Pre-training to improve workshop performance in supervisor skills: an exploratory study of Latino agricultural workers.

Employees with limited education may be excluded from advanced training due to assumptions that they might not learn rapidly. However, preparatory training may be able to overcome missing experience in education. The purpose of this study was to test the hypothesis that computer-based training (CBT) in supervisor skills of Latino agricultural workers would improve subsequent performance in a workshop designed to teach supervisor skills. Ten men born and educated in Mexico participated in the study; all spoke Spanish, the language of the training. Five participants (mean 6.4 years of education) completed supervisor skills CBT, and five participants (mean 8.2 years of education) completed hazard communication (HazCom) CBT as a control condition. Following the CBT, all participants completed a two-day face-to-face workshop on supervisory skills conducted by an experienced behavior management consultant. Although the groups did not differ in their knowledge scores on a multiple-choice test before the face-to-face workshop, after the workshop the HazCom group had a mean test score of 51.2% (SD = 8.7) while the supervisor group had a higher mean test score of 65.2% (SD = 14.3). The difference was marginally significant by a t-test (p = 0.052), and the effect size was large (d = 1.16). The results suggest that computer-based training in supervisor skills can be effective in preparing participants with limited education to learn supervisor skills from a face-to-face workshop. This result suggests that limited educational attainment is not a barrier to learning the complex knowledge required to supervise employees, that pre-training may improve learning in a workshop format, and that training may be presented effectively in a computer-based format to employees with limited education.

Neurobehavioural effects among workers occupationally exposed to organophosphorous pesticides.

AIMS: To identify neurobehavioural deficits among workers exposed to organophosphorous (OP) pesticides in their occupation. METHODS: This study was conducted during the period when pesticides were applied to cotton crops in the fields in Menoufiya Governorate, Egypt. Fifty two occupationally exposed male workers were compared to 50 unexposed male controls who were similar in age, socioeconomic class, and years of education (> or =12 years). All participants completed a questionnaire (assessing personal, occupational, and medical histories), general and neurological clinical examination, neurobehavioural test battery (including tests for verbal abstraction, problem solving, attention, memory, and visuomotor speed), personality assessment, and serological analysis for serum acetylcholinesterase. RESULTS: After correcting for confounders of age and education, the exposed participants exhibited significantly lower performance than controls on six neurobehavioural tests (Similarities, Digit Symbol, Trailmaking part A and B, Letter Cancellation, Digit Span, and Benton Visual Retention). A longer duration of work with pesticides was associated with lower performance on most neurobehavioural tests after adjusting for multiple comparisons. Although serum acetylcholinesterase was significantly lower in the exposed than the control participants, it was not significantly correlated with either neurobehavioural performance or neurological abnormalities. CONCLUSIONS: Occupational exposure to OP pesticides was associated with deficits in a wider array of neurobehavioural functions than previously reported, perhaps because of higher exposure in this population. Moderate chronic OP exposure may not only affect visuomotor speed as reported previously, but also verbal abstraction, attention, and memory.

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.

Parkinsonism and occupational exposure to pesticides.

OBJECTIVE: To examine the risk of parkinsonism related to lifetime occupational exposure to pesticides among a cohort of men, mostly orchardists, in Washington State. METHODS: All 310 subjects in this study had previously participated in a cohort study of men occupationally exposed to pesticides. Subjects were given a structured neurological examination and completed a self administered questionnaire which elicited detailed information on pesticide (insecticide, herbicide, and fungicide) use throughout their working careers. Demographic characteristics were also sought. Subjects had a mean age of 69.6 years (range 49-96, SD 8.1). There were 238 (76.8%) subjects who reported some occupational exposure to pesticides, whereas 72 (23.2%) reported none. Parkinsonism was defined by the presence of two or more of rest tremor, rigidity, bradykinesia, and impairment of postural reflexes in subjects not on antiparkinsonian medication, or the presence of at least one sign if they were on such medication. Parkinson's disease was not studied explicitly because of the difficulty in distinguishing it from other parkinsonian syndromes. A generalised linear model was used to estimate prevalence ratios (PRs) for parkinsonism relative to history of farming, pesticide use, and use of well water. RESULTS: A PR of 2.0 (95% confidence interval (95% CI) 1.0 to 4.2) was found for subjects in the highest tertile of years of exposure to pesticides; a similarly increased, non-significant, PR was found for the middle tertile (1.9 (95% CI 0.9 to 4.0)), although a trend test did not show a significant exposure-response relation. No increased risks were found associated with specific pesticides or pesticide classes, nor with a history of farming or use of well water. CONCLUSION: Parkinsonism may be associated with long term occupational exposure to pesticides, although no associations with specific pesticides could be detected. This finding is consistent with most of the publications on this topic.

