B Hill

The relationships of working memory, secondary memory, and general fluid intelligence: working memory is special.

Recent efforts have been made to elucidate the commonly observed link between working memory and reasoning ability. The results have been inconsistent, with some work suggesting that the emphasis placed on retrieval from secondary memory by working memory tests is the driving force behind this association (Mogle, Lovett, Stawski, & Sliwinski, 2008), whereas other research suggests retrieval from secondary memory is only partly responsible for the observed link between working memory and reasoning (Unsworth & Engle, 2006, 2007). In the present study, we investigated the relationship between processing speed, working memory, secondary memory, primary memory, and fluid intelligence. Although our findings show that all constructs are significantly correlated with fluid intelligence, working memory-but not secondary memory-accounts for significant unique variance in fluid intelligence. Our data support predictions made by Unsworth and Engle (2006, 2007) and suggest that the combined need for maintenance and retrieval processes present in working memory tests makes them special in their prediction of higher order cognition.

Continuous Performance Test (CPT) of College Students With ADHD, Psychiatric Disorders, Cognitive Deficits, or No Diagnosis:

Objective/Method: The Conner’s Continuous Performance Test (CPT) was administered to four groups of adult college students who self-referred for comprehensive psychoeducational evaluation and received either no diagnosis (n = 30) or a diagnosis of ADHD (n = 26), a psychiatric disorder (n = 17), or various cognitive deficits (n = 22). Results: The groups did not differ with respect to age, sex, race, or IQ. Although the ADHD group made more CPT errors of omission, had longer response times, and showed greater variability in responding than the other three groups, these differences did not reach statistical significance when analyzed parametrically using standard scores. But when the pattern of scores across the groups was analyzed nonparametrically, significant and interpretable results emerged. Conclusion: The CPT reliably differentiated between individuals with ADHD and both normal college students and individuals with psychiatric diagnoses but not persons with learning/cognitive disorders.

Can we improve the clinical assessment of working memory? An evaluation of the Wechsler Adult Intelligence Scale–Third Edition using a working memory criterion construct

Working memory is the cognitive ability to hold a discrete amount of information in mind in an accessible state for utilization in mental tasks. This cognitive ability is impaired in many clinical populations typically assessed by clinical neuropsychologists. Recently, there have been a number of theoretical shifts in the way that working memory is conceptualized and assessed in the experimental literature. This study sought to determine to what extent the Wechsler Adult Intelligence Scale–Third Edition (WAIS–III) Working Memory Index (WMI) measures the construct studied in the cognitive working memory literature, whether an improved WMI could be derived from the subtests that comprise the WAIS–III, and what percentage of variance in individual WAIS–III subtests is explained by working memory. It was hypothesized that subtests beyond those currently used to form the WAIS–III WMI would be able to account for a greater percentage of variance in a working memory criterion construct than the current WMI. Multiple regression analyses (n = 180) revealed that the best predictor model of subtests for assessing working memory was composed of the Digit Span, Letter–Number Sequencing, Matrix Reasoning, and Vocabulary. The Arithmetic subtest was not a significant contributor to the model. These results are discussed in the context of how they relate to Unsworth and Engles (2006, 2007) new conceptualization of working memory mechanisms.

A Critical Item Analysis of the QABF: Development of a Short Form Assessment Instrument.

Due to the relative inability of individuals with intellectual disabilities (ID) to provide an accurate and reliable self-report, assessment in this population is more difficult than with individuals in the general population. As a result, assessment procedures must be adjusted to compensate for the relative lack of information that the individual may be able to provide and rely more on the behavioral expression of communication. One method commonly used is the indirect functional assessment that utilizes behavior rating scales developed to gather behavioral data in a short time. One of the few empirically derived and psychometrically sound scales is the Questions About Behavioral Function (QABF), a 25-item questionnaire designed to rate specific behavioral functions and maintaining variables. The purpose of this study was to use both exploratory and confirmatory factor analytic procedures to examine the psychometric properties of the QABF, conduct an item analysis, and determine if a short form version could be developed that is both psychometrically valid and reliable, and clinically useful. Results of the item selection procedure indicated that the original 25 items could be reduced to 15. Evaluation of the 15-item short form showed that the QABF-SF maintained the original five-factor structure of the original form, while maintaining an equivalent degree of reliability and validity. The QABF-SF appears to be a useful tool to aid clinicians in the brief functional assessment of behavior in individuals with ID.

Evaluation of embedded malingering indices in a non-litigating clinical sample using control, clinical, and derived groups

Although recent findings have indicated that a portion of college students presenting for psychoeducational evaluations fail validity measures, methods for determining the validity of cognitive test results in psychoeducational evaluations remain under-studied. In light of this, data are needed to evaluate utility of validity indices in this population and to provide base rates for students meeting research criteria for malingering and to report the relationship between testing performance and the level of external incentive. The authors utilized archival data from: (i) a university psychological clinic (n = 986) and (ii) a university control sample (n = 182). Empirically supported embedded validity indices were utilized to identify retrospectively suspected malingering patients. Group performance, according to invalidity and the level of incentive seeking, was evaluated through a series of multivariate mean comparisons. The current study supports classifying patients according to the level of incentive seeking when evaluating neurocognitive performance and feigned/exaggerated deficits.

