People suffering from chronic pain hate to hear it, but the pain may really be “all in your head” according to a new study funded by the National Institutes of Health.
The research, published in the journal Pain, found that irregularities in the brain may predict whether a person will suffer chronic lower back pain. Scientists say it’s a discovery that may ultimately lead to changes in the way patients are diagnosed and treated.
“We’ve found the pain is triggered by these irregularities in the brain,” said A. Vania Apkarian, a senior author of the study and a professor of physiology at Northwestern University’s Feinberg School of Medicine. “We’ve shown abnormalities in brain structure connections may be enough to push someone to develop chronic pain once they have an injury.”
Using MRI brain scans of people who had a lower back injury, scientists found they could predict with about 85% accuracy which patients’ pain would persist.
“We were surprised how robust the results were and amazed at how well the brain scans predicted persistence of low back pain. Prediction is the name of the game for treating chronic pain,” Apkarian said.
The predictor was a specific irregularity or marker the scientists identified in the axons, pathways in the brain’s white matter that connect brain cells so they can communicate with each other.
Apkarian and his colleagues scanned the brains of 46 people who had an episode of lower back pain for at least four weeks and had not experienced any pain for at least one year before that.
Over the course of the next year, they evaluated the patients’ pain with examinations and questionnaires. About half of the subjects recovered at some time during the year, but the other half continued to have pain, which the researchers categorized as persistent.
The scientists found a consistent difference in white matter between the subjects who recovered and those who experienced pain throughout the year.
The researchers also found that the white matter of subjects who had persistent pain looked similar to a third group of subjects known to suffer from chronic pain. In contrast, the white matter of the subjects who recovered looked similar to that of healthy control subjects.
The abnormalities identified in the study were found in two brain regions involved in processing emotion and pain.
“The abnormality makes them vulnerable and predisposes them to enhanced emotional learning that then amplifies the pain and makes it more emotionally significant,” Apkarian said.
He explained more about his findings in this interview:
Low back pain represents about 28% of all types of pain in the United States. About 23% of these patients suffer chronic, or long-term, low back pain.
“Currently we know very little about why some patients suffer chronic low back pain,” said Debra Babcock, MD, a program director at the National Institute of Neurological Disorders and Stroke.
“The earlier we detect pain will become chronic, the better we may be able to treat patients.”