Epidemiology and prognosis of specific disorders of language and scholastic skills.

Data from a prospective longitudinal study on the development of children born at biological and psychosocial risk were utilised to examine language and learning abilities of 320 children at ages 4.5 and 8 years. Following the research criteria of the ICD-10, specific developmental disorders of speech and language and specific developmental disorders of scholastic skills were diagnosed. Data were also provided for a clinical and general low achievement group according to less stringent criteria. Frequencies in the risk population were low for specific disorders (ICD-10) (0.6%-3.7% depending on age and type of disorder). Higher frequencies were found when a clinical definition (0.6%-13.6%) or overall low achievement score (0.6%-18.6%) was chosen. The impact of well-documented organic and psychosocial risks was analysed. Organic risk affected language abilities at 4.5 years of age but neither language nor learning abilities at 8 years of age. Psychosocial aspects of a child's environment proved to be associated with both specific language and learning abilities. Stability of language disorders, association between language and reading/spelling disorders as well as gender effects were investigated.