significantly correlated with verbal and visual learning/memory abilities, and learning/memory accounted for significant variance in PVT performance (12%-26%). Verbal learning/memory performance accounted for 5%-16% of the variance across the Digit Span PVTs. No significant differences in TOMM T1 and Digit Span PVT scores emerged between verbal/visual learning/memory impairment groups. ChAMP validity scores were lower for the visual learning/memory impairment group relative to the nonimpaired group.

CONCLUSIONS

Findings highlight the utility of including PVTs as standard practice for pediatric populations, particularly when memory is a concern. Consistent with the adult literature, TOMM T1 outperformed other PVTs in its utility even among the diverse clinical sample with/without learning/memory impairment. In contrast, use of Digit Span indices appear to be best suited in the presence of visuospatial (but not verbal) learning/memory concerns. Finally, the ChAMP's embedded validity measure was most strongly impacted by learning/memory performance.

American Academy of Clinical Neuropsychology (AACN) 2021 consensus statement on validity assessment: Update of the 2009 AACN consensus conference statement on neuropsychological assessment of effort, response bias, and malingering

Objective: Citation and download data pertaining to the 2009 AACN consensus statement on validity assessment indicated that the topic maintained high interest in subsequent years, during which key terminology evolved and relevant empirical research proliferated. With a general goal of providing current guidance to the clinical neuropsychology community regarding this important topic, the specific update goals were to: identify current key definitions of terms relevant to validity assessment; learn what experts believe should be reaffirmed from the original consensus paper, as well as new consensus points; and incorporate the latest recommendations regarding the use of validity testing, as well as current application of the term 'malingering.' Methods: In the spring of 2019, four of the original 2009 work group chairs and additional experts for each work group were impaneled. A total of 20 individuals shared ideas and writing drafts until reaching consensus on January 21, 2021. Results: Consensus was reached regarding affirmation of prior salient points that continue to garner clinical and scientific support, as well as creation of new points. The resulting consensus statement addresses definitions and differential diagnosis, performance and symptom validity assessment, and research design and statistical issues. Conclusions/Importance: In order to provide bases for diagnoses and interpretations, the current consensus is that all clinical and forensic evaluations must proactively address the degree to which results of neuropsychological and psychological testing are valid. There is a strong and continually-growing evidence-based literature on which practitioners can confidently base their judgments regarding the selection and interpretation of validity measures.

Performance validity test failure in clinical populations-a systematic review

Performance validity tests (PVTs) are widely used in attempts to quantify effort and/or detect negative response bias during neuropsychological testing. However, it can be challenging to interpret the meaning of poor PVT performance in a clinical context. Compensation-seeking populations predominate in the PVT literature. We aimed to establish base rates of PVT failure in clinical populations without known external motivation to underperform. We searched MEDLINE, EMBASE and PsycINFO for studies reporting PVT failure rates in adults with defined clinical diagnoses, excluding studies of active or veteran military personnel, forensic populations or studies of participants known to be litigating or seeking disability benefits. Results were summarised by diagnostic group and implications discussed. Our review identified 69 studies, and 45 different PVTs or indices, in clinical populations with intellectual disability, degenerative brain disease, brain injury, psychiatric disorders, functional disorders and epilepsy. Various pass/fail cut-off scores were described. PVT failure was common in all clinical groups described, with failure rates for some groups and tests exceeding 25%. PVT failure is common across a range of clinical conditions, even in the absence of obvious incentive to underperform. Failure rates are no higher in functional disorders than in other clinical conditions. As PVT failure indicates invalidity of other attempted neuropsychological tests, the finding of frequent and unexpected failure in a range of clinical conditions raises important questions about the degree of objectivity afforded to neuropsychological tests in clinical practice and research.

A Meta-Analysis of Neuropsychological Effort Test Performance in Psychotic Disorders

