An Overview of Dyskinesia
Dyskinesia is an abnormal, uncontrolled, involuntary movement. It can affect one body part, such as an arm, leg or the head, or it can spread over the entire body. Dyskinesia can look like fidgeting, writhing, wriggling, head bobbing or body swaying. It doesn't happen in everyone with Parkinson's, and in those who do have it, it occurs to different degrees of severity. In some people, dyskinesia may be painful or bothersome to the point that it interferes with exercise, social life or other daily activities. Many people, though, say they prefer having dyskinesia to being rigid or less mobile due to Parkinson's.
Dyskinesia tends to occur most often during times when other Parkinson's symptoms, such as tremor, slowness and stiffness, are well controlled. (This is what doctors and researchers call "on" with dyskinesia.) Stress or excitement can exacerbate dyskinesia.
Cause of Dyskinesia
Dyskinesia typically occurs as a complication of long-term levodopa use. Additional factors that may contribute to dyskinesia include a younger age at diagnosis and the use of higher doses of levodopa for extended periods of time.
Exactly why dyskinesia develops is not well understood, but researchers believe different brain chemicals, such as serotonin, glutamate and dopamine, play a role. Fluctuating levels of dopamine in particular are thought to play a role. In Parkinson's, the brain cells that make dopamine are lost, so dopamine levels decrease. Levodopa temporarily restores dopamine, but because it has to be taken several times per day, dopamine levels rise and fall. This, combined with progressive loss of the dopamine-producing brain cells, makes it impossible to keep a constant level of dopamine in the body and brain, and these fluctuations are believed to contribute to dyskinesia.
Management of Dyksinesia
If you experience bothersome dyskinesia, you can discuss several treatment options with your personal physician:
- Changing your levodopa dosage and/or how often it's taken so you get enough in each dose to control your symptoms but not too much that it causes dyskinesia.
- Switching to an extended-release formulation or continuous infusion of levodopa, which aims to keep the level of medication and therefore dopamine in your system more constant to control symptoms and limit dyskinesia.
- Adding a medication called amantadine to target dyskinesia. Extended-release amantadine was approved to treat dyskinesia in August 2017. (Prior to that, an immediate-release formulation of amantadine, which still may be used in some cases, was available for many years.) Read more about amantadine, levodopa and other Parkinson's medications.
- Undergoing deep brain stimulation (DBS), a surgical procedure. This is not an option for everyone, but for those who've had Parkinson's for at least four years, still benefit from medication, and have dyskinesia and motor fluctuations (significant "off" times, when medication is not working optimally to control symptoms), DBS may be a consideration.
A Note on Levodopa
Because of the potential for dyskinesia with long-term use of levodopa, many people, especially those who are younger at the time of diagnosis, wonder if and when they should start levodopa. Of course, this is an individual decision that needs to be made with your physician, but when Parkinson's symptoms are significant enough that they are interfering with your daily activities, job, exercise or general quality of life, you may want to consider levodopa. Parkinson's medications other than levodopa are available, and these are sometimes prescribed first instead of levodopa. Remember your Parkinson's and your medication regimen are individualized and you have to work with your personal physician to find what works best for you.
Much research is ongoing to better understand the mechanisms of dyskinesia and to find new and better treatments. Several drugs in the pipeline are targeting different brain chemicals and pathways, and many are aiming to keep dopamine levels more constant. A number of surgical trials also are ongoing -- researchers are looking to optimize deep brain stimulation and evaluate a procedure called focused ultrasound.
The Michael J. Fox Foundation has supported many of these efforts, including:
- Identifying novel targets and therapeutic approaches,
- Generating and validating critical tools, including a dyskinesia clinical rating scale (the Unified Dyskinesia Rating Scale) for use in therapeutic trials, and
- Developing approaches to enable more continuous levodopa delivery to maximize control of Parkinson's symptoms while limiting potential drug-induced complications, such as dyskinesia.