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Biomedical subjects

W K Anger

Publications and source records attributed to W K Anger.

51 records · Page 3Linked to original sources
PubMedDate not supplied

Adoption of an adult environmental neurobehavioral test battery.

Nationally recognized experts participated in a 3-day workshop to discuss the complex issues associated with neurobehavioral testing in environmental health settings, and to propose basic and focused test batteries for use in evaluating populations living near hazardous chemical sites. The Adult Environmental Neurobehavioral Test Battery (AENTB), which evaluates major neurobehavioral domains and functions, was adopted by the Agency for Toxic Substances and Disease Registry (ATSDR) for use as a basic screening panel in field studies. Pilot testing of the AENTB demonstrated an examiner training requirement of 3-6 practice sessions, a mean total testing time of 58.0 min (SD = 9.6), and, for 9 of the component tests, a sample size requirement of fewer than 140 (alpha = 0.05, 95% power) to detect a 20% difference between study groups. ATSDR administered the AENTB to 467 persons, selected randomly from 1,382 participants in field study sites in three states. Total testing time varied noticeably by participant age and study site, suggesting an ongoing need for site-specific controls in each field study using the AENTB. Also planned is adoption of a pediatric test battery to evaluate the domains and functions most relevant at major stages of child development.

Adult↗
PubMedDate not supplied

Human behavioral assessment in neurotoxicology: producing appropriate test performance with written and shaping instructions.

Neurotoxic effects are of such breadth and complexity that functional biomarkers (behavioral tests) that integrate many areas of the nervous system predominate in human neurotoxicology research. The increasing distribution of chemical and other manufacturing throughout the world, particularly in developing nations, suggests the acute need to develop biomarkers for chemical exposures and effects that can be employed internationally. A language-free method for training performance on behavioral tests is described, which holds promise for international research that circumvents the vagaries of translation. Four behavioral tests were administered to 74-114 adult US subjects. Procedures, collectively termed shaping, produced effective performance on three tests [Symbol Digit, Vigilant Attention Test (VAT), Digit Span Forward and Backward], and produced appropriate but unacceptably slow performance in initial testing on the Simple Reaction Time test. Effective performance on the Symbol-Digit test also was produced by shaping instruction, without assistance from examiners, in small groups of residents of Taipei (Taiwan) and US children between the ages of 5 and 16.

Adolescent↗
PubMedDate not supplied

Computerized neurobehavioral testing: techniques for improving test instructions.

The development of new computer-administered neuropsychological tests has brought a renewed focus on the issue of written instructions. Designers and programmers often fail to take advantage of the display options and feedback potential available in modern computer systems to maximize the effectiveness of the instruction process. Guidelines from computer interface architecture and behavioral analysis are combined to present three principles for written instructions: precise language, attention focusing, and interactive instruction. A comparison of different instruction formats in the Symbol-Digit and Simple Reaction Time tests shows that the application of these principles can reduce training time without degrading performance.

Adult↗
PubMedDate not supplied

Computer-administration of questionnaires: a health screening system (HSS) developed for veterans.

The introduction of microcomputers in psychological research has spawned a burgeoning number of tests of psychological or behavioral function, but few computerized systems for administering questionnaires have been developed. A Health Screening System (HSS) is described that combines the benefits of the paper-and-pencil format (e.g., convenient navigation within test questions) and the added benefits of computer-implementation (e.g., efficiency, automated scoring). The HSS features; a) appealing test appearance (e.g., text in large-size fonts, color backgrounds); b) clear wording of tests and instructions (identical wording as original tests except when clarity is served by changes); c) limiting need for Examiner-Subject interaction (e.g., continuously available on-line training, navigation within test questions, answer review capability, durable 9-button response unit); d) options (e.g., question skipping, spoken instructions, test questions, and answers on command); e) modification capabilities (e.g., color, text, test layout editing, control of test order, automated breaks, addition of tests to system); and f) extras (e.g., kernel of main instruction on each test screen, digitized video, audio message from Examiner in training, copyright notification on each screen, raw and summary data outputs in spreadsheet formal). Ten HSS tests were administered to 22 US military veterans, who took slightly longer to complete them than did 10 veterans who were administered the same tests in their original paper-and-pencil format. User reaction to the computerized HSS was positive.

Adult↗
PubMedDate not supplied

Symposium on computerized behavioral testing of humans in neurotoxicology research: overview of the proceedings.

