What is brain fog?

McWhirter, Laura; Smyth, Heather; Hoeritzauer, Ingrid; Couturier, Anna; Stone, Jon; Carson, Alan

doi:10.1136/jnnp-2022-329683

Cited by 41 publications

(16 citation statements)

References 9 publications

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“…Although our results support a two-factor model of central fatigue and brain fog, they do not resolve confusion about the overlap between these symptoms. Both are primarily based on patient self-report, lack clear definitions, and are often described in terms of other neuropsychological deficits (e.g., cognitive slowing, problems with working memory, sustained attention) [ 62 , 63 ]. Nevertheless, the support for the two-factor model of central fatigue and brain fog in the present study implies that prevailing assumptions about mental fatigue–and accompanying measures–might merit empirical scrutiny to improve current definitions of the construct and facilitate greater precision in measurement.…”

Section: Discussionmentioning

confidence: 99%

Efficient assessment of brain fog and fatigue: Development of the Fatigue and Altered Cognition Scale (FACs)

Elliott,

Hsiao,

Randolph

et al. 2023

PLoS ONE

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Debilitating symptoms of fatigue and accompanying “brain fog” are observed among patients with various chronic health conditions. Unfortunately, an efficient and psychometrically sound instrument to assess these co-occurring symptoms is unavailable. Here, we report the development and initial psychometric properties of the Fatigue and Altered Cognition Scale (the FACs), a measure of self-reported central fatigue and brain fog. Traumatic brain injury (TBI) was chosen to model and develop the FACs due to research team expertise and established links between TBI and the symptom complex. Potential items were generated by researchers and clinicians with experience treating these symptoms, drawing from relevant literature and review of patient responses to measures from past and current TBI studies. The 20 candidate items for the FACs—ten each to assess altered cognition (i.e., brain fog) and central fatigue–were formatted on an electronic visual analogue response scale (eVAS) via an online survey. Demographic information and history of TBI were obtained. A total of 519 participants consented and provided usable data (average age = 40.23 years; 73% female), 204 of whom self-reported a history of TBI (75% reported mild TBI). Internal consistency and reliability values were calculated. Confirmatory factor analysis (CFA) examined the presumed two-factor structure of the FACs and a one-factor solution for comparison. A measurement invariance test of the two latent constructs (altered cognition, fatigue) among participants with and without TBI was conducted. All items demonstrated normal distribution. Cronbach’s alpha coefficients indicated good internal consistency for both factors (α’s = .95). Omega reliability values were favorable (α’s = .95). CFA supported the presumed two-factor model and item loadings which outperformed the one-factor model. Measurement invariance found the two-factor structure was consistent between the two groups. Implications of these findings, study limitations, and potential use of the FACs in clinical research and practice are discussed.

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Section: Discussionmentioning

confidence: 99%

Efficient assessment of brain fog and fatigue: Development of the Fatigue and Altered Cognition Scale (FACs)

Elliott,

Hsiao,

Randolph

et al. 2023

PLoS ONE

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“…Pain was reported by patients and could include any origin (neuropathic and nociceptive), severity (not typically quantified), and location of pain. The description of cognitive fog was not systematically evaluated, but likely included a variety of cognitive experiences such as forgetfulness, poor concentration, and excessive cognitive effort 22 . Functional seizures were defined as episodes resembling epilepsy or syncope, but not caused by abnormal cortical electrical activity 23 .…”

Section: Methodsmentioning

confidence: 99%

Neuropsychiatric phenotypes in functional movement disorder

Gilmour¹,

Langer²,

Lang³

et al. 2023

CNS Spectr.

