By: Dr Alex Robber
Hypersensitivity in fibromyalgia
Fibromyalgia hypersensitivity is not the same thing as being “too responsive” in the way people usually mean when they throw the word around. It’s not that we’re emotionally fragile, it’s that our physiological response is greater than most people’s, and over the year’s researchers have learned more about how the brains of people with fibromyalgia respond or, rather, overreact to changes occurring around us.
For a long time, we have been conscious that fibromyalgia requires an extreme hypersensitivity. The most obvious thing we’re hypersensitive to is pain, but it doesn’t stop heat, cold, noise, lights, smells, people, movement, confusion causing discomfort there as well. When it comes to pain this hyper-responsiveness is called hyperalgesia.
Hyperalgesia is a disorder that involves this characteristic that has recently been categorized under the umbrella of central sensitivity syndromes, as the symptom is due to central nervous system dysfunction. Continuous work provides us with insight into why and how we get this exaggerated response.
Scientists at the University of Michigan and Pohang University of Science and Technology in South Korea say they have found evidence in the brains of people with fibromyalgia of something called “explosive synchronization.”
Explosive synchronization (ES)
A new study finds that fibromyalgia patients have brain networks that are built to respond quickly to minor changes globally. This pathological hypersensitivity, called explosive synchronization (ES), can be seen in nature in other network phenomena. Researchers from Michigan University and Science and Technology University of Pohang in South Korea show evidence of ES in the brains of people with fibromyalgia, a disorder marked by severe, chronic pain.
The article, published in Scientific Reports, only outlines the second human brain data analysis on ES. “This research shows, for the first time, that hypersensitivity felt by chronic pain patients can result from hypersensitive brain networks,” says co-senior author Richard Harris, Ph.D., associate professor of anesthesiology at Michigan Medicine at the Chronic Pain and Fatigue Research Centre. “The subjects had similar conditions to other explosive-synchronization networks.”
Electrically unstable’ findings
The researchers had reported electrical activity with fibromyalgia in the brains of 10 female participants. The EEG tests from baseline showed hypersensitive and dysfunctional brain networks, Harris said. Importantly, the degree of ES conditions and self-reported severity of chronic pain reporting by patients at the time of EEG testing were strongly correlated.
Lee’s research team and collaborators in South Korea then used computer models of brain activity to compare fibromyalgia patients ‘ stimulation responses to the normal condition. The fibromyalgia model was, as predicted, more sensitive to electrical stimulation than the model with no ES characteristics, Harris says. “We see the chronic brain pain again becoming electrically dysfunctional and sensitive,” says Harris. He says this kind of modeling could help guide future fibromyalgia treatments.
Since ES can be modeled virtually outside the brain or on a computer, researchers can check exhaustively for influential regions that turn a hypersensitive network into a more stable one. Then, these regions could be activated by noninvasive brain stimulation therapies in living humans.
A small stimulus can lead to a dramatic synchronized reaction
In ES, a small trigger will result in a drastic coordinated response in the network, as can happen with a power grid failure (which switches things off quickly) or a seizure (which turns things on quickly). Until recently this phenomenon was researched in physics rather than in medicine.
Researchers say the ongoing attempt to discover how a person develops fibromyalgia is a promising avenue to explore. In comparison to the normal process of slowly connecting various centers in the brain after a stimulus, chronic pain patients have disorders that predispose them to suddenly and explosively link up, “says first author Uncoil Lee, Ph.D., a physicist and anesthesiology assistant professor at Michigan Medicine. Such conditions are like other networks undergoing ES, including power grids, according to Lee.
The Underlying Mechanism
When physicians set out to understand a disease, it’s a vital thing to figure out the “underlying mechanism” of that disorder. It’s the key to why the body behaves just as it is. It’s like trying to repair a broken car without understanding the underlying mechanism, without realizing which component is broken.
If ES is the underlying mechanism behind fibromyalgia’s hypersensitivity, then treating ES would be far more successful than using medications to dull the pain— it could end up being the thing that goes beyond the symptoms and corrects the physiology that’s gone wrong.
One small study, of course, is never definitive. It will take years of work to learn for certain whether this theory is correct, and then more time to find out the best ways to treat it. If those researchers are right, however, this could be a critical first step towards better results for people with fibromyalgia.
The insights may also stretch beyond fibromyalgia
The study not only points the way to the possible alleviation of hypersensitivity in brain networks, but it also shows the power of brain computer models, which could have implications for personalized medicine, as it could allow physicians to see how a given treatment could function before it can be attempted with a specific patient.
The findings may also extend beyond fibromyalgia, according to Richard Harris, co-senior author of the study, PhD, an associate professor of anesthesiology at the University of Michigan, and member of the Chronic Pain and Fatigue Research Center at the university.
“Under many other types of pain, our community and others say that the hypersensitive brain seen in patients with fibromyalgia is likely to present,” he said. “For example, improved functional neural integration between the sensory cortex and other brain networks transcends several diagnoses of pain, an outcome that may be linked to explosive synchronization.”
Reference : The study, “Functional Brain Network Mechanism of Hypersensitivity in Chronic Pain,” was published in the journal Scientific Reports.