No abstract

No abstract

Objectives-The purpose was to study the effects on the nervous system in welders exposed to aluminium and manganese. Methods-The investigation included questionnaires on symptoms, psychological methods (simple reaction time, finger tapping speed and endurance, digit span, vocabulary, tracking, symbol digit, cylinders, olfactory threshold, Luria-Nebraska motor scale), neurophysiological methods (electroencephalography, event related auditory evoked potential (P-300), brainstem auditory evoked potential, and diadochokinesometry) and assessments of blood and urine concentrations of metals (aluminium, lead, and manganese). Results-The welders exposed to aluminium (n = 38) reported more symptoms from the central nervous system than the control group (n = 39). They also had a decreased motor function in five tests. The effect was dose related in two of these five tests. The median exposure of aluminium welders was 7065 hours and they had about seven times higher concentrations of aluminium in urine than the controls. The welders exposed to manganese (n = 12) had a decreased motor function in five tests. An increased latency of event related auditory evoked potential was also found in this group. The median manganese exposure was 270 hours. These welders did not have higher concentrations of manganese in blood than the controls. Conclusions-The neurotoxic effects found in the groups of welders exposed to aluminium and manganese are probably caused by the aluminium and manganese exposure, respectively. These effects indicate a need for improvements in the work environments of these welders. (Occup Environ Med 1996;53:32-40)

No abstract

WENNBERG A, lREGREN A, STRUWEG, CIZINSKY G, HAGMAN M, JOHANSSON L. Manganese exposure in steel smelters a health hazard to the nervous system. Scand J Work En viron Health 1991 ; 17:255-62. In a study of the effects of low-level exposure to manganese (0.19-1.39 mg/rn! for 1-45 years) 30 men (aged 20-64 years) from two steel smelting works and 60 unexposed referents (aged 22-65years) wereexamined with the use of a generalhealth inquiry, electroencephalography, event-related auditory evoked potentials, brain-stem auditory evokedpotentials, diadochokinesometry, simpleand complex reaction time, finger tapping, digit span, mental arithmetic, vocabulary, a coding task, manual dexterity, symptoms, and mood scales, the diagnostic interview scheme, a dynamicrating scalefor neurasthenic syndrome, and a comprehensivepsychopathologicalrating scale. No group differences were found in the electroencephalography or the psychiatric examinations. However, there were increased frequencies of some symptoms, the diadochokinesis was slower, the P-300latency and reaction time wereincreased, and finger-tapping and digit-span performance were impaired in the exposed group . These effects were interpreted as early (subclinical) signs of disturbances of the same type as parkinsonism.Key terms: manganism, neurophysiology, parkinsonism, psychiatry, psychological performance, smelting works, steel industry.Mangan ese ha s a to xic effect on the centra l ner vou s system (I ). A t high exposure levels th ere are two types of effects. In th e acute phase psych iatric sympt oms dominate ("manganese madness" ) with hallucinations, emo tional labili ty, and compulsive and aber rant beha vior. Later , neurological symptoms with muscular wea kness, impa ired speech, headache, clum siness, tremor, mild rigidit y, and hypokinetic (masklike) facial expr essio ns appear. These symptoms are similar to thos e seen in Parkinson's disease, and they are typical of chr onic manganese poi soning. Micro scop ic examinat ion of brains from subjects poi soned by mangan ese has revealed lesions in the extrapyramid al structures (substantia nigra, globus pallidus, subthalamic nucl eus, caudate nucleus, and putamen) similar to those found in Parkinson's disease.Man gani sm was first described in 1837 for mangan ese min ers (2) and later, in 1907, for workers who had pulveri zed pyrolusite (3). There ar e also later case reports (eg, m iner s in Japan, Chile, Morocco , Cuba, Ind ia , Mexico, th e Soviet Union, and the United State s) (4). In all the se cases , the exposure levels were