Stereotypic Movement Disorder
Stereotypic movement disorder is a motor disorder that develops in childhood, typically before grade school, and involves repetitive, purposeless movement. Examples of stereotypic movements include hand flapping, body rocking, head banging, and self-biting. A diagnosis is only given if the repetitive movement causes distress in a child and leads to impairment in day-to-day functioning or results in self-injury.
Simple stereotypic movements, such as rocking back and forth, are common in young children and do not indicate a movement disorder. Complex stereotypic movements, however, are less common and occur in 3 to 4 percent of children. Motor stereotypies are often diagnosed in people with intellectual disabilities and neurodevelopmental conditions but are also found in typically developing children. While the actions may be or appear purposeless, it is possible that stereotypic movements might reduce anxiety in response to external stressors.
- Movement that is repetitive, intentional, and purposeless. Stereotypic movements include hand shaking, waving, or wringing, head banging, self-hitting, and self-biting.
- The movements interfere with daily life, such as by disrupting academics or relationships
- The behavior begins in childhood
- The behavior is not due to another disorder such as obsessive-compulsive disorder or body-focused repetitive behaviors
The type of repetitive movement varies widely and each child presents with their own individually patterned, “signature” behavior. The repetitive movements may increase with boredom, stress, excitement, and exhaustion. Some children may stop their movements if attention is directed toward them or they are distracted, while others may not be able to stop their repetitive movement. Stereotypic movement disorder can be categorized as mild, moderate, or severe. A mild case will allow the individual to suppress the body movements with ease. A moderate case will require protective measures and behavioral modification. A severe case will require continuous monitoring and protective measures to prevent serious injury.
What are “stereotypies”?
Motor stereotypies are involuntary, rhythmic, repetitive, predictable movements that appear purposeful but serve no obvious function or purpose. Examples include repetitive hand waving or rotating, arm flapping, finger wiggling, and more mentioned above.
How is stereotypic movement disorder diagnosed?
The primary way to tell if an individual has stereotypic movement disorder is the presence of the aforementioned stereotypic movements. The disorder is more pronounced, particularly in young children, if body movements such as the biting of lips or poking of eyes that can lead to self-injury are present. A child with no other signs of developmental disability should see a pediatrician if they experience stereotypic movements.
Are stereotypies the same behaviors as “stimming”?
Generally speaking, yes, although the term “stimming” is generally used in the context of people on the autism spectrum. “Stimming" is short for self-stimulatory behavior. In a person with autism, stimming refers to the same stereotypic behaviors as above, including hand-flapping, flicking-fingers, or spinning.
Stereotypic movements are typically observed within the first three years of life. The cause of stereotypic movement disorder is unknown, but several factors are connected to its development. Social isolation, for example, may lead to self-stimulation in the form of stereotypic movements. Environmental stress, such as difficulty in school or at home, can trigger stereotypic behavior. There may also be a genetic component to the condition.
The risk for stereotypic movement disorder is greater among individuals with severe intellectual disabilities. In typically developing children, stereotypic movements can often be suppressed or lessened over time. Among people with intellectual disabilities, however, the stereotyped, self-injurious behaviors can last for many years.
What causes stereotypic movement disorder?
A direct cause is not known. There are risk factors that may impact the expression of the disorder. Social isolation or environmental stress could trigger symptoms. Fear may alter an individual’s physiological state, resulting in an increased frequency of stereotypic behaviors. Lower cognitive functioning is linked to greater risk for stereo­typic behaviors and less favorable response to interventions. Recent research has shown a possible dysfunction in the pathways of gamma-aminobutyric acid in the brain.
Is stereotypic movement disorder related to autism spectrum disorder?
Stereotypic movements may be a presenting symptom of autism spectrum disorder. Motor stereotypies are one of the characteristics of autism spectrum disorder, so an additional diagnosis of stereotypic movement disorder is not given when these repetitive behaviors are better explained by the presence of autism spectrum disorder. However, when stereotypies cause self-injury and become a focus of treatment, both diagnoses may be appropriate.
Is stereotypic movement disorder influenced by genetics?
25 percent of children with motor stereotypies in one study reported positive family histories of motor stereotypies, suggesting that genetics do play a role in the disorder.
Treatment for stereotypic movement disorder may include psychotherapy and behavioral strategies to reduce repetitive movements and minimize the risk for self-harm. A therapeutic technique called differential reinforcement is often used, which relies on positive reinforcement to teach the child to modify his or her behavior. To date, drugs have not proven to be an effective treatment for primary motor stereotypies and are rarely prescribed. As with many conditions that affect children, early identification and treatment lead to better outcomes.
How many people have motor stereotypies?
Simple stereotypic movements, such as rocking, are common in young children. Complex stereotypic movements are much less common, occurring in approximately 3 to 4 percent of young children. In children with intellectual disabilities, the prevalence of stereotypy increases to between 4 to 16 percent.
How long do episodes last?
Stereotypic movements may occur many times during a day, lasting a few seconds to several minutes or longer. The frequency of episodes can vary from several times a day to once every few weeks. The behaviors vary in context, occurring when the individual is engrossed in other activities, when excited, stressed, fatigued, or bored.
What are the potential outcomes of stereotypic movement disorder?
Most infants display the seemingly purposeless arm waving and other attributes of stereotypic movement disorder but quickly grow out of them as they mature into childhood. For those experiencing stereotypic movements as children, therapies can reduce the symptoms in mild and moderate cases. For those with other developmental disabilities or who are on the autism spectrum, the symptoms may not diminish over time.