Cognitive dysfunction

Cognitive dysfunction or cognitive impairment is a symptom in most diagnostic criteria for ME/CFS; some patients call it "brain fog". It is also a common symptom of fibromyalgia which many patients call "fibro fog."

Forms of cognitive dysfunction commonly found in ME/CFS include reduced attention span, brain fog/cognitive fog, cognitive overload, concentration problems, confusion, difficulties with calculations, dyslexia (or linguistic reversals) when fatigued, difficulty absorbing information, difficulty sequencing words and numbers, multi-tasking problems, planning problems, poor working memory, reading or speaking difficulties, short-term memory problems, slowed thought, spatial disorientation, slow processing of information and word-finding problems. A 2016 study found that IQ scores of adolescents with CFS tested lower than the IQ scores of healthy peers with an equivalent school level. Currently it is not known whether lower IQ outcomes are due to concentration problems, a lowered processing speed or the illness itself.

Prevalence

Cognitive dysfunction is extremely common in ME/CFS, and is a symptom used for diagnosis in most case definitions including the current CDC diagnostic criteria for ME/CFS.

Cognitive dysfunction is also a symptom that commonly occurs during post-exertional malaise, which is the hallmark symptom of ME/CFS, and can result from orthostatic intolerance, which is another very common ME/CFS symptom.

See also

Post-exertional malaise.

Symptom recognition

Cognitive dysfunction is a particularly common symptom of ME/CFS, but is also a symptom of many other illnesses.

Mandatory ME/CFS symptom

Cognitive dysfunction is a mandatory diagnostic symptom for ME/CFS with the Canadian Consensus Criteria (CCC).

Optional ME/CFS symptom

Impaired memory or ability to concentrate is a core symptom in the current CDC ME/CFS diagnostic criteria diagnostic criteria, and is required when orthostatic intolerance is not present. Cognitive dysfunction is part of the possible diagnostic symptoms in the International Consensus Criteria (ICC) for myalgic encephalomyelitis (ME).

Diagnosis

• Cognitive Dysfunction and “Brain Fog” in POTS

Possible causes

Neurological changes in ME/CFS

Key neurological pathomechanisms in ME/CFS.
Source: Wirth, K.J., Scheibenbogen, C. & Paul, F. An attempt to explain the neurological symptoms of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. J Transl Med 19, 471 (2021). https://doi.org/10.1186/s12967-021-03143-3

Causes of neurological symptoms in ME/CFS include:

• hyperventilation/hypnocapnia (reduced carbon dioxide levels in the blood)
• intracranial hypertension (increased pressure within the skull and around brain)
• reduced blood flow to the brain
• brain inflammation may also be a factor

Wirth, Scheibenbogen and Paul (2021) state these "can explain cognitive impairment, brain fog, headache, psychomotor slowing, ataxia and loss of coordination of movements, hypersensitivity, sleep disturbances and dysautonomia."

Cerebrospinal fluid changes

Mady Hornig and colleagues have found evidence in the cerebrospinal fluid (CSF) of ME/CFS patients that may explain their cognitive dysfunction.

Brain changes

Figure 1: Results of LORETA current source density in a case with CFS showing widespread decreased current density for delta at 2 Hz and beta (12- 15 Hz) demonstrating a global reduction in brain functioning (blue). The higher frequencies (beta) have been shown to be a function of delta frequencies. In other words, local oscillations are under constant influence of global brain dynamics (Buzsaki, 2006).

Zinn et al. (2016) studied brain functioning in chronic fatigue syndrome and concluded:

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.

Drug and supplements

Drugs, supplements or treatment interventions that may cause cognitive problems in some ME/CFS patients:

• Diphenhydramine (Benadryl) an antihistamine also used to aid sleep
• Certain pain killers, particularly opioids, gabapentin (Neurontin), tricyclic antidepressants including amitriptyline (Elavil, Endep) and nortriptyline (Aventyl, Pamelor)
• sleep medications

Exercise and graded exercise therapy

A healthy person becomes more alert after exercise, but people with ME/CFS find their cognitive difficulties increase, they become much slower at mental activities, and cognitive tasks seem to take extra effort. Graded exercise therapy (GET) / Graded Activity Therapy also has this effect in ME/CFS patients.

See also

Exercise.

Other illnesses or health conditions

Cognitive dysfunction can be caused or made worse by other health conditions, most of which should be ruled out or identified during diagnostic process for ME/CFS:

• Cancer or cancer treatment ("chemo brain")
• Depression
• Fibromyalgia
• Long COVID symptoms
• Lupus
• Menopause
• Multiple sclerosis
• Pregnancy
• Sleep dysfunction or sleep disorders

Potential treatments

Drugs, supplements and other treatments that have been suggested for reducing cognitive impairment and/or improving brain fog include:

• Acetyl-L-carnitine
• Arabinoxylan (ineffective)
• B vitamin complex
• B vitamin
• Clonidine hydrochloride (ineffective)
• Dexamphetamine (weak evidence)
• Dynamic Neural Retraining System
• Fludrocortisone (ineffective)
• Histamine
• Hydrocortisone (most trials show some positive effective)
• Lying down or moving to a semi-reclined position for cognitive tasks
• Methylene blue
• Methylphenidate (weak evidence) and the experimental treatment KPAX002
• Modafinil for alertness but Collatz et al. (2014) found it ineffective
• Moclobemide
• Neurolinguistic programming
• Nimodipine for mental clarity, starting at 30mg, increase up to 60mg if tolerated (weak evidence)
• Phenelzine (ineffective in ME/CFS)
• Rintatolimod (Ampligen)
• Stellate ganglion block in dysautonomia in some long COVID patients
• Valganciclovir (ineffective)
• Yoga

