Definition

Stereotypic movement disorder (SMD) is the rhythmic repetition of body movements called stereotypies. These movements are often harmless or may result in self-harm or social problems.

SMD may happen by itself or with other problems, such as Autism Spectrum Disorder (ASD).

Causes

The cause is not clear. Some children with SMD have family members who had SMD when they were young. There may be a genetic link.

SMD may also be linked to neurological problems or brain injuries in some children.

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Risk Factors

SMD is more common in boys. Things that may raise the risk of SMD are:

• Having a developmental problem, such as ASD
• Family history of SMD

Symptoms

Symptoms are common in children aged 3 to 5 years. It may last longer in some children. Stereotypic movements:

• Affect the arms, hands, head, or entire body
• Are rhythmic
• Do not change over time
• Can be hard to notice or be very noticeable
• Stop when a child’s focus changes

Symptoms may be:

• Thumb sucking
• Biting one’s nails, lips, hands, or other body parts
• Hair twisting
• Rocking
• Teeth clenching or grinding
• Banging the head on objects
• Nodding
• Hand or arm flapping
• Waving
• Wiggling one’s fingers or opening and closing the hands

Diagnosis

The doctor will ask about your child’s symptoms and health past. You will be asked what starts the movements and what makes them stop. A physical exam will be done. Psychological testing will also be done.

Treatment

SMD fades over time in some children. Movements that do not cause problems may not need treatment. Movements that impact social function or cause self-harm will need to be treated. Some choices are:

Prevention

SMD cannot be prevented.