Connecting the PWS Dots | Glossary | Movement Disorder Terms

Glossary: Movement Disorder Terminology

Athetosis: (from Wikipedia) a continuous stream of slow, sinuous, writhing movements, typically of the hands and feet. Movements typical of athetosis are sometimes called athetoid movements. Said to be caused by damage to the corpus striatum of the brain and can also be caused by a lesion of the motor thalamus.

Athetosis is to be distinguished from pseudoathetosis, which is abnormal writhing movement, usually of the fingers, occurring when the eyes are closed, caused by a failure of joint position sense (proprioception), for example in peripheral neuropathy.

Choreoathetosis: (from Wikipedia) movement disorder of intermediate speed, between the slower, writhing movements of athetosis and the quick flitting movements of chorea. Choreoathetosis is the most common form found in children and tends to worsen with attempts at movement, often occurring only while the child is attempting to move.

Choreoathetosis may affect the hands, feet, trunk, neck, and face. In the face, it often lead to uncontrollable nose wrinkling, continual flitting eye movements, and mouth or tongue movements. These disorders are separated from tics, as tics tend to replicate the same set of movements. As well, the child often describes a need to make the tic, with a sense of release once finished. There is no such sense of release following chorea; the movements continually change and flow from one part of the body to another.

Choreoathetosis is sometimes seen as a side effect of lithium.

Tic: (from Wikipedia) sudden, repetitive, stereotyped, nonrhythmic, involuntary movement (motor tic) or sound (phonic tic) that involves discrete groups of muscles. Tics can be invisible to the observer (e.g.; abdominal tensing or toe crunching). Movements of other movement disorders (e.g.; chorea, dystonia, myoclonus) must be distinguished from tics. Other conditions (e.g., autism, stereotypic movement disorder) also include movements which may be confused with tics. Tics must also be distinguished from compulsions of OCD and seizure activity.
Stereotypic movement disorder: Wikipedia) a DSM-IV disorder of childhood involving repetitive, nonfunctional motor behavior (e.g., hand waving or head banging) that markedly interferes with normal activities or results in bodily injury, and persists for four weeks or longer. The behavior must not be due to the direct effects of a substance or another medical condition. In cases when mental retardation is present, the stereotypic or self-injurious behavior must be of sufficient severity to become the focus of treatment. The behavior is not better explained as a compulsion (e.g.; OCD), a tic, a stereotypy as part of a Pervasive Developmental Disorder, or hair pulling (trichotillomania).

Former versions of the DSM (Diagnostic Manual and Statistical Manual of Mental Disorders) used the term Stereotypy/Habit Disorder to designate repetitive habit behaviors that caused impairment to the child.

The repetitive movements that are common with this disorder include thumb sucking, nail biting, nose-picking, breath holding, bruxism, head banging, rocking/rhythmic movements, self-biting, self-hitting, picking at the skin, hand shaking, hand waving, and mouthing of objects.

Childhood habits can appear in various forms, and many people engage in some habits during their lifetime. Habits can range from relatively benign behaviors (e.g.; nail biting) to noticeable or self-injurious behaviors, such as teeth grinding (bruxism). Many habits of childhood are a benign, normal part of development, do not rise to the diagnostic level of a disorder, and typically remit without treatment.

When stereotyped behaviors cause significant impairment in functioning, an evaluation for stereotypic movement disorder is warranted. There are no specific tests for diagnosing this disorder, although some tests may be ordered to rule out other conditions. Other conditions which feature repetitive behaviors in the differential diagnosis include obsessive-compulsive disorder, trichotillomania, vocal and tic disorders (e.g.; Tourette syndrome). Although not necessary for the diagnosis, stereotypic movement disorder most often affects children with mental retardation and developmental disorders. It is more common in boys, and can occur at any age. The cause of this disorder is not known.

Stereotypic movement disorder is often misdiagnosed as tics or Tourette's. Unlike the tics of Tourette's, which tend to onset around age six or seven, repetitive movements typically start before age 2, are more bilateral than tics, consist of intense patterns of movement for longer runs than tics. Tics are less likely to be stimulated by excitement. Children with Stereotypic movement disorder do not always reported being bothered by the movements as a child with tics might.

Prognosis depends on the severity of the disorder. Recognizing symptoms early can help reduce the risk of self-injury, which can be lessened with medications. Stereotypic movement disorder due to head trauma may be permanent. If anxiety or affective disorders are present, the behaviors may persist.