What causes motor stereotypies in normally developing children?
It is unclear what causes repetitive movements in children who are otherwise normal. Recent research showed that 25% of subjects had a family history of primary motor stereotypies or other movements, suggesting the possibility of a genetic predisposition. Johns Hopkins is currently conducting a study to identify whether there is a genetic connection. Learn about the study and how your child can be a part of it. Back to top 2. How common are stereotypic movements in normally developing children? Stereotypic movements in children are common, in fact. While exact numbers are unknown, it has been suggested that common motor stereotypies (e.g., thumb sucking, body rocking, nail biting) may occur in as many as two-thirds of infants and half of children under age 15. Prevalence of complex motor stereotypies (e.g., hand flapping, arm waving) may be as high as 3 to 4% of U.S. preschool children. Back to top 3. When do children usually start these repetitive movements? Typically motor stereotypi
