[Developmental delay in children. Prevalence, aetiology and examination--a situation report].

AIM: Developmental delay (DD) is a serious, lifelong handicap, often accompanied by additional conditions/handicaps. The paper describes the prevalence and aetiology of DD in children in Copenhagen County, Denmark, and discusses how to ensure referral of the children to neuro-paediatric examinations and neurobiological investigations. MATERIALS AND METHODS: From a cohort of 95,400 children, aged 4-15 y, from Copenhagen County, Denmark, 1126 children with IQ=80 were included (98% of the estimated number of children with DD). The children were included from the paediatric department and from school psychologists. Three groups of children were compared with respect to prevalence, aetiology and presence of additional diagnoses: IQ=50 (moderate to profound DD), IQ 51-70 (mild DD) and IQ 71-80 (borderline DD). RESULTS: The prevalence of moderate to profound DD was 4.0/1000, the prevalence of mild DD was 4.9/1000 and the prevalence of borderline DD was 2.9/1000. The aetiology in the three groups was clear in 67%, 40% and 29% of the children respectively. Most commonly, it was prenatal. Additional diagnoses were present in 52% of the children. In total, 26% had never been examined by a neuro-paediatrician. CONCLUSIONS: The prevalence of DD corresponds to studies from the other Nordic countries, but the aetiology is less known in the present material. The aetiology and presence of additional diagnoses could possibly be found in more children if the level of referral to neuro-paediatric examinations is changed.