A cross sectional study was carried out in the welders exposed to manganese and control group. The aim of this study was to assess the adverse effects of manganese on central nervous system of welders.

The study group consisted of 49 welders and the reference group, 49 workers matched with welders for age and educational level in automobile manufacturing company. Concentration of manganese in welding hume, in blood, and cumulative exposure index(CEI) were determined for each subject. For each group, computerized neurobehavioral test including Simple Reaction Time, Digit Symbol, Digit Span, and Finger Tapping Speed of Swedish Performance Evaluation System were applied.

Exposure level of manganese in welders were very low(mean CEI 0.069). Welders exposed to manganese had slower response speed, slower motor steadiness, and shorter memory span than control group. But these differences were not statistically significant. The performance of Finger Tapping Speed tended to lower as environmental and biological exposure index got higher. Other neurobehavioral tests were found to have a little association with the exposure indices.

There was no significant difference of neurobehavioral performance between welders and control group. This study indicates that Finger Tapping Speed measuring motor steadiness might be a one of useful tests for early detection of adverse effects of welding on central nervous system.