Posts tagged chronic pain
Articles and news from the latest research reports.
Researchers report progress in quest to create objective method of detecting pain
A method of analyzing brain structure using advanced computer algorithms accurately predicted 76 percent of the time whether a patient had lower back pain in a new study by researchers from the Stanford University School of Medicine.
The study, published online Dec. 17 in Cerebral Cortex, reported that using these algorithms to read brain scans may be an early step toward providing an objective method for diagnosing chronic pain.
“People have been looking for an objective pain detector — a ‘pain scanner’ — for a long time,” said Sean Mackey, MD, PhD, chief of the Division of Pain Medicine and professor of anesthesiology, pain and perioperative medicine, and of neurosciences and neurology. “We’re still a long way from that, but this method may someday augment self-reporting as the primary way of determining whether a patient is in chronic pain.”
The need for a better way to objectively measure pain instead of relying solely on self-reporting has long been acknowledged. But the highly subjective nature of pain has made this an elusive goal. Advances in neuroimaging techniques have initiated a debate over whether this may be possible. Such a tool would be particularly useful in treating very young or very old patients or others who have difficulty communicating, Mackey said.
In a study published last year in PLoS ONE, Mackey and colleagues used computer algorithms to analyze magnetic resonance imaging scans of the brain to accurately measure thermal pain in research subjects 81 percent of the time. But the question remained whether this could be a successful method for measuring chronic pain.
The goal of the new study was to accurately identify patients with lower back pain vs. healthy individuals on the basis of structural changes to the brain, and also to investigate possible pathological differences across the brain.
Researchers conducted MRI scans of 47 subjects who had lower back pain and 47 healthy subjects. Both groups were screened for medication use and mood disorders. The average age was 37.
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 read the brain scans and classify pain in a completely new set of individuals.
The method successfully predicted the patients with lower back pain 76 percent of the time.
“Lower back pain is the most common chronic condition we deal with,” Mackey said. “In many cases, we don’t understand the cause. What we have learned is that the problem may not be in the back, but in the amplification coming from the back to the brain and nervous system. In this study, we did identify brain regions we think are playing a role in this phenomena.”
Discovery could eventually help diagnose and treat chronic pain
More than 100 million Americans suffer from chronic pain. But treating and studying chronic pain is complex and presents many challenges. Scientists have long searched for a method to objectively measure pain and a new study from Brigham and Women’s Hospital advances that effort. The study appears in the January 2013 print edition of the journal Pain.
"While we need to be cautious in the interpretation of our results, this has the potential to be an exciting discovery for anyone who suffers from chronic pain," said Marco Loggia, PhD, the lead author of the study and a researcher in the Pain Management Center at BWH and the Department of Radiology at Massachusetts General Hospital. "We showed that specific brain patterns appear to track the severity of pain reported by patients, and can predict who is more likely to experience a worsening of chronic back pain while performing maneuvers designed to induce pain. If further research shows this metric is reliable, this is a step toward developing an objective scale for measuring pain in humans."
Specifically, researchers studied 16 adults with chronic back pain and 16 adults without pain and used a brain imaging technique called arterial spin labeling to examine patterns of brain connectivity (that is, to examine how different brain regions interact, or “talk to each other”). They found that when a patient moved in a way that increased their back pain, a network of brain regions called Default Mode Network exhibited changes in its connections. Regions within the network (such as the medial prefrontal cortex) became less connected with the rest of the network, whereas regions outside network (such as the insula) became connected with this network. Some of these observations have been noted in previous studies of fibromyalgia patients, which suggests these changes in brain connectivity might reflect a general feature of chronic pain, possibly common to different patient populations.
"This is the first study using arterial spin labeling to show common networking properties of the brain are affected by chronic pain," said study author Ajay Wasan, MD, MSc, Director of the Section of Clinical Pain Research at BWH. "This novel research supports the use of arterial spin labeling as a tool to evaluate how the brain encodes and is affected by clinical pain, and the use of resting default mode network connectivity as a potential neuroimaging biomarker for chronic pain perception."
Extended sleep reduces pain sensitivity
A new study suggests that extending nightly sleep in mildly sleepy, healthy adults increases daytime alertness and reduces pain sensitivity.
"Our results suggest the importance of adequate sleep in various chronic pain conditions or in preparation for elective surgical procedures," said Timothy Roehrs, PhD, the study’s principal investigator and lead author. "We were surprised by the magnitude of the reduction in pain sensitivity, when compared to the reduction produced by taking codeine."
The study, appearing in the December issue of the journal SLEEP, involved 18 healthy, pain-free, sleepy volunteers. They were randomly assigned to four nights of either maintaining their habitual sleep time or extending their sleep time by spending 10 hours in bed per night. Objective daytime sleepiness was measured using the multiple sleep latency test (MSLT), and pain sensitivity was assessed using a radiant heat stimulus.
Results show that the extended sleep group slept 1.8 hours more per night than the habitual sleep group. This nightly increase in sleep time during the four experimental nights was correlated with increased daytime alertness, which was associated with less pain sensitivity.
In the extended sleep group, the length of time before participants removed their finger from a radiant heat source increased by 25 percent, reflecting a reduction in pain sensitivity. The authors report that the magnitude of this increase in finger withdrawal latency is greater than the effect found in a previous study of 60 mg of codeine.
