Research Roundup

Here is a quick overview of three interesting research studies that haven’t already been covered in CFIDSLink or the CFIDS Chronicle.

Chronic Pain Damages the Brain
Researchers at Northwestern University’s Feinberg School of Medicine in Chicago have found that chronic pain harms the brain’s wiring. In a study published in the February issue of the Journal of Neuroscience, the researchers found that long-term pain disrupts the equilibrium of the brain, causing the front region of the cortex to stay at full throttle instead of calming down.

"This continuous dysfunction in the equilibrium of the brain can change the wiring forever and could hurt the brain," says Dr. Dante Chialvo, one of the study’s authors. “We know that when neurons fire too much they may change their connections with other neurons or even die because they can’t sustain high activity for so long.”

Dr. Chialvo and his colleagues used functional magnetic resonance imaging (fMRI) to scan the brains of people with chronic low back pain and a group of pain-free controls while both groups were performing a simple visual attention task—tracking a moving bar on a computer screen. In the group with no pain, the researchers found that in a healthy brain all the regions exist in a state of equilibrium. When one region is active, the others quiet down. But in the people with chronic pain, the front region of the cortex was stuck on full throttle, wearing out neurons and altering their connections to each other.

The study concludes that chronic pain can disrupt brain function and cause problems like disturbed sleep, anxiety, depression and difficulty making decisions. The researchers say that the study points to the importance of finding new ways to treat pain not only to control the symptoms, but to prevent harm to the brain.

Baliki MN, Geha PY, Apkarian AV, Chialvo DR. Beyond feeling: chronic pain hurts the brain, disrupting the default-mode network dynamics. J Neurosci. 2008; 28(6):1398-403.

Fibro Pain Linked to Changes in Brain Molecule
Researchers at the University of Michigan Health System have published a study showing a link between pain and a brain molecule called glutamate. The study, published in the March issue of Arthritis and Rheumatism, suggests that decreasing the level of glutamate in people with fibromyalgia (FM)—with techniques like acupuncture—can reduce pain significantly.

Glutamate is an excitatory neurotransmitter that functions in pain-processing pathways, transmitting information between neurons in the nervous system. The researchers suspected this particular molecule of playing a role in FM because previous research demonstrated that some brain regions in people with FM, such as the insula, seem to be highly excited.

The research team used proton magnetic resonance spectroscopy (H-MRS), a noninvasive brain imaging technique, to determine if there was indeed a link between glutamate levels and pain. Using H-MRS images before and after a four-week course of acupuncture, the investigators found that not only was the pain reduced by the acupuncture, but the reduction in pain corresponded to a reduction in glutamate levels in the insula. Patients with greater reductions in pain showed greater reductions in glutamate.  

Dr. Richard Harris, lead author of the study, says that “If these findings are replicated, investigators performing clinical treatment trials in fibromyalgia could potentially use glutamate as a surrogate marker of disease response.” However, because this study was so small, with only 10 FM patients, more research is required to determine if glutamate could be used as a biomarker of disease severity.

Harris RE, Sundgren PC, Pang Y, Hsu M, Petrou M, Kim SH, McLean SA, Gracely RH, Clauw DJ. Dynamic levels of glutamate within the insula are associated with improvements in multiple pain domains in fibromyalgia. Arthritis Rheum. 2008 Mar;58(3):903-7.

Economic Impact of CFS Is Staggering
A study published April 8 in Dynamic Medicine adds to the evidence that CFS imposes a substantial economic burden on the United States. The study, led by Dr. Leonard Jason at DePaul University, examined both community-based and tertiary samples of patients and found that the annual economic impact of CFS was $18.7 billion for the community sample and $23.9 billion for the tertiary sample.

This is just the second study ever to measure the economic impact of CFS in the United States. The first, published by researchers at the CDC in 2004, found that the total value of lost productivity was $9.1 billion annually. The CDC study didn’t include health care costs in its estimates. The new 2008 study included both direct and indirect costs to determine the economic impact of the illness. Direct costs refer to medical costs like office visit charges, medical tests and medication costs. Indirect costs refer to work productivity losses, disability reimbursements, cost of services provided by caretakers, transportation and other expenses that aren’t direct medical costs.

To determine the economic burden of CFS, Dr. Jason and his team used the estimate that more than 800,000 adults in America have CFS.  This estimate is below the prevalence figure currently used by the CDC, which estimates that at least one million American adults, and possibly as many as four million, have CFS.

For the complete text of the study, go to http://www.dynamic-med.com/content/7/1/6.

Jason, LA, Benton MC, Valentine L, Johnson A, Torres-Harding S. The economic impact of ME/CFS: individual and societal costs. Dynamic Medicine 2008, 7:6.

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