Determinants of exposure to endocrine disruptors following hurricane Harvey.

Hurricane Harvey was a category four storm that induced catastrophic flooding in the Houston metropolitan area. Following the hurricane there was increased concern regarding chemical exposures due to damage caused by flood waters and emergency excess emissions from industrial facilities. This study utilized personal passive samplers in the form of silicone wristbands in Houston, TX to both assess chemical exposure to endocrine disrupting chemicals (EDCs) immediately after the hurricane and determine participant characteristics associated with higher concentrations of exposure. Participants from the Houston-3H cohort (n = 172) wore a wristband for seven days and completed a questionnaire to determine various flood-related and demographic variables. Bivariate and multivariate analysis indicated that living in an area with a high Area Deprivation Index (ADI) (indicative of low socioeconomic status), identifying as Black/African American or Latino, and living in the Houston neighborhoods of Baytown and East Houston were associated with increased exposure to EDCs. These results provide evidence of racial/ethnic and socioeconomic injustices in exposure to EDCs in the Houston Metropolitan Area. Since the multiple regression models conducted did not fully explain exposure (0.047 < R2 < 0.34), more research is needed on the direct sources of EDCs within this area to create effective exposure mitigation strategies.

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.

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.

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.

Test-retest reliability of psychological and neurobehavioral tests self-administered by computer.

A series of 12 psychological and 7 neurobehavioral performance tests were administered twice to a nonclinical normative sample with 1 week between administrations. The tests were presented in a self-administered computerized format. One week test-retest reliabilities were comparable to conventional administration formats. The results suggest that individual test reliability is not affected when tests are administered as part of an extensive multi-measure battery. Computer administered test reliability coefficients also were compared to a Mixed Format (computer-conventional) administration with mixed format reliabilities generally similar to the reliabilities of published conventional tests but also generally lower than same format testing. Compared to psychological test reliability, neurobehavioral test reliability appeared more vulnerable to decreases with mixed format testing. These conclusions should not be generalized to all computer implemented tests as the qualities of the test implementation will affect the outcome.

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.