Relative absence of neuropsychological deficit in patients with low grade astrocytomas

Given the current accuracy and precision of modern brain imaging technology, there is presumed to be little utility in neuropsychological assessment procedures in patients with brain tumors. The primary exposure of many clinical neuropsychologists to patients with brain tumors is during their training, in the form of didactic classroom activities, such as reviewing the brain tumor cases of early investigators in the field. Historically, these brain tumors were the more aggressive and destructive tumors, such as grade III and IV astrocytomas, that could be identified with pre CT and pre MRI technology. With current imaging technology, low grade tumors that might previously have gone undiagnosed for years can be detected and patients followed over time. This series of cases represents documentation of the very unique neuropsychological status of patients with relatively slow growing, infiltrative brain tumors classified as grade II astrocytomas. The potential relevance of neuropsychological assessment for such cases is discussed.     

The detection of malingering in neuropsychological assessment

Although malingering, or the manipulation of data by the patient, is a problem commonly faced by neuropsychologists, there has been little systematic investigation of this problem. This paper reviews the literature on the detection of malingering in assessment instruments commonly used by clinical neuropsychologists. Criticism of previous research is discussed, and suggestions are made both for future research and for clinical practice.     

Alcohol,head injury,and neuropsychological function

Evidence is reviewed indicating that the extent of alcohol abuse alone cannot account for the neuropsychological deficits observed in alcoholics, and that alcohol abuse and head injury may interact in some patients to influence neuropsychological status. Alcohol abuse both increases the risk for head trauma and potentiates the resulting brain injury, which can lead to negative neuropsychological consequences. Clinicians involved in the treatment of addiction should assess patients for history of head injury, and neuropsychological deficits consequent to both head injury and ethanol. These deficits may limit patient ability to comply with addiction rehabilitation programs. Conversely, clinicians in acute care and rehabilitation of the sequelae of head trauma should routinely assess their patients for substance abuse, because such abuse can have a significant impact on recovery from brain injury.     

A taxonomy of neurobehavioral functions applied to neuropsychological assessment after head injury

Neuropsychological dysfunctions after traumatic brain injury are classified into a taxonomy to plan a comprehensive examination, and organize and report findings for diagnosis and treatment: consciousness, information processing, sensorimotor, neurophysiological, cerebral personality disorders, intelligence, memory, language, stress, psychodynamic, identity and weltanschauung, adaptation, complex adaptive functions, and development of children. Widerange sampling enhances the detection of acute and late-developing dysfunctions, and diagnosis of complex syndromes. Historical, personality, and injury data are components of the assessment. Issues discussed include underestimation of brain injury, malingering, interaction of symptoms, symptom persistence, and noncerebral lesional contributors to impairment after mild head injury.     

Emotional disturbances and their interaction with neuropsychological deficits

The interaction and relationships between neuropsychological tests (which are principally oriented to intellectual and cognitive abilities) and tests of personality and emotional status are complex, but nevertheless important in the clinical assessment of brain-damaged persons. Are indications of emotional disturbances to be expected as a direct consequence of brain damage? If so, how can the indications of emotional disturbances be differentiated from results obtained with psychiatrically disturbed (non-brain-damaged) subjects? Some authors have presumed that emotional disturbances, such as depression, acute anxiety, etc., in their own right cause impaired performances on neuropsychological tests, whereas other authors have proposed that brain damage predisposes the individual to demonstrate evidence of emotional disturbances. If emotional disturbances cause impairment on neuropsychological tests, why is it that so many emotionally disturbed persons without brain damage tend to perform normally on neuropsychological tests? This review of relevant publications considers (1) different general approaches to these questions and their implications for neuropsychology, (2) evidence of differential sensitivity to brain damage of neuropsychological and emotional instruments, (3) the sensitivity and specificity of self-assessments and complaints of head-injured subjects, (4) MMPI findings among head-injured subjects and in interaction with neuropsychological measurements, and (5) principles and guidelines that may be of value in clinical application of findings reported in the literature.     

Issues associated with repeated neuropsychological assessments

Distinguishing practice effects from other factors in repeated neuropsychological assessments are discussed in the context of research studies and clinical/forensic assessments. Potential methodological procedures for reducing the impact of practice effects in research settings are outlined. In contrast, the potential clinical utility and interpretation of practice effects in clinical assessments and forensic evaluations are highlighted.     

Experience-dependent neuropsychological recovery and the treatment of chronic alcoholism

This paper reviews the relationship between cognitive status and treatment outcome in chronic alcoholics, the natural history of recovery, and the role of cognitively oriented remediation programs in facilitating recovery. Seven studies of experience-dependent recovery are described in which behavioral improvement was noted. Various recommendations for treatment over the course of recovery are made, guided by anticipated changes in capacity to process complex information over time.     

