Brief screening indexes for malingering: A confirmation of Vocabulary minus Digit Span from the WAIS-III and the Rarely Missed Index from the WMS-III

This study investigated the specificity of empirically derived screening measures for the detection of symptom exaggeration in persons with a diagnosis of alcohol abuse (n = 30), polysubstance abuse (n = 43), or head trauma (n = 27). The first measure evaluated was Vocabulary (V) minus Digit Span (DS) (Mittenberg, Theroux-Fichera, Zielinski, & Heilbronner, 1995); the second measure was the Rarely Missed Index (RMI) for the WMS-III Logical Memory subtest (Killgore & Della-Pietra, 2000). V-DS misclassified 0% of individuals in the alcohol abuse group, 2% of those in the polysubstance abuse group, and 0% of head injury cases. RMI misclassification rates were 3%, 5%, and 7% for the alcohol abuse, polysubstance abuse, and head injury groups, respectively. Overall accuracy rates were 99% for V-DS and 95% for RMI.     

Using the WMS-III to Detect Malingering: Empirical Validation of the Rarely Missed Index (RMI)

To detect malingering during memory assessment, we evaluated item response biases to the Logical Memory Delayed Recognition (LMDR) subtest of the WMS-III. In a sample of 50 healthy volunteers who were completely naïve to the content of the Logical Memory stories, 6 LMDR items were correctly endorsed above chance probabilities. These 6 rarely missed items significantly discriminated 51 patients with neurological impairment from 36 volunteers who attempted to feign head injury and poor cognitive performance. A weighted combination of the 6 items was summed to form a single Rarely Missed Index (RMI). The RMI accurately classified over 98% of participants and demonstrated high sensitivity (97%) and specificity (100%) in discriminating between analog malingerers and patients. Because the RMI is calculated directly from the LMDR items, it has the advantage of requiring no additional administration time or materials, and thus may serve as a quick screen for dissimulation that can be obtained without additional testing.     

Brief Screening Indexes for Malingering: A Confirmation of Vocabulary Minus Digit Span from the WAIS-III and the Rarely Missed Index from the WMS-III

This study investigated the specificity of empirically derived screening measures for the detection of symptom exaggeration in persons with a diagnosis of alcohol abuse(n?=?30), polysubstance abuse(n?=?43), or head trauma(n?=?27). The first measure evaluated was Vocabulary(V)minus Digit Span(DS)(Mittenberg, Theroux-Fichera, Zielinski, & Heilbronner, 1995); the second measure was the Rarely Missed Index(RMI)for the WMS-III Logical Memory subtest(Killgore & DellaPietra, 2000). V-DS misclassified 0%of individuals in the alcohol abuse group, 2%of those in the polysubstance abuse group, and 0%of head injury cases. RMI misclassification rates were 3%, 5%, and 7%for the alcohol abuse, polysubstance abuse, and head injury groups, respectively. Overall accuracy rates were 99%for V-DS and 95%for RMI.     

The vulnerability of self-reported disability measures to malingering: a simulated ADHD study

Objective: Making diagnostic and accommodation decisions for potential Attention-Deficit/Hyperactivity Disorder (ADHD) in adults is difficult, as the assessor often relies more on self-reported symptoms and functional disability than in childhood evaluations. Malingering of ADHD occurs frequently in the educational setting and for a variety of reasons, including the potential benefits of access to stimulant medications and academic accommodations. Method: The present study utilized a simulation design to examine the potential for malingering of self-reported functional disability on the World Health Organization Disability Schedule 2.0 (WHODAS). Participants were 167 students from two Midwestern universities. Thirty-six self-reported a previous diagnosis of ADHD, and the remaining 131 students were randomly assigned to one of three conditions: best effort, malingering for the purpose of receiving stimulant medication, or malingering for the purpose of receiving extra time accommodations. Results: Individuals in both malingering groups reported higher levels of disability on all domains of the WHODAS compared to healthy controls and individuals with ADHD. There were no significant differences between malingering groups. Conclusions: Results suggest the WHODAS is susceptible to non-credible responses and should not be relied upon solely as a measure of disability in the context of ADHD evaluations.     

Electrical coupling of astrocytes in rat hippocampal slices under physiological and simulated ischemic conditions

