Self-reported disability-seeking predicts PVT failure in veterans undergoing clinical neuropsychological evaluation

Using behavior and eye-fixations to detect feigned memory impairment

Background

Detecting invalid cognitive performance is an important clinical challenge in neuropsychological assessment. The aim of this study was to explore behavior and eye-fixations responses during the performance of a computerized version of the Test of Memory Malingering (TOMM-C) under standard vs. feigning conditions.

Participants and methods

TOMM-C with eye-tracking recording was performed by 60 healthy individuals (31 with standard instruction - SI; and 29 were instructed to feign memory impairment: 21 Naïve Simulators - NS and 8 Coached Simulators - CS) and 14 patients with Multiple Sclerosis (MS) and memory complaints performed. Number of correct responses, response time, number of fixations, and fixation time in old vs. new stimuli were recorded. Nonparametric tests were applied for group comparison.

Results

NS produced fewer correct responses and had longer response times in comparison to SI on all three trials. SI showed more fixations and longer fixation time on previously presented stimuli (i.e., familiarity preference) specially on Trial 1, whereas NS had more fixations and longer fixation time on new stimuli (i.e., novelty preference) specially in the Retention trial. MS patients produced longer response time and had a different fixation pattern than SI subjects. No behavioral or oculomotor difference was observed between NS and CS.

Conclusion

Healthy simulators have a distinct behavioral and eye-fixation response pattern, reflecting a novelty preference. Oculomotor measures may be useful to detect exaggeration or fabrication of cognitive dysfunction. Though, its application in clinical populations may be limited.

Importance of validity testing in psychiatric assessment: evidence from a sample of multimorbid post-9/11 veterans

OBJECTIVE

Performance validity (PVTs) and symptom validity tests (SVTs) are necessary components of neuropsychological testing to identify suboptimal performances and response bias that may impact diagnosis and treatment. The current study examined the clinical and functional characteristics of veterans who failed PVTs and the relationship between PVT and SVT failures.

METHOD

Five hundred and sixteen post-9/11 veterans participated in clinical interviews, neuropsychological testing, and several validity measures.

RESULTS

Veterans who failed 2+ PVTs performed significantly worse than veterans who failed one PVT in verbal memory (Cohen's d = .60-.69), processing speed (Cohen's d = .68), working memory (Cohen's d = .98), and visual memory (Cohen's d = .88-1.10). Individuals with 2+ PVT failures had greater posttraumatic stress (PTS; β = 0.16; p = .0002), and worse self-reported depression (β = 0.17; p = .0001), anxiety (β = 0.15; p = .0007), sleep (β = 0.10; p = .0233), and functional outcomes (β = 0.15; p = .0009) compared to veterans who passed PVTs. 7.8% veterans failed the SVT (Validity-10; ≥19 cutoff); Multiple PVT failures were significantly associated with Validity-10 failure at the ≥19 and ≥23 cutoffs (p's < .0012). The Validity-10 had moderate correspondence in predicting 2+ PVTs failures (AUC = 0.83; 95% CI = 0.76, 0.91).

CONCLUSION

PVT failures are associated with psychiatric factors, but not traumatic brain injury (TBI). PVT failures predict SVT failure and vice versa. Standard care should include SVTs and PVTs in all clinical assessments, not just neuropsychological assessments, particularly in clinically complex populations.

The impact of race and other demographic factors on the false positive rates of five embedded Performance Validity Tests (PVTs) in a Veteran sample

INTRODUCTION

It is common to use normative adjustments based on race to maintain accuracy when interpreting cognitive test results during neuropsychological assessment. However, embedded performance validity tests (PVTs) do not adjust for these racial differences and may result in elevated rates of false positives in African American/Black (AA) samples compared to European American/White (EA) samples.

METHODS

Veterans without Major Neurocognitive Disorder completed an outpatient neuropsychological assessment and were deemed to be performing in a valid manner (e.g., passing both the Test of Memory Malingering Trial 1 (TOMM1) and the Medical Symptom Validity Test (MSVT), (n = 531, EA = 473, AA = 58). Five embedded PVTs were administered to all patients: WAIS-III/IV Processing Speed Index (PSI), Brief Visuospatial Memory Test-Revised: Discrimination Index (BVMT-R), TMT-A (secs), California Verbal Learning Test-II (CVLT-II) Forced Choice, and WAIS-III/IV Digit Span Scaled Score. Individual PVT false positive rates, as well as the rate of failing two or more embedded PVTs, were calculated.

RESULTS

Failure rates of two embedded PVTs (PSI, TMT-A), and the total number of PVTs failed, were higher in the AA sample. The PSI and TMT-A remained significantly impacted by race after accounting for age, education, sex, and presence of Mild Neurocognitive Disorder. There were PVT failure rates greater than 10% (and considered false positives) in both groups (AA: PSI, TMT-A, and BVMT-R, 12-24%; EA: BVMT-R, 17%). Failing 2 or more PVTs (AA = 9%, EA = 4%) was impacted by education and Mild Neurocognitive Disorder but not by race.

CONCLUSIONS

Individual (timed) PVTs showed higher false positive rates in the AA sample even after accounting for demographic factors and diagnosis of Mild Neurocognitive Disorder. Requiring failure on 2 or more embedded PVTs reduced false positive rates to acceptable levels across both groups (10% or less) and was not significantly influenced by race.

Validation and psychometric properties of the Word Choice Test-10 as an abbreviated performance validity test

Objective: The objective of the current investigation was to validate and establish the psychometric properties of an abbreviated, 10-item version of the Word Choice Test (WCT). Method: Data from one hundred ten clinically-referred participants (M age = 55.92, SD = 14.07; M education = 13.74, SD = 2.43; 84.5% Male) in a Veterans Affairs neuropsychology outpatient clinic was analyzed. All participants completed the WCT, the TOMM T1, the WMT, and the Digit Span subtest of the WAIS-IV as part of a larger battery of neuropsychological tests. Results: Correlation analyses revealed significant relationships between the 10-item WCT-10, the TOMM T1, the RDS forward/backward, as well as the IR, DR, and CNS subtests of the WMT. ROC analysis for the WCT-10 indicated optimal cutoff of 2 or more errors, with 52% sensitivity and 97% specificity (AUC=.786, p<.001), compared with the standard administration of the WCT with a cutoff of 8 or more errors, which had 67% sensitivity and 91% specificity. Specificity/sensitivity values remained adequate at a cutoff of two or more errors when participants with cognitive impairment (Sensitivity=.52, Specificity=.92) and without cognitive impairment (Sensitivity=.52, Specificity = 1.0) were examined separately. Conclusions: The present investigation revealed that the WCT-10, an abbreviated free-standing PVT comprised of the initial 10 items of the WCT, demonstrated clinical utility in a mixed clinical sample of Veterans and was robust to cognitive impairment. This abbreviated PVT may benefit researchers and clinicians through adequate identification of invalid performance while minimizing completion time.