cTRAIN: a computer-aided training system developed in SuperCard for teaching skills using behavioral education principles.

A computer-aided training program was developed in SuperCard and piloted with professional painters. Taking a modern programmed-instruction/behavioral-education approach, cTRAIN is structured as a series of information sets. Each information set consists of a series of information screens (three to five recommended) followed by quiz screens (one to three recommended) structured as four-response multiple choice questions. Correct quiz responses produce positive feedback and continuation in the series, whereas incorrect responses result in "error" feedback and return the student to the beginning of the information set to repeat the same information screens and the same quiz question. This report demonstrates a specific implementation, respiratory protection requirements, using the flexible cTRAIN system for developing training modules. Fifteen adults completed the respiratory protection program, demonstrating substantial and significant (p < .0001 by paired t test) gains from baseline pretest (19.4 out of 30 questions) to the immediate posttest (28.1). Performance remained elevated (26.4) on a retest taken 1 week later.

Assessment of neurobehavioral function with computerized tests in a population of hispanic adolescents working in agriculture.

In recent years there has been heightened concern over the potential of occupational or environmental exposures to affect neurological function in children and adolescents. The current study was designed to develop computerized tests to effectively assess neurobehavioral function in Hispanic adolescents working in agriculture and to evaluate those tests in Hispanic youths working in agriculture and in a non-agricultural group. After exclusions, 96 adolescents currently working in agriculture (AG) and 51 adolescents currently non-migratory and not working in agriculture (Non-AG) were tested. Neurobehavioral tests were selected from the computerized Behavioral Assessment and Research System. AG test performance was significantly below Non-AG performance on the cognitive tests. However, educational and cultural differences between the AG and Non-AG groups may explain this difference. Repeat testing of the AG group revealed substantially improved performance, further supporting educational or cultural differences as an explanation for the group differences. Together, these results expose the limitations in case-control or cross-sectional designs for testing migrant worker populations in the United States. Longitudinal or cross-sectional designs with repeat testing offer more promise and may be essential for drawing accurate conclusions in migrant worker groups where there are no truly equivalent comparison or control groups.

Neurobehavioral deficits in Persian Gulf veterans: additional evidence from a population-based study.

Reports of low-concentration nerve gas exposures during the Gulf War (GW) have spurred concern about possible health consequences and symptoms reported by many returning veterans. The Portland Environmental Hazards Research Center is studying veterans from the northwest United States who report persistent, unexplained "Gulf War" symptoms (cases) and those who do not report those symptoms (controls). An epidemiological survey focused on exposures and symptoms was mailed to a random sample of GW veterans from Oregon and southwestern Washington. Volunteers recruited from survey respondents agreed to undergo a thorough medical examination and psychological and neurobehavioral assessment. Persistent symptoms with no medical explanation associated with Persian Gulf service (e.g., fatigue, muscle pain, memory deficits) beginning during or after the war qualified respondents as cases. The 239 cases with unexplained symptoms and the 112 controls without symptoms were administered a computerized assessment battery of 12 psychosocial and 6 neurobehavioral tests. Replicating and extending previous interim findings, a subgroup of veterans emerged from the initial analysis in the form of extreme outliers which produced a visually and quantitatively obvious bimodal distribution. This led, as it had previously, to analyses of the outliers as a separate group (labeled "slow ODTP"), which confirmed the initial findings of neurobehavioral differences between the outliers and the other cases and controls and provided more convincing evidence that the majority of cases who report neurobehavioral symptoms have no objective evidence of neurobehavioral deficits. However, the larger group of symptomatic veterans do have highly significant and compelling evidence of psychological distress based on scores from 11 separate psychological tests. Whereas the cases differed from the controls by poorer neurobehavioral test performance, extraction of the slow ODTP participants (almost all cases) eliminated neurobehavioral performance differences between the remaining cases and the controls and provided support for the hypothesis that the slow ODTP cases might have been from the unhealthy end of the GW population prior to the war. However, there was no evidence of poor motivation, pre-GW educational differences, or greater association with abnormal psychological function in this group than in other cases or controls.

