Chronic occupational exposure to manganese and neurobehavioral function.

Comprehensive examinations of neurobehavioral function were performed in two groups of workers with chronic exposure to industrial manganese, and two control groups. Group 1 included 17 exposed workers without parkinsonism while Group 2 consisted of four exposed workers with parkinsonian syndrome resulting from chronic manganese poisoning. Group 3 was composed of eight idiopathic parkinsonian patients while Group 4 included 19 control subjects. Age, sex, and educational level of these four groups were matched. The neuropsychological battery consisted of tests of orientation, intelligence, learning and memory, language and communication, visuospatial and visual perception, visual attention, manual dexterity, and information processing speed. There was no evidence of neurobehavioral impairment in the non-parkinsonian workers whereas impaired general intelligence, visuoperceptive impairment and defective manual dexterity, as well as slowdown in response speed were manifested in the parkinsonian workers.