A canonical correlation analysis of intelligence and executive functioning.

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.

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

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 trees provided more accurate predictions of FSIQ scores than does the more traditional regression approach. Implications of these results are discussed.

Assessing sensory-motor deficits in pediatric traumatic brain injury.

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. Children's 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.

The presence and predictive value of astereognosis and agraphesthesia in patients with Alzheimer's disease.

Sensory and motor functions are good markers of neurocognitive decline due to their proximity and hierarchical relationship to high-order processes. The current study investigated if patients with Alzheimer's disease (AD) differed from a healthy control group in two tactile perceptual processes: astereognosis and agraphesthesia. Analyses were also conducted to see if these tactile processes were predictive of higher-order cognitive functioning. Twenty-eight patients with AD (mean age = 75.86) were compared to 28 healthy control subjects (mean age = 76.38) and were administered the Dean-Woodcock Sensory Motor Battery and the Woodcock-Johnson Psychoeducational Battery-Revised. Results suggest the patients with AD demonstrated significantly higher levels of tactile disturbance and astereognosis while agraphesthesia was able to predict a substantial portion of the variance in 3/7 cognitive tests and 4/7 cognitive tests, respectively. This included measures of fluid reasoning, visual processing, crystallized language, short-term memory, and auditory processing. These results suggest that astereognosis and agraphesthesia may be good markers of the extent of cognitive impairment in AD and should be included in neuropsychological evaluations due to their functional importance.

Cortical and subcortical sensory-motor impairment in patients with major depression: a preliminary analysis.

Assessment of patients with depression tends to focus on the psychiatric symptoms of the disorder to quantify distress, potential for suicide, and helps determine the appropriate course of treatment. However, research increasingly reveals comorbid organic and biological deficits in higher order cortical skills and subcortical processes which should be considered when assessing the depressed patient. The current study investigated the presence of cortical and subcortical sensory deficits in a group of 36 patients with Major Depressive Disorder as compared to a group of normal controls. The results of a MANOVA indicated a significant performance difference between depressed and nondepressed participants (Wilks' Lambda = .437, F = 3.68, p > .001). Subsequent univariate tests showed normals performed better on 29 of 35 variables of a sensory-motor battery. Deficits in sensory and motor functioning can have a profound impact on patient functioning and may remit with treatment. Thus, a comprehensive neuropsychological battery for patients with depression should include standardized and psychometrically sound measures of sensory and motor functioning.

The influence of corrected visual acuity on visual attention and incidental learning in patients with multiple sclerosis.

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.

When is neuropsychological testing medically necessary for children on medicaid in New Mexico?

Healthcare for poor children, also known as Medicaid, is disproportionately relied upon by citizens of poor states such as New Mexico, where (a) there are more unintended pregnancies, (b) domestic violence during and after pregnancies occurs with regularity, (c) youth substance use is much more common, (d) crime rates are some of the worst in the country, (e) many never graduate from high school, and (f) incarceration is often inevitable. Yet, there is a dearth of research into the neuropsychological health of these children. Meanwhile, nonneuropsychologists working for managed care organizations routinely deny authorization for neuropsychological testing based on a lack of medical necessity. The present article addresses the question of neuropsychological medical necessity using community-based neuropsychological data from New Mexico collected on Medicaid and non-Medicaid youth via retroactive chart review. Downstream fiscal implications that are related to the eventual cost of mental illness and crime among those with poor neuropsychological health are discussed.

The neurocognitive outcome of nocardia: a brief, longitudinal case study.

Nocardia infection is a rare bacterial disorder that tends to affect the lungs and, in immunocompromised individuals, may progress to the brain. The brief, consecutive neuropsychological and neurobehavioral data of a 49-year-old male who developed multiple nocardia-related brain abscesses in the left frontal, occipital, and right cerebellar areas are reviewed. Neuropsychological findings indicated that he maintained mild-to-moderate impairments, primarily in executive functions, upon follow-up evaluation 43 days subsequent to baseline evaluation. This case demonstrates the utility of brief, serial neuropsychological screening in tracking the progression of an infectious process for the purposes of treatment planning and disposition.

Predicting global and specific neurological impairment with sensory-motor functioning.

The present study assessed the ability of the Dean-Woodcock Sensory-Motor Battery (DWSMB) to distinguish between normal subjects and neurologically impaired individuals. Scores from the subtests of the DWSMB for 250 normal and 250 neurologically impaired individuals were randomly assigned to two equal groups to allow for cross-validation. The DWSMB was able to correctly identify 92.8% of the cases, identifying 94.4% of the normal population and 91.2% of the neurologically impaired subjects. The cross-validation correctly identified 87.2% of the total cases, identifying 91.2% of the normal subjects and 83.2% of the neurologically impaired subjects. An additional discriminant analysis indicated that the DWSMB correctly identified the following cases: 44.9% cardio-vascular accidents, 66.7% multiple sclerosis, 40% seizures, 42% traumatic brain injuries, 62.7% dementia, and 54.5% Parkinson's disease. The results add to the validity of the DWSMB by providing evidence of its ability to differentiate between neurologically impaired and normal individuals.

Predicting verbal fluency using Word Reading: Implications for premorbid functioning.

The estimation of premorbid general intellectual functioning using word reading tests has a rich history of validation and is a common assessment practice for neuropsychologists. What is less well-researched is the approach used to estimate premorbid functioning of non-intellectual domains, such as executive functions, including verbal fluency. The current study evaluated this relationship with 41 adult college students who completed the Word Reading subtest of the Wechsler Individual Achievement Test-Second Edition (WIAT-II) and the Verbal Fluency test from the Delis-Kaplan Executive Function System (D-KEFS). Path analysis indicated that only Letter Fluency (a measure of phonemic fluency) was statistically significantly related to Word Reading and the relationship was somewhat weak. The relationship between Category Fluency (a measure of semantic fluency) and Category Switching (a measure of verbal fluency cognitive set-shifting) to Word Reading was nonsignificant. Participants also completed the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III), and as expected a strong relationship was found between Word Reading and the Verbal IQ (VIQ), Performance IQ (PIQ), and Full Scale Intelligence Quotient (FSIQ). Results of this study strongly suggest that caution be exercised when extrapolating an estimate of premorbid verbal fluency abilities from measures of word reading.