Discriminating mild parkinsonism: methods for epidemiological research.

Methods for the efficient and accurate detection of parkinsonism are essential for epidemiological studies. We sought to determine whether parkinsonism could be detected by a neurologist from a videotaped assessment and whether neurobehavioral methods (motor, cognitive, and sensory) discriminated between patients with Parkinson's disease (PD) and controls. Fifteen patients with mild PD (Hoehn and Yahr I-III) were compared to 15 age-, sex-, and education- matched controls. Each participant underwent a videotaped neurological examination (based on the Unified Parkinson's Disease Rating Scale, UPDRS), administered by a trained technician, and reviewed by a neurologist, as well as a series of neurobehavioral tests. The neurologist identified PD patients with 86% sensitivity and 100% specificity. Among the neurobehavioral tests, finger tapping, combined with one or more among olfaction, visual contrast sensitivity, or Paired Associates Learning, correctly classified 90%, or more, of subjects. Individual psychological tests did not discriminate reliably between groups. We conclude that videotaped assessments of parkinsonism or objective tests of motor and sensory function can accurately detect patients with PD. Both approaches have potential for identifying PD cases, but the latter may be more efficient for screening.

Neurobehavioral testing in humans.

The evaluation of the effects of chemical exposures on humans is a worldwide concern, and most chemicals have not been evaluated for neurotoxic effect. Human neurobehavioral research or clinical evaluations of populations exposed to chemicals must be carefully planned and structured. This unit describes the steps required to create such a study, select the appropriate measures, and evaluate the results.

Development of a neurobehavioral battery for children exposed to neurotoxic chemicals.

In recent years there has been heightened concern over the potential impact of environmental exposures on neurological function in children. Children are thought to be especially vulnerable to neurotoxic effects due to a number offactors including play behavior, differences in metabolism, and the development state of the brain. Performance tests from the computerized Behavioral Assessment and Research System (BARS) and other non-computerized tests have been combined to develop a brief battery that assesses multiple neurobehavioral functions in preschool children aged 4-6. Tests were selected to assess a variety of cognitive functions including attention, memory, motor speed and coordination and other executive functions. The battery has also been translated into Spanish and developed for use with Latino populations. Four to six-year-old children are particularly challenging because of the shorter attention span and lower motivation to complete an extended test session. When testing this group it is important to maintain the motivation of the child throughout the entire session in order to obtain accurate performance measures. A series of sequential pilot studies were used to select and develop appropriate methods and parameters for the tests in the battery. Although English-speaking children were able to complete the initial battery with minimal difficulties, several difficulties were encountered when the tests were administered to a Latino population. Cultural differences made some material inappropriate for testing due to unfamiliarity with the material, and in some cases items in a test had more than one correct translation which made administration difficult.

Neurobehavioral deficits associated with chronic fatigue syndrome in veterans with Gulf War unexplained illnesses.

