Establishing the base rate of performance invalidity in a clinical electrical injury sample: Implications for neuropsychological test performance.

Objective: The base rate of neuropsychological performance invalidity in electrical injury, a clinically-distinct and frequently compensation-seeking population, is not well established. This study determined the base rate of performance invalidity in a large electrical injury sample, and examined patient characteristics, injury parameters, and neuropsychological test performance based on validity status.Method: This cross-sectional study included data from 101 patients with electrical injury consecutively referred for post-acute neuropsychological evaluation. Eighty-five percent of the sample was compensation-seeking. Multiple performance validity tests (PVTs) were administered as part of standard clinical evaluation. For patients with four or more PVTs, valid performance was operationalized as less than or equal to one PVT failure and invalid performance as two or more failures.Results: Frequency analysis revealed 66% (n = 67) had valid performance while 29% (n = 29) demonstrated probable invalid performance; the remaining 5% (n = 5) had indeterminate validity. No significant differences in demographics or injury parameters emerged between validity groups (0 vs. 1 vs. ≥2 PVT failures). In contrast, the electrical injury group with invalid performance performed significantly worse across tests of processing speed and executive abilities than those with valid performance (ps< .05, ηp2 = .19-.25).Conclusions: The current study is the first to establish the base rate of neuropsychological performance invalidity in electrical injury survivors using empirical methods and current practice standards. Patient and clinical variables, including compensation-seeking status, did not differ between validity groups; however, neuropsychological test performance did, supporting the need for multi-method, objective performance validity assessment.

Working Memory, Processing Speed, and Memory Functioning Are Minimally Predictive of Victoria Symptom Validity Test Performance.

A sound performance validity test is accurate for detecting invalid neuropsychological test performance and relatively insensitive to actual cognitive ability or impairment. This study explored the relationship of several cognitive abilities to several performance indices on the Victoria Symptom Validity Test (VSVT), including accuracy and response latency. This cross-sectional study examined data from a mixed clinical sample of 88 adults identified as having valid neurocognitive test profiles via independent validity measures, and who completed the VSVT along with objective measures of working memory, processing speed, and verbal memory during their clinical neuropsychological evaluation. Results of linear regression analyses indicated that cognitive test performance accounted for 5% to 14% of total variance for VSVT performance across indices. Working memory was the only cognitive ability to predict significant, albeit minimal, variance on the VSVT response accuracy indices. Results show that VSVT performance is minimally predicted by working memory, processing speed, or delayed verbal memory recall.

Examination of the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) validity and substantive scales in patients with electrical injury.

Objective: Electrical injury (EI) is a distinct subtype of traumatic injury that often results in a unique constellation of cognitive sequelae and unusual sensory experiences due to peripheral nervous system injury that are uncommon in general medical/neurological populations and have been unexplored with the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF). Method: This study examined performance patterns on MMPI-2-RF validity and substantive scales among 62 EI patients who underwent neuropsychological evaluation, of which 46 demonstrated valid symptom reporting and neurocognitive test performance via multiple independent validity indicators and were retained for analysis. Results: Valid EI patients scored significantly higher than the MMPI-2-RF normative sample on several validity scales with the largest effect sizes on F-r (Infrequent Responses), Fs (Infrequent Somatic Responses), FBS-r (Symptom Validity), and RBS (Response Bias), and ≥33% obtaining elevated scores on these scales per standard interpretive criteria. Review of item content on these scales revealed several reflect disturbances in sensation, physical functioning, and/or cognition that are not infrequent in this population. Further, MMPI-2-RF clinical profiles did not reveal generalized distress or noncredible over-reporting. Rather, similar to the MMPI-2, valid EI patients had a specific pattern related to physical/sensory symptoms and reduced positive emotions with elevations on restructured clinical (RC) scale 1 (somatic complaints), somatic/cognitive specific problem scales, and low positive emotions (RC2). Conclusions: Elevations on some MMPI-2-RF validity scale may capture some degree of actual EI sequela that neuropsychologists need to consider to prevent erroneously concluding that a credible EI patient is over-reporting when s/he is reporting bona fide, EI-related symptoms.

