Identification of Malingered Head Injury on the Wechsler Adult Intelligence Scale – 3rd Edition

Head injured patients show an IQ subtest pattern that can be discriminated from the profile produced by individuals who attempt to malinger intellectual decline due to head trauma. The current paper demonstrates that previously replicated methods for making this discrimination on the WAIS – R generalize to the WAIS – 3. The discriminant function equation accurately classified 83% of nonlitigating head-trauma patients with documented injuries and 72% of persons simulating intellectual impairment due to head trauma. A total of 45% of litigating mild head-trauma patients with purported intellectual decline but no documented loss of consciousness, hospitalization, or CT abnormality were classified as malingering by the discriminant function. A Vocabulary-Digit Span difference score provided 71% overall diagnostic accuracy, and may be informative when screening profiles by visual inspection or when complete WAIS – 3 results are unavailable.     

Detecting Incomplete Effort with Digit Span from the Wechsler Adult Intelligence Scale—Third Edition

The current study evaluated the utility of the Digit Span subtest in discriminating patients with mild head trauma from individuals referred for independent neuropsychological evaluation with objective evidence of poor effort. Various indices from the Digit Span subtest were evaluated to determine the best discriminator of brain injury from poor motivation patient groups: Digit Span Forward, Digit Span Backwards, Reliable Digit Span, Digit Span Age-Corrected Scaled Score, and the difference score between the Vocabulary and Digit Span scaled scores. The Digit Span scaled score was found to be the best discriminating index. A cutoff score of less than or equal to 7 accurately classified 75% of persons in the incomplete effort group and 69% of persons in the TBI group. Application of this cutoff score to a non-litigating mild brain injury group yielded a 77% correct classification rate. However, Digit Span scaled score accounted for a modest amount of variation and it is not recommended as a stand-alone validity measure.     

Material-specific retroactive interference effects of the Wechsler Adult Intelligence Scale–Fourth Edition on the Wechsler Memory Scale–Fourth Edition in a nonclinical sample

Introduction: This study investigated proactive and retroactive interference effects between the Wechsler Memory Scale–Fourth Edition (WMS–IV) using the flexible approach, and the Wechsler Adult Intelligence Scale–Fourth Edition (WAIS–IV). Method: One hundred and eighty nonclinical participants were assigned to a four (visual interference, verbal interference, visual and verbal interference, vs. no interference) by two (retroactive vs. proactive) between-subjects design. The administration order of the tests was counterbalanced (i.e., administration of the WAIS–IV prior to the WMS–IV, and the WAIS–IV administered during the delay interval of the WMS–IV). Results: The WAIS–IV produced significant retroactive interference effects on the WMS–IV; however, no proactive interference effect was observed. The retroactive interference effect was dependent on material specificity. Conclusions: The results indicate that material presented within the delay of the WMS–IV can have a significant effect on subsequent delayed recall. Clinicians should carefully consider the effects associated with carry-over effects of these tests when using them in combination.     

Detecting Feigned Impairment with the Digit Span and Vocabulary Subtests of the Wechsler Adult Intelligence Scale—Third Edition

The WAIS-III Digit Span and Vocabulary subtests were investigated as indicators of feigned cognitive impairment. Participants included 64 undergraduates randomly assigned to control, symptom-coached, or test-coached groups. Six previously researched validity indicators were examined. We hypothesized that symptom-coached participants would perform worse relative to test-coached simulators. Analyses determined both simulator groups performed lower than controls on all indicators except Vocabulary. Symptom-coached participants, however, did not differ from test-coached participants on any indicator. Classification accuracies for these six indicators ranged from 42 to 78%. While the WAIS-III validity indicators hold some promise, they should not be employed as independent measures.     

