Christian Schutte

Concurrent Validity of Three Forced-Choice Measures of Symptom Validity

Forced-choice measures of recognition memory are used to assess the validity of an evaluation by using cutoff scores that discriminate individuals demonstrating good effort from those who are intentionally performing suboptimally. The current study evaluated three measures of motivation in a clinical sample of over 150 individuals. The Forced-Choice subtest from the California Verbal Learning Test and the Test of Memory Malingering generated comparable percentages of poor effort at 23% and 21%, respectively, yet they did not have complete concordance. Overall detection of poor performance using the 85% cut score on the three easy subtests from the Medical Symptom Validity Test (MSVT; Green, 2004) fell at 37%. When the MSVT cut score was lowered to 70%, the failure rate dropped to 21%, consistent with the other two measures and embedded measures of effort. The data are discussed in terms of adjusting the MSVT cut score and examining comparability in detection rates across these measures of symptom validity.

Derivation of a Composite Measure of Embedded Symptom Validity Indices

Assessment of effort on cognitive testing has become a suggested standard in both forensic and clinical neuropsychological assessment. Both stand-alone and empirically derived embedded measures have been developed, however guidelines for combining several measures are not always available. This study used logistic regression analysis to derive a multivariable composite to detect suboptimal effort using scores extracted from commonly administered neuropsychological tests. A model predicting suboptimal effort, as defined by performance on the Medical Symptom Validity Test, was created with 124 participants using variables from the California Verbal Learning test 2nd edition, Rey Complex Figure Test and the Wechsler Memory Scale 3rd edition. The model reliably predicted suboptimal effort (χ2 = 44.37, p < .001) with excellent discrimination (AUC = .84).The MMPI-2 Restructured Form (MMPI-2-RF; Ben-Porath & Tellegen, 2008) is replacing the MMPI-2 as the most widely used personality test in neuropsychological assessment, but additional validation studies are needed. Our study examines MMPI-2-RF Validity scales and the newly created Somatic/Cognitive scales in a recently reported sample of 82 traumatic brain injury (TBI) litigants who either passed or failed effort tests (Thomas & Youngjohn, 2009). The restructured Validity scales FBS-r (restructured symptom validity), F-r (restructured infrequent responses), and the newly created Fs (infrequent somatic responses) were not significant predictors of TBI severity. FBS-r was significantly related to passing or failing effort tests, and Fs and F-r showed non-significant trends in the same direction. Elevations on the Somatic/Cognitive scales profile (MLS-malaise, GIC-gastrointestinal complaints, HPC-head pain complaints, NUC-neurological complaints, and COG-cognitive complaints) were significant predictors of effort test failure. Additionally, HPC had the anticipated paradoxical inverse relationship with head injury severity. The Somatic/Cognitive scales as a group were better predictors of effort test failure than the RF Validity scales, which was an unexpected finding. MLS arose as the single best predictor of effort test failure of all RF Validity and Somatic/Cognitive scales. Item overlap analysis revealed that all MLS items are included in the original MMPI-2 Hy scale, making MLS essentially a subscale of Hy. This study validates the MMPI-2-RF as an effective tool for use in neuropsychological assessment of TBI litigants.

Test-retest reliability of the Traumatic Brain Injury Screening Instrument.

The Traumatic Brain Injury Screening Instrument (TBISI) was implemented in Veterans Affairs medical facilities in an attempt to identify Operation Enduring Freedom and Operation Iraqi Freedom (OEF/OIF) veterans with possible mild TBI. Despite its widespread implementation, the reliability and validity of the screening tool has not yet been established. The current study reports preliminary findings on the test-retest reliability of the TBISI in 44 OEF/OIF veterans referred for neuropsychological evaluation following a positive TBI screen. Results suggest overall poor test-retest reliability of the TBI screening tool with regard to type of event, injuries sustained, and resulting sequelae. These findings underscore the importance of further investigation of its psychometric properties to promote accurate identification and referral of veterans with possible TBI.

The Relationship Between Visual Contrast Sensitivity and Neuropsychological Performance in a Healthy Elderly Sample

Visual acuity and contrast sensitivity are two visual domains affected by normal aging; however, the potential impact of well-documented changes in these abilities on neuropsychological assessment is relatively unstudied. The current study examined the relationship between these abilities and neuropsychological performance in a healthy, community-based elderly sample. Fifty-one individuals (Age: M = 79.6) were assessed for visual acuity and visual contrast sensitivity, and received a brief neuropsychological battery. Results indicated contrast sensitivity was significantly related to neuropsychological performance on visually based measures, but not auditory measures. Visual acuity was only weakly related to neuropsychological performance. Clinical implications for assessment of elderly individuals are discussed.