Psychotic disorders are characterized by a generalized neurocognitive deficit (i.e., performance 1.5 SD below controls across neuropsychological domains with no specific profile of differential deficits). A motivational account of the generalized neurocognitive deficit has been proposed, which attributes poor neuropsychological testing performance to low effort. However, findings are inconsistent regarding effort test failure rate in individuals with psychotic disorders across studies (0-72%), and moderators are unclear, making it difficult to know whether the motivational explanation is viable. To address these issues, a meta-analysis was performed on data from 2205 individuals with psychotic disorders across 19 studies with 24 independent effects. Effort failure rate was examined along with moderators of effort test type, forensic status, IQ, positive symptoms, negative symptoms, diagnosis, age, gender, education, and antipsychotic use. The pooled weighted effort test failure rate was 18% across studies and there was a moderate pooled association between effort failure rate and global neurocognitive performance (r = .57). IQ and education significantly moderated failure rate. Collectively, these findings suggest that a nontrivial proportion of individuals with a psychotic disorder fail effort testing, and failure rate is associated with global neuropsychological impairment. However, given that effort tests are not immune to the effects of IQ in psychotic disorders, these results cannot attest to the viability of the motivational account of the generalized neurocognitive deficit. Furthermore, the significant moderating effect of IQ and education on effort test performance suggests that effort tests have questionable validity in this population and should be interpreted with caution.

Performance and Symptom Validity Assessment in Patients with Apathy and Cognitive Impairment

OBJECTIVE

Performance and symptom validity tests (PVTs and SVTs) measure the credibility of the assessment results. Cognitive impairment and apathy potentially interfere with validity test performance and may thus lead to an incorrect (i.e., false-positive) classification of the patient's scores as non-credible. The study aimed at examining the false-positive rate of three validity tests in patients with cognitive impairment and apathy.

METHODS

A cross-sectional, comparative study was performed in 56 patients with dementia, 41 patients with mild cognitive impairment, and 41 patients with Parkinson's disease. Two PVTs - the Test of Memory Malingering (TOMM) and the Dot Counting Test (DCT) - and one SVT - the Structured Inventory of Malingered Symptomatology (SIMS) - were administered. Apathy was measured with the Apathy Evaluation Scale, and severity of cognitive impairment with the Mini Mental State Examination.

RESULTS

The failure rate was 13.7% for the TOMM, 23.8% for the DCT, and 12.5% for the SIMS. Of the patients with data on all three tests (n = 105), 13.5% failed one test, 2.9% failed two tests, and none failed all three. Failing the PVTs was associated with cognitive impairment, but not with apathy. Failing the SVT was related to apathy, but not to cognitive impairment.

CONCLUSIONS

In patients with cognitive impairment or apathy, failing one validity test is not uncommon. Validity tests are differentially sensitive to cognitive impairment and apathy. However, the rule that at least two validity tests should be failed to identify non-credibility seemed to ensure a high percentage of correct classification of credibility.

Symptom and performance validation in patients with subjective cognitive decline and mild cognitive impairment

Nonauthentic symptom claims (overreporting) and invalid test results (underperformance) can regularly be expected in a forensic context, but may also occur in clinical referrals. While the applicability of symptom and performance validity tests in samples of dementia patients is well studied, the same is not true for patients with subjective cognitive decline (SCD) and mild cognitive impairment (MCI). A sample of 54 memory-clinic outpatients with evidence of SCD or MCI was studied. We evaluated the rate of positive results in three validity measures. A total of 7.4% of the patients showed probable negative response bias in the Word Memory Test. The rate of positive results on the Structured Inventory of Malingered Symptomatology was 14.8% while only one participant (1.9%) scored positive on the Self-Report Symptom Inventory using the standard cutoff. The two questionnaires were moderately correlated at .67. In a combined analysis of all results, five of the patients (9.3%) were judged to show evidence of probable negative response bias (or probably feigned neurocognitive impairment). In the current study, a relatively small but nontrivial rate of probable response distortions was found in a memory-clinic sample. However, it remains a methodological challenge for this kind of research to reliably distinguish between false-positive and correct-positive classifications in clinical patient groups.

Eliciting Response Bias Within Forced Choice Tests to Detect Random Responders

The Forced Choice Test (FCT) can be used to detect malingered loss of memory or sensory deficits. In this test, examinees are presented with two stimuli, one correct and one incorrect, in regards to a specific event or a perceptual discrimination task. The task is to select the correct answer alternative, or guess if it is unknown. Genuine impairment is associated with test scores that fall within chance performance. In contrast, malingered impairment is associated with purposeful avoidance of correct information, resulting in below chance performance. However, a substantial proportion of malingerers intentionally randomize their responses, and are missed by the test. Here we examine whether a ‘runs test’ and a ‘within test response ‘bias’ have diagnostic value to detect this intentional randomization. We instructed 73 examinees to malinger red/green blindness and subjected them to a FCT. For half of the examinees we manipulated the ambiguity between answer alternatives over the test trials in order to elicit a response bias. Compared to a sample of 10,000 cases of computer generated genuine performance, the runs test and response bias both detected malingered performance better than chance.