Minimal cerebral lesions, peri- and prenatal, as a possible cause of the minimal brain dysfunction syndrome

The existence of organic lesions in Minimal Brain Dysfunction is hypothetical. It is possible however that some of the minor lesions resulting from pre- or perinatal brain damage could explain this syndrome. Such lesions are described briefly. In the perinatal period a transient perfusion failure can result in localized brain damage in the cortex, white matter or more rarely basal ganglia. Before birth lesions occuring in the last trimester of pregnancy do not significantly differ from those occuring at birth, and their origin is also circulatory. During the first semester, a particular type of post migratory malformation also due to perfusion failure, microgyria, may remain localized to one cortical segment. A brief note is made of the possible relation between virus infections and disturbances of brain circulation. The problems of microcephaly without evident brain destruction, and the possible absence of all cerebral morphological alteration in certain mental defective are discussed.