The Symposium on Computerized Behavioral Testing of Humans in Neurotoxicology Research, held in Portland, OR (USA), on June 21-23, 1995, is the subject of the 23 articles in this issue of Neurotoxicology and Teratology. It is the first open forum to focus exclusively on computer-implemented behavioral test methods for neurotoxicology. Both the Symposium and this proceedings have been organized around the topics: new technologies and new batteries, confounders and methodologic factors, special populations (children), sensory and motor testing, clinical applications, and neurotoxicology research. The Symposium emphasized common approaches to computerized testing, highlighted fundamental differences in strategies for the selection of tests, and produced tangible evidence that the NES2 test battery has become a pervasively used instrument for presenting valid tests in human neurotoxicology research. However, the dominant impression drawn from the Symposium is that there is a methodologic vigor in the field of computerized behavioral testing. This is revealed by the appearance of new test batteries, criticism of existing procedures, challenges to the existing order of test selection, and the identification of analytic covariates for commonly used tests.

Behavior↗
PubMedDate not supplied

Two-stage evaluation of exposure to mercury and biomarkers of neurotoxicity at a hazardous waste site.

Communities surrounding the Rocky Mountain Arsenal (RMA), a Superfund site in Colorado, were studied in order to determine whether exposures to mercury were greater among persons who resided there than among residents of a comparison area 12-15 miles distant. From a census-based stratified random sample, 469 persons were interviewed and urine samples were obtained for biomonitoring. Mercury was detected in urine from 32 (6.8%) of the 469 persons sample at a detection limit of 5 ppb. Trace levels of mercury (detectable, but nonquantifiable) were found in 80 (17.1%) of the persons sampled. Neither the frequency of detection, the arithmetic mean, nor the geometric mean value for urine mercury was found to be statistically different when persons living near the site were compared to persons from the more distant comparison area. The risk of mercury exposure associated with demographic variables, residence, occupation, hobbies, dietary habits, water supply, housing, and activity patterns was evaluated. In the second stage of the evaluation, the Neurobehavioral Core Test Battery (NCTB) is being used to assess individual functional deficits and nervous system disorders associated with exposure to mercury and other neurotoxic chemicals.

Adolescent↗
PubMedDate not supplied

Psychological differences between veterans with and without Gulf War unexplained symptoms. Portland Environmental Hazards Research Center.

OBJECTIVE: The objective of this study was to assess measures of psychological and neurobehavioral functioning to determine their association with unexplained symptoms in Gulf War veterans. METHODS: An epidemiological survey focusing on exposures and symptoms was mailed to a random sample of Gulf War veterans from Oregon and southwestern Washington. Volunteers were recruited from survey respondents who agreed to undergo a thorough medical examination and psychological and neurobehavioral assessment. Persistent symptoms with no medical explanation associated with service in the Persian Gulf (eg, fatigue, muscle pain, and memory deficits) that began during or after the war qualified respondents as cases. The 241 veterans with unexplained symptoms were classified as case subjects, and the 113 veterans without symptoms were classified as control subjects. All veterans completed a battery of computerized assessment tests consisting of 12 psychosocial and 6 neurobehavioral tests. Differences between case and control subjects on neurobehavioral and psychological variables were assessed with univariate and multivariate statistical comparisons. RESULTS: Case subjects differed substantially and consistently from control subjects on diverse psychological tests in the direction of increased distress and psychiatric symptoms. Case subjects had small but statistically significant deficits relative to control subjects on some neurobehavioral tests of memory, attention, and response speed. A logistic regression model consisting of four psychological variables but no neurobehavioral variables classified case and control subjects with 86% accuracy. CONCLUSIONS: Our results revealed that Gulf War veterans who report symptoms associated with that conflict differed on multiple psychological measures in the direction of increased distress and performed more poorly on neurobehavioral measures when compared with control subjects who did not report symptoms. This suggests that psychological differences have a prominent role in investigation of possible explanations of Gulf War symptoms.

Adult↗
PubMedDate not supplied

Posttraumatic stress symptomatology is associated with unexplained illness attributed to Persian Gulf War military service.

OBJECTIVE: Controversy exists concerning unexplained illness in Persian Gulf War veterans, especially regarding the contribution of psychological trauma. We sought to determine if war zone trauma or posttraumatic stress symptomatology (PTSS) are associated with illnesses reported by Gulf War veterans that were documented by medical examination but not attributable to a medical diagnosis. METHODS: A total of 1119 (55% response rate) of 2022 randomly sampled veterans of the United States Persian Gulf War were screened and 237 cases and 113 controls were identified by medical examination for a case-control study comparing Persian Gulf War military veterans with or without medically documented, but unexplained, symptoms. Multivariate logistic regression and cross-validation analyses examined self-report measures of demographics, subjective physical symptoms and functioning, psychiatric symptoms, stressors, war zone trauma, and PTSS, to identify correlates of case-control status. RESULTS: Posttraumatic stress symptomatology and somatic complaints were independently associated with case status, as were (although less consistently) war zone trauma and depression. Age, education, and self-reported health, stress-related somatization, pain, energy/fatigue, illness-related functional impairment, recent stressors, and anxiety were univariate (but not multivariate) correlates of case status. CONCLUSIONS: PTSS related to war zone trauma warrants additional prospective research study and attention in clinical screening and assessment as a potential contributor to the often debilitating physical health problems experienced by Persian Gulf War veterans.

