Brain fog

Brain fog manifests as impaired working memory and concentration accompanied by difficulty processing complex information.

It is a type of cognitive impairment experienced by ME/CFS patients. Fibromyalgia patients often refer to it as "fibro fog".

Causes
Brain fog is a common symptom of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome, but can also be caused - or linked to - other illnesses:
 * during chemotherapy, the mild cognitive impairment is often called "chemo brain" or "chemo fog"
 * depression - concentration problems may be described as brain fog
 * Ehlers-Danlos syndrome (EDS) patients may use the term brain fog to refer to the "inability to focus and maintain concentration" that is common in people with EDS, although ME/CFS is also common in people with EDS
 * the endocrine disorder hypoparathyroidism, which also causes mood problems
 * brain fog is common in people with fibromyalgia, and is often referred to as "fibro fog"
 * gluten sensitivity or celiac disease
 * hepatitis C virus
 * hypocalcemia - low levels of calcium in the blood, which also causes fatigue and many other symptoms
 * brain fog may be described by people with Ehlers-Danlos syndrome (EDS) as the "inability to focus and maintain concentration" that common in people with EDS, although ME/CFS is also common in people with EDS
 * Lyme disease patients may use the term brain fog to describe an impairment in thinking
 * postural orthostatic tachycardia syndrome (POTS) or other forms of orthostatic intolerance cause brain fog, "impaired cognition" and many other symptoms occur when a person stands or moves to an upright position
 * brain fog may be used to describe memory impairment resulting from concussion or traumatic brain injury
 * sarcoidosis-associated brain fog, which also causes fatigue
 * Sjögren's syndrome
 * Postorgasmic illness syndrome

Prevalence

 * Katrina Berne reports a prevalence of 75-100% for confusion and inability to think clearly.

Notable studies
"Our case study confirmed the pattern of dysregulation in the cortex reviewed in the introduction. Furthermore, since both periods of phase shift/lock durations were found to be significantly shorter, that might contribute to an increased rate of phase reset, also seen in our data. Phase reset deregulation--phase locking periods being too brief and phase reset happening too often—appear to be consistent with the associated lower rate of information processing and reaction times found in the ME and CFS literature. These deregulated states represent the brain during nonoptimal functioning, rendering it inefficient for most types of information processing functioning, whether it is executive functioning, memory, perceptual reasoning or information processing speed. When phase lock is significantly less than normal, as in this data set, the ability of the brain to sustain commitment of resources to mediate different functions is severely compromised. Phase shift duration in this data is also hypoactive, meaning that significantly less neurons are being recruited to perform a function than normal. The results here indicate slowed verbal comprehension, executive functions, perceptual reasoning, processing speed and memory, the sum total of which is known as cognitive impairment."
 * 2013, What is brain fog? An evaluation of the symptom in postural tachycardia syndrome
 * 2016, qEEG / LORETA in Assessment of Neurocognitive Impairment in a Patient with Chronic Fatigue Syndrome: A Case Report




 * 2018, Cognitive Impairment in Fibromyalgia: A Meta-Analysis of Case–Control Studies - (Abstract)

Learn more

 * 2013, Brain Fog in ME/CFS: What's Going On? - Solve ME/CFS
 * 2016, Case Study: “Brain Fog” in CFS can be seen in qEEG/Loreta - #MEAction
 * 2018, Study Identifies the Types of Cognitive Dysfunction That Are Most Prevalent in Fibromyalgia

"According to the Marshall Pathogenesis, cognitive dysfunction is caused by microbes. More severe forms of cognitive dysfunction are seen in diseases such as Alzheimer's, diseases for which there is strong evidence of a bacterial etiology. Often associated with chronic fatigue syndrome,1) cognitive dysfunction is also seen in patients with multiple sclerosis,2) depression,3) fibromyalgia,4) and dozens of others diseases."
 * Cognitive dysfunction (brain fog)