Effects of iodine deficiency on mental and psychomotor abilities.

Severe iodine deficiency may lead to endemic cretinism, which is characterized by a number of abnormalities, such as mental retardation, neurological abnormalities and hearing disorders. These abnormalities may occur in various combinations, but impaired mental development is always a component. The present study was attempted to determine whether there is also evidence of mental retardation, perhaps to a lesser degree, in that part of the population that manifest no symptoms of cretinism, the non-cretins, in an iodine-deficient area. Results of an extensive test battery have been collected in two village populations: one village in an area with severe iodine deficiency and a control village in a non-iodine-deficient area. Both villages were situated in Central Java, Indonesia. In the selected villages the total population between the ages of 6 and 20 years participated in this study. No evidence of significant mental retardation has been detected in the non-cretin group in the severely iodine-deficient area. Significant differences between the two populations, however, have been found with regard to a number of perceptual and neuro-motor abilities.