Mammalian protoplasmic astrocytes are extensively coupled through gap junction channels but the biophysical properties of these channels under physiological and ischemic conditions in situ are not well defined. Using confocal morphometric analysis of biocytin‐filled astrocytic syncytia in rat hippocampal CA1 stratum radiatum we found that each astrocyte directly couples, on average, to 11 other astrocytes with a mean interastrocytic distance of 45 μm. Voltage‐independent and bidirectional transjunctional currents were always measured between directly coupled astrocyte pairs in dual voltage‐clamp recordings, but never from astrocyte–NG2 glia or astrocyte–interneuron pairs. The electrical coupling ratio varied considerably among astrocytes in developing postnatal day 14 rats (P14, 0.5–12.4%, mean = 3.6%), but became more constant in young adult P21 rats (0.18–3.9%, mean = 1.6%), and the coupling ratio declined exponentially with increasing pair distance. Electrical coupling was not affected by short‐term oxygen–glucose deprivation (OGD) treatment, but showed delayed inhibition in an acidic extracellular pH of 6.4. Combination of acidic pH (6.4) and OGD, a condition that better represents cerebral ischemia in vivo, accelerated the inhibition of electrical coupling. Our results show that, under physiological conditions, 20.7–24.2% of K⁺ induced currents can travel from any astrocytic soma in CA1 stratum radiatum to the gap junctions of the nearest neighbor astrocytes, but this should be severely inhibited as a consequence of the OGD and acidosis seen in the ischemic brain. © 2009 Wiley‐Liss, Inc.     

Psychological assessment of malingering in psychogenic neurological disorders and non-psychogenic neurological disorders: relationship to psychopathology levels

Background and purpose:  It remains unknown whether psychological distress causes malingering in patients with psychogenic symptoms.
Methods:  We studied 26 patients with psychogenic neurological disorders on psychopathology and malingering in comparison with 26 patients with various neurological conditions and 18 matched healthy controls (HC).
Results:  Psychogenic patients showed the highest levels of psychological complaints and malingering, but non-psychogenic neurological patients also showed significantly more psychological distress and malingering compared with HC. Psychological distress was related to the degree of malingering, in both patient groups.
Conclusion:  This data does not formally support a causal relationship between psychological distress and psychogenic neurological disorders, but suggests that a part of the psychological complaints is a general result of having an illness. The clinical implication of this study is that psychological distress is not sufficient for diagnosing functional complaints. Also, if a patient scores normal on a test for malingering, this does not mean that he or she is not suffering from psychogenic symptoms.     

A comparative study of posttraumatic stress disorder assessment under standard conditions and in the field

Little is known about the performance of clinician‐administered structured diagnostic interviews when given under variable levels of examiner training and monitoring. We sought to explore this question. We examined the performance of a self‐report questionnaire and a structured clinical interview in the assessment of post‐traumatic stress disorder (PTSD) in two community samples of war veterans. One sample was interviewed under standard conditions (N = 372) and the other under unknown and less standardized conditions (N = 420), more closely approximating ‘field conditions’. Interview results were used to predict questionnaire‐based PTSD status. Kappas, sensitivities, specificities, and positive predictive powers were moderate and of similar magnitude in both samples. Our results suggest that even under uncertain (‘field’) conditions, clinician‐administered structured interviews can produce results comparable to those produced under more tightly controlled conditions. Copyright © 2006 John Wiley & Sons, Ltd.     

Ionic currents in the sensory epithelium examined in isolated electroreceptors ofPlotosus under simulated in situ conditions

K-blockers suppressed damped oscillation ofPlotosus electroreceptors in situ. Ca-blockers abolished V-dependent non-linear responses, as well, and shifted the DC level in the ampulla by ca. −1 mV. Thus, the in situ receptor is held depolarized with maintained Ca current in the basal membrane of receptor cells. The oscillation involves Ca-activated transient K current in the same membrane, which contributes to the initial sensory adaptation, and presumably also to stabilizing the sensitive receptors.     

Utility of the trail making test in the assessment of malingering in a sample of mild traumatic brain injury litigants

The Trail Making Test (TMT) is one of the most commonly administered tests in neuropsychological assessments. It has been shown to be a valid indicator of brain damage due to traumatic brain injury (TBI), as well as a number of other neuropathological conditions. TMT error and ratio scores have been suggested as possible markers of malingering. The present study examined the utility of various TMT scores as malingering measures in 94 TBI litigants. Litigants were divided into those suspected of (n = 27) and those not suspected of malingering (n = 67) based on scores obtained on the Test of Memory Malingering and/or the Rey 15-Item Test. TMT errors did not discriminate between suspected and nonsuspected malingerers; however, the overall level of performance on the TMT was suppressed in suspected malingerers. The TMT ratio score was significantly lower in litigants suspected of malingering, although the clinical utility of this ratio is minimal. Results of the present study suggest using caution when interpreting TMT scores as markers of malingering in TBI litigants.     

An assessment of the Newcastle Anxiety Depression Index

The Newcastle Anxiety and Depression Diagnostic Index (NADDI) has been reviewed, and its advantages and disadvantages discussed. One hundred eighty-seven patients were examined, and grouped into three categories by means of the NADDI, which produced a unimodal distribution of score. These three groups were studied in respect of the Hamilton Depression and SCL-90 self-rating scales. Significant profile differences were found on both scales. Patients with pure anxiety and pure depression were more distressed than the intermediate group of mixed anxiety-depressed patients. The NADDI scale items were compared in four clinical groups of primary endogenous, primary nonendogenous depression, generalized anxiety, and panic disorder. Most differences were found when panic disorder was compared to the other three groups, and generalized anxiety disorder received minimal validation. Treatment response was also examined.     

