Abstract
Children presenting with Developmental Coordination Disorder or clumsiness often exhibit signs of minor neurological dysfunction (MND). The data of the Groningen Perinatal Project, a long-term follow-up project on the relations between prenatal and perinatal adversities and neurological, behavioral, and cognitive development revealed that two basic forms of MND can be distinguished: simple and complex MND. During school age children with simple MND are characterized by the presence of one or two dysfunctional clusters of MND, in adolescence by the presence of choreiform dyskinesia or hypotonia. Probably the major sources of origin of simple MND are genetic constitution and stress during early life. Simple MND might reflect the lower tail of the normal distribution of the quality of non-pathological brain function. In line with this hypothesis is the finding that simple MND is associatedwith only a moderately increased risk for learning- and behavioral problems. Children with complex MND present at school age with at least three dysfunctional clusters of MND, in adolescence with problems in fine manipulation or coordination. Perinatal adversities play an evident etiological role in the development of complex MND, suggesting that it might be attributed to a lesion of the brain at early age. In line with this idea is the finding that complex MND shows a strong correlation with attention and learning problems.