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Stanford scientists work towards developing a “painometer”

Stanford scientists work towards developing a "painometer"

About two years ago, Stanford neurologist Sean Mackey, MD, PhD, was asked by defense lawyers in a workman’s compensation case to serve as an expert witness. A man, burned by chemicals at work, wanted compensation from his employer for chronic pain, and his attorney was attempting to use brain scanning evidence to prove that his client was in chronic pain. Functional magnetic resonance imaging scans of his brain showed heightened activity in a network of regions associated with pain. But the question was, did this prove he was in pain?

According to Mackey, definitely not. The case was settled out of court.

“I was very critical of the findings,” Mackey recently told me. “In fact, they had not proven that this person had chronic pain. He may well have been in chronic pain, but current technology could not determine this.”

That experience helped spark Mackey’s interest in working toward finding technology that could someday achieve such a goal. Now, a study based on work from Mackey’s lab has taken a first step toward the development of a diagnostic tool that would use patterns of brain activity to give an objective physiologic assessment of whether someone is in pain.

The press release I wrote about the study, which was published online in PLoS One today, specifies that this is preliminary research and that much more needs to be done before the creation of a usable “painometer.” But early results are promising:

Researchers took eight subjects, and put them in the brain-scanning machine. A heat probe was then applied to their forearms, causing moderate pain. The brain patterns both with and without pain were then recorded and interpreted by advanced computer algorithms to create a model of what pain looks like. The process was repeated with a second group of eight subjects.

The idea was to train a linear support vector machine — a computer algorithm invented in 1995 — on one set of individuals, and then use that computer model to accurately classify pain in a completely new set of individuals.

The computer was then asked to consider the brain scans of eight new subjects and determine whether they had thermal pain.

“We asked the computer to come up with what it thinks pain looks like,” co-author Neil Chatterjee said. “Then we could measure how well the computer did.” And it did amazingly well. The computer was successful 81 percent of the time.

Such a tool, which could possibly be useful someday in a court of law, has long been sought after by physicians, Mackey told me. The current method of “self-reporting” – when doctors ask patients to rank their pain on a scale of 1-to-10 – is limiting, he said. Too many patients, especially the very young and the very old, have difficulty communicating pain. “Wouldn’t it be great if we had a technique that could measure pain physiologically?” he asked.

Previously: Using philosophy to create a vocabulary of pain, No pain, no gain. Not!, Relieving Pain in America: A new report from the Institute of Medicine, Stanford’s Sean Mackey discusses recent advances in pain research and treatment and Oh what a pain
Photo by El Gran Dee

7 Responses to “ Stanford scientists work towards developing a “painometer” ”

  1. Robert Says:

    While an algorithm written in 1995 to asses where pain is from a theoretical perspective may seem novel, I think that showing true pain would be more useful. The team from Uppsala Sweden seems to have found a way to show actual pain using a tracer protein and a PET scan. To me Evidence based as opposed to a theoretical location of pain would be more useful. With this protein and the fact that researchers have now identified the HCN2 gene as the gene responsible for chronic pain, a more targeted set of pharmaceuticals might be a better research area.
    Maybe until then you should focus on patient care. From what the reviews online of the Stanford pain team suggest, your patient care is extremely lacking. Most of your Pain doctors have bedside manner and a level of care that is extremely poor for such a large research hospital. Instead of focusing on litigation, you should have your team focus on patients.

  2. Tracie White Says:

    Thank you for your comment. This study doesn’t focus on litigation. The goal is to help provide better care for patients by helping to gain a more accurate measure of pain levels, particularly in patients who can’t communicate well – the very young and the very old.

  3. Saumitra Says:

    Good comments above. Would like to ask you Tracie if pain thresholds for different people are different, can you still establish a base line?

  4. Sean Mackey Says:

    Saumitra, I was fairly convinced going into this study that the highly individual nature of pain perception (e.g. different pain thresholds for example) would preclude our ability to objectively detect the presence or absence of pain. I was wrong – as born out by the results – but pleasantly surprised. There appears to be enough commonality in a human brain pain response to allow that pattern of brain activity to be used to detect another person’s state of pain. Again, this was under carefully controlled conditions and should not be extrapolated to chronic pain or any other painful condition. It is a novel first step however.
    WRT the initial posting, we are committed to providing the best we can in patient care to the approximately 10,000 patients who are treated in our Stanford Pain Management Center each year. Anything less is unacceptable.

  5. Saumitra Says:

    Sean: I appreciate your efforts in replying to my comment.I had attended your excellent talk on fMRI Engrams – Personalized Profiles of Pain and Emotion at Stanford on 02/28/2011. I remember you talking about S2 area and that specific lesions in brain can delete pain sensation.

  6. harper Says:

    I am in the middle of a situation that has made it painfully clear (pun intended) that there is a huge need for a better way to assess pain.I am a chronic pain patient (20 years)who for the first time has been assaulted by a doctor whose priority (stated and well known) is to get all his patients (I am not even his patient, my doc is on maternity leave) off pain meds. I was attacked to such an extent I shut down and became self destructive.I am on the mend, I hope, but his callousness and lack of empathy (of knowledge re: pain) so shocked me that, well, I just do not know where to turn. I hate the thought of lawyers but where else do I go when my doc just straight does not believe me. I even have a letter from my previous doctor outlining my situation but because he does not feel the MRI shows ENOUGH I am screwed. What do I do…where do I go? At this point I am resigned to weaning off all meds just to avoid any more hell, but then will come the other hell…pain.I am alone and lost in a new state with few friends, no family, and no where to turn. Any thoughts? Sorry to bitch and moan. H

  7. harper Says:

    Also, I have offered to take a lie detector or brain scan to prove my case and he just chuckled. He also chuckled when I asked if he had ever gone through withdrawal. He had just halfed my meds with no explantation the week previous (I waited for 1.5 hours in the waiting room but he could not be bothered to tell me why he had halfed my extremeley strong pain meds putting me into semi withdrawal)and I was curious whether he knew what that meant for me. He looked at me like “what do you mean have I gone through withdrawal, what do you think I am, a junky?” I think every doctor who has the power to cut someones narcotic meds should be required to go through what he put me through. Empathy, empathy, empathy.

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