Dystonia is a general term which describes involuntary movements and extended muscle contractions - a range of movement disorders. The patient has twisting body movements, tremor and unusual or awkward postures. For some patients the whole body may be involved in the movements, while for others only certain parts of the body are affected.
Dystonia symptoms may be linked to specific tasks, such as writing, as in writer's cramp. Dystonia may be inherited, but without a genetic pattern - a sporadic inheritance. People may develop dystonia symptoms as a result of taking certain medications. Some diseases, such as some forms of lung cancer may also produce signs and symptoms of dystonia.
Scientists have identified a gene responsible for at least one form of dystonia. Some patients respond well to dopamine, while others may benefit from sedative-type medications, or even surgery.
Although dystonia is a neurological condition, experts say that cognitive abilities (intelligence), memory, and communication skills are not affected.
According to the American Association of Neurological Surgeons, dystonia may affect as many as 250,000 people in the United States. They suggest that it is the third most common movement disorder behind essential tremor and Parkinson's disease1.
According to the National Health Service (NHS), UK, approximately 38,000 people have dystonia in the UK, out of a total population of 61 million.
Although most cases of dystonia start in patients aged between 40 and 60 years, it can hit all age groups.
Dystonia can be classified according to its underlying case:
Cases in which the only sign or symptoms is dystonia. The medical team cannot identify any disease or neurological damage that may have caused the dystonia.
When dystonia signs and symptoms occur as a consequence of an underlying condition - usually genetic, neurological or an injury which affects the nervous system.
Dystonia is also defined according to body part(s) affected:
- Focal dystonia - only one part of the body is affected.
- Segmental dystonia - two or more regions of the body are affected. The regions are somehow connected to each other, for example, the neck and shoulder.
- Multifocal dystonia - at least two regions of the body that are not connected to each other are affected. Such as an arm on one side as well as one leg on the other side of the body.
- Generalized dystonia - both legs and other regions of the body are affected.
- Hemidystonia - half of the entire body is affected.
Dystonia can also be classified according to age of onset:
- Early-onset dystonia - when dystonia signs and symptoms appear during the first thirty years of the patient's life. Symptoms are usually first noticed in a limb. Typically, the dystonia will eventually spread to other parts of the body.
- Late onset dystonia - most typically, onset of signs and symptoms appear in patients aged between 40 and 60 years. In the majority of cases symptoms start either in the neck, one of the arms or head, and generally do not spread.
Symptoms of dystonia
A symptom is something the patient feels and reports, while a sign is something other people, such as the doctor notice. For example, pain may be a symptom while a rash may be a sign.
Patients' signs and symptoms will depend mainly on the type of dystonia they have. Below are some common examples:
1) Cervical dystonia
Cervical dystonia is also known as torticollis; the most common form. Cervical dystonia affects only one body part (focal dystonia) and generally starts later on in life (late-onset dystonia). The neck muscles are affected. The patient may experience:
- Twisting of the head and neck
- Pulling forward of the head and neck
- Pulling backwards of the head and neck
- Pulling sideways of the head and neck.
Patients may experience mild to severe symptoms. If muscle spasms and contractions are frequent and severe enough, the patient may also experience stiffness and pain.
Experts are not sure why, but say that touching the chin, neck or back of the head can often relieve symptoms considerably.
The muscles around the eyes are affected. This is a focal (just one part of the body is affected), late-onset type of dystonia. The patient may experience:
- Photophobia (sensitivity to light)
- Irritation in the eye(s)
- Excessive blinking, often uncontrollable
- Eyes close uncontrollably. Patients with severe symptoms may find it impossible to open their eyes for several minutes.
Signs and symptoms may become more and less severe depending on what time of day it is. The majority of patients find that symptoms worsen as the day progresses.
3) Dopa-responsive dystonia
A type of generalized, early-onset dystonia (both legs and other parts of the body are affected, onset occurs from ages 5 to 30 years). This type of dystonia responds well to levodopa, a dopamine medication - hence the name.
Typically, a patient will experience symptoms between 6 and 16 years of age. The most common symptom is a stiff, unusual walk, with the sole of the foot bent upwards. In some cases the foot may turn outwards at the ankle.
Muscle stiffness and spasms in the arms and torso is not uncommon.
4) Hemifacial spasm
This is a focal (just one part of the body is affected), late-onset type of dystonia. The patient experiences spasms in the muscles on one side of the face. Symptoms may be more prominent when the individual is under mental stress or physically tired.
5) Laryngeal dystonia
This is a focal (just one part of the body is affected), late-onset type of dystonia. The muscles in the voice box (larynx) spasm. The larynx muscle spasming may be inwards or outwards.
Patients may sound very quiet and breathy when they speak, or strangled - depending on which way the muscle spasm.
Myoclonus dystonia - this is a segmental, late onset dystonia (occurs after 40 years of age, two or more body regions are affected). The arm, neck and torso muscles are affected. Patients with spasms may look as though they are receiving an electric shock (sudden, jerky movements).
6) Oromandibular dystonia
This segmental, late-onset type of dystonia affects the jaw and mouth muscles. The patient's mouth can pull outwards and upwards.
Some patient will only have symptoms when the muscles of the mouth and jaw are being used, while others may experience symptoms even at other times (when muscles are not in use). Often, patients with symptoms when their mouth and jaw muscles are not being used may experience relief when talking or chewing.
Some patients may have dysphagia (problems swallowing).
7) Writer's cramp
The patient experiences uncontrollable cramps and movements in the arm and wrist. It is a late-onset, focal type of dystonia. This is a task-specific dystonia, because most patients already do a lot of writing before onset of symptoms appear.
Other task-specific dystonias
- Musician's cramp
- Typist's cramp
- Golfer's cramp.
8) Generalized dystonia
Patients are usually children at the beginning of puberty. Hence, it is an early-onset dystonia. Symptoms generally are felt in one of the limbs, and eventually spread to other parts of the body.
The patient may experience:
- Muscle spasms
- An abnormal, twisted posture, due to contractions and spasms in the limbs and torso
- A limb (or foot) may turn inwards
- Parts of the body may suddenly jerk rapidly.
9) Paroxysmal dystonia
Muscle spasms and abnormal body movements only happen at specific moments; otherwise the patient has no symptoms at all (at other times). It is a rare type of dystonia.
Signs of paroxysmal dystonia may resemble those of epilepsy during a seizure (fit). When symptoms come on suddenly, they are known as an attack. Only the muscles are affected during an attack. The patient does not lose consciousness, and will be aware of his/her surroundings, unlike a patient with epilepsy. An attack can last for just a few minutes; and in some cases may persist for several hours. The following triggers may bring on an attack:
On the next page we look at the causes of dystonia and how it is diagnosed. On the final page we discuss the available treatments for dystonia, from medications to physical therapy and surgery.