A CLEVER DOCTOR can deliver a painless injection by distracting the child with a lollipop or funny story. An adrenalin-pumped athlete can finish the game on an injured limb without noticing. Scientists at the cutting edge of pain research are looking at how elements such as distraction and stress can help us learn more about what pain is and how to treat it.
The concept of pain itself is hard to pin down. It can occur for an obvious reason, such as when we stub a toe or, as with a migraine, can have no clear underlying cause. Cancer researchers have found that its intensity can vary depending on how positive or happy the patient is or how much emotional support they have.
The classic definition of pain describes it as having sensory, emotional and social aspects, explains Prof Chris Eccleston, director of the Centre for Pain Research at the University of Bath in the UK. While this definition works well, Eccleston says he would also define pain in terms of interruptive quality or how often a person is aware of and interrupted by pain as they go about their daily life.
Another way to look at pain is to ask what its function is. What is the point of pain? “From an evolutionary perspective, pain is a fundamentally social experience,” says Eccleston. “If you’re in acute pain and you cry out, this will warn others in the environment of danger. Also, as humans, we have an urge to communicate suffering. While pain is a private event, it is a social experience. Pain alerts others to your suffering so that they may help.”
While pain is usually thought of as short lived and symptomatic of an underlying injury or disease, there are types that will endure for a lifetime and pain this is a result of faulty wiring in nerves or pain receptors.
Chronic or long-term pain is increasingly being viewed not as a symptom but as a disease in itself. “Too often people attribute chronic pain to the ageing process but there are many reasons,” says David Finn, co-director of the Centre for Pain Research at NUI Galway.
Take, for example, a broken bone that is reset but the person is left in chronic pain. The damage has caused a permanent change in the nervous system that relays pain. “While the initial injury is healed, the pain receptors in the brain continue to fire spontaneously,” he says.
This can happen to an exaggerated degree in the form of phantom limb pain. Long after the patient’s arm or leg has been amputated, the pain will persist in the missing limb. It can be successfully treated with mirror therapy: a phantom foot cramp can disappear when the patient “sees” and flexes their right foot in a reflection of their left.
In terms of measurement, pain is assessed in a clinical setting by the numerical rating scale used for adults and the faces pain scale for children, which uses a visual guide of smiling and sad faces to rate from “no pain” to “very much pain”.
Eccleston and the centre at Bath are looking to develop a new scale that incorporates their pain research in terms of intrusion, and measures it in terms of time on a scale of seconds to hours. “Pain grabs your attention away from the task at hand and back to your body. A successful analgesic or painkiller is one that results in pain interrupting you as infrequently as possible.”
Pain, especially in the case of chronic pain or cancer pain, is not necessarily treatable by painkillers. “For some patients drugs just won’t work unfortunately; there is not enough relief. Cognitive behavioural therapy can be effective in the acceptance of pain and realising that it won’t go away,” says Finn.
Dr Shelagh Wright, a retired lecturer in psycho-oncology at Dublin City University, explains that cognitive behavioural therapy is a recognition that mind and body interact and that how a person thinks impacts upon their behaviour and how they feel.
This form of therapy centres on empowering the patient and teaching techniques to improve their coping skills. “These skills impact psychologically and physically on how people behave. It improves their quality of life and sense of self-control because what pain does – and any major disease such as cancer in the longer term – is [it] erodes people’s sense of mastery, self-esteem and control.
“There is a range of different types of cognitive behavioural therapy. What is important in pain management is tailoring the therapy to the patient’s requirements,” adds Wright.
Finn and his colleagues also acknowledge the importance of the mind-body connection; they are investigating the relationship between stress and pain. The project, funded by Science Foundation Ireland, looks at how acute stress can actually suppress pain. Think of the soldier on the battlefield, the rugby player who pushes through the pain barrier, or the accident victim who feels nothing shortly after being injured. “We’re investigating stress-induced suppression of pain. This is a survival response to pain whereby the individual feels nothing until they leave the situation.”
Finn explains that it is short-lived but quite potent and the centre is looking at what happens in the brain in terms of the pain receptors and proteins involved.
Ultimately, pain is part of the human condition, says Eccleston, and will continue to be as life expectancy increases. “We are foolish to think that modern science can banish pain altogether. It is designed to be protective, an alarm system.”
Chronic pain The economic truth
CHRONIC OR long-term pain is far more common than we might realise. One in five people in Ireland suffers from this condition.
Most of us know someone who is affected by chronic pain, says Dr David Finn, co-director at the Centre for Pain Research at NUI, Galway.
Last year the centre produced the Prime study, which looked at chronic pain in an Irish context. “It was carried out in order to get a grasp on the scale of the pain problem in Ireland. No one had ever done this properly. It looked at how many people suffer from chronic pain as well as what it costs the economy.”
In terms of economic impact, Finn says chronic pain costs an estimated €4.6 billion a year, or 5 per cent of GDP. “The figures are staggering. This is far in excess of the cost of cancer or heart disease.”
The study also found that for the Irish, chronic pain is quite literally a pain in the posterior. The most common form is lower back pain, as reported by 47.6 per cent of those who took part.
Participants were asked to rate the intensity of their pain on a scale of one to four, with four being the most intense. While 35 per cent rated their pain as low grade it was found that almost 20 per cent of Irish people suffering from chronic pain report theirs as grade four, which is defined as high intensity and severely limiting.
While obvious causes such as car accidents, illness or sports injuries were cited as the source of chronic pain for many of the respondents, it seems as though they are not aware or do not have sufficient knowledge of something that has been part of their lives for so long. A surprising 42.7 per cent of those who took part in the Prime study cited the cause of their chronic pain as unknown.
The pain goes deeper: sufferers have been enduring chronic pain for an average of 7.6 years and it has knock-on effects. The study found that levels of depression were significantly higher among individuals who suffer from chronic pain when compared to those who are pain free.
Now, at least, we are beginning to understand the impact of chronic pain globally and in Ireland. “For a long while it wasn’t taken seriously or properly understood,” says Finn. “In the last 10 to 15 years some really good research and clinical studies have been carried out and in some ways chronic pain is considered a disease in its own right.”
