Andrew S. Davis

Children with Down Syndrome: Implications for Assessment and Intervention in the School.

Down syndrome is the most common genetic cause of mental retardation and one of the most frequently occurring neurodevelopmental genetic disorders in children. Children with Down syndrome typically experience a constellation of symptomology that includes developmental motor and language delay, specific deficits in verbal memory, and broad cognitive deficits. Children with Down syndrome are also at increased risk of medical problems, which can exacerbate their cognitive deficits. Although the diagnosis of Down syndrome is facilitated by cytogenetic testing and the unique physical phenotype, the development of proper interventions for this group of children is less obvious. Despite their functional deficits, children with Down syndrome possess relative strengths, which can be the focus of interventions. This article reviews the etiology and developmental course of Down syndrome, appraises examples of empirically validated interventions, and discusses neurocognitive processing issues that should be considered during a psychoeducational evaluation for intervention.

The Canonical Relationship Between Sensory-Motor Functioning and Cognitive Processing in Children with Attention-Deficit/Hyperactivity Disorder

Children with Attention-Deficit/Hyperactivity Disorder (ADHD) typically exhibits a pattern of behavioral deficits, impairment in academic achievement, and cognitive processing, and presents with sensory-motor deficits. This study examined the relationships between sensory-motor tasks, cognitive processing, and academic achievement for a group of 67 children with ADHD. Strong canonical correlations emerged between sensory-motor functioning and academic achievement (.93) and sensory-motor functioning and cognitive processing (.98). An analysis of the redundancy coefficient showed that sensory-motor skills accounted for 65% of the variance in the achievement variables and 31% of the variance in the cognitive processing variables. The strong relationship between sensory-motor skills and higher order cognitive processes indicates that early assessment of sensory-motor skills may be useful in the identification of subsequent deficits in academic performance. Neuropsychologists should carefully consider the contribution of sensory-motor functioning to the more widely studied and assessed constructs of academic, behavioral, and emotional problems in children with ADHD.

TEST REVIEW: Dean C. Delis, Edith Kaplan & Joel H. Kramer, Delis Kaplan Executive Function System (D-KEFS), The Psychological Corporation, San Antonio, TX, 2001.

The Delis Kaplan Executive Function System (D-KEFS; Delis, Kaplan, & Kramer, 2001) is a comprehensive battery of nine individually administered tests that provides normative and qualitative data assessing higher level cognitive functions (reasoning, problem solving, planning, etc.). Executive functions can be defined as capacities that enable a person to engage successfully in independent, purposive, self-serving behavior (Lezak et al, 2005). Each test in the D-KEFS is designed to be a stand-alone measure of executive functioning, and there are no aggregate indexes, or composite scores. The battery offers one of the first psychometrically sound, nationally normed set of tests designed exclusively for the assessment of verbal and nonverbal executive functions in children, adolescents, and adults. Indeed, normative data are based on a sample of over 1,700 individuals ranging in age from 8 to 89 years. Neuropsychologists will be familiar with many of the tests in the D-KEFS, such as a version of a tower test and a trail-making test, yet the D-KEFS has greatly improved on earlier, psychometrically troubled versions of these tasks. A strength of the D-KEFS is that, in addition to overall performance scores for each of the nine tests, the D-KEFS provides process scores that offer insight into performance scores. Results from the D-KEFS can be used to assess the integrity of the frontal systems of the brain, and to determine how deficits in higher order thinking may impact an individual’s functioning. Individual performance can be used to develop coping strategies and rehabilitation programs tailored to an individual patient’s profile of strengths and weaknesses in executive functioning. The D-KEFS is a battery of cognitive assessment; as such, only a neuropsychologist with formal training and experience should administer and interpret the battery. ADMINISTRATION

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Executive functioning is one of the most researched and debated topics in neuropsychology. Although neuropsychologists routinely consider executive functioning and intelligence in their assessment process, more information is needed regarding the relationship between these constructs. This study reports the results of a canonical correlation study between the most widely used measure of adult intelligence, the Wechsler Adult Intelligence Scale, 3rd edition (WAIS-III; Wechsler, 1997), and the Delis-Kaplan Executive Function System (D-KEFS; Delis, Kaplan, & Kramer, 2001). The results suggest that, despite considerable shared variability, the measures of executive functioning maintain unique variance that is not encapsulated in the construct of global intelligence.

A canonical correlation analysis of intelligence and executive functioning.

The assessment of sensory-motor functions is a key component of pediatric neuropsychological evaluations following traumatic brain injury (TBI). Sensory-motor processes have recently been shown to be related to larger neural structures and functions, rather than a secondary role played in the past. Recent research has shown sensory-motor functioning serves as a marker for the integrity of the central nervous system. Childrens behavior following a TBI has greater variation than seen in adults, which may well relate to greater natural variation and maturational effects. With the recent findings of greater importance of sensory-motor functions, the need for psychometrically sound measures is stressed and various measures are outlined.

