What are movement disorders?
Children with movement disorders have unwanted movements or trouble moving in the way they intend to. The term “movement disorders” is broad and includes a wide variety of conditions with a wide variety of causes. While children with paralysis or spasticity also have difficulty moving, movement disorders are different in that the abnormal movements are “extra” or added on to movements children intend to make.
Movement disorders can affect single or multiple parts of the body, and may change in location and severity over time. The abnormal movements may happen on their own, or may occur only when the child is moving or trying to make a specific kind of movement. Sometimes the movements are more apparent at certain times of day or have specific triggers or situations that make them worse.
What are the types of movement disorders?
Types of movement disorders include:
Chorea is a symptom of a neurologic injury, not a disease in and of itself. Children with chorea have irregular, flowing movements that are sometimes described as “dance-like.” Sometimes the movements are incorporated into motions the child intends to make. They can be slow and writhing, or more forceful. If chorea affects the legs, children may frequently stumble and have difficulty walking but rarely fall.
Chorea in children can be caused by a brain injury at birth, head trauma, infection, inflammation, or as a toxic reaction to medications. In some cases, it can have a genetic cause.
Tremor is a rhythmic shaking or trembling of a limb. It sometimes occurs in children as a complication of an underlying illness or head injury, as a side effect of heavy medications, or as an effect of genetic disease. Tremor can occur at rest or during movement, and can occur alone or with other symptoms such as weakness of the limb and difficulty in fine-tuning movements.
Tremor sometimes runs in families. The most common inherited form is known as essential tremor.
Sometimes tremor is just a temporary part of a child’s motor development; in other cases, it may be long-lasting. Unlike most other movement disorders, children can sometimes consciously suppress tremors.
Myoclonus is a movement disorder involving very quick, sudden, involuntary muscle jerks that the child cannot suppress. The jerks can be occasional or frequent, and may occur randomly or in a semi-rhythmic pattern. Myoclonus sometimes has triggers, like holding the body in a certain posture, being touched, or startled. In other cases, symptoms may seem to appear for no reason.
Myoclonus is often a benign condition with no long-term effect on a child’s health, but it is critical to be evaluated by a movement disorders specialist to identify the type of myoclonus and its cause.
Myoclonus may occur after a severe brain injury, or can result from a metabolic disorder or a neurodegenerative disease. It can also be part of a seizure disorder called myoclonic epilepsy, and for that reason, it’s often recommended that children with myoclonus be tested for epilepsy.
In children with dystonia, faulty brain signals cause groups of muscles to contract abnormally. Rather than contracting in a coordinated way, muscles may contract in opposition to each other: both “push” and “pull” muscles are active at the same time, causing painful or uncomfortable twisting movements and awkward, contorting postures.
Dystonia is often triggered by specific actions, like writing or walking, but can also occur when the child is at rest. Symptoms often start in one part of the body, such as the hand, leg, or mouth, and then spread to other body areas.
Tics are sudden, involuntary movements or sounds that come and go over time. They are fairly common in children and usually can be treated by a general pediatrician. Muscle tics can involve any body part and may vary in severity — from very mild and hardly noticeable to very disruptive, frequent, and severe. Children are usually able to suppress tics, at least temporarily, but will feel a building sense of “wrongness” or “push” as they resist the tic.
If tics persist despite treatment, the child may need to see a specialist in movement disorders. About 10 to 15 percent of children will see their tics progress and become potentially disabling, but most tic disorders resolve or become minimal by the time a child reaches their 20s.
If a child has both vocal and motor tics that last longer than a year, they have Tourette's syndrome.
Children with parkinsonism have at least two symptoms of Parkinson disease: muscle rigidity, balance problems or frequent falls, slow movement, or tremor while at rest. By itself, parkinsonism is the least common movement disorder in children. Most often, the symptoms occur as a side effect of medications. Parkinsonism can also result from genetic conditions causing brain degeneration, such as Wilson disease, juvenile Huntington disease, and lysosomal disorders, and from various forms of brain injury.
Ataxia is a failure of motor coordination caused by injury or dysfunction of the cerebellum. Its symptoms are clumsiness, poor balance, irregularity of movements, and inability to perform fine-tuned or smooth movements.
Ataxia can have different patterns. Some cases begin abruptly, as a result of a stroke, inflammation, or infection, and typically get better as these causes are treated. Other types of ataxia repeatedly come and go, and are caused by epilepsy, genetic mutations, metabolic disorders, or atypical types of migraine.
Functional neurological disorders
In addition to the above conditions, it is not uncommon for movement disorders in children to follow stressful life events. A condition known as functional neurological symptom disorder, sometimes called conversion disorder, can cause any of the movement disorders described above, even when no neurologic cause or condition can be identified.
Functional disorders also can occur in children with other neurological problems and make an existing movement disorder worse. The good news is most children recover from this type of movement disorder with retraining by physical therapists and continued supportive care from a neurologist. In some cases, children may benefit from joined care with a psychologist or psychiatrist.
What are the causes of movement disorders?
Movement disorders can result from many types of brain injury, such as head trauma, infection, inflammation, metabolic disturbances, toxins, or unintended side effects of medications. They can also be a symptom of other, underlying diseases or conditions, including genetic disorders.
How we care for movement disorders
At Boston Children’s Hospital, we have a team of specialists who specialize in diagnosing and treating movement disorders in children. We evaluate and care for children with ataxia, chorea, dystonia, myoclonus, tremor, tic disorders, Tourette’s syndrome, and other movement disorders.
Movement Disorders | Diagnosis & Treatments
How are movement disorders diagnosed?
Because movement disorders and their causes are so varied, the tests used to diagnose these disorders can also vary. These may include:
- genetic testing
- metabolic testing
- specialized MRI imaging of the brain
- electroencephalogram (EEG) to evaluate the child for seizures
How are movement disorders treated?
Treatment of movement disorders varies from child to child, depending on the type of disorder and the underlying cause. Some children with movement disorders may only need observation, as many disorders improve as children develop.
When treatment is necessary, options may include:
- oral medications to relax muscles and ease stiffness, tremors and spasms
- injections of botulinum toxin (Botox) for dystonia that affects a single body part, and sometimes for tic disorders and myoclonus
- dopamine (levodopa) for parkinsonism
- an implanted baclofen pump can be helpful for dystonia mixed with spasticity that does not get better with oral medications
- deep brain stimulation is a treatment for primary dystonia that does not respond to medications
Some children with movement disorder may also benefit from:
- physical therapy to strengthen or stretch the affected limbs and muscles
- occupational therapy to help overcome any limitations caused by abnormal movements
- support to help the family and child cope with ongoing symptoms of movement disorders
- neuropsychiatric testing, when the movement disorder is accompanied by cognitive or behavioral problems
What is the long-term outlook for movement disorders?
How well a child will do depends on the type of movement disorder, its cause, how well the movement disorder is treated and how soon treatment is started. For example, a child with primary dystonia can live a normal life if they are treated early, while dystonia that goes undiagnosed and untreated for many years can become permanently disabling.
Other movement disorders, such as tic disorders, may eventually go away on their own or become much milder.
If the movement disorder is part of a serious genetic or degenerative disorder, there may be no treatment. In most cases, though, there are interventions that can relieve children’s symptoms, in some cases dramatically.