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Stereotypic Movement Disorder—Child
(SMD)
Sterr-e-o-tipp-ik Movement Disorder
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:
Behavioral Therapy
Distraction helps to stop the movements. Behavioral therapy can help a child see patterns and reduce or stop movements with positive reinforcement.
Cognitive behavioral therapy (CBT) may also be used to change patterns of thinking that are not helpful. It may not be helpful in very young children.
Medication
There is no specific medicines to treat SMD. Medicine may be chosen for children who do not respond to therapy.
Prevention
SMD cannot be prevented.
RESOURCES:
Family Doctor—American Academy of Family Physicians
http://www.familydoctor.org
Healthy Children—American Academy of Pediatrics
http://www.healthychildren.org
REFERENCES:
Disorders of childhood: Stereotypic movement disorders. MentalHelp.net website. Available at: https://www.mentalhelp.net/articles/disorders-of-childhood-stereotypic-movement-disorder. Accessed July 18, 2019.
Primary (non-autistic) motor stereotypies. Johns Hopkins Medicine website. Available at: http://www.hopkinsmedicine.org/neurology_neurosurgery/centers_clinics/pediatric-neurology/conditions/motor-stereotypies/index.html. Accessed July 18, 2019.
Your child’s stereotypies. Evelina London website. Available at: http://www.evelinalondon.nhs.uk/resources/patient-information/your-childs-stereotypies.pdf. Updated August 2016. Accessed July 18, 2019.
Last reviewed September 2020 by EBSCO Medical Review Board Chelsea Skucek, MSN, BS, RNC-NIC Last Updated: 12/29/2020