Pain and Parkinson’s: ask the expert
We’re learning more about how common pain is for people with Parkinson’s. In this blog, we explore the research into what causes this symptom, and what the future of pain research holds.
We’re joined by Dr Monty Silverdale, Chief Investigator on the largest ever study of pain in Parkinson’s, who answers some of the big questions on this topic.
What is the connection between pain and Parkinson’s?
Pain is very common in Parkinson’s. Our recent study demonstrated that around 80% of people with Parkinson’s will experience pain and around 40% reported moderate to severe pain. This is much higher than would be expected in a group of people without Parkinson’s of similar ages.
What are the different types of pain that people with Parkinson’s experience?
There are lots of different types of pain that people with Parkinson’s experience. The most common type is what we call musculoskeletal pain, which means pain around the joints. In our study, 66% of people with Parkinson’s who had pain as a symptom had musculoskeletal pain.
Other common types of pain include shooting pains down the limbs called radicular pain, painful muscle contractions called dystonic pain and a generalised constant dull aching, which we call central pain. Some people with Parkinson’s have an uncomfortable desire to keep moving their legs, especially at night, which is called Restless Leg Syndrome.
Are some people with Parkinson’s more likely to experience pain than others?
We think it is very likely that there are types of Parkinson’s where people experience pain and types of Parkinson’s where there is very little pain. In our study, although pain is very common, many people had no pain whatsoever, even those with quite advanced Parkinson’s.
People who were more likely to experience severe pain were also more likely to have movement complications and mental health symptoms. Being younger and female were also contributing factors to pain. The severity of movement problems and thinking and memory problems did not have a statistically significant effect on the severity of pain.
What are the current treatment options for pain in Parkinson’s?
At the moment treatment options for pain in Parkinson’s are fairly limited. The most important aspect of treatment is to control the Parkinson’s movement symptoms and reduce the number of ‘off’ periods (when medication stops working) people have. Pain is often worse during ‘off’ periods, therefore keeping people ‘on’ can help.
Some Parkinson’s medications have been shown to help with pain, including rotigotine and safinamide. But it is not clear whether these medications improve pain by reducing ‘off’ periods or have specific mechanisms that address the pain.
Some pain killers, such as oxycodone, have been shown to help pain in Parkinson’s. The trouble with oxycodone is that it is quite a strong medication and therefore may have side effects. An antidepressant drug called duloxetine has also been shown to help pain in some people with Parkinson’s, and the effect is probably separate from its antidepressant action. Deep brain stimulation will also help some people with Parkinson’s.
Only a small proportion of the participants in our study were using drugs which target central mechanisms to help manage pain. Our results suggest that more widespread use of these medications should be considered as a treatment option.
Can you share some of your findings so far?
Our study findings have confirmed that pain is extremely common in Parkinson’s. We can’t ignore pain as a symptom of Parkinson’s anymore.
In our study of people with early — moderate Parkinson’s, pain had a greater effect on quality of life than motor impairment and a comparable effect to motor complications, such as dyskinesia. Given the amount of research that has gone into understanding movement problems in Parkinson’s, it is clear that there needs to be more research into the causes of pain and exploring new treatments.
We have also shown that pain in Parkinson’s is not always related to mobility problems and other Parkinson’s symptoms. It can be completely separate. In the past people thought that mobility problems, such as stooped posture, stiff limbs, reduced movements and muscle contractions, were the main cause of pain. Our findings demonstrate that this is not the case.
In a separate study, we have shown that the response to a painful stimulus is exaggerated in people with Parkinson’s. It appears that the Parkinson’s brain actually magnifies pain. So for example, if someone with Parkinson’s injures their leg, they will experience more pain than someone without Parkinson’s with the same leg injury. We believe that this is one of the main reasons why pain in Parkinson’s is so common.
What are the remaining research questions about Parkinson’s pain?
We now understand a great deal about why pain is so common in Parkinson’s. The next challenge is to turn this increased understanding into improved treatments for this very common symptom.
Lots of neurotransmitters — chemical messengers in the brain — are altered in Parkinson’s. In our ongoing research we are aiming to identify which of these changes cause the Parkinson’s brain to magnify pain. Once we understand this, we hope this information will help us to develop better treatments for pain in Parkinson’s.
This blog is not meant as health advice if you would like to now more about pain in Parkinson’s, visit the Parkinson’s UK website.
You should always consult a qualified health professional or specialist before making any changes to treatment or lifestyle.
Huge thanks to Dr Monty Silverdale, Consultant Neurologist at Salford Royal NHS Foundation Trust.