Brain Fog: It's All In Your Head

Posted by Jennie Ann Freiman MD on

Brain fog is commonly recognized as a cluster of symptoms that include forgetfulness, confusion, trouble concentrating, and a distracted, almost out-of-body sense of detachment. It can be linked to the use of medication (chemo-brain), health conditions (fibro-fog, lupus-fog, thyroid-fog and others) and/or lifestyle-related. In all cases, brain fog is not a medically or psychologically recognized diagnosis, which makes it hard for patients to be taken seriously by their health care providers. Doctors traditionally confirm a diagnosis with “hard” evidence, objective findings supported by lab tests, rather than subjective complaints and symptoms. Finally, things are changing: the recent use of neuroimaging gives credence to what those experiencing brain fog have always known: the sense of living in a cloud is very real. Brain fog objectively falls within the spectrum of cognitive impairment. Imaging studies show the foggy brain is challenged both by physical defects and subpar performance.

CT and MRI scans are useful for evaluating brain structure, assessing its physical state. PET, SPECT and fMRI (functional MRI) show the brain in action, how it functions in terms of blood flow, metabolic activity and oxygen use. fMRI maps brain activity in areas responsible for memory formation, decision-making, language, emotion and pain, among others. The foggy brain has some combination of physical and functional gaps that translate to reduced mental function, distraction, and difficulty communicating, coping, and interacting socially. Day-to-day living and quality of life suffer.

Neuroimaging studies support these conditions:

Chemo-brain: Up to 1/3 of people who undergo chemotherapy experience some version of brain fog, which can be short term or long lasting. It’s hard to know exactly how many people are affected because cognitive reserve can compensate for loss of mental function, which causes the real incidence of brain fog to be underestimated. For breast cancer treatment, the most studied form of chemotherapy-related cognitive impairment, rates are as high as 40% and higher in the case of women treated before menopause. MRI findings include total brain shrinkage, especially in the hippocampus, the memory center. PET scans show changes in brain metabolism, with less energy use in areas responsible for planning and prioritizing. fMRIs detect reduced blood flow to and through the brain and less brain connections, commonly resulting in distraction and weakened verbal memory.

Fibro-fog: Brain fog is one of the most common complaints with fibromyalgia, a complex disorder of generalized and widespread pain, fatigue and reduced function. The same holds true for chronic fatigue syndrome. Both conditions are tough to pinpoint and tend to be diagnosed by exclusion, defaulted to when nothing else explains the findings. Common laboratory tests are not useful in these cases. On MRI, fibro-fog is characterized by structural defects in gray matter, the brain’s cells and their connections. Neuroinflammation and alterations in brain patterns for pain signaling are seen on fMRI. fMRI findings are so specific that researchers believe they have uncovered a potential neurophysiologic “signature,” objective brain patterns unique to fibromyalgia. These results await further scientific confirmation. Stanford investigators report a specific neuroimaging signature has also been found for chronic fatigue syndrome and, in the future, may be valuable as a biomarker of that condition.

Thyroid-fog (also known as “cold brain syndrome”): Thyroid hormone is essential for normal brain development and function, so it’s no surprise that when lacking, cognitive performance is impaired. Neuroimaging studies in hypothyroidism show decreased brain connections and metabolic alterations in multiple areas involved in learning, memory, attention and mood. A 2014 study found that adults with significant hypothyroidism experience impaired driving similar to driving under the influence of alcohol. Study subjects were tested on a driving simulator, confirming impaired function that risks both personal and public health. When the thyroid doesn’t work, energy production is lowered. In the brain, less energy means less function.

Lupus-fog: Neuroinflammation is behind much of the physical and functional limitations found in this, rheumatoid arthritis, and other auto-immune disorders. The main neuroimaging correlates for lupus relate to fatigue, mood disturbances (especially depression) and fuzzy mental function.

Some quick tips for brain fog:

  • Identify, and if possible eliminate, any medication, prescription and over-the-counter, known to be linked to cognitive impairment, including cholesterol-lowering statins, sleeping pills and anticholinergic allergy and acid reflux drugs.
  • Seek treatment for associated medical conditions, in addition to those listed above, including depression, menopause, hepatitis C and lyme disease.
  • Address lifestyle contributors including stress, sleep disturbance, heavy metal and other environmental toxins, food allergies and additives, nutritional deficiencies, and lack of exercise.
  • Anti-inflammatory supplements and cognitive behavioral therapy are helpful interventions. 

Summary: There are distinct differences in the structure and function of the healthy brain vs. the foggy brain. Brain fog is real, and yes, objective studies show it’s all in your head.

Disclaimer: This article was created for informational purposes only, is not intended to provide medical advice, diagnosis or treatment and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Views expressed here do not necessarily reflect those of Oobroo™ Inc or its staff.

References available on request: email

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  • Thanks for your comment, George! The study didn’t exactly identify what was meant by “significant” hypothyroidism, so absent exactly knowing what that is, anyone with hypothyroidism (myself included!) need to be mindful when driving.

    Dr Freiman on
  • I found this fascinating, especially noting hypothyroidism affects driving like alcohol. Thank you. George of Santa Fe.

    George Bayless on

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