Comparison of a video-based assessment and a multiple stimulus assessment to identify preferred jobs for individuals with significant intellectual disabilities

The authors compare two methods of identifying job preferences for individuals with significant intellectual disabilities. Three individuals with intellectual disabilities between the ages of 19 and 21 participated in a video-based preference assessment and a multiple stimulus without replacement (MSWO) assessment. Stimulus preference assessment procedures typically involve giving participants access to the selected stimuli to increase the probability that participants will associate the selected choice with the actual stimuli. Although individuals did not have access to the selected stimuli in the video-based assessment, results indicated that both assessments identified the same highest preference job for all participants. Results are discussed in terms of using a video-based assessment to accurately identify job preferences for individuals with developmental disabilities.     

Development of a patient-reported assessment to identify placebo responders in a generalized anxiety disorder trial

Placebo response is thought to be a primary contributor to uninformative (failed) trials in clinical drug development. This study describes the development of a patient-reported assessment to detect likely placebo responders. A novel scale, the Placebo Response Screening Scale (PRSS), was developed to assess domains expected to be associated with placebo response. The scale was administered during the screening visit of a 4-week, placebo-controlled study of alprazolam and an investigational compound in 211 patients with generalized anxiety disorder (GAD). Items that predicted placebo response were identified. Sensitivity and specificity of the instrument were used to determine a threshold score for use in screening likely placebo response. The PRSS was then evaluated by comparing active treatment and placebo groups and subsetting the groups based on subject PRSS scores. Twenty items were selected for being predictive of patient global improvement rating, clinician global improvement rating, or improvement on Hamilton Rating Scale for Anxiety (HAM-A) scores in placebo-arm patients. Receiver operating characteristic concordance values ranged from 0.77 to 0.96 for the different definitions of placebo responder. A cut-score of 50 on a scale of 0-100 was chosen to maximize sensitivity (range 0.67-0.79) and specificity (range 0.78-1.00). Fifty-six patients with scores of 50 or higher were flagged as potential placebo responders. Excluding these 56 patients from the analysis resulted in a greater separation of active treatment from placebo. The PRSS is a promising tool for predicting placebo response in clinical trials and requires further use and validation.     

Development of the language subtest in a developmental assessment scale to identify Chinese preschool children with special needs

This study reports on the development of the language subtest in the Preschool Developmental Assessment Scale (PDAS) for Cantonese-Chinese speaking children. A pilot pool of 158 items covering the two language modalities and the three language domains was developed. This initial item set was subsequently revised based on Rasch analyses of data from 324 multi-stage randomly selected children between 3 and 6 years of age. The revised 106-item set demonstrated adequate measurement properties, including targeting and uni-dimensionality. The revised 106-item set successfully discriminated preschool children in the three age groups, and between preschool children and their age peers with special education needs (SEN). Results from this study support the collection of normative data from a larger population sample of children to examine its accuracy in identifying language impairment in children with SEN. Test development procedures reported in this study provide insight for the development of language subtests in multi-domain developmental assessment tools for children speaking other varieties of Chinese.     

Aggregation across multiple indicators improves the detection of malingering: relationship to likelihood ratios

Recent literature shows that aggregating across multiple symptom validity test (SVT) failures increases the probability of malingering over use of one indicator alone, supporting the criteria proposed by Slick, Sherman, and Iverson (1999) that require multiple sources of evidence for diagnosis of malingering. The present study reanalyzes with likelihood ratios data previously published by Larrabee (2003a) on litigants with definite malingering, contrasted with non-malingering patients with moderate and severe traumatic brain injury. Chaining of likelihood ratios demonstrated an increase in probability of malingering when multiple test scores were positive, with values ranging from. 713 to. 837 for one failed SVT,. 936 to. 973 for two failed SVTs, and. 989 to. 995 for three failed SVTs. Posterior probabilities of malingering derived from chaining of likelihood ratios closely approximated those obtained by direct computation of Positive Predictive Power, particularly when three SVTs were failed. Moreover, the five SVTs employed in these analyses did not intercorrelate significantly, satisfying the assumption that the tests be independent for chaining of likelihood ratios. Posterior probabilities derived from chaining of likelihood ratios, holding sensitivity and specificity constant at. 50 and. 90, respectively, and varying the malingering base rate from. 10 to. 90, showed a wide range of values,. 357 to. 978, for failure of one SVT. Failure of two SVTs yielded probabilities ranging from. 735 to. 996. Failure of three SVTs yielded values ranging from. 933 to. 999, demonstrating high probabilities of malingering irrespective of the base rate. These data support the Slick et al. recommendation that multiple positive findings are necessary for diagnosis of malingering. Suggestions are made for modification of the Slick et al. criteria based on the current results.