Symptoms & Classifications
There are many types of dystonia, and dystonia is classified in specific ways. The classifications can help guide diagnosis and treatment.
To accurately determine the type of dystonia a person has, physicians look at several major factors:
Dystonia can occur in people of all ages. Certain types of dystonia tend to begin at specific ages. Dystonia in infants and children will likely require a different treatment plan than dystonia that occurs in middle-age or older adults.
Dystonia is also classified anatomically. When dystonia affects only one part of the body, it is called focal dystonia.
Segmental dystonia affects two or more connected body areas (for example the neck, shoulder, and arm). If two or more areas in different parts of the body are affected, the dystonia is termed multifocal (for example the eyes and vocal cords).
Generalized dystonia refers to dystonia that is not limited to a single part of the body but affects multiple muscle groups throughout the body. Generalized dystonia typically affects muscles in the torso and limbs, and sometimes the neck and face. Axial dystonia specifically affects the torso.
When dystonia only affects muscles on one side of the body, it is called hemidystonia
Certain dystonias are task-specific, meaning the symptoms occur only when the person is performing a specific action or movement.
If symptoms only occur in "episodes" that last for minutes or hours, the terms paroxysmal dystonia and dyskinesias are used.
The word torsion is sometimes used, usually in reference to generalized, axial, or segmental dystonia. Torsion refers to the twisting element of dystonia. It describes muscles contracting against each other.
There are many causes for dystonia. Dystonia may occur due to an inherited or new genetic mutation. Dystonia may also result from changes in brain activity caused by another health condition such as a traumatic brain injury. Certain drugs are known to cause dystonia. However, for many people who develop dystonia, there is no identifiable cause.
Dystonia can be associated with numerous diseases and conditions. These include specific vascular conditions, infections, brain tumors, metabolic conditions, neurodegenerative disorders, demyelinating disorders, and structural conditions.