[Dysphatic development: clinical importance and neurological background]

The timely treatment of children with developmental dysphasia is important in the prevention of subsequent learning and behaviour disorders. The pathophysiology of developmental dysphasia is complex and depends on age. In the preverbal and early verbal phase the severity of the clinical picture is determined by accompanying motor function pathology (simple motor function, dysarthria, general and oral dyspraxia) and by receptive pathology (hearing, and auditory perception). In the verbal period linguistic problems become more prominent (syntax, morphology, semantics and verbal memory), these problems might be accompanied by oral motor symptoms. The different developmental language syndromes become more apparent with time. After kindergarten age the oral motor and perceptual problems diminish, but the language disorders, that influence communication and scholastic learning, remain. In a small number of children without oral motor, perceptual and memory problems, there exists a 'bare or nuclear syndrome', a so called 'pure dysphasia', without other neurological signs. In these children there is perhaps a genetically determined developmental disorder on a restricted neuronal level (no brain damage!). In more than half of the patients this syndrome is accompanied by other neurological signs, predominantly pointing to the left cerebral hemisphere. Furthermore there can be signs from the right cerebral hemisphere, the corpus callosum and from the afferent fibers systems for auditory perception. The nature and causes of these disorders are extremely variable, so that one cannot speak of the neural substrate or the pathogenesis. The diagnosis and the treatment can optimally only be performed by an experienced team, the expertise of which has to penetrate into the school education system.