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Objective Functional movement disorder (FMD), the motor-dominant subtype of functional neurological disorder, is a complex neuropsychiatric condition. Patients with FMD also manifest non-motor symptoms. Given that patients with FMD are diagnosed based on motor phenotype, the contribution of non-motor features to the neuropsychiatric syndrome is not well characterized. The objective of this hypothesis-generating study was to explore potential novel, neuropsychiatric FMD phenotypes by combining movement disorder presentations with non-motor comorbidities including somatic symptoms, psychiatric diagnoses, and psychological traits. Methods This retrospective chart review evaluated 158 consecutive patients with a diagnosis of FMD who underwent deep phenotyping across neurological and psychiatric domains. Demographic, clinical, and self-report features were analyzed. A data-driven approach using cluster analysis was performed to detect patterns when combining the movement disorder presentation with somatic symptoms, psychiatric diagnoses, and psychological factors. These new neuropsychiatric FMD phenotypes were then tested using logistic regression models. Results Distinct neuropsychiatric FMD phenotypes emerged when stratifying by episodic vs. constant motor symptoms. Episodic FMD was associated with hyperkinetic movements, hyperarousal, anxiety, and history of trauma. In contrast, constant FMD was associated with weakness, gait disorders, fixed dystonia, activity avoidance, and low self-agency. Pain, fatigue, somatic preoccupation, and health anxiety were common across all phenotypes. Conclusion This study found patterns spanning the neurological-psychiatric interface that indicate that FMD is part of a broader neuropsychiatric syndrome. Adopting a transdisciplinary view of illness reveals readily identifiable clinical factors that are relevant for the development and maintenance of FMD.

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“…169 So-called brain fog has been described in association with a wide range of illnesses, drugs, and behaviors, including Long-COVID. 172…”

Section: Functional Neurological Disordersmentioning

confidence: 99%

“…Evidence does not support the existence of separate cognitive disorders in CFS, Fibromyalgia, and FND.” 169 So-called brain fog has been described in association with a wide range of illnesses, drugs, and behaviors, including Long-COVID. 172 …”

Section: Functional Somatic Disorders (Diagnostic and Statistical MA...mentioning

confidence: 99%

Long COVID as a functional somatic symptom disorder caused by abnormally precise prior expectations during Bayesian perceptual processing: A new hypothesis and implications for pandemic response

Joffe,

Elliott

2023

SAGE Open Medicine

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This review proposes a model of Long-COVID where the constellation of symptoms are in fact genuinely experienced persistent physical symptoms that are usually functional in nature and therefore potentially reversible, that is, Long-COVID is a somatic symptom disorder. First, we describe what is currently known about Long-COVID in children and adults. Second, we examine reported “Long-Pandemic” effects that create a risk for similar somatic symptoms to develop in non-COVID-19 patients. Third, we describe what was known about somatization and somatic symptom disorder before the COVID-19 pandemic, and suggest that by analogy, Long-COVID may best be conceptualized as one of these disorders, with similar symptoms and predisposing, precipitating, and perpetuating factors. Fourth, we review the phenomenon of mass sociogenic (functional) illness, and the concept of nocebo effects, and suggest that by analogy, Long-COVID is compatible with these descriptions. Fifth, we describe the current theoretical model of the mechanism underlying functional disorders, the Bayesian predictive coding model for perception. This model accounts for moderators that can make symptom inferences functionally inaccurate and therefore can explain how to understand common predisposing, precipitating, and perpetuating factors. Finally, we discuss the implications of this framework for improved public health messaging during a pandemic, with recommendations for the management of Long-COVID symptoms in healthcare systems. We argue that the current public health approach has induced fear of Long-COVID in the population, including from constant messaging about disabling symptoms of Long-COVID and theorizing irreversible tissue damage as the cause of Long-COVID. This has created a self-fulfilling prophecy by inducing the very predisposing, precipitating, and perpetuating factors for the syndrome. Finally, we introduce the term “Pandemic-Response Syndrome” to describe what previously was labeled Long-COVID. This alternative perspective aims to stimulate research and serve as a lesson learned to avoid a repeat performance in the future.

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What is brain fog?

Cited by 41 publications

References 9 publications

Efficient assessment of brain fog and fatigue: Development of the Fatigue and Altered Cognition Scale (FACs)

Efficient assessment of brain fog and fatigue: Development of the Fatigue and Altered Cognition Scale (FACs)

Neuropsychiatric phenotypes in functional movement disorder

Long COVID as a functional somatic symptom disorder caused by abnormally precise prior expectations during Bayesian perceptual processing: A new hypothesis and implications for pandemic response

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