Dystonia is a disorder characterized by involuntary muscle contractions resulting in repetitive movements and abnormal postures. It designates both a symptom and a group of diseases with multiple causes and responding to complex and controversial classifications and evolving with scientific advances. Dystonia, as a symptom, can be very debilitating and very painful. It affects around 45 people in France, according to the Association of People with Dystonia. (000)

Muscle contractions can be prolonged or intermittent. They cause dystonic movements which are generally twisting and distorting movements. These involuntary movements can be accompanied by tremors. It should be noted, however, that dystonia is by no means an obsessive-compulsive disorder, nor is it a tic disorder.

Dystonias are classified according to the areas of the body they affect: focal, segmented, multifocal, generalized. Focal cervical dystonia is the most common of the dystonias. It is also called spastic torticollis because it causes uncontrolled movements of the head.

Dystonia is caused by disorders of the central nervous system, but its underlying causes (and mechanisms) are still poorly understood. They could be due to abnormalities affecting areas of the brain. Imbalances in neurotransmitters (transmitting nerve impulses between neurons) could also be involved. Most cases of dystonia would develop due to a combination of genetic and environmental factors. Dystonia can have multiple origins and there are three main groups of dystonias depending on their origin:

• Idiopathic dystonias, the underlying causes of which are not identified.
• Acquired (or secondary) dystonias resulting from infection, drug exposure, brain damage (birth trauma from lack of oxygen, tumor, stroke, hemorrhage) .
• Genetic dystonias, caused by mutations in several genes, are often sporadic but sometimes inherited. They are declared in generalized form, often from childhood or adolescence.

Many genetic diseases can be associated with dystonia (Huntington’s disease, Wilson’s disease, etc.). Moreover, the term pseudo-dystonia is misused to designate conditions resembling dystonia such as Chiari malformation or Dupuytren’s disease.

There is no curative treatment and symptomatic treatments are adapted to each particular form of dystonia. Botulinum toxin injections are the most effective treatment for reducing muscle spasms and relieving pain by blocking the release of a neurotransmitter responsible for muscle contraction, acetylcholine. Botulinum toxin therapy is particularly effective in treating focal dystonias, such as cervical dystonia and laryngeal dystonia. Several drugs are sometimes prescribed to inhibit the neurotransmitters GABA and acetylcholine, but they are not specific to the treatment of dystonia and have side effects.

When these treatments do not relieve the patient, the use of several types of surgery is possible. Among them is deep brain stimulation, which involves surgically implanting electrodes in specific regions of the brain and an electrical pulse generator to interfere with and block the electrical signals responsible for symptoms. Finally, other therapeutic approaches such as speech therapy and physiotherapy should not be neglected to improve the management of stress caused by the condition.