More than 70 million people in the United States have chronic pain. Although hypnosis has been shown to be effective in controlling pain, it is not used as often as it could be by physicians and psychologists. Recent research now demonstrates how the brain responds during hypnotic analgesia.
"There are two discrete neurological systems of pain involved" says Helen Crawford, professor emeritus of psychology at Virginia Tech. "We found evidence that, during hypnotic analgesia, the prefrontal cortex directs other areas of the brain to reduce or eliminate awareness of pain.
"It tells us a lot about attention in general — about our abilities to attend to or ignore stimuli in the environment," she says.
Crawford's research demonstrates that hypnotizable people can successfully use hypnosis to help them ignore pain because they have a strong ability to direct their attention away from things and filter out distractions.
"Hypnosis is a state of focused attention. Individuals who can ignore distractions — who work in a noisy environment and tune it out, for example — are often responsive to hypnosis," Crawford explains.
Funded by the National Institutes of Health, Crawford and her graduate students, with consultation from Scott Jamison, an M.D. from Christiansburg, Va., and Karl Pribram, director of the Center for Brain Research and Informational Sciences at Radford University, conducted research on whether chronic sufferers of low-back pain can find relief through hypnosis and how hypnosis affects the electrophysiology of the areas of the brain responsible for the ability to perceive pain in people with and without chronic pain.
"Pain is an awareness created by the brain. Over time a strong memory of pain is created so future pain may be easier to feel because the message gets through more quickly. Hypnosis can help break that memory pattern," Crawford reports.
In earlier research with colleagues at the University of Pennsylvania, regional cerebral blood flow (CBF) was observed. CBF increased with pain, but increased even further when subjects successfully used hypnotic analgesia. "Increased CBF in the prefrontal region during the successful inhibition of pain is a result of higher mental effort," Crawford says.
In Crawford's recent research project, she and colleagues worked with 17 volunteers who had been referred by physicians and chiropractors. The research subjects ranged in age from 19 to 43. Each had experienced low back pain from between six months to 11 years. Seventy-one percent had damaged disks. They had tried various medical treatments, from pain relievers to surgery.
During the study, the volunteers kept pain, medication, and sleep diaries so they could observe the possible effect of applying skills learned during the experimental research at home.
During the first session, the researchers used a neutral experimental pain (ice water) to train the volunteers to suppress pain during hypnosis. Pain control techniques included relaxation and imagery, such as imagining that the arm is in a glove, or that they are somewhere else -- on a beach playing volleyball or in the mountains riding horses.
"Hypnosis makes the subject relaxed and open to suggestions, and heightens the imagery," says Crawford. Once learned, the techniques can be used again later in a non-hypnotic environment.
Some of the volunteers were able to reduce their pain to zero on the first day. And while they worked with reducing the experimental pain, some found they were also experiencing less pain in their backs.
"In the process of the research, they relaxed their whole body, including their backs," says Crawford.
In the next two experimental sessions, researchers gave two experimental pains to the subjects and studied their brain waves when they were and were not using pain control techniques When given painful sharp stimuli to the finger over 30 trials, the brain waves showed less reactivity to them when they used hypnotic analgesia techniques than when they attended to the pain. "The pain still registers in the brain but perception is inhibited," Crawford reports.
The researchers encouraged the volunteers to apply their newly learned pain suppression techniques at home and at work to their own low back pain. By the end of the study, most of the volunteers had reduced the amount of pain medication they needed in order to be able to sleep; 35 percent stopped pain medication at bedtime. Many of the subjects reported it took them less time to fall asleep at night. Overall reported depression decreased over the three weeks.
Crawford suggests that hypnosis and psychological therapy for pain be introduced early as adjuncts in medical treatments for pain -- before strong pain memories develop, and before surgery and long regimens of drug treatment. The National Institute of Health technology assessment panel concurs that "behavioral therapies for chronic cancer pain should be accepted as part of cancer treatment," and cites Crawford's work (Journal of the National Cancer Institute, Nov. 15, 1995).
Crawford is going to repeat her research with a new electrode system with 128 electrodes on the surface of the brain (The first research used 19 contact points.) in order to pick up a higher degree of electrical activity of a greater portion of the brain. The goal is to refine and localize the structures and processes involved.
— Written by Sally Harris