Training the brain to reduce pain could be a promising approach for treating phantom limb pain and complex regional pain syndrome, according to an internationally known neuroscience researcher speaking today at the American Pain Society's Annual Scientific Meeting, www.ampainsoc.org.
G. Lorimer Moseley, PhD, professor of clinical neurosciences at University of South Australia and Neuroscience Research Australia, and head of the Body in Mind research team, www.bodyinmind.org, told the plenary session audience that the brain stores maps of the body that are integrated with neurological systems that survey, regulate, and protect the integrity of the body physically and psychologically. These cortical maps govern movement, sensation and perception, and there is growing evidence, according to Moseley, showing that disruptions of brain maps occur in people with chronic pain. The best evidence is from those with phantom limb pain and complex regional pain syndrome, but there is also data from chronic back pain.
Moseley's research is focused on the role of the brain and mind in chronic and complex pain disorders. Through collaborations with clinicians, scientists and patients, the Body in Mind team is exploring how the brain and its representation of the body change when pain persists, how the mind influences physiological regulation of the body, how the changes in the brain and mind can be normalized with treatment.
"We're learning that chronic pain is associated with disruption of brain maps of the body and of the space around the body. When the brain determines the location of a sensory event, it integrates the location of the event in the body with a map of space. Disruption of these processes might be contributing to the problem," said Moseley. He added that it is possible for the body to be unharmed but the brain will respond by causing pain because it misinterpreted a benign stimulus as an attack. "We want to gradually train the brain to stop trying to protect body tissue that doesn't need protecting."
Moseley said the brain can "rewire" itself, a process called neuroplasticity. Often painful stimuli triggered by a broken bone or other trauma cause the brain to rewire and, as a result, the damage signal is never switched off after the initial body trauma is resolved. The result: Chronic pain. So if the brain is capable of changing to cause persistent pain, can it be changed back to normal to alleviate pain?
"The brain is the focal point of the pain experience, but the plasticity phenomena can be harnessed to help alleviate pain," Moseley said.
He further stated that disrupted cortical body maps may contribute to the development or maintenance of chronic pain and, therefore, could be viable targets for treatment. One treatment approach involves targeting motor systems through a process Moseley calls graded motor imagery. It relies on using visual images to help the brain change its perceptions of the body after prolonged pain stimuli. "For someone with phantom limb pain, the brain's body map still includes the severed arm or leg, and without any real stimuli from the region, it continues to produce pain," Moseley explained.
He reported that studies with graded motor imagery have shown encouraging results in complex regional pain syndrome and in phantom limb pain.
"Our work shows that the complex neural connections in the brain not only are associated with chronic pain, they can be reconnected or manipulated through therapy that alters brain perceptions and produce pain relief," said Moseley.
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