Sun, Sep 25, 2005 - Page 9 News List

Scientists look for new understanding of pain

By Alok Jha  /  THE GUARIDNA , LONDON

Scientists opened a new frontier last week in their understanding of one of life's most basic processes: pain. A research unit will, within tight ethical limits, shock, heat and poke people in an attempt to understand how the human body produces that hurting feeling.

Given that most people feel pain of some kind nearly every day, scientists are surprisingly still in the dark about how the process works. The new multimillion pound pain clinical research hub at King's College hospital in London will use state-of-the-art imaging techniques to look inside the brains and nervous systems of people suffering from pain. The aim is to discover fresh ways to measure pain and work out the effectiveness of current treatments.

Scientists will not just study the pain associated with trapping fingers in a door, a bee sting or a sharp poke in the ribs, all of which are defense mechanisms crucial for survival.

The ultimate goal at the unit, a planned five-year collaboration between King's College hospital, King's College London and the pharmaceutical company Pfizer, is to understand chronic pain.

"The area we're looking at is when the pain becomes pathological," said Dr. Magdi Hanna, director of pain services at King's College hospital and clinical director of the research center.

"The pain has no function itself other than leading to other problems. When you have chronic pain from diabetes, that doesn't defend you at all. Or pain as a result of shingles, that doesn't defend you from anything," she said.

About one in seven people in the UK suffers from some sort of chronic pain.

"Patients in chronic pain at the moment are really having a raw deal both from facilities available across the country and the availability of medicines and treatments," Hanna said. "More than 60 percent of people in chronic pain are not treated. Generally, the wider medical population do not recognize the symptoms of chronic pain and the seriousness as much as they should."

Chronic pain not only affects quality of life but also has various physiological effects. "Our immune response suffers when we have chronic pain, our defense mechanism suffers, our cardiovascular system suffers, control of our blood pressure becomes poorer, our heart functions less well," Hanna said.

The unit will use everything from basic sensory equipment to test response to various stimuli to functional magnetic resonance imaging to look at what is happening in the brain in real time when a person is feeling pain.

"The only thing we know at the moment is that we think there is a special area that responds to painful stimuli -- this is what we call the pain matrix," Hanna said.

The pain matrix includes areas such as the amygdala, the brain's alarm bell for danger, and the frontal cortex, the seat of the brain's higher cognitive functions. In addition, the relay station at the center of the brain, the thalamus, lights up. As does the insula, the part of our brains responsible for recognizing pain and disgust. But exactly how each bit of this complex system is activated in response to a painful event is a mystery.

Another task for the research team is to make pain easier for scientists to measure.

"Until now, we've only ever had people's subjective measures of pain," said Steve Williams, head of imaging sciences at the institute of psychiatry at King's College London. "We don't know whether one person's ouch is equivalent to the next person's ouch, as we've never had an objective way of measuring it."

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