July 2, 2012
Chronic Pain – It’s All In Your Head
redOrbit Staff & Wire Reports - Your Universe Online
Researchers at Northwestern University claim that they have discovered why one person who suffers an injury can recover completely, while another individual suffering a similar injury will go on to suffer chronic pain.
What they have discovered is that the difference is all in a person's head. To clarify, the scientists used longitudinal brain imaging to track subjects with recent back injuries, and discovered that two sections of the brain (those related to emotional and motivational behavior) communicate with each other.
The more they do so, the researchers discovered, the greater the chance that a person will go on to develop chronic pain. Their findings, which have been published in the journal Nature Neuroscience, could provide medical professionals with a new way to develop theories to treat this type of pain, which reportedly affects between 30 and 40 million American adults.
"For the first time we can explain why people who may have the exact same initial pain either go on to recover or develop chronic pain," A. Vania Apakarian, senior author of the paper and professor of physiology at the Northwestern University Feinberg School of Medicine, said in a statement.
"The injury by itself is not enough to explain the ongoing pain. It has to do with the injury combined with the state of the brain. This finding is the culmination of 10 years of our research," Apakarian added. "It may be that these sections of the brain are more excited to begin within certain individuals, or there may be genetic and environmental influences that predispose these brain regions to interact at an excitable level."
At the start of the study, the research team was able to predict, with 85% accuracy, which participants would go on to develop chronic pain. They did so by gauging the amount of interaction between the frontal cortex and the nucleus accumbens, and learning that the more emotional reaction the brain produces at the initial injury was linked to an increased chance that the pain would persist after the injury had healed.
Apakarian said that the team is hopeful that they will be able to develop new treatment therapies as a result of their findings. In 2011, the National Academy of Sciences reported that back pain and other types of chronic discomfort cost an estimated $600 billion each year.
"A total of 40 participants who had an episode of back pain that lasted four to 16 weeks -- but with no prior history of back pain -- were studied," the university said. "All subjects were diagnosed with back pain by a clinician. Brain scans were conducted on each participant at study entry and for three more visits during one year."