Normative data for eight neuropsychological tests based on a Danish sample

Normative neuropsychological data have been provided using a sample of 101 persons aged 20 to 54 years. Eighty-seven of the subjects were recruited among patients who had undergone minor surgery, and 14 subjects were volunteers from the staff at the hospital laundry. The measures consisted of seven subjects from the WAIS-R, the trail-making test, symbol digit modalities test, auditory-verbal learning test, story recall test, visual gestalt test, recurring figures test, verbal fluency, and Purdue pegboard test. These measures were selected because of suitability in regard to time taken for testing each subject and their sensitivity to subtle changes in neuropsychological functioning. The sample was arbitrarily divided into three age groups, and for each of the three samples, mean, standard deviation, and range were calculated for each test. The results of the Information and Vocabulary subtests from the WAIS-R, education, and social status were applied as independent variables in linear regression analyses where each of the neuropsychological tests, in turn, was the dependent variable. For the oldest age group, age in addition was used as an independent variable. Significant linear relationships, which accounted for an optimal part of the variance, were selected for clinical application.     

Analysis of the elements of attention: A neuropsychological approach

A model for conceptualizing the components or elements of attention is presented. The model substitutes for the diffuse and global concept of attention a group of four processes and links them to a putative system of cerebral structures. Data in support of the model are presented; they are derived from neuropsychological test scores obtained from two samples, the first consisting of 203 adult neuropsychiatric patients and normal control subjects, and the second, an epidemiologically-based sample of 435 elementary school children. Principal components analyses of test scores from these two populations yielded similar results: a set of independent elements of attention that are assayed by different tests. This work presents a heuristic for clinical research in which the measurement of attention is essential.     

Self-Reported Delinquency,neuropsychological deficit,and history of attention deficit disorder

This study was designed to evaluate the possibility that a pattern of cognitive deficit is associated with delinquent behavior, while avoiding some of the methodological problems of previous research. The Self- Report Early Delinquency instrument and a research battery of neuropsychological tests were administered blindly to an unselected cohort of 678 13- year- olds. Because the diagnosis of attention deficit disorder (ADD) was found at markedly elevated rates in the backgrounds of these delinquents, the possibility was examined that the neuropsychological deficits of delinquents might be limited to delinquents with histories of ADD. Although delinquents with past ADD were more cognitively impaired than non-ADD delinquents, both groups scored significantly below nondelinquents on verbal, visuospatial, and visualmotor integration skills. In addition, ADD delinquents scored poorly on memory abilities. Subjects with ADD who had not developed delinquent behavior were not as cognitively impaired as ADD delinquents, suggesting that it is the specific comorbidity of ADD and delinquency that bears neuropsychological study.This work was supported by USPHS Grant 1 R23 MH-42723-01 from the Antisocial and Violent Behavior Branch of the National Institute of Mental Health. The Dunedin Multidisciplinary Health and Development Research Unit is supported by the Medical Research Council of New Zealand. Appreciation is expressed for the methodological advice of Prof. Sarnoff A. Mednick, and for the data collection efforts of Mrs. Pat Brasch, Mrs. Kathleen Campbell, Mr. Rich Poulton, and the psychometrists who administered the WISC-R.     

Comprehensive driving assessment: neuropsychological testing and on-road evaluation of brain injured patients

The study investigates the correspondence between neuropsychological test results and on-road driving performance among 55 patients with a CT-verified brain damage or documented neurological disorder (cerebrovascular accident: 43, traumatic brain injury: 5, multiple sclerosis: 4, other: 3). 5 patients showed unimpaired test profiles and passed the on-road evaluation. 18 patients showed severe neuropsychological deficits contrary to driving and were not recommended for on-road evaluation. Of the remaining 32 patients with some neuropsychological deficits, all 100% in the minor impaired group (n = 8) passed the driving evaluation, compared to 69% in the mildly impaired (n = 16) and 38% in the moderately impaired group (n = 8). Measures of reduced visuoconstructive ability, reaction time, visual attention, and awareness of cognitive impairments, were found to discriminate between groups. It is concluded that neuropsychological assessment of targeted functions provide an ecological valid prediction of driving skill after brain damage, but that on-road evaluation is needed as supplement in cases with ambiguous test findings.     

Separate Digits tests: A brief history,a literature review,and a reexamination of the factor structure of the test of memory and learning (TOMAL)

Following a brief history of Digit Span, a review of 27 articles, selected from 76, addresses the question of whether to scale Digits Forward and Backward separately. The review begins with studies involving Digits Forward, followed in turn by studies of Digits Backward and of both subtests. Finally, the loadings of four TOMAL subtests, Digits Forward and Backward and Letters Forward and Backward, undergo examination in the context of two, three, and four factor promax solutions, with corresponding varimax solutions provided for comparison. The analysis leads to several conclusions. Though Digits Forward and Backward show similarities, they load differently in the three and four factor solutions; Digits Backward also displays a spatial element, and perhaps a transformative element, not apparent in Digits Forward. Moreover, the differences between the two measures have important neurologic and diagnostic implications.     