The National Adult Reading Test: restandardisation against the Wechsler Adult Intelligence Scale—Fourth edition

Since publication in 1982, the 50-item National Adult Reading Test (NART; Nelson, 1982; NART–R; Nelson & Willison, 1991) has remained a widely adopted method for estimating premorbid intelligence both for clinical and research purposes. However, the NART has not been standardised against the most recent revisions of the Wechsler Adult Intelligence Scale (WAIS-III; Wechsler, 1997, and WAIS-IV; Wechsler, 2008). Our objective, therefore, was to produce reliable standardised estimates of WAIS-IV IQ from the NART. Ninety-two neurologically healthy British adults were assessed and regression equations calculated to produce population estimates of WAIS-IV full-scale IQ (FSIQ) and constituent index scores. Results showed strong NART/WAIS-IV FSIQ correlations with more moderate correlations observed between NART error and constituent index scores. FSIQ estimates were closely similar to the published WAIS and WAIS-R estimates at the high end of the distribution, but at the lower end were approximately equidistant from the highly discrepant WAIS (low) and WAIS-R (high) values. We conclude that the NART is likely to remain an important tool for estimating the impact of neurological damage on general cognitive ability. We advise caution in the use of older published WAIS and/or WAIS-R estimates for estimating premorbid WAIS-IV FSIQ, particularly for those with low NART scores.     

Similarities and Differences in Wechsler Intelligence Scale for Children—Third Edition (WISC-III) Profiles: Support for Subtest Analysis in Clinical Referrals

Our study supports the reliability and validity of profile analysis in children with neurobiological disorders. Three mutually exclusive WISC-III profiles were identified that characterized the majority of children with autism (low coding or Freedom from Distractibility Index with low Comprehension), attention deficit hyperactivity disorder and learning disability (low Coding or FDI without low comprehension), and brain injury (low Performance without low Coding or FDI). The profiles suggest attention, writing, and performance speed deficits in autism, ADHD, and LD; global visual-motor problems in brain injury; and specific difficulty with language comprehension and social reasoning in autism. Children with anxiety, depression, and behavior disorders did not exhibit distinct profiles. Our profile analysis is based on the simple rank ordering of standard scores. The profiles are clinically useful because they may alert clinicians to certain diagnostic possibilities, they reveal characteristic strengths and weaknesses that have implications for educational intervention, and they are consistent with preliminary WISC-IV data.     

Normal Variability of Children’s Scaled Scores on Subtests of the Dutch Wechsler Preschool and Primary scale of Intelligence – Third Edition

Intelligence tests are included in millions of assessments of children and adults each year (Watkins, Glutting, & Lei, 2007a Watkins, M. W., Glutting, J. J. and Lei, P. 2007. Validity of the Full-Scale IQ when there is significant variability among WISC-III and WISC-IV factor scores. Applied Neuropsychology, 14: 13–20. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar], Applied Neuropsychology, 14, 13). Clinicians often interpret large amounts of subtest scatter, or large differences between the highest and lowest scaled subtest scores, on an intelligence test battery as an index for abnormality or cognitive impairment. The purpose of the present study is to characterize “normal” patterns of variability among subtests of the Dutch Wechsler Preschool and Primary Scale of Intelligence – Third Edition (WPPSI-III-NL; Wechsler, 2010 Wechsler, D. (2010). WPPSI-III-NL Nederlandstalige bewerking: Technische handleiding [Dutch version of the WPPSI-III-NL: Technical and interpretive manual] (2nd ed). Amsterdam, The Netherlands: Pearson Assessment and Information BV. (Dutch adaptation by: Hendriksen, J., & Hurks, P., 2010).  [Google Scholar]). Therefore, the frequencies of WPPSI-III-NL scaled subtest scatter were reported for 1039 healthy children aged 4:0–7:11 years. Results indicated that large differences between highest and lowest scaled subtest scores (or subtest scatter) were common in this sample. Furthermore, degree of subtest scatter was related to: (a) the magnitude of the highest scaled subtest score, i.e., more scatter was seen in children with the highest WPPSI-III-NL scaled subtest scores, (b) Full Scale IQ (FSIQ) scores, i.e., higher FSIQ scores were associated with an increase in subtest scatter, and (c) sex differences, with boys showing a tendency to display more scatter than girls. In conclusion, viewing subtest scatter as an index for abnormality in WPPSI-III-NL scores is an oversimplification as this fails to recognize disparate subtest heterogeneity that occurs within a population of healthy children aged 4:0–7:11 years.     