Adult↗
PubMedDate not supplied

Environmental equity and pesticide exposure.

Although people of color and low-income groups bear a disproportionate share of the health risks from exposure to pesticides, research attention has been meager, and data on acute and chronic health effects related to their toxic exposures are generally lacking. Increased resources are needed both to study this issue and to mitigate problems already identified. People of color should be a major research focus, with priority on long-term effects, particularly cancer, neurodevelopmental and neurobehavioral effects, long-term neurological dysfunction, and reproductive outcome. Suitable populations at high risk that have not been studied include noncertified pesticide applicators and seasonal and migrant farm workers, including children.

Body Burden↗
PubMedDate not supplied

Neurobehavioral effects of methyl N-butyl ketone and methyl N-amyl ketone in rats and monkeys: a summary of NIOSH investigations.

The results from four NIOSH investigations concerning the neurobehavioral effects of methyl n-butyl ketone (MBK) and methyl n-amyl ketone (MAK) on experimental animals are summarized. The investigations were initiated following clinical reports of neurologic sequelae in humans exposed to these ketone solvents. In order to explore both acute and chronic effects of MBK and MAK, two general types of studies were conducted: 1) neurophysiologic evaluation of monkeys and rats following chronic inhalation, and 2) behavioral effects in rats following oral or intraperitoneal administration. Results from chronic inhalation studies after 4 months of 1000 ppm MBK exposure (all exposures: 6 hrs/day, 5 days/week) showed the following: decreased motor nerve conduction velocities (NCV) in the ulnar and sciatic-tibial nerves, reduced amplitude of evoked muscle action potentials (MAP), lengthened latency of components of the visual evoked brain potential, decreased body weight, and hindlimb drag. Decrements in sciatic-tibial NCV and MAP amplitude were found after 9 months exposure to 100 ppm MBK. In contrast, exposure to approximately 1000 ppm MAK for 9 months had no adverse affects on neurophysiologic indicators of nervous system integrity. Dose-response investigations of the effects of MBK (oral) and MAK (ip) showed for both solvents a reduction in the response rate of rats trained on a multiple schedule of reinforcement.

Action Potentials↗
PubMedDate not supplied

Effects of acute oral administration of lithium compounds on multiple schedule performance in rats.

Adult male Sprague-Dawley rats were given acute oral administrations of lithium carbonate or lithium chloride at concentrations of 100, 200, and 300 mg/kg. Barpressing performance on a multiple fixed ratio 20/fixed interval 5 minute schedule was measured daily. The 200 and 300 mg/kg administrations of lithium chloride produced significant decreases in barpressing performance and all levels of lithium carbonate produced significant changes in performance. A 24 hour delay in the maximal behavioral effect of the 300 mg/kg dose of lithium carbonate paralleled previous findings showing delays in peak brain lithium levels after oral administration of lithium carbonate.

Administration, Oral↗
PubMedDate not supplied

Neurobehavioral tests used in NIOSH-supported worksite studies, 1973-1983.

Between 1973 and 1983, the National Institute for Occupational Safety and Health (NIOSH) published 11 studies which reported the neurobehavioral effects of chronic exposures to industrial chemicals among working groups. This paper reviews the objectives, testing methods, findings and conclusions of these studies. The studies employed a single rationale for selecting tests--tests sensitive to the types of effects reported for the chemical under study were utilized in each case. As a result, different sets of tests were used for different studies. This strategy is distinct from the approach suggested in the other reports in these proceedings which advocate the use of a uniform test battery. The wide variety of neurobehavioral effects produced by chemicals found in the environment argues for a rationale of tailoring test selection in many situations, particularly those where the range of expected effects has been fairly well established for the chemical under study.

Humans↗
PubMedDate not supplied

Neurobehavioral testing of chemicals: impact on recommended standards.

Historically, the American Conference of Governmental Industrial Hygienists (ACGIH) has served as a major source of information on recommended safe exposure limits (Threshold Limit Values or TLV's) for chemicals most frequently encountered in U. S. industry and of known toxicologic significance. A review of the ACGIH Documentation book, which details the basis for their judgements, has indicated that 167 of the 588 chemicals for which they assigned recommended standards have, as one of their bases, direct nervous system effects. In order to increase the impact of future behavioral toxicology research on recommended standards, the neurotoxicologist can utilize certain strategies: (a) Focus on established mixtures in the environment of interest or select exposures of particular chemical classes, considering population size and severity of effect; (b) Ensure that the results of the study are referable to the expected route of exposure in the environment of interest; and (c) Select tests with face validity for non-psychologists, using reference substances. Finally, the neurotoxicologist is urged to consider effects related to safety as well as health in developing his/her research.

Air Pollutants, Occupational↗