Notable studies

• 2022, Systematic review and meta‐analysis of cognitive impairment in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) - (Full text)
• 2016, Cognitive Dysfunction in Chronic Fatigue Syndrome: a Review of Recent Evidence - (Abstract)
• 2016, The impact of chronic fatigue syndrome on cognitive functioning in adolescents - (Full text)
• 2016, qEEG / LORETA in Assessment of Neurocognitive Impairment in a Patient with Chronic Fatigue Syndrome: A Case Report - (Full text)
• 2011, Cognitive deficits in patients with chronic fatigue syndrome compared to those with major depressive disorder and healthy controls - (Full text)

• 2006, Cognitive dysfunction relates to subjective report of mental fatigue in patients with chronic fatigue syndrome - (Full text)
• 2015, Less efficient and costly processes of frontal cortex in childhood chronic fatigue syndrome - (Full Text)
• 2001, Neuropsychological functioning in chronic fatigue syndrome: a review - (Abstract)

Disability

In 2018 Brian Vastag was able to prove the severity of his chronic fatigue syndrome cognitive dysfunction with qEEG and cognitive tests, which proved he had "significant problems with visual perception and analysis, scanning speed, attention, visual motor coordination, motor and mental speed, memory, and verbal fluency" winning his long term disability (LTD) claim in the United States.

See also

• Fibromyalgia
• Long COVID
• Aphasia
• Dyscalculia
• Dysphasia
• Memory problems
• Word-finding problems
• Myalgic encephalomyelitis (M.E.)
• Long COVID

Learn more

• 2015, Dr. Gudrun Lange Reviews Neuropsychological Testing for CFS and FM
• 2016, Case Study: "Brain Fog" in CFS can be seen in qEEG/Loreta
• 2018, Study Identifies the Types of Cognitive Dysfunction That Are Most Prevalent in Fibromyalgia
• Jun 4, 2018, Victory For ME Disability Claim – U.S. Court Upholds Plaintiff's Lawsuit After Being Denied Disability

cognition Thought processes, including attention, reasoning, and memory.

cognition Thought processes, including attention, reasoning, and memory.

Canadian Consensus Criteria (CCC) - A set of diagnostic criteria used to diagnose ME/CFS, developed by a group of practicing ME/CFS clinicians in 2003. The CCC is often considered to be the most complex criteria, but possibly the most accurate, with the lowest number of patients meeting the criteria. Led to the development of the International Consensus Criteria (ICC) in 2011.

International Consensus Criteria (ICC) - A set of diagnostic criteria, based on the Canadian Consensus Criteria, that argued for the abandonment of the term "chronic fatigue syndrome" and encouraged the sole use of the term "myalgic encephalomyelitis".

β β / Β. Greek letter beta (a symbol used in science), equivalent to "b".

graded exercise therapy (GET) - A gradual increase in exercise or activity, according to a pre-defined plan. Focuses on overcoming the patient's alleged unhelpful illness beliefs that exertion can exacerbate symptoms, rather than on reversing physical deconditioning. Considered controversial, and possibly harmful, in the treatment or management of ME. One of the treatment arms of the controversial PACE trial.

myalgic encephalomyelitis (M.E.) - A disease often marked by neurological symptoms, but fatigue is sometimes a symptom as well. Some diagnostic criteria distinguish it from chronic fatigue syndrome, while other diagnostic criteria consider it to be a synonym for chronic fatigue syndrome. A defining characteristic of ME is post-exertional malaise (PEM), or post-exertional neuroimmune exhaustion (PENE), which is a notable exacerbation of symptoms brought on by small exertions. PEM can last for days or weeks. Symptoms can include cognitive impairments, muscle pain (myalgia), trouble remaining upright (orthostatic intolerance), sleep abnormalities, and gastro-intestinal impairments, among others. An estimated 25% of those suffering from ME are housebound or bedbound. The World Health Organization (WHO) classifies ME as a neurological disease.

myalgic encephalomyelitis (M.E.) - A disease often marked by neurological symptoms, but fatigue is sometimes a symptom as well. Some diagnostic criteria distinguish it from chronic fatigue syndrome, while other diagnostic criteria consider it to be a synonym for chronic fatigue syndrome. A defining characteristic of ME is post-exertional malaise (PEM), or post-exertional neuroimmune exhaustion (PENE), which is a notable exacerbation of symptoms brought on by small exertions. PEM can last for days or weeks. Symptoms can include cognitive impairments, muscle pain (myalgia), trouble remaining upright (orthostatic intolerance), sleep abnormalities, and gastro-intestinal impairments, among others. An estimated 25% of those suffering from ME are housebound or bedbound. The World Health Organization (WHO) classifies ME as a neurological disease.

dysautonomia disorders of the autonomic nervous system that cause disturbances in all or some autonomic functions, may cause problems regulating autonomic functions, including heart rate, blood pressure, body temperature, and digestion. Can cause symptoms including lightheadedness, fainting, unstable blood pressure, and orthostatic intolerance.

cytokine any class of immunoregulatory proteins secreted by cells, especially immune cells. Cytokines are small proteins important in cell signaling that modulate the immune system. (Learn more: me-pedia.org)

World Health Organization (WHO) - "A specialized agency of the United Nations that is concerned with public health. It was established on 7 April 1948, and is headquartered in Geneva, Switzerland. The WHO is a member of the United Nations Development Group. Its predecessor, the Health Organization, was an agency of the League of Nations." The International Statistical Classification of Diseases and Related Health Problems (ICD) is maintained by WHO.