Impact of the Presence of Alcohol at the Time of Injury on Acute and One-Year Cognitive and Functional Recovery After Traumatic Brain Injury

ABSTRACT The presence of alcohol is clearly a risk factor for sustaining a traumatic brain injury (TBI); however, the impact of alcohol on injury severity, and functional or cognitive outcome is unclear, as there is mixed evidence in the literature. This study examined 482 participants in a large urban medical center with documented mild-complicated to severe TBI and blood alcohol testing for functional and cognitive outcome. Functional outcomes were measured by the Functional Independence Measure (FIM) and cognitive outcomes were measured using neuropsychological tests known to be sensitive to the sequelae of TBI. Consistent with the hypotheses, there was a statistically significant negative impact of alcohol intoxication at the time of injury on Glasgow Coma Scale (GCS); however intoxication only lowered GCS by an average of 1.9 points. There was a statistically significant relationship between blood alcohol levels (BAL) and FIM at the time of admission to inpatient rehabilitation, but BAL accounted for only 3% of the variance in FIM total score. There was no relationship between BAL and FIM at discharge from rehabilitation or at 1-year follow-up. There was no statistically significant relationship between BAL at the time of injury and cognitive functioning at 1-year follow-up; however, contrary to the hypotheses GCS failed to show a strong relationship with cognitive outcome.

The Utility of the Post-concussive Symptom Questionnaire

The Post-concussive Symptom Questionnaire (PCSQ) and its short forms were evaluated to determine their utility in measuring symptom validity as brief self-report measures in 112 individuals referred for a neuropsychological evaluation. First, the relationships between the PCSQ forms and measures of cognitive performance (Wechsler Adult Intelligence Scale-Fourth Edition Full-Scale IQ, California Verbal Learning Test-Second Edition Trials 1-5 Total T-score, Trails B, FAS), general distress (Minnesota Multiphasic Personality Inventory [MMPI]-2 M8), and self-report symptom validity (MMPI-2 FBS Symptom Validity Scale [FBS] and Response Bias Scale [RBS]) were investigated to determine construct validity. Measures of self-report symptom validity explained the greatest amount of variance. Second, receiver operating characteristics curve analyses were conducted to determine the predictive value of the PCSQ forms in detecting over reporting on the FBS and the RBS in addition to establishing optimal cutoff scores. On the basis of the proposed cutoff scores, sensitivity, specificity, positive predictive power, negative predictive power, and hit rates were calculated.

Parsimonious prediction of Wechsler Memory Scale, Fourth Edition scores: Immediate and delayed memory indexes

Research on previous versions of the Wechsler Memory Scale (WMS) found that index scores could be predicted using a parsimonious selection of subtests (e.g., Axelrod & Woodard, 2000). The release of the Fourth Edition (WMS–IV) requires a reassessment of these predictive formulas as well as the use of indices from the California Verbal Learning Test–II (CVLT–II). Complete WMS–IV and CVLT–II data were obtained from 295 individuals. Six regression models were fit using WMS–IV subtest scaled scores—Logical Memory (LM), Visual Reproduction (VR), and Verbal Paired Associates (VPA)—and CVLT–II substituted scores to predict Immediate Memory Index (IMI) and Delayed Memory Index (DMI) scores. All three predictions of IMI significantly correlated with the complete IMI (r = .92 to .97). Likewise, predicted DMI scores significantly correlated with complete DMI (r = .92 to .97). Statistical preference was indicated for the models using LM, VR, and VPA, in which 97% and 96% of the cases fell within two standard errors of measurement (SEMs) of full index scores, respectively. The present findings demonstrate that the IMI and DMI can be reliably estimated using two or three subtests from the WMS–IV, with preference for using three. In addition, evidence suggests little to no improvement in predictive accuracy with the inclusion of CVLT–II indices.

Substitution of California Verbal Learning Test, second edition for Verbal Paired Associates on the Wechsler Memory Scale, fourth edition.

Two common measures used to evaluate verbal learning and memory are the Verbal Paired Associates (VPA) subtest from the Wechsler Memory Scales (WMS) and the second edition of the California Verbal Learning Test (CVLT-II). For the fourth edition of the WMS, scores from the CVLT-II can be substituted for VPA; the present study sought to examine the validity of the substitution. For each substitution, paired-samples t tests were conducted between original VPA scaled scores and scaled scores obtained from the CVLT-II substitution to evaluate comparability. Similar comparisons were made at the index score level. At the index score level, substitution resulted in significantly lower scores for the AMI (p = .03; r = .13) but not for the IMI (p = .29) or DMI (p = .09). For the subtest scores, substituted scaled scores for VPA were not significantly different from original scores for the immediate recall condition (p = .20) but were significantly lower at delayed recall (p = .01). These findings offer partial support for the substitution. For both the immediate and delayed conditions, the substitution produced generally lower subtest scores compared to original VPA subtest scores.

Parsimonious Estimation of the Wechsler Memory Scale, Fourth Edition Demographically Adjusted Index Scores: Immediate and Delayed Memory

The recent release of the Wechsler Memory Scale Fourth Edition contains many improvements from a theoretical and administration perspective, including demographic corrections using the Advanced Clinical Solutions. Although the administration time has been reduced from previous versions, a shortened version may be desirable in certain situations given practical time limitations in clinical practice. The current study evaluated two- and three-subtest estimations of demographically corrected Immediate and Delayed Memory index scores using both simple arithmetic prorating and regression models. All estimated values were significantly associated with observed index scores. Use of Lins Concordance Correlation Coefficient as a measure of agreement showed a high degree of precision and virtually zero bias in the models, although the regression models showed a stronger association than prorated models. Regression-based models proved to be more accurate than prorated estimates with less dispersion around observed values, particularly when using three subtest regression models. Overall, the present research shows strong support for estimating demographically corrected index scores on the WMS-IV in clinical practice with an adequate performance using arithmetically prorated models and a stronger performance using regression models to predict index scores.