Pediatric Movement Disorders - Dystonia

Examination

The child being evaluated for dystonia must be observed at rest, with action of the parts of the body affected by dystonia, as well as actions unrelated to the dystonia. For example, a child with foot dystonia must be observed while sitting, standing, walking, and performing tasks with the hands. Mental distraction is also helpful; when possible, the evaluator may use language or mathematical tasks to distract the child.

These types of distractions may help to determine the specific triggers for the dystonic movements. They may also assist in evaluating if other body parts are subtly affected when provoked by attempted movement, stress, or distraction. It is important to test the child during certain activities to observe dystonia-obstructing movement or excessive movements. These activities include...

• Reaching movements of the arms
• Speaking
• Tongue movement

When dystonia is present at rest, it is important to examine children when they are as relaxed as possible. Any stress or discomfort may worsen the symptoms.

Muscle tone is not necessarily increased in children with dystonia; however, tone may be increased and the examiner may have difficulty in differentiating dystonia from spasticity or parkinsonian rigidity. This determination becomes particularly difficult when dystonia and spasticity are simultaneously present. This occurs frequently in children with cerebral palsy. It is equally important to examine for other movement disorders, such as ataxia or myoclonus, as this may provide clues to a particular diagnosis.

The timing of dystonia throughout the day is important. Dopa-responsive dystonia may improve upon awakening in the morning or after a nap; then the symptoms may become progressively worse throughout the day. Other forms of dystonia may be worse upon morning awakening. Dystonia is usually not present during sleep. Continued stiffness of the limbs during sleep suggests possible spasticity or fixed joint contractures.

There are several genetic causes of dystonia that may have autosomal dominant inheritance. Therefore, a thorough family history of dystonia or other neurological diseases is very important. The history of the onset of dystonia is useful, but occasionally confusing as dystonia may start many years after the causative event. As always, a toxin exposure or chronic use of certain medications (particularly neuroleptics and other psychiatric medications) must be investigated. Such medicines may cause dystonia even after they have been stopped.