Motor stereotypies (also called stereotypic movement disorder), are rhythmic, fixed movements that do not seem to have a purpose, but are predictable in pattern and location on the body.
These movements are involuntary and typically last for seconds to minutes, appear multiple times a day, and are associated with periods of engrossment, excitement, stress, fatigue or boredom. Episodes stop when the person is distracted. Sometimes they are misdiagnosed as obsessive-compulsive disorders or tics.
- Stereotypies are subdivided into two groups, primary and secondary, depending on the existence of other behavioral or neurological findings.
- Primary motor stereotypies are those occurring in a child who is otherwise developing normally.
- Motor stereotypies occurring in children who have developmental conditions such as autism, mental retardation, or vision or hearing impairment are called secondary motor stereotypies.
Types of Motor Stereotypies
Common: This category is not well defined and there may be overlap with very common habits in children. Typical motor stereotypies may include activities such as thumb sucking, nail or lip biting, hair twirling, body rocking, self-biting, teeth clenching or grinding, and head banging. These behaviors typically resolve in childhood, but some may persist into young adulthood.
Head nodding: Children with this sort of motor stereotypy nod their heads from side to side (as if signaling “no”), up and down (“yes”), or shoulder to shoulder. The nodding is occasionally accompanied by up-gaze eye deviations or movements of the hands or feet.
Complex motor stereotypies (CMS): These movements include hand or arm flapping or waving, wiggling fingers in front of the face, rotating or opening and closing the hands and finger wiggling. Generally, a child will simultaneously perform the movement bilaterally (on both the right and left sides). Movements are often accompanied by mouth opening or head posturing and are often performed while pacing or hopping. CMS usually appear in the first three years of a child’s life and often persist. Though primary motor stereotypies are common, the cause is unknown.
Treatment for Motor Stereotypies
Children with primary complex motor stereotypies often minimize the impact of symptoms on their quality of life; however, there are overarching concerns about social stigmatization, classroom disruption and interference with academic activities.
Treatment with medication is not likely to be effective, but behavioral therapy can be beneficial. Research has shown that therapist-based training using a combination of awareness and differential reinforcement of other behaviors may be successful in reducing movements.
Other studies have shown that the most effective approach uses an instructional DVD as a home-based, parent-administered behavioral therapy with support from a therapist.