Original footage of the Chilean miners with manganism published in Neurology in 1967.

Manganism has captured the imagination of neurologists for more than a century because of its similarities to Parkinson disease and its indirect but seminal role in the "l-dopa miracle." We present unpublished footage of the original case series reported in Neurology® in 1967 by Mena and Cotzias depicting the typical neurologic signs of manganism in 4 Chilean miners and their response to high doses of l-dopa.

[Evaluating work intensity in major and auxiliary occupations of by-product coke industry].

The article covers evaluation of work strain in major and auxiliary occupations of by-product coke industry. The study results conclude that occupational activity of by-product coke industry workers, under exposure to occupational hazards, affects the workers' performance. Major occupations workers demonstrate higher level of functional strain of CNS, poor concentration of attention and lower ability to switch over, decreased general performance, vs. the auxiliary occupations workers who demonstrated increased cardiovascular and neuro-muscular strain due to occupational activity.

Pitfalls in clinical assessment of neurotoxic diseases: negative effects of repeated diagnostic evaluation, illustrated by a clinical case.

Exposure to different toxic substances can have acute and chronic neurological and neuropsychiatric health effects on humans. Patients often report impaired concentration and memory, irritability, fatigue, instability of affect and difficulties in impulse control. The diagnostic process for neurotoxic diseases is complex and relies heavily on the exclusion of differential diagnosis and substantiating the cognitive complaints by neuropsychological assessment. Diagnostic evaluations have the purpose to help the patient by finding an explanation for the symptoms to guide treatment strategy or prevent further deterioration. But what if the diagnostic process in itself leads to problems that can be quite persistent and difficult to manage? The iatrogenic, or sick-making, side effects of the diagnostic process are the main focus of this case study.

How does an occupational neurologist assess welders and steelworkers for a manganese-induced movement disorder? An international team's experiences in Guanxi, China Part II.

The Occupational Medicine Forum is prepared by the ACOEM Occupational and Environmental Medical Practice Committee and does not necessarily represent an official ACOEM position. The Forum is intended for health professionals and is not intended to provide medical or legal advice, including illness prevention, diagnosis or treatment, or regulatory compliance. Such advice should be obtained directly from a physician and/or attorney.

Neurologic symptoms and neuropathologic antibodies in poultry workers exposed to Campylobacter jejuni.

OBJECTIVES: To examine associations between occupational exposure to live poultry with Campylobacter exposure, Campylobacter-associated neurologic symptoms, and neuropathologic antibodies. METHODS: Questionnaires, serum samples, and stool specimens were collected from 20 poultry workers and 40 community referents. Campylobacter exposure was evaluated by stool culture and serum antibodies; neurologic symptoms were assessed by questionnaire; and neuropathologic antibodies were measured by serum anti-glycolipid antibody concentrations. RESULTS: Poultry workers had significantly higher anti-Campylobacter immunoglobulin G titers compared with that of referents (P < 0.05); they were significantly more likely to report multiple Campylobacter-associated neurologic symptoms; and male poultry workers had a higher point risk estimate for detectable neuropathologic anti-glycolipid immunoglobulin G titers (P = 0.07) compared with male referents. CONCLUSIONS: These data suggest that poultry workers are at elevated risk of Campylobacter exposure and may be at elevated risk for Campylobacter-associated neurologic sequelae.

Hänninen lecture: problems and prevention: research in developing countries and immigrant populations from developing countries.

The tradition of this excellent Triennial International Symposium, now in its Ninth gathering, has focused first on methods and later on effects in neurotoxicology. I respectfully suggest that it is time to add prevention to our agenda in order to focus not just on finding problems, but also on solving them. Otherwise our research runs the risk of making conditions worse for the participants because we inform them they have a problem but do not show them how to prevent that problem. Many barriers have been surmounted since the early days of this Symposium. Methods developed in industrialized nations have been modified and used in populations with limited education. Now, the primary barriers to effective collaborations are institutional. Perhaps the most challenging are companies that can bar a research study, or may welcome the opportunity to safeguard their workforce. A focus on prevention can increase the willingness of institutions, including companies, to accept and support research that examines neurotoxic effects of chemical exposures. This is because we are offering positive value, not simply uncovering a problem for them to fix. The cTRAIN software program is an illustration of a computer-based training method developed by neurotoxicologists that has been implemented in a variety of populations. This includes those from a developing country with limited education and those with college degrees. Training can provide prevention, can easily be appended to any neurotoxicology research study and is well within the skill set of the neurotoxicology community of scientists.

Interpretation of small effect sizes in occupational and environmental neurotoxicology: individual versus population risk.

