Brain fog, 2026, Bojnowska & Debowska

[Dolphin]

https://www.elgaronline.com/display/book/9781035349173/entry13.xml?tab_body=abstract-copy1

13: Brain fog
Urszula Bojnowska
and
Agata Debowska
in Elgar Encyclopedia of Personality and Individual Differences


Category: ChapterPublished: 22 Oct 2026Page Range: 56–58
Collection: Psychology 2026DOI: https://doi.org/10.4337/9781035349173.00018Publisher: Edward Elgar Publishing
Keywords: Brain fog; Cognitive dysfunction; Brain fog scale; BFS; Standardized assessment; Long COVID

• Abstract
• References

This chapter explores the phenomenon of brain fog, a subjective experience of cognitive dysfunction characterized by forgetfulness, mental fatigue, and confusion. Frequently associated with conditions such as Chronic Fatigue Syndrome, Postural Tachycardia Syndrome, and long COVID, brain fog significantly diminishes patients’ quality of life by impairing daily functioning, academic performance, and productivity.

Historically, research on brain fog has been hindered by a lack of standardized clinical definitions and inconsistent measurement approaches.

To address this gap, recent advancements have led to the development of the Brain Fog Scale (BFS).

The BFS is a validated, 23-item self-report tool that quantifies brain fog across three dimensions: mental fatigue, impaired cognitive acuity, and confusion.

By providing a structured and reliable assessment method, the BFS aims to unify clinical evaluation and facilitate future research into this pervasive cognitive impairment.

 

[RainbowCloud]

Forgetfulness and confusion aren’t features of brain fog to me… an inability to access higher level thinking without extreme systemic debilitation is more accurate in my own experience.

 

[rainy]

Brain Fog Scale (BFS)

Mental fatigue
1. My thinking has been slow
2. I have felt mentally exhausted
3. I have felt fatigued
4. I have been easily distracted
5. I have found myself getting annoyed
6. I have felt sleepy

Impaired cognitive acuity
7. I have found it difficult to remember and understand new information
8. I have found myself forgetting certain words, such as the names of objects
9. I have found it difficult to think logically
10. I have found it difficult to concentrate
11. I couldn’t think clearly
12. I have had a hard time finding the right words
13. I have found it difficult to organise my thoughts
14. I have felt like my mind’s gone blank
15. I have found it difficult to understand words when reading

Confusion
16. I have had a hard time understanding what others say
17. I have been daydreaming
18. I have felt spacey
19. I have felt confused
20. I have experienced thought blocking
21. I have felt lost
22. I have felt absent, as if I were living in my own world
23. My thoughts have been moving quickly

 

[RainbowCloud]

Re: the Brain Fog Scale

Numbers 4 and 5 could be for other reasons than mental fatigue so I find it strange it’s already definitively categorised as such.

And of the entire confusion section, only 19 is confusion and the rest don’t fit this definition at all to my mind.

 

[rainy]

«I have felt mentally exhausted» and «I have felt fatigued» is the same question. I would assume fatigue here to mean mental fatigue, since its written under the category «mental fatigue» on a brain fog questionnaire.

«I couldn’t think clearly» and «difficult to organise thoughts» would be close to duplicates for me as well.

While «daydreaming» is my favorite way to spend time, and brainfog holds my daydreaming back from it’s full potential.

It doesn’t make sense to me that inability to think logically, something that has a devastating impact on your life, could give you the same amount of points as daydreaming.

This scale doesn’t measure the devastation that my brainfog is at all. And I think people I know without ME/cfs, who work full time but maybe have undiagnosed ADHD, would score quite high on this questionnaire as well.