Epilepsy & IQ: The clinical utility of the Wechsler Adult Intelligence Scale–Fourth Edition (WAIS–IV) indices in the neuropsychological assessment of people with epilepsy

We examined Wechsler Adult Intelligence Scale–Fourth Edition (WAIS–IV) General Ability Index (GAI) and Full Scale Intelligence Quotient (FSIQ) discrepancies in 100 epilepsy patients; 44% had a significant GAI > FSIQ discrepancy. GAI–FSIQ discrepancies were correlated with the number of antiepileptic drugs taken and duration of epilepsy. Individual antiepileptic drugs differentially interfere with the expression of underlying intellectual ability in this group. FSIQ may significantly underestimate levels of general intellectual ability in people with epilepsy. Inaccurate representations of FSIQ due to selective impairments in working memory and reduced processing speed obscure the contextual interpretation of performance on other neuropsychological tests, and subtle localizing and lateralizing signs may be missed as a result.     

Use of the Tower of London – Drexel University,Second Edition (TOLDX) in Adults With Traumatic Brain Injury

The Tower of London – Drexel University, Second Edition (TOL^DX) was investigated in order to determine the efficacy of using this instrument in evaluating the impact of traumatic brain injury on cognitive functioning in adults. Performance on the TOL^DX was compared among 56 individuals with complicated mild to severe traumatic brain injury (“sTBI”), 68 individuals with uncomplicated, mild traumatic brain injury (“mTBI”), and 124 demographically matched, healthy controls. Both TBI groups performed worse than controls on TOL^DX measures of executive time (ET) and number of moves used (TMS), but only patients with sTBI were more likely to be impaired on TMS (i.e., performing at least 1.5 SD below the mean). Poorer performance on TMS was associated with increasing length of coma. Although poor sensitivity of this measure limits its use in isolation, the TOL^DX may provide a complementary measurement of aspects of problem-solving deficit in TBI that may not be captured by other tests.     

Indicators of suboptimal performance embedded in the Wechsler Memory Scale–Fourth Edition (WMS–IV)

Introduction. Recognition and visual working memory tasks from the Wechsler Memory Scale–Fourth Edition (WMS–IV) have previously been documented as useful indicators for suboptimal performance. The present study examined the clinical utility of the Dutch version of the WMS–IV (WMS–IV–NL) for the identification of suboptimal performance using an analogue study design.

Method. The patient group consisted of 59 mixed-etiology patients; the experimental malingerers were 50 healthy individuals who were asked to simulate cognitive impairment as a result of a traumatic brain injury; the last group consisted of 50 healthy controls who were instructed to put forth full effort.

Results. Experimental malingerers performed significantly lower on all WMS–IV–NL tasks than did the patients and healthy controls. A binary logistic regression analysis was performed on the experimental malingerers and the patients. The first model contained the visual working memory subtests (Spatial Addition and Symbol Span) and the recognition tasks of the following subtests: Logical Memory, Verbal Paired Associates, Designs, Visual Reproduction. The results showed an overall classification rate of 78.4%, and only Spatial Addition explained a significant amount of variation (p < .001). Subsequent logistic regression analysis and receiver operating characteristic (ROC) analysis supported the discriminatory power of the subtest Spatial Addition. A scaled score cutoff of <4 produced 93% specificity and 52% sensitivity for detection of suboptimal performance.

Conclusion. The WMS–IV–NL Spatial Addition subtest may provide clinically useful information for the detection of suboptimal performance.     

Temporal Stability of the Dutch Version of the Wechsler Memory Scale—Fourth Edition (WMS-IV-NL)

Objective: The Wechsler Memory Scale—Fourth Edition (WMS-IV) is one of the most widely used memory batteries. We examined the test–retest reliability, practice effects, and standardized regression-based (SRB) change norms for the Dutch version of the WMS-IV (WMS-IV-NL) after both short and long retest intervals. Method: The WMS-IV-NL was administered twice after either a short (M = 8.48 weeks, SD = 3.40 weeks, range = 3–16) or a long (M = 17.87 months, SD = 3.48, range = 12–24) retest interval in a sample of 234 healthy participants (M = 59.55 years, range = 16–90; 118 completed the Adult Battery; and 116 completed the Older Adult Battery). Results: The test–retest reliability estimates varied across indexes. They were adequate to good after a short retest interval (ranging from .74 to .86), with the exception of the Visual Working Memory Index (r = .59), yet generally lower after a long retest interval (ranging from .56 to .77). Practice effects were only observed after a short retest interval (overall group mean gains up to 11 points), whereas no significant change in performance was found after a long retest interval. Furthermore, practice effect-adjusted SRB change norms were calculated for all WMS-IV-NL index scores. Conclusions: Overall, this study shows that the test–retest reliability of the WMS-IV-NL varied across indexes. Practice effects were observed after a short retest interval, but no evidence was found for practice effects after a long retest interval from one to two years. Finally, the SRB change norms were provided for the WMS-IV-NL.     

