Pain helps you minimise damage to your body by warning you when you’re hurt. Acute pain is caused by injuries, illnesses or surgery and tells your brain that something is wrong. Chronic pain, on the other hand, persists long after the cause has gone and your body should have healed. Every year the NHS spends £5 billion to treat chronic back pain alone.
Why is chronic pain so difficult to deal with?
Like any other chronic illness, chronic pain persists for a long time. It can be hard to find a cure and patients can endure a lifetime of suffering. Even though the pain seems to come from the body, ultimately it’s the brain that interprets the sensation of pain.
So how does your brain relate to your body when you feel pain?
Just like sight and touch, pain is part of your sensory system. Your senses provide you with vital information about the world around you. If you get your skin stuck in a zip, you’re able to react immediately.
A sensory map in your brain quickly tells you where the pain is. During your lifetime this map grows and changes in relation to your movements, sensations and even your injuries.
Can learning how the brain changes in relation to lasting pain lead to more effective relief?
For the first time, researchers at Northwestern University in Chicago have seen a change in grey matter in chronic pain patients. Scientists hope to understand the mechanisms that cause this change and use the knowledge to develop new therapies for chronic pain.
One particular type of chronic pain has already helped researchers understand more about how the brain changes in relation to serious injury – phantom limb pain.
If you suffer a serious injury such as an amputation, your brain’s sensory map no longer matches what you see or do. This happens because every adult brain has neuroplasticity – the potential to remould. About 60–80% of amputees develop pain in their missing limb. Sometimes the sensations can be as simple and strange as the feeling of a hand brushing their cheek. Other times it is persistent and hard to treat. Using mirrors or more complex virtual-reality games can help some people.
Scientists think the reason why virtual-reality games can reduce chronic pain is because of the adult brain’s ability to change. But could we use these treatments more effectively in future?
‘Our research has shown that virtual reality can reduce pain for hours, but we know little of its long-term effectiveness,’ says Jonathan Cole, a consultant in clinical neurophysiology at Poole Hospital and Bournemouth University. ‘What we really want to do is teach people to do this as soon as they lose their limb. The longer you wait, the more time the brain has had to grow the wrong connections and reinforce the pain.’
‘Because the adult brain is dynamic and changes throughout our life, it’s certainly possible that in future virtual-reality techniques could be extended to treating other common pain problems, such as certain types of back pain. However, virtual reality doesn’t always work for everyone,’ says Ilan Lieberman, a pain consultant at Spire Manchester Hospital.
So is there an overarching solution to chronic pain?
‘Over the past 50 years, people have been looking for a one-size-fits-all treatment for chronic pain,’ says Vania Apkarian, a leading chronic pain researcher at Northwestern University. Vania thinks treatments in the future will be tailored to the individual.
‘With today’s advances in brain imaging, we can see that the brain of every chronic pain patient is structurally and psychologically different. We found that there are different forms of chronic pain, each with their unique brain imprint. You can’t expect to treat them all in the same way.’
In an ideal future, doctors would be able to use medical scans to look into the brain of a patient and see exactly where things have gone wrong.
This level of insight is what Vania’s research team are trying to achieve.
‘We’re entering into unknown territories, testing drugs that may reveal brain areas involved in chronic back pain. I can’t disclose more for now, but if successful, it will provide evidence that understanding brain mechanisms of chronic pain can lead to targeted therapies.’