Gulf War unexplained illnesses (GWUI) are a heterogeneous collection of symptoms of unknown origin known to be more common among veterans of the Gulf War than among nonveterans. In the present study we focused on one of these unexplained illnesses. We tested the hypothesis that in a sample of Persian Gulf War veterans chronic fatigue syndrome (CFS) was associated with cognitive deficits on computerized cognitive testing after controlling for the effects of premorbid cognitive differences. We obtained Armed Forces Qualification Test (AFQT) data acquired around the date of induction into the military on 94 veterans of the Gulf War, 32 with CFS and 62 healthy controls. Controls performed better than participants diagnosed with CFS on the AFQT. Cognitive deficits were associated with CFS on 3 of 8 variables after the effect of premorbid AFQT scores was removed with ANCOVA.

Cognitive tests: interpretation for neurotoxicity? (Workshop summary).

The appropriate use and interpretation of cognitive tests presents important challenges to the toxicologist and to the risk assessor. For example, intelligence cannot be measured directly; rather intelligence is quantified indirectly by scoring responses (i.e., behaviors) to specific situations (problems). This workshop, "Cognitive Tests: Interpretation for Neurotoxicity?" provided an overview on the types of cognitive tests available and described approaches by which the validity of such tests can be assessed. Unlike many tools available to the toxicologist, cognitive tests have a particular advantage. Being noninvasive and species-neutral, the same test can be performed in different mammalian species. This enhances one's ability to assess the validity of test results. Criteria for test validity include comparable responses across species as well as similar disruption by the same neurotoxicant across species. Test batteries, such as the Operant Test Battery, have indicated remarkable similarity between monkeys and children with respect to performance of certain tasks involving, for example, short-term memory. Still, there is a need for caution in interpretation of such tests. In particular, cognitive tests, especially when performed in humans, are subject to confounding by a range of factors, including age, gender, and, in particular, education. Moreover, the ability of such tests to reflect intelligence must be considered. Certain aspects of intelligence, such as the ability to plan or carry out specific tasks, are not well reflected by many of the standard tests of cognition. Nonetheless, although still under development, cognitive tests do hold promise for reliably predicting neurotoxicity in humans.

Establishing stable test performance in tests from the Behavioral Assessment and Research System (BARS).

Research to identify adverse effects in humans chronically exposed to neurotoxic substances in the workplace or environment typically assesses people at one point in time in a cross-sectional study. The most widely used strategy employs performance measures taken from a single point in time and compares these with either performance of a control group or established normative data. However, multiple comparison points of the same people on the same test allow the dissection of acute--from chronic--exposure effects, among other important questions. When performance measures are used from multiple points in time, within-subject deviations are examined. For either research design, the goal is to minimize the effects of practice and to obtain stable performance on a test. Demographic variables such as age, education, and cultural background or ethnicity influence performance on neurobehavioral tests. These variables may also influence the development of stable performance. Different populations may have different learning curves so that stable performance on a test is achieved with different amounts of practice. This is especially important when making comparisons across groups that may not have equivalent backgrounds. The performance of three groups, English-speaking adults, Spanish-speaking adolescents, and Spanish-speaking migrant adolescents, was examined. Each group completed a battery of neurobehavioral tests from the Behavioral Assessment and Research System (BARS) during four sessions. Repeated measures ANOVAs were used to investigate performance across time. Tests measuring motor performance produced stable performance from the first session. More complex tasks that involved attention and memory showed a practice effect across sessions.

Lessons learned--15 years of the WHO-NCTB: a review.

