Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Brain study of back pain sufferers yields intriguing results


Scans show amplified pain signals in patients with back pain of unknown origin

Patients with lower back pain that can’t be traced to a specific physical cause may have abnormal pain-processing pathways in their brains, according to a new study led by University of Michigan researchers.

The effect, which as yet has no explanation, is similar to an altered pain perception effect in fibromyalgia patients recently reported by the same research team.

In fact, the study finds, people with lower back pain say they feel severe pain, and have measurable pain signals in their brains, from a gentle finger squeeze that barely feels unpleasant to people without lower back pain. People with fibromyalgia felt about the same pain from a squeeze of the same intensity.

But the squeeze’s force must be increased sharply to cause healthy people to feel the same level of pain -- and their pain signals register p in different brain areas.

The results, which will be presented Oct. 27 at the annual meeting of the American College of Rheumatology in New Orleans, may help lead researchers to important findings on lower back pain, and on enhanced pain perception in general.

Senior authors Richard Gracely, Ph.D., and Daniel Clauw, M.D., did the study at Georgetown University Medical Center and the National Institutes of Health, but are now continuing the work at the University of Michigan Health System. In May, they and their colleagues published a paper in the journal Arthritis and Rheumatism on pain perception in fibromyalgia patients.

To correlate subjective pain sensation with objective views of brain signals, the researchers used a super-fast form of MRI brain imaging, called functional MRI or fMRI. They looked at the brains of 15 people with lower back pain whose body scans showed no mechanical cause, such as a ruptured disk, for their pain. They also looked at 15 fibromyalgia patients and 15 normal control subjects.

As a result, they say, the study offers the first objective method for corroborating what lower back pain patients report they feel, and what’s going on in their brains at the precise moment they feel it. And, it continues to give researchers a road map of the areas of the brain that are most -- and least -- active when patients feel pain. The researchers hope that further study on larger groups of patients will yield more information on altered pain processing.

"The fMRI technology gave us a unique opportunity to look at the neurobiology underlying tenderness, which is a hallmark of both lower back pain and fibromyalgia," says Clauw. "These results, combined with other work done by our group and others, have convinced us that some pathologic process is making these patients more sensitive. For some reason, still unknown, there’s a neurobiological amplification of their pain signals."

Lower back pain affects nearly all Americans from time to time, especially those who are overweight, sedentary or work in physically demanding jobs. The pain can interfere with life and work; problems stemming from lower back pain are the second most frequent cause of lost work days in adults under the age of 45, ranking below only the common cold.

Much of the pain may be due to pulled muscles, strained ligaments, damaged joints or small tears in the disks that act as cushions between the bones of the spine -- all causes that don’t show up well on X-rays but often can be seen on CT or conventional MRI scans. These physical causes often disappear after a few weeks, but many patients have chronic or recurring lower-back pain.

In the study, the lower-back pain patients were examined by CT scan to rule out mechanical causes of their pain. Then they, the fibromyalgia patients and the healthy control subjects had their brains scanned by fMRI for more than 10 minutes while a small, piston-controlled device applied precisely calibrated, rapidly pulsing pressure to the base of their left thumbnail. The pressures were varied over time, using painful and non-painful levels that had been set for each patient prior to the scan.

The study’s design gave two opportunities to compare patients and controls. The subjective comparison measured the pressure levels at which the pain rating given by back pain patients, fibromyalgia patients and control subjects was the same. The objective comparison looked at the rating that the three types of participants gave when the same level of pressure was applied.

The researchers found that it only took a mild pressure to produce self-reported feelings of pain in the lower-back pain and fibromyalgia patients, while the control subjects tolerated the same pressure with little pain.

"In both the back pain patients and the fibromyalgia patients, that same mild pressure also produced measurable brain responses in areas that process the sensation of pain," says Clauw. "But the same kind of brain responses weren’t seen in control subjects until the pressure on their thumb increased substantially."

Though brain activity increased in many of the same areas in both patients and control subjects, there were striking differences, too. All the subjects had increased activity in eight areas of their brains, but lower-back pain patients showed no increased activity in two areas that were active in both fibromyalgia patients and normal control subjects. Meanwhile, fibromyalgia patients showed increased activation in two other areas not active in back pain patients and healthy subjects.

This response suggests that lower-back pain patients have enhanced response to pain in some brain regions, and a diminished response in others, Clauw says.

The study was supported in part by the National Fibromyalgia Research Association, the U.S. Army and the NIH. In addition to Clauw and Gracely, the research team included Thorsten Giesecke and Masilo Grant of UMHS, Karen Munoz of NIH, Reshma Kumar of Georgetown, and Alf Nachemson of the University of Gotenberg, Sweden.

Kara Gavin | EurekAlert!
Further information:

More articles from Health and Medicine:

nachricht Inflammation Triggers Unsustainable Immune Response to Chronic Viral Infection
24.10.2016 | Universität Basel

nachricht Resolving the mystery of preeclampsia
21.10.2016 | Universitätsklinikum Magdeburg

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Ice shelf vibrations cause unusual waves in Antarctic atmosphere

25.10.2016 | Earth Sciences

Fluorescent holography: Upending the world of biological imaging

25.10.2016 | Power and Electrical Engineering

Etching Microstructures with Lasers

25.10.2016 | Process Engineering

More VideoLinks >>>