According to the authors, this is the first study to show that extended sleep in mildly, chronically sleep deprived volunteers reduces their pain sensitivity. The results, combined with data from previous research, suggest that increased pain sensitivity in sleepy individuals is the result of their underlying sleepiness.
Where does it hurt? Pain map discovered in the human brain
Scientists have revealed the minutely detailed pain map of the hand that is contained within our brains, shedding light on how the brain makes us feel discomfort and potentially increasing our understanding of the processes involved in chronic pain.
The map, uncovered by scientists at UCL, is the first to reveal how finely-tuned the brain is to pain. Published in the Journal of Neuroscience, the study uses fMRI techniques in conjunction with laser stimuli to the fingers to plot the exact response to pain across areas of the brain.
“The results reveal that pain can be finely mapped in the brain,” said lead author Dr Flavia Mancini (UCL Institute of Cognitive Neuroscience). “While many studies have examined the brain response to pain before, our study is the first to map pain responses for the individual digits of the human hand.”
Using an fMRI brain imaging technique originally created to map the visual field, the researchers were able to distinguish the brain’s responses to painful laser heat stimuli on each finger in seven healthy participants, and to study their organisation in the brain.
This enabled the team to produce a fine-grained map showing how pain in the right hand results in certain parts of the brain being activated in the primary somatosensory cortex, an area in the left hemisphere of the brain which is involved in processing bodily information.
When comparing this pain map to ones generated by non-painful touch to the right hand, the researchers found that the two were very similar, with each map aligning with one another in each of the seven volunteers tested.
“The cells in the skin that respond to pain and the cells that respond to touch have very different structures and distributions, so we were surprised to find that the maps of pain and of touch were so similar in the brain,” said Dr Mancini. “The striking alignment of pain and touch maps suggests powerful interactions between the two systems.”
The pain maps could be used to provide markers for the location of pain in the human brain, enabling clinicians to see how patients’ brains reorganise following chronic pain.
“We know that the organisation of other sensory maps in the brain is altered in patients with chronic pain,” said Professor Patrick Haggard (UCL Institute of Cognitive Neuroscience). “Our method could next be used to track the reorganisation of brain maps that occurs in chronic pain, providing new insights into how the brain makes us feel pain. Therefore, measuring the map for pain itself is highly important.”
(Source: ucl.ac.uk)
In a world of chronic pain, individual treatment possible
An investigation into the molecular causes of a debilitating condition known as “Man on Fire Syndrome” has led Yale researchers to develop a strategy that may lead to personalized pain therapy and predict which chronic pain patients will respond to treatment.
More than a quarter of Americans suffer from chronic pain and nearly 40 percent do not get effective relief from existing drugs. In many common conditions such as diabetic neuropathy, no clear source of pain is found.
The new study published in the Nov. 13 issue of Nature Communications used sophisticated atomic modeling techniques to search for mutations found in a rare, agonizing, and previously untreatable form of chronic pain called erythromelagia, commonly referred to as “Man on Fire Syndrome.” Researchers discovered that one of those mutations seem to predicted whether a patient would respond positively to drug treatment.
“Hopefully we can use this knowledge to help chronic pain patients in more systematic ways, and not depend upon trial and error,” said Yang Yang, postdoctoral research associate in the Department of Neurology and lead author of the paper.
How does electrical stimulation affect the brain? A project by Aalto University and the University of Helsinki, launched in early 2012, studies the impact mechanism of deep brain stimulation and develops electrochemical sensors for more effective measuring of neurotransmitters in the brain. The long-term goals of the research are more specific treatment for Parkinson’s disease and many other diseases of the nervous system.
Chronic pain distorts sufferers’ sense of space and time
July 24, 2012
Einstein’s famous theory of relativity proposed that matter can distort space and time. Now a new study recently published in the journal Neurology suggests that chronic pain can have the same effect.
Neuroscientists from the University of South Australia, Neuroscience Research Australia and the University of Milano Bicocca in Italy, studied people with chronic back pain, the most common painful condition which costs western countries billions of dollars in lost productivity every year.
They presented identical vibration stimuli to the painful area and a non-painful area and noted that the stimuli were processed more slowly by the brain if they came from the painful area.
The most striking finding, however, was that the same effect occurred if the stimuli were delivered to a healthy body part being held near the painful area.
Lead author of the study, Professor Lorimer Moseley from the University of South Australia, says it was not altogether surprising that, in people with chronic pain, there are changes in the way the brain processes information from and about the painful body part.
“But what is remarkable is that the problem affects the space around the body as well as the body itself,” Prof Moseley says.
Experiments showed that if a hand was held near the painful area of the back, the brain would almost ‘neglect’ that hand.
“The potential similarity between our findings and the time-space distortion predicted by the relativity theory is definitely intriguing,” Prof Moseley says.
“Obviously, here it is not external space that is distorted but the ability of the brain to represent that space within its neural circuitry.
“This finding opens up a whole new area of research into the way the brain allows us to interact with the world and how this can be disrupted in chronic pain.”
Provided by University of South Australia
Source: medicalxpress.com