[Pediatric dysphasia. II. The current concepts of its neurobiological mechanisms].

This survey deals with the underlying biological causes and pathogenetic mechanisms of developmental dysphasia. There can be a basic syndrome of "pure dysphasia"; these children are very likely to have a genetically determined developmental disorder on a limited neuronal level (no cerebral damage of any kind) on a developmental disorder by other factors such as an abnormal cortical architecture and abnormal symmetry of the hemispheres. In somewhat more than half the patients, the basic syndrome of pure dysphasia is accompanied by other neurological signs, most of which are indicative of functional disorders of the left hemisphere. There can also be symptoms of the right hemisphere, of the corpus callosum and of the afferent pathway systems for auditory perception. The nature and causes of these anomalies can be multifarious, so that it is unfeasible to speak of the substrate or the pathogenesis.