Can we take the pain out of Parkinson’s?
Pain plays a vital role in protecting us from the world around us — although this can be hard to appreciate when you stub your toe! Pain helps us to remove ourselves from harm and prevents us from putting ourselves at risk again. But what happens when pain stops being helpful, and where are we when it comes to treating chronic pain?
Throughout our body we have special nerve cells that can detect damage and send messages back to our brains. When our brain processes these messages we experience pain. Being able to detect pain means we know when damage is being done and can take action to stop it — for example by moving a hand out of scalding water.
Around 12% of the UK population take prescription pain killers. These drugs help to dampen our experience of pain by interfering with the way the brain receives or processes messages about pain. A short course of paracetamol, the most commonly used pain killer in the UK, may be sufficient to manage pain. But what happens when the pain doesn’t go away, or when the pain killers we have don’t seem to be effective? This is the case for many people with Parkinson’s who experience something called chronic pain.
Chronic pain is pain that lasts more that 12 weeks, and while there can be many causes of it, there is evidence that Parkinson’s changes the way the brain responds to pain.
People with Parkinson’s may experience different types of pain. The most common type is musculoskeletal, usually felt as an aching in the joints and limbs. Pain can also be caused by muscle cramps or involuntary muscle contractions (dystonia). Other types of pain include shooting pains that travel down the arms, legs, fingers and toes, as well as a wide-spread dull aching.
We don’t know exactly what causes chronic pain in Parkinson’s, which is why we are currently funding research projects trying to unpick this. With your help, we’re pushing forward research to get to new treatments, faster.
Tracking Parkinson’s and genetic changes
Tracking Parkinson’s is the largest ever detailed study of people with Parkinson’s. The aim of the project is to identify biomarkers, or measurable changes in the body, that would allow us to accurately diagnose and measure the progression of Parkinson’s.
Other studies have taken advantage of the detailed data collected through Tracking Parkinson’s. One of these projects is looking into whether chronic pain in Parkinson’s is associated with genetic changes in COMT, a protein which breaks down chemical messengers, including dopamine, in the brain.
The team, lead by Dr Monty Silverdale, already know that small changes in the COMT gene are associated with pain in people who do not have Parkinson’s. If the same is true for people with the condition, it could lead to new treatments may be available to alleviate this pain.
Lessons from fibromyalgia
Another way researchers are tackling pain is to look for clues from other conditions that can cause chronic pain, such as fibromyalgia and diabetes. At the University of Manchester, researchers are investigating if expectation can affect how much pain we actually feel.
People with fibromyalgia, a long-term condition that causes wide-spread pain, were told that they would receive a moderately painful burst of heat from a laser three seconds after the screen they were looking at changed colour. The participants then rated how painful this experience was.
Interestingly, the areas of the brain that respond to pain became overactive after the screen changed colour, but before the participants felt the laser. So the expectation of pain lead to a heightened experience of pain.
Fortunately, there may be a way to combat this heightened sense of pain and help people manage their experience of pain. The Manchester team have discovered that training people with fibromyalgia in meditation techniques can reduce the expectation of pain, and so reduce experience of pain.
The researchers are now exploring if an expectation of pain can lead to a more painful experience in people with Parkinson’s. If so, people with Parkinson’s may benefit from the same meditation training that helped people with fibromyalgia.
They are also planning to explore if a loss of dopamine, or other brain chemicals that are altered in Parkinson’s, may be causing chronic pain. This could lead to the development of new and better treatment.
Research has suggested that many people do not report pain as a specific symptom to their specialist and there are no specific guidelines for its management.
This is what inspired Professor Chaudhuri, and his team at King’s College London, to create a Parkinson’s-specific pain scale.
The tool is designed to be used by health care professionals to establish the severity and frequency of the different types of pain people with Parkinson’s experience. There are 14 questions to complete, which gives an overall score reflecting how much of a burden the pain is for the person with Parkinson’s.
The team hope that a standardised tool to assess pain in Parkinson’s will allow us to manage and alleviate pain better in the future.
Research is helping us to better understand the causes of chronic pain and discovering ways to manage this symptom better. Better understanding of non-motor symptoms like pain will help to develop better, more personalised treatments.
If you would like to discuss how non-motor symptoms, like pain, affect you, our Parkinson’s UK non-motor symptom questionnaire may be of use.
The questionnaire can help you to communicate about your non-motor symptoms to your health care professionals, who may be able to offer treatments or therapies.
Just fill out and give to your GP or Parkinson’s specialist.
And if you enjoyed this post, you can find our more about pain in Parkinson’s in David Dexter’s recent blog post Parkinson’s symptoms may be affecting people’s experience of pain:
Our work is totally dependent on donations. The groundbreaking research we fund isn’t possible without supporters like you. With your help, we’re pushing forward research to get to new treatments, faster.
This blog is not meant as health advice. You should always consult a qualified health professional or specialist before making any changes to your medications or treatments.