Study Helps Explain ‘Brain Fog’ in Chronic Fatigue Syndrome

Chronic fatigue syndrome and fibromyalgia were both met with skepticism from doctors in the past. But as fibromyalgia has gained mainstream acceptance, chronic fatigue syndrome (CFS), also called myalgic encephalomyelitis (ME/CFS), has continued to meet with confusion and disbelief.

That researchers can’t agree on a name for CFS shows just how little is known about a condition that affects at least 1 million Americans. Doctors don’t know what causes the chronic exhaustion and cognitive impairment of CFS. The only medical treatments are antidepressants and sleeping pills.

Learn More About Chronic Fatigue Syndrome »

Dr. Mady Hornig, an associate professor of epidemiology at Columbia University’s Mailman School of Public Health and her colleagues at the Chronic Fatigue Initiative are pushing hard to show that CFS is a real physical ailment. 

The more that we can demonstrate … there’s something biologically different in the blood and in the brain in individuals with ME/CFS, the more advances we can make toward upending that entrenched and mistaken view of the illness.
Dr. Mady Hornig, Columbia University

Last month, Hornig published a paper that found a unique immune signature in the blood of CFS patients. That paper claimed to be the first to offer proof that CFS is a “biological illness.”

“The more that we can demonstrate with objective evidence that there’s something biologically different in the blood and in the brain in individuals with ME/CFS, the more advances we can make toward upending that entrenched and mistaken view of the illness,” Hornig told Healthline.

In a second paper published today, Hornig and her colleagues showed differences in the number of immune molecules in the cerebrospinal fluid of healthy patients and those with CFS. That fluid “gives kind of a window to what’s going on in the brain,” explained Suzanne Vernon, Ph.D., the scientific director of the Solve ME/CFS Initiative. 

An immune response in the brain could explain the cognitive impairment CFS patients call “brain fog.” 

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What Is ‘Brain Fog’?

Patients who are experiencing severe symptoms of CFS, which tend to ebb and flow, complain they have difficulty retrieving memories. Some even find themselves unable to sign their own names, Hornig said. 

patient and doctor

CFS-sufferers don’t forget so much as have difficulty calling up their memories.

“It’s the effort that they require to process things that you need to do even simple tasks,” Hornig said. Patients often describe this “brain fog” as the single worse symptom of CFS.

Hornig’s new study compared snapshots of immune molecules called cytokines in the cerebrospinal fluid of long-time chronic fatigue patients to patients with multiple sclerosis (MS) and to a healthy control group. 

Many of the cytokines were less common in the CFS group, most notably interleukin 6. In animal research, scientists have shown that the brain needs interleukin 6 in order to form memories. CFS and MS patients did have higher levels of one cytokine — eotaxin — than the healthy volunteers.

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A picture is emerging of CFS as an autoimmune disease that, like MS, has both physical and neurological symptoms.

“This work further substantiates the reality of this profound pathology that’s happening in ME/CFS patients,” Vernon said.

Immune Disturbance Is a Clue, Not an Answer

With some cytokines at lower levels and a few at higher levels, the study results “indicate a markedly disturbed immune signature” akin to patterns seen in cases of autoimmunity, the study authors concluded.

What we aim to do with this research is to fill up the empty toolkits of clinicians ... There are no clear diagnostic tests, and there are no treatments in those toolkits either.
Dr. Mady Hornig, Columbia University

But a “disturbed” immune processes isn’t specific enough to pinpoint the cause of the condition. It could be a virus or an allergy that sends the immune system off course, according to Hornig. 

There’s still work to be done, in other words. 

“What we aim to do with this research is to fill up the empty toolkits of clinicians,” Hornig said. “There are no clear diagnostic tests, and there are no treatments in those toolkits either. We want to get some traction so that there isn’t a disincentive for physicians to diagnose this illness.”

Learn More: Institute of Medicine Says ‘Chronic Fatigue’ Should Get a New Name »