Focal task-specific dystonia

Other Names: FTSD; Focal dystonia; Focal, segmental or multifocal dystonia; Task-specific dystonia; Focal task specific dystonia; Task-specific focal dystonia Focal task-specific dystonia (FTSD) is a movement disorder that is localized to a specific part of the body. The dystonias are a group of movement problems characterized by involuntary, sustained muscle contractions, tremors, and other uncontrolled movements. FTSD interferes with the performance of particular tasks, such as writing, playing a musical instrument, or participating in a sport. Additionally, FTSD has been reported in tailors, shoemakers, hair stylists, and people who frequently type or use a computer mouse.

Cause

The causes of focal dystonia are unknown, although the disorder likely results from a combination of genetic and environmental factors. It is possible that the different forms of FTSD have different underlying causes. Researchers have found that at least some cases are related to malfunction of the basal ganglia, which are structures deep within the brain that help start and control movement.

Risk factors

Task-specific focal dystonia can affect people who play sports and engage in other occupations involving repetitive, highly practiced movements. For example, some golfers experience involuntary jerking of the wrists during putting, a condition known informally as "the yips." Cramps and spasms of the hand and arm muscles can also affect tennis players, billiards players, dart throwers, and other athletes. Additionally, task-specific dystonia has been reported in tailors, shoemakers, hair stylists, and people who frequently type or use a computer mouse.

Symptoms

muscle cramps or spasms in the hand, wrist, or forearm interfere with holding a pen or pencil,loss of fine-motor control in the hand and wrist muscles,muscle cramps or spasms involving the lips, tongue, or jaw. The abnormal movements associated with task-specific focal dystonia are usually painless, although they can cause anxiety when they interfere with musical performance and other activities. Severe cases can cause professional disability.

Inheritance

Most cases of focal dystonia are sporadic, which means they occur in people with no history of the condition in their family. However, at least 10 percent of affected individuals have a family history which seems to follow an autosomal dominant pattern of inheritance.

Autosomal dominant pattern, a 50/50 chance.

Treatment

This condition is often treated with injections of botulinum neurotoxin A (BoNT/A). BoNT/A reduces the symptoms of the disorder but it is not a cure for dystonia. Since the root of the problem is neurological, doctors have explored sensorimotor retraining activities to enable the brain to "rewire" itself and eliminate dystonic movements. The work of several doctors such as Nancy Byl and Joaquin Farias has shown that sensorimotor retraining activities and proprioceptive stimulation can induce neuroplasticity, making it possible for patients to recover substantial function that was lost to focal dystonia.

The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition.

• Botulinum toxin type A (Brand name: Botox)Treatment of cervical dystonia in adults to decrease the severity of abnormal head position and neck pain associated with cervical dystonia. Treatment of blepharospasm or strabismus associated with dystonia in adults (patients 12 years of age and above).
• Botulinum toxin type B (Brand name: Myobloc) Treatment of patients with cervical dystonia to reduce the severity of abnormal head position and neck pain associated with cervical dystonia.