Scheme of normal and polymicrogyric cortex

Stereotypies

Stereotypies are considered purposeless, fixed forms of expression or response that may interfere with normal behavior. Stereotypies may represent a transient phenomenon in children, but may be associated with a variety of severe neurologic disorders, including specific biochemical disorders, such as Rett syndrome and Lesch Nyhan disease, and the whole spectrum of autistic disorders and pervasive developmental disorders. Stereotypic disorders may require intervention, especially when harmful, but often do not. Treatment is highly individualized.