The dystonias are movement disorders in which sustained muscle contractions cause twisting and repetitive movements or abnormal postures. The movements, which are involuntary and sometimes painful, may affect a single muscle, a group of muscles (such as those in the arms, legs or neck) or the entire body.

• Torticollis is a focal dystonia that is limited to the head and neck. In most cases, due to the muscle contractions, the head tilts toward one shoulder while the chin tilts to the other. It can be associated with head tremors or jerking movements. Torticollis may cause pain, facial deformity and effect everyday functions if it is not treated. Oral and injectable medications combined with physical therapy are most commonly administered to relieve pain and reduce symptoms of this disorder. In extreme cases that do not respond to medications, deep brain stimulation surgery can be an effective option.
• Blepharospasm is a focal dystonia that is limited mainly to the muscles around the eyes and can cause forceful closure of the eyes, especially when the eyes are exposed to bright light. This disorder can often be very effectively treated with botulinum toxin to relax the overactive eye muscles causing the eye closure.
• Writer’s cramp is a focal dystonia that affects the upper extremity and tends to occur when the patient is writing or doing other specific tasks, such as typing or shaving. The hand tends to curl and cramp, making the task difficult. This can often be treated by injecting the overactive arm muscles with botulinum toxin. Other dystonias, referred to as task-specific dystonias, occur when a body part develops abnormal posturing during specific movements, such as playing a musical instrument. It is often treated similarly to writer’s cramp.
• Spasmodic dystonia (sometimes referred to as spasmodic dysphonia) is a focal dystonia that involved the vocal cords and can cause the voice to sound whispery or constricted. Treatment often involves injecting the vocal cords with botulinum toxin to relax the overactive muscles that are affecting the speech.
• Tardive dyskinesia is a relatively uncommon form of dystonia caused by the long-term use of neuroleptic drugs. Neuroleptic drugs are generally prescribed for psychiatric disorders, as well as for some gastrointestinal and neurological disorders. Tardive dyskinesia is characterized by repetitive, involuntary, purposeless movements. Features of the disorder may include grimacing, tongue protrusion, lip smacking, puckering and pursing and rapid eye blinking. Rapid movements of the arms, legs and trunk may also occur. It can also present as a dystonia, like torticollis. Involuntary movements of the fingers may appear as though the patient is playing an invisible guitar or piano. Treatment often involves medications as well as stopping the neuroleptic that may be causing the syndrome if possible.

Causes

About half the cases of dystonia have no apparent connection to any other disease or injury and are called primary or idiopathic dystonia. Of the primary dystonias, many cases appear to be genetic and are inherited. Dystonias can also be symptoms of other diseases, some of which may be hereditary. In these cases, and in cases were dystonia occurs following damage to the brain (such as after a birth-related injury or stroke), it is referred to as a secondary dystonia.

Symptoms

Early symptoms may include deterioration in handwriting, foot cramps, or a dragging foot after running or walking some distance. Other possible symptoms are tremor and voice or speech difficulties.

In some individuals, symptoms of a dystonia appear in childhood. For other individuals, the symptoms emerge in late adolescence or early adulthood. Dystonia can begin in one part of the body and spread to others over time. In many individuals, however, it remains confined to one part of the body and can remain stable for long periods of time.

Some dystonias remain a focal problem while others spread to involve other parts of the body over time. In general, adults tend to have focal dystonias that affects one body part only (like turning of the neck or closure of the eyes) and often remains confined to that area alone.

Diagnosis

The diagnosis of most movement disorders are made based on the clinical exam and history. A neurological examination assesses motor and sensory skills, the functioning of one or more cranial nerves, hearing and speech, vision, coordination and balance, mental status, and changes in mood or behavior, among other abilities. A movement disorder exam often focuses on additional features like tremor analysis, muscle tone, posture and balance.

However, in many cases, additional screening tests are useful to clarify the diagnosis. Laboratory screening tests of blood, urine or other substances are used to help diagnose disease, better understand the disease process and monitor levels of therapeutic drugs. Certain tests provide general information, while others are used to identify specific health concerns.

Genetic testing or counseling can help parents who have a family history of a neurological disease determine if they are carrying one of the known genes that cause the disorder or find out if their child is affected. Some movement disorders, especially those affecting young patients, have a known genetic component that can be tested in the blood.