MENTAL RETARDATION A MRI study of 146 Brazilian children

We re p o rt results of a magnetic ressonance imaging (MRI) study of 146 Brazilian childre n , whose intelligence quotient scored less than 70. 50% of MRI examinations did not exhibit any signal of structural lesion (N group), whereas a focal thinning at the junction of the body and splenium of the corpus callosum; ventricular asymmetry; periventricular leukomalacia; gliosis and arachnoid cysts were among the most frequent findings in the remaining of subjects (L group). Maternal stress and altered blood pre ss u re were the most frequent findings in the pre-natal history of both N and L children. Familial antecedents of mental deficiency were re p o rted in 30% of both groups, whereas familiar history of alcoholism was important in N group (60% in N versus 0% in L groups). Neuropsychomotor development was delayed in 80% of the children in both groups. Aggressiveness is the most frequent finding in the post-natal childre n history.