Assessment and rehabilitation of acquired visuospatial and proprioceptive deficits associated with visuospatial neglect

Visuoperceptual disruptions are among the most common, and most debilitating, of the aftereffects following stroke or head injury. Visuospatial neglect in particular, which frequently occurs as a result of insult to the right cerebral hemisphere, has a variety of implications for patient welfare and outcome. And while there exists a great deal of useful information in the area of visual neglect, it is spread out amongst near-countless journal articles, book chapters, and workshop summaries. Thus, it is the purpose of this paper to provide an overview of various topics relating to visuospatial disturbances. Areas covered include theories on sequelae and neuropathology, common direct and indirect complications, rates and types of recovery, past and current trends in assessment and rehabilitation techniques, and thoughts on directions for future research.

The use of clozapine among individuals with intellectual disability: A review

Clozapine has been approved in the United States since 1990 for refractory or treatment resistant schizophrenia in the general population. However, as with many other antipsychotic medications, it is being prescribed for reasons other than those indicated. Among individuals with intellectual disabilities, clozapine is increasingly being prescribed to treat behavioral problems, although the empirical evidence for such a practice is lacking. This review was undertaken as an attempt to summarize the available studies regarding the use of clozapine for behavioral purposes among individuals with intellectual disabilities. Findings of our review suggest that the effectiveness of clozapine in targeting challenging behaviors among individuals with intellectual disabilities is relatively inconclusive at present. We discuss reasons why these limitations exist and offer some solutions to help alleviate these limitations.

The Relation of Executive Functioning to CVLT-II Learning, Memory, and Process Indexes

Previous research has found that executive functioning plays a role in memory performance. This study sought to determine the amount of variance accounted for in the California Verbal Learning Test-Second Edition (CVLT-II) by a global executive-functioning factor score. Archival data were extracted from 285 outpatients in a mixed neurologic sample. Measures used included: CVLT-II, Wisconsin Card-Sorting Test (Perseverative Errors), Trail-Making Test-Part B, Controlled Oral Word Association Test, Animal Naming, and Wechsler Adult Intelligence Scale-Third Edition Similarities. Executive data were reduced to a single executive-functioning factor score for each individual. Regression was used to determine the amount of variance accounted for by executive functioning in CVLT-II performance. Executive functioning accounted for minimal variance (0%–10%) in the following CVLT-II indexes: Total Learning (Trials 1–5), Semantic Clustering, Repetitions, Intrusions, and False Positives. However, executive functioning accounted for substantial variance (24%–31%) in CVLT-II performance for both Short- and Long-Delay Recall indexes and most discriminability indexes. CVLT-II indexes that would intuitively be associated with executive functioning accounted for a smaller-than-expected amount of variance. Additionally, level of executive functioning was related to level of CVLT-II performance. These results suggest that clinicians should consider executive deficits when interpreting mild-to-moderate memory impairments in recall and discriminability functions but that executive abilities have little effect on other aspects of memory.

Validation of the coin rotation test: a simple, inexpensive, and convenient screening tool for impaired psychomotor processing speed.

Objectives:The Coin Rotation Test is a simple, convenient, and cost-effective measure of psychomotor processing speed that has been used in neurologic examinations at the Louisiana State University Health Sciences system for almost 20 years. On the Coin Rotation Test, participants rotate a coin through serial 180 degree turns using the thumb, index, and middle fingers for 10 seconds. In the current study, we sought to validate the Coin Rotation Test on a hospital-based sample by determining the tasks sensitivity and specificity in detecting psychomotor processing speed impairment on a well-established criterion measure, the Grooved Pegboard Test. Methods:Participants included a sample of 161 participants obtained in a hospital setting (86 neurology clinic, 79 waiting area family practice clinic) who volunteered to complete several tasks of motor functioning and the Coin Rotation Test. Results:The Coin Rotation Test was found to be significantly correlated with a number of measures of motor functioning, suggesting a high level of convergent validity. Using a binary receiver operator characteristic curve analysis, the Coin Rotation Test predicted fine motor and psychomotor processing speed impairment with 0.80 sensitivity and 0.62 specificity for dominant hand performance and 0.83 sensitivity and 0.43 specificity for nondominant hand performance when a cut-score of 13 or fewer coin rotations was used. Conclusions:These results support the utility of the Coin Rotation Test as a convenient and inexpensive psychomotor processing speed screening tool in clinical settings.

Cognitive Intra-Individual Variability Has a Positive Association with Traumatic Brain Injury Severity and Suboptimal Effort

This study examined intra-individual variability in a large sample (n = 629) of individuals with a history of mild traumatic brain injury (mTBI) or TBI referred for neuropsychological evaluation. Variability was assessed using the overall test battery mean standard deviation (OTBM SD). We found a negative linear relation between OTBM and OTBM SD (r = -.672) in this sample with a history of neurologic pathology, indicating that the variability is inversely related to cognitive performance and contrary to what is observed in most normative data. Analyses revealed main effects for OTBM and OTBM SD across three TBI severity groups: loss of consciousness (LOC) <1 h, LOC 1 h-6 days, and LOC >6 days. These effects were found for both a valid performance group (no failed embedded validity measures; n = 504) and an invalid performance group (failed one or more embedded validity measures; n = 125). These findings support that cognitive intra-individual variability is increased uniquely by both neuropathology and suboptimal effort, there is a dose-response relationship between neuropathology and cognitive variability, and intra-individual variability may have utility as a clinical index of both.