The Pain-o-meter: Seeing Pain

(Ivanhoe Newswire) — More than 100 million Americans suffer chronic pain. Detecting this pain relies heavily on self-reporting, which can be confusing or ill-communicated. Now, researchers from the Stanford University School of Medicine have taken a first step toward developing a diagnostic tool that could eliminate this major hurdle in pain medicine.
“People have been looking for a pain detector for a very long time,” Sean Mackey, MD, PhD, chief of the Division of Pain Management, and associate professor of anesthesiology was quoted as saying.
“We rely on patient self-reporting for pain, and that remains the gold standard,” Dr. Mackey adds, “But there are a large number of patients, particularly among the very young and the very old, who can’t communicate their pain levels. Wouldn’t it be great if we had a technique that could measure pain physiologically?”
The subjective nature of pain has made this an elusive goal. However, advances in neuroimaging techniques have re-invigorated the debate over whether it might be possible to measure pain physiologically.
According to a study that will be published in the online journal PLoS ONE, the new tool would use patterns of brain activity to give an objective physiologic assessment of whether someone is in pain. The scientists used functional magnetic resonance imaging (MRI) scans of the brain combined with advanced computer algorithms to accurately predict thermal pain in healthy subjects.
“We’re hopeful we can eventually use this technology for better detection and better treatment of chronic pain,” Dr. Mackey was quoted as saying.
The idea for the study was born at a 2009 Stanford Law School event organized by Stanford Law professor Hank Greely, which Dr. Mackey attended. The event brought together neuroscientists and legal scholars to discuss how the neuroimaging of pain could be used and abused in the legal system.
“At the end of the symposium, there was discussion about the challenges of creating a ‘painometer’,” Dr. Mackey was quoted as saying.
$600 billion in medical expenses are accrued every year by chronic pain patients, according to a study released by the Institute of Medicine. The study also found cultural biases against pain sufferers, portraying them as liars about their pain.
According to Greely this not only complicates the delivery of appropriate treatment, but also creates hundreds of thousands of legal cases each year that hinge on the existence of pain.
“A robust, accurate way to determine whether someone is in pain or not would be a godsend for the legal system,” Greely was quoted as saying.
Two young scientists were up to the challenge, Neil Chatterjee, MD/PhD student at Northwestern University, and Justin Brown PhD and first author of the study.
They put eight subjects in the brain-scanning machine; and applied a heat probe to their forearms causing moderate pain. The brain patterns were then recorded and interpreted by the computer to create a model of what pain looks like.
The computer was then asked to consider the brain scans of eight new subjects and determine whether they had thermal pain. The computer did amazingly well, successfully detecting what pain looks like 81 percent of the time.
“I was definitely surprised,” Chatterjee was quoted as saying.
Researchers stressed that future studies are needed to determine whether these methods will work to measure various kinds of pain, and whether they can distinguish between pain and other emotionally arousing states such as anxiety or depression.
SOURCE: PLoS ONE, published online September 13, 2011