Some have questioned the importance of the small effect sizes generally reported in epidemiological studies of neurotoxicity. To some extent, this reflects a failure to appreciate the critical distinction between individual and population risk. In the first part of the paper, arguments are marshaled to support the contention that small shifts in the mean value of a health index within a study sample can, under some circumstances, carry substantial implications for the health status of the population from which the study sample was drawn. Under such circumstances, a population-based approach to prevention might be as effective as a patient-based approach. The second part clarifies conditions under which this will be true (e.g., a monotonic relationship between a health index and risk of disease) and conditions under which it might not (e.g., a J-shaped relationship). In the third part, the relative levels of uncertainty in characterizing individual versus population risk are explored. In neurotoxicological studies, uncertainty in characterizing individual risk could be reduced by adjusting, in addition to bone fide confounders, for covariates that are strong predictors of outcome and by more assiduous efforts to characterize major effect modifiers.

Using self-report measures in neurobehavioural toxicology: can they be trusted?

Questionnaires are one of the most common methodologies used in research on neurobehavioural effects in occupational and environmental health, most commonly for gathering information on demographic characteristics, psychological or neurological symptoms, mood state, or exposure to hazards. Questionnaires are self-report measures, so by definition are subjective, although their degree of subjectivity depends on the phenomenon they are measuring. For some phenomena questionnaires are used because they are convenient but the information can be obtained from other sources. For other phenomena questionnaire or self-report is the only way of obtaining the information, for example, feelings and experiences, mood or emotions. Questionnaires are essential tools in psychological and neurobehavioural research as they can tap into aspects of nervous system function that cannot be readily measured in other ways. Despite the obvious need for self-report measures, there are a number of serious issues that threaten their validity as effective indicators of neurobehavioural function. This paper considers the implications of some of the major problems with self-report measures, focusing particularly on current approaches to measurement of symptoms and mood. It includes issues relating to validity of measures such as demand characteristics, malingering and under or over reporting, individual differences and problems of language and question style. It also includes issues relating to the interpretation of self-report measures, the relationship between self-report and performance measures, whether they reflect primary or secondary effects and whether they can be used as diagnostic criteria for neurobehavioural functional effects of occupational or environmental exposure. The paper looks at some of the current approaches to overcoming these problems including using interviews and observational methods and improving psychometric qualities of these measures. Self-report measures are important tools in our arsenal of measures of the neurobehavioural effects of occupational and environmental exposure, but they need to be used with care.

The neurology of aviation, underwater, and space environments.

It can be seen that aspects of different environments can have adverse effects on normal, healthy nervous systems. Aerospace and underwater neurology consultants are often required to evaluate aviators, divers, or astronauts who have neurologic problem to determine whether they should be granted a waiver. In general, these considerations include course of the disorder (static, progressive, or paroxysmal), potential for sudden incapacitation that may compromise safety, predictability of course of the disorder, ability to monitor disease, and potential adverse effects of medications. A background in the toxic effects of an abnormal environment on the nervous system can be used to make better clinical judgements when considering effects of exposing someone with an abnormal nervous system to such environmental stressors.

Solvent-related chronic toxic encephalopathy as a target in the worker's mental health research

O artigo se propõe a discutir os fundamentos teóricos que compõem o diagnóstico de encefalopatia crônica relacionada a solventes no campo da saúde mental do trabalhador, propondo-o como um objeto de pesquisa desse campo. São apresentados postulados da psiquiatria, da neurologia e da saúde do trabalhador que contribuem para a elaboração pluridisciplinar dessa categoria diagnóstica.

Quantifying postural tremor in workers exposed to low levels of manganese.

The aim of this study was: (1) To determine the minimum number of characteristics necessary to discriminate between postural tremor recorded in control subjects (CO), in subjects exposed to manganese (MN), and in patients with Parkinson's disease (PD), and (2) to examine the continuum of changes between the three groups examined. Workers previously exposed to Mn (n = 10), patients with PD (n = 10), and control subjects (CO) (n = 11) underwent a clinical examination. Blood Mn was measured at the end of exposure time for the MN group and 12 months later at the beginning of the experiment for all groups. Postural tremor with visual feedback was recorded in the index finger with a laser system. Statistical criteria were used to reduce computed tremor characteristics to a minimal set of reliable discriminating variables. Two variables were retained namely corrected wobble (CW), describing the morphology of the tremor oscillations, and variability ratio (VR), describing proportional power of tremor. Both variables had an overall correct classification rate of 77.4%. Blood Mn levels at the time of the experiment were similar for all groups and had insignificant correlation with tremor variables. However, blood Mn levels in workers which were also measured at the end of exposure time (i.e., 12 months before) showed significant correlation (Spearman's rank coefficient) with both harmonic index (rho = 0.70, P = 0.03) and first maximum of the autocorrelation function (rho = 0.89, P = 0.001). We conclude that (1) the tremor of workers exposed to Mn could be adequately described with only two variables; (2) a continuum of changes between tremor recorded in control subjects, in subjects exposed to Mn and in patients with PD was observed, with the MN group always found in between the control (CO) and the PD groups; (3) while blood Mn levels in workers were back at control levels at the time of the experiment, the effect of Mn on postural tremor was still detected. Thus our method has the potential to detect the effect of Mn on tremor with only two variables even after Mn level in the blood is back to normal values.