Why Does He Rock His Body?

Patient Presentation
A 2.5-year-old male came to clinic for his health supervision visit. He was an only child, had moved many times since he was born, and had had only intermittent healthcare. His mother had no concerns about his health or development and described him as a happy child who would play by himself without causing problems. He liked to play with spinning or wheeled toys for long time periods. He had little contact with children of his own age and the adults were mainly family members who liked him because “he didn’t cause too many problems.” His mother said that he said a few words but didn’t put many together. Her main concern was that he spent a lot of time rocking his body wherever he was. It never bothered him or others, and he would stop if engaged. Once in a while, she said that he would also “twirl” his body around and occasionally would fall on the floor but never hurt himself. The past medical history revealed a term birth but with little prenatal care.

The pertinent physical exam showed a happy boy, who would rock in the chair or on the table if not actively engaged. His vital signs were normal and growth was 25% for all parameters. He would look at the examiner but only fleetingly, and would look and smile at his mother for longer. He would vocalize in the room but had no words. His neurological examination was normal but he also tended, but not always, to hold his elbows flexed with arms slightly extended from the body. His mother said she called him “her little bird,” when he would do this, and with questioning she did not describe any other movements of the arms or hands.

The diagnosis of a child who had neurodevelopmental delay in at least speech and socialization was noted, along with the body rocking sterotypie and arm positioning preference. The pediatrician discussed that the body rocking could be a way to ease boredom or to self-soothe but could also be a sign of a developmental problem, which he was worried about because of the speech delay and limited socialization seen in the office. The mother acknowledged that he did do some unusual things like the body rocking that she was worried about but she felt, “he just needs some more time to grow.” She agreed to receiving his routine health care including some catch-up vaccinations and referral for additional developmental evaluation. The patient’s clinical course reveled that he followed up once for additional vaccines and had started his evaluations including speech. He was lost to followup after that visit.

Stereotypies are “…patterned, repetitive, purposeless, involuntary movements that are also rhythmic and continual and tend to change little over time.” They occur at all times of the day, and can get worse with stress or heightened emotions including happiness. Stereotypies more often occur in children with developmental disabilities (up to 61%), sensory impairments (e.g. blindness) or social deprivation. They can be present more often in patients with autism (up to 88%). They can be seen in ~7% of normally developing children too. Their onset is before age 3 years and tend to improve over years, but often persist into adulthood.

Examples of simple stereotypies including thumb sucking, nail biting, leg shaking, and teeth grinding. Complex motor sterotypies’ examples include hand flapping, arm waving, opening/closing of the hands or finger wiggling, orofacial movements and mouth opening.

Primary complex stereotypies occur in patients without an underlying neurodevelopmental condition whereas secondary occurs in those with other such conditions such as Lesch-Nyhan syndrome. Co-morbid diagnoses that can occur with sterotypies include attention deficit hyperactivity disorder, anxiety, obsessive-compulsive disorder, tics, developmental coordination disorder, and learning disorders.

Learning Point
Body rocking is a stereotypie that can be seen in different situations including:

  • Self-stimulation, helps with boredom
  • Self-soothing, helps with concentration
  • Learned
  • Situational
  • Neurodevelopmental problems including Autism – for some Autism patients this may be a way to be able to pay more attention and process what is going on around them.
  • Genetic – Angleman syndrome, Fragile X syndrome, Lesch-Nyhan syndrome, Cornelia de Lange syndrome, Rett syndrome, etc.

Body rocking differential diagnosis also includes seizures, motor tics and other movement disorders such as ataxia, dystonia, myoclonus, tremor, Tourette syndrome, rhythmic movement disorder

The Motor Sterotypy Severity Scale is one of several caregiver rating scales. It looks at the number of stereotypies, their frequency, intensity and how much they impair the patient globally. For example, this patient had only 1 identified sterotypie (body rocking), it very frequently but not always occurred, it was quite marked in intensity but wouldn’t cause injury to the patient, and at that time was causing only subtle to minor problems for the patient and family. Had the child been older or in an out-of-home setting, the behavior may potentially have caused additional problems for the child or family.

Questions for Further Discussion
1. What is the criteria for diagnosing autism spectrum disorder?
2. How does Fragile X syndrome present?
3. What developmental screening is recommended to be performed during health maintenance visits?
4. How often do you see sterotypies in your practice?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for this topic: Child Mental Health

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Katherine M. Stereotypic Movement Disorders. Semin Pediatr Neurol. 2018;25:19-24. doi:10.1016/j.spen.2017.12.004

Zalta A, Hou JC, Thonnat M, Bartolomei F, Morillon B, McGonigal A. Neural correlates of rhythmic rocking in prefrontal seizures. Neurophysiol Clin. 2020;50(5):331-338. doi:10.1016/j.neucli.2020.07.003

McCarty MJ, Brumback AC. Rethinking Stereotypies in Autism. Semin Pediatr Neurol. 2021;38:100897. doi:10.1016/j.spen.2021.100897

Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa