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    Brain Study Examines How People Feel Pain

    Brain Study Examines How People Feel Pain


    Filed at 7:56 p.m. ET
    WASHINGTON (AP) -- Pain that brings tears to one person's eyes may be barely noticed by someone else, and that can be a problem for doctors deciding on treatment.

    The answer: Listen to the patient, a new study says. Some people really do feel more pain than others.

    ``We have all met people who seem very sensitive to pain as well as those who appear to tolerate pain very well,'' said Robert C. Coghill of Wake Forest University Baptist Medical Center.

    ``Until now, there was no objective evidence that could confirm that these individual differences in pain sensitivity are, in fact, real,'' said Coghill, lead investigator on the paper published Monday in the online edition of Proceedings of the National Academy of Sciences.

    The study of brain activity showed that some people respond more strongly to pain.

    ``One of the critical things is, it provides physicians with the evidence they need to have confidence in patients' reports of pain and use that to guide treatment,'' Coghill said.

    The researchers used magnetic resonance imaging to study the brains of 17 volunteers. The skin of each volunteer's lower right leg was heated with a heating pad.

    After each heating the participants gave their estimate of how painful it was and the two sessions were averaged. On a one-to-10 scale various individuals rated the heating pain from a low of one to a high of ``almost nine.''

    When the researchers compared the brain scans to the pain ratings of the volunteers they found that parts of the brain known to be involved in experiencing pain were more active in people who said they felt more pain.
    In particular, they found increased activity in the primary somatosensory cortex, which deals with pain location and intensity, and the anterior cingulate cortex, which handles unpleasant feelings caused by pain.

    But they found little difference between people in the activity of the thalamus, which helps transmit pain signals from the spinal cord to brain regions.

    That may indicate that incoming pain signals are being delivered by the spinal cord in a similar way for different people, but once they arrive in the brain they are handled differently.

    Coghill said the study found no difference in response to heat pain between men and women.

    His paper comes six months after researchers at the University of Michigan reported finding a gene that can make people more or less sensitive to pain, depending on the form they inherit.

    In that study, brain scans showed that painkilling chemicals called endorphins were much more active in the brains of people who reported less sensitivity to pain.

    On the Net:

    I suffer with chronic pain, it is with me 24 hours a day. I have had to learn to tolerate high pain levels. On the number scale I am at a 5-6 most of the day but when my pain medication starts to wear off before the next dose (even with my breakthrough meds.) I am at a level higher than the numbers go.

    It is the kind of pain that the article describes, it takes my breath away. A person who does not suffer from chronic pain could not even handle my lower pain numbers 5-6.

    I think I speak for all chronic painers, we are one tough bunch of people. Day after Day we succumb to higher levels of pain than most people will experience in there entire lives.

    So many of us lock the pain away so well that people have a hard time understanding and believeing us when we say our numbers are high.

    We suffer in silence, we try to make others around us unaware of the nightmare we are liveing.

    When friends would tell me they had a headache and they are in alot of pain, I would think to myself that I wished thats all I felt.

    My personal journey to hell started 6 years ago. I had to have a laminectomy on L4-L5. I went back to work after 4 weeks. I WAS a chef for over 19 yreas, I ended up blowing the discs out after about 3 weeks of work. I then had a second laminectomy. After about five weeks into aqua physical therapy I blew them again. My third operation I had to have a lumbar fusion, I am now the proud owner of some titamun, and permenet nerve damage. I can no longer work, I have such burning pain in my right leg from the lower back to the tip of my toes. Sometime it feels like there are worms on fire crawling under my skin, and then some days it feels like a lightning bolt shooting down my leg and tries to bust through my toes.

    There is not a number high enough to rate that kind of pain, and in the past two years it has gotten worse. I have a large mass of scar tissue that is growing and wraping around my nerve bundle. So how do you rate that? I know every day I am going to be in pain, but I never know to what degree its going to be. I feel it but yet I'm able to block it out. So basicaly when my numbers are at 5-6 thats a real good place for me, at that level I'm able to block it out enough so I can at least get out of bed, walk around in the house without my cane, and cook dinner for me and my husband, But at that level a normal persons numbers would be alot higher because they dont have the pain long enough to be able to learn how to block some of it out.

    I feel if doctors want us painers to use the number system there should be a different scale for us,,some higher numbers for us to work with. Our pain is not a normal pain, it takes ahold of us and sucks our very soul when it gets high, my lower back sometimes feel like someone is takeing a butcher knife and stabbing me with it, turning the knife deep into my spine. When I have that knid of pain 10 is the low number then.



      Different people feel pain differently once the sensation leaves the spinal cord

      Different people feel pain differently once the sensation leaves the spinal cord

      Brad Evenson
      National Post

      Tuesday, June 24, 2003

      CREDIT: Darren Hauck, The Associated Press

      Vladimir Guerrero of the Monteal Expos: His brain knows being hit with a pitch hurts.

      Everyone has heard of rugby players who shrug off gashes, bruises and contusions, while more delicate people faint when they get a sliver. Now researchers say brain imaging technology can show which individuals can withstand pain the most.

      The findings also prove that people usually don't exaggerate their pain sensations.

      "We have all met people who seem very sensitive to pain as well as those who appear to tolerate pain very well," said lead investigator Robert Coghill, a professor of medicine at Wake Forest University in Winston-Salem, N.C. "Until now, there was no objective evidence that could confirm that these individual differences in pain sensitivity are, in fact, real."

      Scientists have long understood that pain has an emotional component. Two people who suffer the same injury may report wildly differing amounts of agony. For example, people who are stressed or depressed tend to suffer greater pain than healthy people, while battlefield reports tell of soldiers who barely noticed when they received wounds in the heat of battle.

      In the current study, the researchers burned a group of 17 volunteers with a small device that heats the skin up to 49° Celsius -- about the temperature of a ceramic coffee mug full of scalding coffee -- while monitoring their brain activity with a magnetic resonance imaging (MRI) scanner. The subjects would then rate their pain on a scale of one to 10.

      When the researchers looked at the thalamus, the brain region that transmits pain signals up the spinal cord to high brain centres, they saw little difference in activation among the volunteers. But the subjects who rated their pain highest had much greater activity in their primary somatosensory cortex, which detects where a painful stimulus originates and how much it hurts. Similarly, they had more activity in the anterior cingulate gyrus, where the unpleasant emotions arising from pain are processed.

      "This finding raises the intriguing possibility that incoming painful information is processed by the spinal cord in a generally similar manner," said Dr. Coghill. "But, once the brain gets involved, the experience becomes very different from one individual to the next."

      Dr. Coghill noted the pain rating reported by the volunteers and their MRI scans were similar, suggesting people aren't faking when they complain of intense pain, even if an injury is mild. "These findings confirm that self-reports of pain intensity are highly correlated to brain activation and that self-reports should guide treatment of pain."

      The intensity of pain a person feels is shaped by several factors, said Dr. Coghill. These include a person's experience with a particular kind of pain, the person's state of mind at the time, and the meaning that a person places on a particular stimulus.

      For example, he said, a subject in one of his previous pain studies was impervious to the pain of having capsicum -- the main ingredient in chili peppers -- injected into his skin. "That's usually a real tough one," he said. Yet the subject was very sensitive to heat pain.

      "His response was that when he was kid, he worked for his grandfather who was a beekeeper, and he got stung all the time. And so that stinging sensation of capsaisin was not nearly as painful to him as it would be to me."

      A person's mental state at the time of the pain can also have a major effect. People who are concentrating on tasks tend not to feel pain until they are finished.

      The study is published today in the journal Proceedings of the National Academy of Sciences.

      © Copyright 2003 National Post

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