Until recently, chronic pain was often dismissed as psychological because it often has no obvious physiological cause, with doctors telling patients ‘it’s all in your head’.
That approach is being consigned to history. In the last two years, scientists have used technology known as fMRI (functional magnetic resonance imaging) to provide images of chronic pain patterns in the brain — and shown that it does have a biological basis, and is the result of a dysfunctional signalling system.
‘fMRI scans on people with back pain show that for the first ten to 15 weeks, the same part of the brain that is involved in the immediate response to an injury — the sensory brain regions — are involved,’ says pain management expert Professor Jane Ballantyne. ‘But as the pain continues, that pattern changes. After a year, it’s clear that chronic pain is experienced in the emotional part of the brain.’
Chronic pain increases activity in the brain areas that can amplify pain signals, adds Irene Tracey, a professor of pain research at the University of Oxford. ‘This mechanism is like a tap, and in chronic pain patients it’s turned all the way up and jammed there permanently.’
Her most recent study, published in October 2018 in the journal Arthritis and Rheumatology, showed that central sensitisation syndrome (as the changes caused by chronic pain are known) can also amplify long-term pain where there is an identifiable cause, such as osteoarthritis.
The study showed those affected experience more severe arthritic knee pain both before and after joint replacement surgery. ‘We know that the pain button can also be turned down, even blocking pain signals completely, for instance when the brain is distracted by the euphoria of crossing the finish line of a marathon’, says Professor Tracey.
The hope is that the combination of this new understanding, together with pain management, can bring relief to chronic pain sufferers, she says.
© Daily Mail