Cassitto Mg

Experiences with the Milan Automated Neurobehavioral System (MANS) in occupational neurotoxic exposure

It is known that in neurobehavioral toxicology, the data obtained by means of psychological testing can acquire sense only when testing conditions and procedures, among others, are kept under rigorous control. This demand, together with the diffusion of multicentered studies aimed at finding mutual agreement on the parameters to be measured and the interpretation criteria to be adopted, has determined our decision to convert six out of the seven tests of the WHO-NCTB into a computer-aided system (MANS). The choice of one of the two systems depends on the characteristics of the testing situation and on the different requirements of clinical, epidemiological and experimental studies. The validation of MANS, as to its reliability and sensitivity, is ongoing but some data have already been collected which show a high correlation of the computer-administered test results with the paper and pencil form as well as a good degree of discriminating power in different testing situations. The experience, made in the past three years, seems to show that the goal of having a simple, easy to handle and reliable instrument to be used and, if necessary easily adapted to a variety of situations and cultures, has been met. Further work is to be carried out to confirm its validity in the early detection of neurobehavioral impairments due to neurotoxic agents.

Comparison of Performance from Three Continents on the WHO-Recommended Neurobehavioral Core Test Battery1

To address the need for standardized test batteries, an expert group convened by the World Health Organization (WHO) and the U.S. National Institute for Occupational Safety and Health during 1983 proposed the Neurobehavioral Core Test Battery (NCTB) to identify nervous system effects of chemical exposures in human populations worldwide. To determine the feasibility of using the NCTB in varied cultures, a cross-cultural assessment was conducted under WHO auspices. Data were collected in 10 countries of Europe, North and Central America, and Asia from over 2300 males and females who were not exposed to chemicals at work, within five age ranges between 16 and 65. Results suggest that performance on two NCTB tests (Simple Reaction Time, Benton Visual Retention) is very similar in a broad range of countries and that performance on four other NCTB tests (Santa Ana, Digit Symbol, Digit Span, Aiming) is relatively more variable from country to country, in both males and females. However, data collected from very poorly educated males in one country revealed very low performance levels suggesting that the NCTB may not provide an adequate reference group for identifying (behavioral) neurotoxic effects in such populations. More research is thus needed on evaluating neurotoxicity in poorly educated subjects.

Prevalence of Abnormal Neurobehavioral Scores in Populations Exposed to Different Industrial Chemicals1

The aim of the study is to establish the prevalence of neurobehavioral scores of occupationally exposed subjects below the 10th percentile rank of normalized curves obtained on a referent population. The Milan Automated Neurobehavioral System (MANS) was administered to 400 drivers from public and private firms; their data were distributed on the basis of age and years of school attendance and were normalized by determining percentile rank equivalence. The exposed population is made up of 20 lead- and zinc-exposed subjects, 18 welders exposed to aluminum for less than 1 year, 150 exposed to different metals in the ferromanganese production, 73 lithographic operators exposed to gasoline and petroleum, 197 exposed to solvents mixtures in the paint manufacture, and 23 dropouts of the same firm. The percentages of scores below 10th percentile rank were calculated in the different exposure groups and in the different age-school attendance ranges. The prevalence of results below the 10th percentile rank was found to be related to the intensity of the exposures and to the low levels of school attendance. In the 20–29 and the 30–39 age ranges, there was a prevalence of POMS scale scores below 10th percentile rank, in the 50–59 age range, the percentages were high for the Digit Symbol, the mean value of Simple Reaction Time, Serial Digit Learning, and Benton Visual Recognition.

Carbon Disulfide and the Central Nervous System: A 15-Year Neurobehavioral Surveillance of an Exposed Population1

Carbon disulfide-induced neurobehavioral effects are well known and do not need further evidence. Carbon disulfide vasculopathy and the syndromic complex resulting in depression, loss of memory and concentration, and behavior disturbances have been widely demonstrated. Less known is the evolution of the symptomatology when the environmental conditions are consistently improved, that is, the reversibility or the progression of the dysfunctions observed. This paper reports on a neurobehavioral follow-up in a viscose rayon factory carried out, in intervals, from 1974 to 1990. Several successive improvements were implemented in the plant through the years, until finally, the most radical changes were made at the end of the Seventies and these resulted in exposure levels far below the current Threshold Limit Values. A total of 493 subjects were examined and some of them were reexamined up to six times. The last examination was completed in September, 1990. In this paper, studies by our group over the 15 years of monitoring are discussed. The results show that the general mental state, as measured by neurobehavioral methods, reflects past and current exposure. This point was explored by dividing the subjects into six groups on the basis of their length of exposure and year of examination and by comparing their performances. The results show that even exposure to levels of carbon disulfide not exceeding 8 mg/m3 may induce absentmindedness and difficulties in perceptive abilities.