Stereotypic Movement Disorder
Stereotypic movement disorder is a condition in which a person engages in repetitive, often rhythmic, but purposeless movements. In some cases, the movements may result in self-injury. For this behavior to be considered a disorder, the repetitive movements must continue for at least four weeks, and they must interfere with the person's normal daily functioning. This disorder most often affects children with mental and developmental retardation.
What Are the Symptoms of Stereotypic Movement Disorder?
The repetitive movements that are common with this disorder include:
- Banging the head
- Nail biting
- Picking at the skin
- Handshaking or waving
- Mouthing of objects
What Causes Stereotypic Movement Disorder?
The cause of stereotypic movement disorder is not known. However, the movements tend to increase if the person is stressed, frustrated, or bored. Some things which have been known to cause the disorder are certain physical conditions, head injuries, and use of some drugs (such as cocaine).
How Common Is Stereotypic Movement Disorder?
This condition most often affects children with neurological (brain and nerve) disorders and/or mental retardation. It can occur at any age and is more common in boys than in girls.
How Is Stereotypic Movement Disorder Diagnosed?
If symptoms of stereotypic movement disorder are present, the doctor will begin an evaluation by performing a complete medical history and physical exam. Although there are no lab tests to specifically diagnose stereotypic movement disorder, the doctor may use various tests -- such as neuroimaging studies and blood tests -- to rule out physical illness or medication side effects as the cause of the symptoms.
Diagnosis of stereotypic movement disorder is made if symptoms suggest the disorder, they persist for four weeks or longer, and they interfere with normal functioning.
How Is Stereotypic Movement Disorder Treated?
The goals of treatment are to treat any injuries due to the behavior and to ensure the child's safety, as well as to improve the child's ability to function. The child's surroundings may need to be modified to reduce the risk of injury. For example, a child that bangs his or her head may need to wear a helmet to protect against a head injury.