Dystonia is usually linked to a disturbance in the part of the brain that controls movement.
Dystonia is common in the general population. However, in people living with Parkinson’s disease, it is most often associated with the amount of levodopa in your body.
Dystonia usually occurs when the effect of one dose of levodopa wears off, before the next dose is taken. For example, you may wake up in the morning with a twisted body part (toe, foot, etc.). This painful twisting may prevent you from getting out of bed before the morning dose starts to take effect. This dystonia is called OFF dystonia. It is related to a lack of levodopa.
More rarely, dystonia can also be caused by brain over-stimulation with levodopa. This is called ON dystonia. It is related to excess dopamine. This type of dystonia is similar to dyskinesias, which may involve larger uncontrollable body movements.
The characteristics of dystonia and dyskinesia may seem similar but you need to be able to differentiate between them because their treatments are different.
Dystonia may also be a specific symptom of Parkinson’s disease unrelated to levodopa use. Foot dystonia may be the first motor symptom, especially in young people.