Performance validity testing in a clinical sample of adults with sickle cell disease.

OBJECTIVE: Neuropsychologists utilize performance validity tests (PVTs) as objective means for drawing inferences about performance validity. The Test of Memory Malingering (TOMM) is a well-validated, stand-alone PVT and the Reliable Digit Span (RDS) and Reliable Digit Span-Revised (RDS-R) from the Digit Span subtest of the WAIS-IV are commonly employed, embedded PVTs. While research has demonstrated the utility of these PVTs with various clinical samples, no research has investigated their use in adults with sickle cell disease (SCD), a condition associated with multiple neurological, physical, and psychiatric symptoms. Thus, the purpose of this study was to explore PVT performance in adults with SCD. METHOD: Fifty-four adults with SCD (Mage = 40.61, SD = 12.35) were consecutively referred by their hematologist for a routine clinical outpatient neuropsychological evaluation. During the evaluation, participants were administered the TOMM (Trials 1 and 2), neuropsychological measures including the WAIS-IV Digit Span subtest, and mood and behavioral questionnaires. RESULTS: The average score on the TOMM was 47.70 (SD = 3.47, range = 34-50) for Trial 1 and 49.69 (SD = 1.66, range = 38-50) for Trial 2. Only one participant failed Trial 2 of the TOMM, yielding a 98.1% pass rate for the sample. Pass rates at various RDS and RDS-R values were calculated with TOMM Trial 2 performance as an external criterion. CONCLUSIONS: Results support the use of the TOMM as a measure of performance validity for individuals with SCD, while RDS and RDS-R should be interpreted with caution in this population.

Imaging chronic traumatic brain injury as a risk factor for neurodegeneration.

Population-based studies have supported the hypothesis that a positive history of traumatic brain injury (TBI) is associated with an increased incidence of neurological disease and psychiatric comorbidities, including chronic traumatic encephalopathy, Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. These epidemiologic studies, however, do not offer a clear definition of that risk, and leave unanswered the bounding criteria for greater lifetime risk of neurodegeneration. Key factors that likely mediate the degree of risk of neurodegeneration include genetic factors, significant premorbid and comorbid medical history (e.g. depression, multiple head injuries and repetitive subconcussive impact to the brain, occupational risk, age at injury, and severity of brain injury). However, given the often-described concerns in self-report accuracy as it relates to history of multiple TBIs, low frequency of patient presentation to a physician in the case of mild brain injuries, and challenges with creating clear distinctions between injury severities, disentangling the true risk for neurodegeneration based solely on population-based studies will likely remain elusive. Given this reality, multiple modalities and approaches must be combined to characterize who are at risk so that appropriate interventions to alter progression of neurodegeneration can be evaluated. This article presents data from a study that highlights uses of neuroimaging and areas of needed research in the link between TBI and neurodegenerative disease.

Anatomical correlates of age-related working memory declines.

Aging studies consistently show a relationship between decreased gray matter volume and decreased performance on working memory tasks. Few aging studies have investigated white matter changes in relation to functional brain changes during working memory tasks. Twenty-five younger and 25 older adults underwent anatomical magnetic resonance imaging (MRI) scans to measure gray matter volume, diffusion tensor imaging (DTI) to measure fractional anisotropy (FA) as a measure of white matter integrity, and functional magnetic resonance imaging (fMRI) while performing a working memory task. Significant increases in activation (fMRI) were seen in the left dorsal and ventral lateral prefrontal cortex with increased working memory load and with increased age (older showing greater bilateral activation). Partial correlational analyses revealed that even after controlling for age, frontal FA correlated significantly with fMRI activation during performance on the working memory task. These findings highlight the importance of white matter integrity in working memory performance associated with normal aging.