Differential Disruption of Blood–Brain Barrier in Severe Traumatic Brain Injury

Background

Traumatic brain injury (TBI) is a significant cause of death and disability in young adults, but not much is known about the incidence and characteristics of blood–brain barrier (BBB) dysfunction in this group. In this proof of concept study, we sought to quantify the incidence of BBB dysfunction (defined as a cerebrospinal fluid (CSF)–plasma albumin quotient of ≥0.007) and examine the relationship between plasma and CSF levels of proteins and electrolytes, in patients with severe TBI.

Methods

We recruited 30 patients, all of whom were receiving hypertonic 20 % saline infusion for intracranial hypertension and had external ventricular drains in situ. Simultaneous CSF and blood samples were obtained. Biochemical testing was performed for sodium, osmolality, potassium, glucose, albumin, immunoglobulin-G, and total protein.

Results

Eleven patients (37 %) showed evidence of impairment of passive BBB function, with a CSF–plasma albumin quotient of ≥0.007. There were strong positive correlations seen among CSF–plasma albumin quotient and CSF–plasma immunoglobulin-G quotient and CSF–plasma total protein quotient (r = 0.967, P < 0.001 and r = 0.995, P < 0.001, respectively). We also found a higher maximum intracranial pressure (24 vs. 21 mmHg, P = 0.029) and a trend toward increased mortality (27 vs. 11 %, P = 0.33) in patients with BBB disruption.

Conclusions

In summary, passive BBB dysfunction is common in patients with severe TBI, and may have important implications for effectiveness of osmotherapy and long-term outcomes. Also, our results suggest that the CSF–plasma total protein quotient, a measurement which is readily available, can be used instead of the CSF–plasma albumin quotient for evaluating BBB dysfunction.     

Clinical utility of the Wechsler Memory Scale — Fourth Edition (WMS-IV) in patients with intractable temporal lobe epilepsy

IntroductionThe Wechsler Memory Scale (WMS) is one of the most widely used test batteries to assess memory functions in patients with brain dysfunctions of different etiologies. This study examined the clinical validation of the Dutch Wechsler Memory Scale — Fourth Edition (WMS-IV-NL) in patients with temporal lobe epilepsy (TLE).MethodThe sample consisted of 75 patients with intractable TLE, who were eligible for epilepsy surgery, and 77 demographically matched healthy controls. All participants were examined with the WMS-IV-NL.ResultsPatients with TLE performed significantly worse than healthy controls on all WMS-IV-NL indices and subtests (p < .01), with the exception of the Visual Working Memory Index including its contributing subtests, as well as the subtests Logical Memory I, Verbal Paired Associates I, and Designs II. In addition, patients with mesiotemporal abnormalities performed significantly worse than patients with lateral temporal abnormalities on the subtests Logical Memory I and Designs II and all the indices (p < .05), with the exception of the Auditory Memory Index and Visual Working Memory Index. Patients with either a left or a right temporal focus performed equally on all WMS-IV-NL indices and subtests (F(15, 50) = .70, p = .78), as well as the Auditory–Visual discrepancy score (t(64) = − 1.40, p = .17).ConclusionThe WMS-IV-NL is capable of detecting memory problems in patients with TLE, indicating that it is a sufficiently valid memory battery. Furthermore, the findings support previous research showing that the WMS-IV has limited value in identifying material-specific memory deficits in presurgical patients with TLE.     

Validation of the Lebanese Childhood Autism Rating Scale – Second Edition – High Functioning Version

This paper presents the psychometric properties of the Lebanese version of the Childhood Autism Rating Scale Second Edition, High Functioning Version (CARS2-HF). The participants consisted of 30 children aged 6–18 years among which 24 had a clinical diagnosis of Asperger disorder or Pervasive Developmental Disorder-Not Otherwise Specified and 6 had a clinical diagnosis of Attention Deficit Hyperactivity Disorder (ADHD). All participants were verbally fluent and had IQ estimates of 80 or higher, determined with the Wechsler Nonverbal Scale of Ability (WNV). Forward and backward translation of the CARS2-HF and the Childhood Autism Rating Scale Second Edition, Questionnaire for Parents or Caregivers (CARS2-QPC) was completed before the administration of the scales. The results of this study showed that the Lebanese CARS2-HF has a high degree of internal consistency (.92), inter-rater reliability (.97), and test–retest reliability (.99). Receiver Operating Characteristic (ROC) analysis determined that individuals with total raw scores below 26 are less likely – to be in the autism spectrum. This instrument can be used in screening and assessing for ASD in high-functioning Lebanese and Arab speaking individuals.     

