Utility of Green's Word Memory Test Free Recall Subtest as a Measure of Verbal Memory: Initial Evidence from a Temporal Lobe Epilepsy Clinical Sample

Evaluation of the classification accuracy of multiple performance validity tests in a mixed clinical sample

The Test of Memory Malingering (TOMM) and Word Memory Test (WMT) are among the most well-known performance validity tests (PVTs) and regarded as gold standard measures. Due to the many factors that impact PVT selection, it is imperative that clinicians make informed clinical decisions with respect to additional or alternative PVTs that demonstrate similar classification accuracy as these well-validated measures. The present archival study evaluated the agreement/classification accuracy of a large battery consisting of multiple other freestanding/embedded PVTs in a mixed clinical sample of 126 veterans. We examined failure rates for all standalone/embedded PVTs using established cut-scores and calculated pass/fail agreement rates and diagnostic odds ratios for various combinations of PVTs using the TOMM and WMT as criterion measures. TOMM and WMT demonstrated the best agreement, followed by Word Choice Test (WCT). The Rey Fifteen Item Test had an excessive number of false-negative errors and reduced classification accuracy. The Digit Span age-corrected scaled score (DS-ACSS) had highest agreement. Findings lend further support to the use of a combination of embedded and standalone PVTs in identifying suboptimal performance. Results provide data to enhance clinical decision making for neuropsychologists who implement combinations of PVTs in a larger clinical battery.

Examining Traditional and Novel Validity Indicators from the Medical Symptom Validity Test Across Levels of Verbal and Visual Memory Impairment

OBJECTIVE

This cross-sectional study examined accuracy of traditional Medical Symptom Validity Test (MSVT) validity indicators, including immediate recognition (IR), delayed recognition (DR), and consistency (CNS), as well as a novel indicator derived from the mean performance on IR, DR, and CNS across verbal, visual, and combined learning and memory impairment bands.

METHOD

A sample of 180 adult outpatients was divided into valid (n = 150) and invalid (n = 30) groups based on results of four independent criterion performance validity tests. Verbal and visual learning and recall were classified as indicative of no impairment, mild impairment, or severe impairment based on performance on the Rey Auditory Verbal Learning Test and Brief Visuospatial Memory Test-Revised, respectively.

RESULTS

In general, individual MSVT subtests were able to accurately classify performance as valid or invalid, even in the context of severe learning and memory deficits. However, as verbal and visual memory impairment increased, optimal MSVT cut-scores diverged from manual-specified cutoffs such that DR and CNS required cut-scores to be lowered to maintain adequate specificity. By contrast, the newly proposed scoring algorithm generally showed more robust psychometric properties across the memory impairment bands.

CONCLUSIONS

The mean performance index, a novel scoring algorithm using the mean of the three primary MSVT subtests, may be a more robust validity indicator than the individual MSVT subtests in the context of bona fide memory impairment.

Feasibility, Contrast Sensitivity and Network Specificity of Language fMRI in Presurgical Evaluation for Epilepsy and Brain Tumor Surgery

Language fMRI has become an integral part of the planning process in brain surgery. However, fMRI may suffer from confounding factors both on the patient side, as well as on the provider side. In this study, we investigate how patient-related confounds affect the ability of the patient to perform language fMRI tasks (feasibility), the task sensitivity from an image contrast point of view, and the anatomical specificity of expressive and receptive language fMRI protocols. 104 patients were referred for language fMRI in the context of presurgical procedures for epilepsy and brain tumor surgery. Four tasks were used: (1) a verbal fluency (VF) task to map vocabulary use, (2) a semantic description (SD) task to map sentence formation/semantic integration skills, (3) a reading comprehension (RC) task and (4) a listening comprehension (LC) task. Feasibility was excellent in the LC task (100%), but in the acceptable to mediocre range for the rest of the tasks (SD: 87.50%, RC: 85.57%, VF: 67.30%). Feasibility was significantly confounded by age (p = 0.020) and education level (p = 0.003) in VF, by education level (p = 0.004) and lesion laterality (p = 0.019) in SD and by age (p = 0.001), lesion laterality (p = 0.007) and lesion severity (p = 0.048) in RC. All tasks were comparable regarding sensitivity in generating statistically significant image contrast (VF: 90.00%, SD: 92.30%, RC: 93.25%, LC: 88.46%). The lobe of the lesion (p = 0.005) and the age (p = 0.009) confounded contrast sensitivity in the VF and SD tasks respectively. Both VF and LC tasks demonstrated unilateral lateralization of posterior language areas; only the LC task showed unilateral lateralization of anterior language areas. Our study highlights the effects of patient-related confounding factors on language fMRI and proposes LC as the most feasible, less confounded, and efficiently lateralizing task in the clinical presurgical context.

Semantic and episodic memory in adults with temporal lobe epilepsy

The primary aims were to (1) identify the factor structure of tests thought to measure semantic and episodic memory and (2) examine whether patterns of impairment would show a double dissociation between these two memory systems at an individual level in patients with temporal lobe epilepsy (TLE). The secondary aim was to explore the impact of epilepsy-related variables on performance. This retrospective study involved a cohort of 54 adults who had been diagnosed with TLE and had undergone a neuropsychological assessment that included four memory tests traditionally used to measure either semantic memory (picture naming, animal fluency) or episodic memory (story recall, word list recall) at a single epilepsy surgery center in Australia. Principal component analysis revealed two factors albeit with unexpected loadings. Picture naming and story recall loaded on one factor. Animal fluency and word list recall loaded on another factor. There was no evidence of a double dissociation between semantic and episodic memory at an individual level. Left hemisphere seizure focus and early age of seizure onset related to worse performance on word list recall, picture naming and animal fluency, respectively. Our study highlights the importance of caution when interpreting the results of neuropsychological assessments, as not all putative tests of semantic and episodic memory may necessarily be measuring the same construct. Future directions for research are also considered.

Validation of the Advanced Clinical Solutions Word Choice Test (WCT) in a Mixed Clinical Sample: Establishing Classification Accuracy, Sensitivity/Specificity, and Cutoff Scores

This study examined the Word Choice Test’s (WCT) utility as a performance validity test in a mixed clinical sample of veterans referred for neuropsychological evaluation. Participants completed Green’s Word Memory Test (WMT), WCT, and Test of Memory Malingering (TOMM) Trial 1. Using the WMT as the criterion for valid performance, logistic regressions examined the WCT and TOMM’s classification accuracy for those with and without cognitive impairment (CI). Receiver operating characteristic curves were used to establish cut scores which maximized the sensitivity/specificity of each measure. In those without CI, both tests showed good classification accuracy (86.7% and 85.0%, respectively). Among those with CI, the TOMM retained good classification accuracy (82.3%), while the WCT’s decreased considerably (69.4%). Optimal WCT cut scores differed based on impairment status, with a higher sensitivity/specificity trade-off among those with CI. Successful performance on the WCT appeared to rely more heavily on cognitive processes unrelated to performance validity.