Based on expert recommendations, the World Health Organization (WHO) recommended the Neurobehavioral Core Test Battery (NCTB) in 1983 to detect neurotoxicity in world-wide populations. The NCTB consists of 7 neurobehavioral tests (Digit Symbol, Digit Span, Benton visual memory test/recognition form, Santa Ana dexterity test, Simple Reaction Time, Pursuit Aiming II, and Profile of Mood States). Research with the NCTB provides the context for the results of a mini-symposium held in 1999 to discuss the lessons learned about using the NCTB in working populations. Speakers from Africa, Asia, Europe, and North America reviewed data from 94 studies using the NCTB, including 63 from China, 13 from Korea, 11 from Poland, three from South Africa, three from the USA, and one from Ecuador. Although a consensus was not sought in the symposium, the key lessons learned that emerged from the various presentations, were: * The NCTB is effective in testing adults with 12 or more years of formal education, but can not reliably test persons with less than 9 years of education. * People from cultures very different from those in Europe and North America (eg, aboriginal and African cultures) may not be tested effectively by the NCTB, although others such as at least some Asian populations, can be. To address this problem, the construct validity of the NCTB should be established in a wide range of countries. * The POMS measures of emotion proved to be very sensitive to neurotoxic exposures in several countries, but the POMS was the NCTB test most affected by cultural differences. The Digit Symbol or the Milan modification of that test was also highly sensitive to neurotoxic exposures. * Examiner drift following training to administer the NCTB is a significant problem in technically trained Examiners. Pursuit Aiming II is very difficult to score reliably.

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.

Comparison of MMPI-2 profiles of Gulf War veterans with epileptic and nonepileptic seizure patients.

As part of a larger study of illnesses related to service in the Gulf War, MMPI-2 profiles of epileptic seizure (ES) patients; nonepileptic seizure (NES) patients; Gulf War veterans with unexplained cognitive, psychological, musculoskeletal, fatigue, or dermatologic symptoms; and asymptomatic Gulf War veterans (Controls) were analyzed. There were 70 people in each group. Seizure diagnosis was based upon intensive EEG monitoring. Gulf War cases were mildly abnormal on MMPI-2 Scales Hs and D and significantly higher than controls on 8 of 10 MMPI-2 clinical scales, but they were significantly lower than NES patients on several scales including Hs and Hy.

Smiling faces and other rewards: using the Behavioral Assessment and Research System (BARS) with unique populations.

Concern about the exposure of children and adolescents to occupational and environmental hazards has increased, and so has the need to develop testing methods that can adequately assess the effects of exposure in children. A computerized testing system, the Behavioral Assessment and Research System (BARS), was successfully modified to test both younger populations and populations which do not speak English, the original language of the battery. These adaptations were modifications of the existing features of the BARS system which was designed to assess the broadest possible audience: simple language instructions broken down into basic concepts (step-by-step training with competency testing at each instruction step); a token dispenser along with a "smiling face" stimulus that reinforced appropriate performance; and adjustable parameter settings (e.g., number of trials, difficulty). Data from four groups demonstrate the feasibility of using BARS with children as young as preschool age and for non-English speaking children.

The Texarkana mercury incident.

In November 1997, 2 teenagers allegedly removed a large amount of metallic mercury from an abandoned sign plant and distributed the material among friends. One teenager developed symptoms and admitted playing with mercury to his physician. His blood mercury was elevated. In February 1998, faculty from the University of Texas Health Center at Tyler conducted an investigation that included in-depth evaluations on 10 patients with urine mercury concentrations up to 100 micrograms/L. Exposure pathways and timelines were reconstructed from records assembled by the Arkansas State Health Department epidemiologist. Mercury contamination was found among teenagers, children, and adults who came in contact with the metal. Biomarkers of exposure documented reduction in mercury concentrations after these persons were removed from their homes and sources of mercury. Neurobehavioral assessment, including assessment of tremor, failed to establish a relationship between mercury exposure and performance.

Neurobehavioral deficits in Persian Gulf veterans: evidence from a population-based study. Portland Environmental Hazards Research Center.

Reports of low-concentration nerve gas exposures during the Persian Gulf War have spurred concern about possible health consequences and refocused interest on the symptoms reported by many returning military veterans. The Portland Environmental Hazards Research Center is studying veterans from the Northwest USA who report persistent, unexplained "Persian Gulf" symptoms (cases) or who do not report those symptoms (controls). Of the first 101 veterans studied, cases differed substantially from controls on a broad range of psychological tests indicative of increased distress. A subgroup of cases was identified with objective deficits on neurobehavioral tests of memory, attention, and response speed.