Clinical utility of the Wechsler Memory Scale—Fourth Edition (WMS-IV) in predicting laterality of temporal lobe epilepsy among surgical candidates

This study evaluated the accuracy of the Wechsler Memory Scale—Fourth Edition (WMS-IV) in identifying functional cognitive deficits associated with seizure laterality in localization-related temporal lobe epilepsy (TLE) relative to a previously established measure, the Rey Auditory Verbal Learning Test (RAVLT). Emerging WMS-IV studies have highlighted psychometric improvements that may enhance its ability to identify lateralized memory deficits. Data from 57 patients with video-EEG-confirmed unilateral TLE who were administered the WMS-IV and RAVLT as part of a comprehensive presurgical neuropsychological evaluation for temporal resection were retrospectively reviewed. We examined the predictive accuracy of the WMS-IV not only in terms of verbal versus visual composite scores but also using individual subtests. A series of hierarchal logistic regression models were developed, including the RAVLT, WMS-IV delayed subtests (Logical Memory, Verbal Paired Associates, Designs, Visual Reproduction), and a WMS-IV verbal–visual memory difference score. Analyses showed that the RAVLT significantly predicted laterality with overall classification rates of 69.6% to 70.2%, whereas neither the individual WMS-IV subtests nor the verbal–visual memory difference score accounted for additional significant variance. Similar to previous versions of the WMS, findings cast doubt as to whether the WMS-IV offers significant incremental validity in discriminating seizure laterality in TLE beyond what can be obtained from the RAVLT.     

The Expression Changes of Cystathionine-β-synthase in Brain Cortex After Traumatic Brain Injury

Cystathionine-β-synthase (CBS) catalyzes the condensation of serine with homocysteine to form cystathionine and occupies a crucial regulatory position between the methionine cycle and the biosynthesis of cysteine by transsulfuration. It was reported that CBS was a novel marker of both differentiation and proliferation for certain cell types, suggesting that CBS represents a survival-promoting protein. However, its expression and function in the central nervous system lesion are not well understood. To investigate changes of CBS after traumatic brain injury (TBI) and its possible role, mice TBI model was established by controlled cortical impact system, and the expression and cellular localization of CBS after TBI was investigated in the present study. Western blot analysis revealed that CBS was present in normal mice brain cortex. It gradually decreased, reached a valley at the third day after TBI, and then restored to basal level. Importantly, more CBS was colocalized with neuron. In addition, Western blot detection showed that the third day postinjury was also the apoptosis peak indicated by the elevated expression of caspase-3. Importantly, immunohistochemistry analysis revealed that injury-induced expression of CBS was colabeled by Bcl-2 and had no co-localization with caspase-3. These data suggested that CBS may be implicated in the apoptosis of neuron and involved in the pathophysiology of brain after TBI.     

Are Direct Anticoagulants Safer in Traumatic Brain Injury Compared to Warfarin?

Neurocritical Care -     

The Nature of Processing Speed Deficits in Traumatic Brain Injury: is Less Brain More?

The cognitive constructs working memory (WM) and processing speed are fundamental components to general intellectual functioning in humans and highly susceptible to disruption following neurological insult. Much of the work to date examining speeded working memory deficits in clinical samples using functional imaging has demonstrated recruitment of network areas including prefrontal cortex (PFC) and anterior cingulate cortex (ACC). What remains unclear is the nature of this neural recruitment. The goal of this study was to isolate the neural networks distinct from those evident in healthy adults and to determine if reaction time (RT) reliably predicts observable between-group differences. The current data indicate that much of the neural recruitment in TBI during a speeded visual scanning task is positively correlated with RT. These data indicate that recruitment in PFC during tasks of rapid information processing are at least partially attributable to normal recruitment of PFC support resources during slowed task processing.