Computerized assessment in neuropsychology: A review of tests and test batteries

This article contains detailed reviews of 13 computerized neuropsychological and performance test batteries and six stand-alone computer tests. Tasks found on these instruments are described and tables illustrate which batteries employ which measures. In addition to issues of reliability and validity, special considerations apply to computerized assessment. These issues are discussed and readers are provided information to help them assess computerized tests in relation to their particular clinical and research needs. Since many computerized tests were developed as performance assessment tools, the relationship between performance and neuropsychological assessment is examined.     

Forensic neuropsychology: The art of practicing a science that does not yet exist

Despite its future promise, neuropsychological evidence generally lacks scientifically demonstrated value for resolving legal issues, and thus, if admitted into court, should be accorded little or no weight. In support of this contention, examples of problems and limits in forensic neuropsychology are described. These include contrasts between the clinical and forensic context; the base-rate problem; lack of standardized practices; problems assessing credibility or malingering; difficulties determining prior functioning, limits in the capacity to integrate complex data; and the lack of relation between judgmental accuracy and education, experience, or credentials. Some possible counterarguments are also addressed.     

Neuropsychological changes in children with cancer: The treatment of missing data in longitudinal studies

Researchers conducting longitudinal studies with children or adults are inevitably confronted with problems of attrition and missing data. Missing data in longitudinal studies is frequently handled by excluding from analyses those cases for whom data are incomplete. This approach to missing data is not optimal. On the one hand, if data are missing at random, then dropping incomplete cases ignores information collected on those cases that could be used to improve estimates of population parameters (e.g., means, variances, covariances, and growth rates) and improve the power of significance tests of statistical hypotheses. On the other hand, if data are not missing at random, then dropping incomplete cases leads to biased parameter estimates and hypothesis tests that may be internally and externally invalid. This study uses three years of follow-up data from a longitudinal investigation of neuropsychological outcomes of cancer in children to demonstrate the problems presented by missing data in repeated measures designs and some solutions. In evaluating potential biasing effects of attrition, the study extends previous research on neuropsychological outcomes in pediatric cancer by inclusion of patients whose disease had relapsed, and by comparison of surviving and nonsurviving patients. Although the data presented have specific relevance to the study of neuropsychological outcome in pediatric cancer, the problems of missing data and the solutions presented are relevant to a wide variety of diseases and conditions of interest to researchers in child and adult neuropsychology.     

The logic of neuropsychological research and the problem of patient classification in aphasia

A critical analysis is presented of the assumptions that must be made to use the data from aphasia to constrain models of normal language processing. The implication of these assumptions for patient classification and research methodology in aphasia is considered.     

Suitability of published neuropsychological test norms for urban African secondary school students in South Africa

Variations in neuropsychological test performance as a function of ethnic/cultural group membership, socioeconomic and educational status are widely documented. In South Africa, issues of cultural difference, sociopolitical disadvantage, cognitive and educational limitations, are of particular relevance. Accordingly, this study investigated the performance on a neuropsychological test battery of urban African high school students. A group of 100 Soweto students in Grades 8–12, and a second group of 152 sixth grade Soweto students aged 13–15 years, scored significantly lower on most of the measures than their American counterparts, as reflected in published norms. Results also demonstrated a significant difference in test performance as a function of educational grade. The findings confirmed the need for using norms and approaches which are appropriate to a given population when interpreting and addressing neuropsychological test performance.     

Cognitive Event-Related Potentials in Neuropsychological Assessment

Neuropsychology is a behavioral approach to studying the brain, and an integration of neuropsychology with on-line processing measures of brain function is important for advancing the understanding of brain–behavior relationships. Cognitive event-related potentials (ERPs) are on-line processing measures that are of interest to neuropsychologists because they are linked to familiar neuropsychological test paradigms and because they have reached a degree of standardization sufficient to make them applicable in individual assessment. A selective review of cognitive ERPs is given, focusing on studies of attention in the oddball paradigm and arguing that an adequate assessment of attention is basic in understanding higher order cognitive functions. General principles for using ERP data to supplement and clarify neuropsychological analysis are discussed, and available evidence on dementia and traumatic head injury is reviewed. It is concluded that ERPs are a useful supplement to neuropsychological assessment. Although diagnostic use of ERPs must be guarded because of limited standardization and validation, information-processing analysis with ERPs may aid significantly in interpretation of behavioral data.