Which condition presents as repetitive, patterned, rhythmic, and complex involuntary movements seen in autism, Rett syndrome, Sydenham chorea, and Tourette disorder, including slapping, flapping, bruxism, rocking, and twirling?

• A. Myoclonus
• B. Tics
• C. Stereotypy
• D. Tourette disorder

Answer: (C)

Repetitive, patterned, rhythmic, and complex movements that are nonfunctional are characteristic of stereotypy. In autism and Rett syndrome, stereotypies are common and include slapping, hand-flapping, bruxism, rocking, and twirling. These behaviors are distinct from tics, which are sudden, rapid, intermittent, and typically nonrhythmic movements or sounds seen in Tourette syndrome; myoclonus involves brief, shock-like jerks; Tourette disorder centers on multiple motor and vocal tics rather than the stable, patterned sequences of stereotypies. So the described movements align with stereotypy.