Assessing Sensory-Motor Deficits in Pediatric Traumatic Brain Injury

The ability to differentiate between neurologically impaired and normal individuals is an important component in a valid neuropsychological battery. However, limited research exists regarding the ability of sensory-motor batteries to differentiate between the two groups. This study used Classification and Regression Tree Analysis (CART) to identify which measures of sensory-motor functioning from the Dean-Woodcock Sensory Motor Battery (DWSMB) would best differentiate between neurologically impaired and normal individuals, as well as identify which subtests would provide the best pathognomic power. The results revealed that a number of clinically useful nodes emerged that enabled the differentiation between groups with a small number of tasks. The primary separation variable was the Gait and Station subtest, a measure of subcortical motor functioning. Auditory Acuity and Clock Construction also provide important pathognomic information. A cross validation was conducted to determine the integrity of the generated decision tree, and results revealed that the generated model correctly predicted 84.5% of the normal group and 71.4% of the neurologically impaired sample. The results from the present analysis provides further evidence for the construct validity of the DWSMB.

Classification and regression tree analysis of a neurologically impaired and normal sample using sensory-motor tasks.

The factor structure of the Dean-Woodcock Sensory Motor Battery was examined using exploratory factor analysis with promax rotation. Participants (n = 1,651) were composed of 701 neurologically impaired individuals and 950 normal individuals. Three factors, accounting for almost 58.2% of the total test variation, emerged from the data and were labeled Simple Sensory Skills, Motor and Complex Sensory Skills, and Subcortical Motor Skills and Auditory/Visual Acuity. Hypothesized cross loadings were present, especially between the first two factors, which highlighted the parallel nature of sensory-motor skills. The third factor demonstrated the least amount of cross loadings, which reinforced the demarcation of cortical and subcortical motor skills measured by the DWSMB. The results also indicated that the factors were separated by the complexity of the cortical sensory-motor tasks. The factor structure, combined with an analysis of the interfactor correlations, provides evidence for construct validity of the DWSMB.

CORTICAL AND SUBCORTICAL CONSTRUCTS OF THE DEAN-WOODCOCK SENSORY MOTOR BATTERY: A CONSTRUCT VALIDITY STUDY

Visual disturbance is one of the hallmarks of multiple sclerosis (MS), yet clinical neuropsychologists rarely quantitatively assess visual acuity using standardized and norm-referenced measures. This is a significant oversight because disturbances in visual acuity can have an obvious and profound impact on neuropsychological tests which rely upon visual attention and/or scanning. This study investigated the relationship between corrected visual acuity and a widely used measure of visual attention and incidental learning in a group of 35 patients with MS. Regression analysis indicated that corrected visual acuity accounted for 21.3% of the variance in a Coding subtest. The results suggest neuropsychologists and other health care providers should exercise caution in interpreting visually based tests for patients with MS and should assess visual acuity with standardized and norm-referenced measures.

The Influence of Corrected Visual Acuity on Visual Attention and Incidental Learning in Patients with Multiple Sclerosis

Statistical prediction of an outcome variable using multiple independent variables is a common practice in the social and behavioral sciences. For example, neuropsychologists are sometimes called upon to provide predictions of preinjury cognitive functioning for individuals who have suffered a traumatic brain injury. Typically, these predictions are made using standard multiple linear regression models with several demographic variables (e.g., gender, ethnicity, education level) as predictors. Prior research has shown conflicting evidence regarding the ability of such models to provide accurate predictions of outcome variables such as full-scale intelligence (FSIQ) test scores. The present study had two goals: (1) to demonstrate the utility of a set of alternative prediction methods that have been applied extensively in the natural sciences and business but have not been frequently explored in the social sciences and (2) to develop models that can be used to predict premorbid cognitive functioning in preschool children. Predictions of Stanford–Binet 5 FSIQ scores for preschool-aged children is used to compare the performance of a multiple regression model with several of these alternative methods. Results demonstrate that classification and regression treesprovided more accurate predictions of FSIQ scores than does the more traditional regression approach. Implications of these results are discussed.

The prediction of intelligence in preschool children using alternative models to regression

The accurate diagnosis of Dementia of the Alzheimers Type (DAT) continues to be an area of difficulty for the fields of neuropsychology and neurology. The introduction of new medications that appear to mediate the insidious progression of the disorder increases the need for timely differentiation of DAT from other dementia-related disorders. The present study examined the relationship between hemispheric differences in regional cerebral blood flow with corresponding lateral neuropsychological processing deficits in patients with DAT. Eighty patients with a diagnosis of DAT were administered Single Photon Emission Computerized Tomography (SPECT) scans and a battery of left and right hemisphere neuropsychological-based tasks. The results of ANOVA indicated that patients with DAT who were not suffering from perfusion deficits exhibited significantly fewer neuropsychological deficits than did patients with DAT who had perfusion deficits. The neuropsychological tests that measured verbal ability, logical memory, word-pair learning, reading, arithmetic, and visual-perceptual organization were all significantly lower in the group with perfusion deficits. Further analysis indicated that patients with left hemisphere perfusion deficits tended to have poorer neuropsychological skills than did individuals with right hemisphere perfusion deficits, diffuse perfusion deficits, and no perfusion deficits. A Stepwise Discriminant Analysis was unable to use the neuropsychological variables to classify patients accurately into perfusion deficit groups.