Last week, my blog on Botulinum toxin injections in the treatment of Parkinson’s disease mentioned several (PD) symptoms, one of which is dystonia. This week, let’s dig deeper to get a fuller understanding of dystonia as it relates to PD.
What is dystonia?
Dystonia is a movement disorder in which there are involuntary and repetitive muscle movements that cause a part of the body to twist or assume a particular posture. Various body parts can be affected by dystonia in Parkinson’s, including the eyes, neck, trunk and limbs. Dystonia can be painful and can interfere with a person’s desired movement. It’s important to note that many people with PD do not develop dystonia and conversely, there are numerous causes of dystonia which are unrelated to PD, including genetic disorders, brain lesions, and medication side effects. There are also dystonia syndromes that occur with no clear cause. However, dystonia can be a feature of several neurologic diseases, including PD.
Dystonia and Parkinson’s
Body parts that can be affected with dystonia in Parkinson’s
Repetitive and sustained eye closure is known as blepharospasm. To the observer, this looks like increased blinking, which may increase in certain situations such as in bright light. The frequent blinking/eye closures can interfere with activities such as reading or driving. This can be associated with PD, but may also accompany other forms of parkinsonism such as Progressive Supranuclear Palsy. The most common treatment for this disorder is Botulinum toxin injections.
Repetitive and sustained movements of the neck are known as cervical dystonia. The neck can tilt, turn, bend forward, bend backwards, or assume a position that is a combination of these movements. This can be associated with PD, but may also accompany other forms of parkinsonism. The most common scenario in PD and parkinsonian disorders, is a neck that is mostly bent forward or flexed. The medical community debates whether this posturing is due to dystonia, which causes an overactivity of the muscles in the front of the neck that pull the neck down, or due to a muscle abnormality that weakens the muscles in the back of the neck that keep the neck upright. There seems to be an association between exposure to dopamine agonists and rapid-onset neck flexion in a subset of people. A flexed neck can be difficult to treat. If the neck flexion occurred soon after a change of dopaminergic medication, your doctor may consider changing the medications back to the way they were taken prior. On occasion, a soft collar may be helpful. Botulinum toxin injections are an option. However, a flexed neck is the most difficult neck posture to inject successfully. This is mostly because the muscles that flex the neck are deep and difficult to reach safely with standard techniques. Muscle visualization techniques, such as with the use of ultrasound, may allow these muscles to be injected more easily. The neck flexion muscles are also in close proximity to the muscles involved in swallowing, so injecting them with Botulinum toxin comes with more of a risk of swallowing difficulties or dysphagia as a side effect than injections for other neck postures.
In PD, the trunk can tilt to one side or flex forward. Forward flexion of the trunk is known as camptocormia. Similar to neck flexion, it is unclear whether the flexion is due to dystonia causing overactivity of muscles that pull the trunk down, or weakness of the muscles that keep the trunk upright. Typically, although the forward flexion may appear very profound when upright, the patient can lie flat in a bed or sometimes even straighten up against a wall, demonstrating that the flexion is not due to a permanent deformation. Treatment options are similar to those available for neck flexion. Spinal surgeries which attempt to straighten the torso have been reported in a handful of patients. Results were mixed including a very high rate of surgical complications. These surgeries are generally not performed.
A common dystonia in young onset PD involves toe curling or foot plantarflexion and inversion (ankle moving towards the ground and/or turning in). This dystonia often occurs only in particular circumstances such as while walking or running. Treatment choices include the array of possibilities listed above.
How dystonia is caused in Parkinson’s cases
First and foremost, dystonia can be a symptom of Parkinson’s disease itself. Particularly in young onset PD, foot dystonia may appear as the first motor symptom that is experienced. If dystonia occurs in isolation, the diagnosis of PD may only become clear as other symptoms appear. If dystonia occurs as the predominant symptom of PD, the patient and his/her doctor must decide how to treat it – either by starting dopaminergic medications to see if this helps the dystonia or by targeting the dystonia itself, possibly with Botulinum toxin injections.
Once medications for PD have been started, dystonia may appear when there is a decrease in brain dopamine levels, which could occur first thing in the morning before taking medication or when a dose of medication is wearing off. If this is the pattern that is noted, there are various strategies that can be implemented to decrease OFF time. Depending on when the OFF time occurs, these approaches may include taking a long-acting Levodopa formulation before bed, increasing the number of doses per day or adding a medication to lengthen the amount of time that a dose works.
Alternatively, dystonia can be caused by treatment with Levodopa. Readers may be aware of Levodopa-induced dyskinesias, which are rapid, writhing movements that can occur as a side effect of Levodopa treatment. When the movements caused by Levodopa are more sustained and twisting in nature than the typical dyskinesias, then they are referred to as dystonic dyskinesias. Dyskinesias (both typical and dystonic) occur in two temporal patterns – when dopamine levels are at their peak in the brain, typically in the middle of a dose; or when brain dopamine levels are rising or falling quickly, typically at the beginning and at the end of a dose. If either of these patterns are noted, there are various strategies that can be implemented. These may include smoothing out the Levodopa doses in order to prevent both brain dopamine peaks as well as rapid increases or decreases in brain dopamine levels. In addition, Amantadine or Amantadine CR can be tried to control both typical and dystonic dyskinesias.
It is critical to figure out the relationship between medication timing and dystonia to determine whether it is a symptom of OFF time or a side effect of Levodopa, which are essentially opposite scenarios. One of the best ways to do that is to keep a diary recording medication doses and symptoms. For a more complete analysis of strategies to prevent OFF time and to control dystonic dyskinesias, please see this APDA webinar.
In addition to keeping a diary, another approach that can help you and your doctor better understand what’s causing your dystonia involves using wearable technology which can record when a patient is off and when a patient is dyskinetic based on his/her movements. The data captured in some of the available devices can be analyzed by your doctor and used to adjust medications.
Treating Dystonia in Parkinson’s
Treatment options for dystonia include:
- Dopaminergic medication adjustment as discussed above
- Botulinum toxin injections of the affected muscles
- Physical therapy to loosen and strengthen the dystonic body part
- Trying other medications that target the dystonia directly such as muscle relaxants or anti-cholinergic medications
- Use of a device to provide a sensory trick*.
- Deep brain stimulation can be considered in difficult-to-treat situations
*To minimize their dystonia, some people have success using an interesting tactic called a sensory trick. A sensory trick is defined as a physical gesture (such as a touch on a particular body part) that mitigates the production of the dystonia. For example, touching the eyebrow may help keep the eyes open, or touching the chin may keep the neck from twisting. In my clinical practice, one woman wears metals rings on her dystonic fingers to help them assume a more normal position. Another man wears 5-toed shoes to prevent dystonic toe curling
Tips and takeaways
- Dystonia is a common motor symptom of Parkinson’s disease, although does not affect everyone with PD
- Dystonia can be due to the disease itself or can be a complication of Levodopa treatment, in much the same way as Levodopa-induced dyskinesias
- In order to distinguish between those two possibilities, consider keeping a diary of medication timing and symptoms
- Treatment options for dystonia in PD include dopaminergic medication adjustments, Botulinum toxin injections, oral medications that target dystonia, physical therapy, use of a device that mitigates the dystonia, and deep brain stimulation.
- If you are experiencing dystonia, be sure to talk to your doctor about it so you can determine ways to make it more manageable and comfortable for you.