Dystonia and Parkinson’s: ask the expert
Intense muscle spasms called dystonia are a common feature of Parkinson’s. In this blog we explore the research into this important and painful symptom.
We’re joined by Professor Kailash Bhatia, an international expert in movement disorders including Parkinson’s and dystonia, who answers some of the key questions on this complex topic.
What is dystonia?
Dystonia is the term used to describe uncontrollable and sometimes painful muscle spasms caused by incorrect signals from the brain. These spasms produce repetitive twisting and sustained muscle contractions which result in abnormal movements and postures.
Dystonia is a recognised condition in it’s own right and is estimated to affect at least 70,000 people in the UK. Find out more about dystonia on the Dystonia Society website.
There are many different forms of dystonia. For example people who inherit a particular genetic mutation can develop dystonia in childhood. Another common form of dystonia is ‘task specific dystonia’ which is when the muscle cramps are triggered by a particular activity, such as writing which causes painful muscle contractions in the hands (writers cramp).
But dystonia can also be a symptom or a sign of other conditions including Parkinson’s.
How does dystonia usually affect people with Parkinson’s?
Dystonia can affect people with Parkinson’s in different ways at different times.
Some people with young onset forms of the condition, may experience dystonia as one of their first symptoms. Often the dystonia affects the feet and causes them to turn inwards and is ‘exertion-induced’, so people may find get it in their feet after running or walking.
Other people may experience dystonia during ‘off periods’ — when the effects of their Parkinson’s medication wear off.
What do we know about the connection between dystonia and Parkinson’s?
There is still a lot to learn about the connections between Parkinson’s and dystonia but we know that both arise from problems in the circuit inside our brains responsible for controlling our movements, which is called the basal ganglia.
More recently, research has begun to reveal some of the potential genetic links between the two conditions.
Studies have shown that people with a rare inherited form of Parkinson’s caused by changes in a gene called parkin not only tend to develop Parkinson’s symptoms at a younger age but are also more likely to experience dystonia in their feet.
More recently, I was involved in a large genetic study which suggested that genetic mutations which cause a form of childhood-onset dystonia may also play a role in the development of Parkinson’s.
Mutations in a gene called GCH1 result in a severe reduction of dopamine production and cause symptoms that appear in childhood, often about the age of six, including dystonia in the lower limbs. The symptoms respond very well to levodopa medication and as a result it is called dopa-responsive dystonia (DRD).
We studied the families of children with DRD and found older relatives who carry the same genetic defect who developed Parkinson’s-like symptoms in adulthood. Crucially, when these individuals had a brain scan that we use to help diagnose Parkinson’s (called a DaTSCaN), they looked like they had typical Parkinson’s.
This demonstrated that mutations in GCH1 can lead not only to dystonia in childhood but also to Parkinson’s in adulthood — which is some of the most compelling evidence yet linking the two conditions.
What are the current treatment approaches ?
As with so many aspects of Parkinson’s, there is no ‘one size fits all’ approach for treating dystonia, but there are a range of things that can be helpful, including:
- Adjusting Parkinson’s medication. This may include using fast-acting or longer-acting drugs, which can be effective if people experience dystonia primarily when their Parkinson’s medication wears off.
- Non-drug approaches. Some people may also find that being relaxed helps with their dystonia. What makes someone relax differs from one person to the next, but you may find having a warm bath or massage helpful, or trying complementary therapies such as yoga.
- Other drug treatments. There are a range of different drugs that can be used to help to relax muscles, and in some cases Botulinum Toxin (botox) injections can be helpful.
- Surgery. Surgery for dystonia is not common, but may be considered if you don’t respond to drug treatment. Surgical procedures that are already used for Parkinson’s, such as deep brain stimulation, have been shown to help dystonia.
Are there any promising new potential treatments being developed?
One of the most interesting new approaches currently being explored for dystonia is non invasive brain stimulation using approaches like Transcranial Magnetic Stimulation (TMS) and transcranial direct current stimulation (tDCS).
In these therapies, a magnetic coil is placed over the skull and used to focus a small magnetic or electrical pulse painlessly into the brain. The pulse stimulates cells within the brain in an attempt to disrupt the faulty messages that may be causing dystonia.
There have already been some promising results published from small studies which involved people with non-Parkinson’s forms of dystonia, and my colleagues here at University College London are now exploring whether this experimental therapy might be helpful for people with Parkinson’s.
What are the remaining research questions?
There are still many questions to answer in dystonia research, in particular in understanding why people develop it and how it is linked with genetic changes and other conditions like Parkinson’s.
Another area that I’m especially interested in is understanding the connection between dystonia and the postural problems that can affect people with Parkinson’s.
Camptocormia, also known as bent spine syndrome (BSS), affects a significant number of people with Parkinson’s but how and why it develops is unclear. I believe that dystonia may be involved in the early stages of these kinds of severe postural problems, and that if we understood this better and could catch it earlier we could potentially prevent the progression to full blown problems.
This blog is not meant as health advice. You should always consult a qualified health professional or specialist before making any changes to treatment or lifestyle.
Huge thanks to Professor Kailash Bhatia, Professor of Clinical Neurology at the Institute of Neurology, UCL, Queen Square, London and Honorary Consultant Neurologist at the affiliated National Hospital for Neurology, Queen Square.