Brain fog can have a significant impact on people’s lives, including work, relationships, psychological well-being, and performance of daily activities.
Research, including studies funded by ME Research UK, shows that brain fog in ME/CFS has been associated with:
- Changes in the structure of the brain,
- Dysfunction of nerve cells (neurones),
- Ongoing low-grade inflammation,
- Reduced blood flow to the brain,
- Dysregulation of the immune system,
- Reduced availability of energy to the brain,
- Potential autoimmunity.
While researchers are making progress with studies relating to brain fog, it is essential to recognise that they face many challenges, including, but not limited to
- Lack of validated biomarker and reliance on self-reported information.
- The complexity of brain fog (rather than a single symptom, it includes multiple things like poor focus, memory issues, and mental slowness).
The following will discuss the above research difficulties in more detail, and provide ME Research UK resources relevant to research into brain fog in ME/CFS.
Research challenges
Lack of validated biomarker and reliance on subjective self-reported information.
As with ME/CFS overall, there is no validated biomarker for brain fog. Rather, the symptom is often measured using self-reported information. While these measures do provide insight into self-reported brain fog, they are subjective, which means that the questions could be interpreted differently by different participants. While some studies do look more closely at the brain using tools like Magnetic Resonance Imaging (MRI) scans, these scans are not specific to brain fog and may not fully capture the symptom in people with ME/CFS.
The complexity of brain fog
Brain fog is complex, and made up of several symptoms including trouble focusing, memory lapses, mental fatigue, and slow processing. In fact, in the 2021 NICE guidelines for the diagnosis and management of ME/CFS state that brain fog “may include problems finding words or numbers, difficulty in speaking, slowed responsiveness, short-term memory problems, and difficulty concentrating or multitasking.” Due to this complexity, brain fog is very difficult to capture accurately in research, and different studies often look at different areas of the symptom, or use different methods to assess it, meaning that results may not be comparable.
Resources
1. ME Research UK articles relating to the brain and cognitive function:
- Brain fog. Part 1: An introduction to cognitive function
- Brain fog. Part 2: Cognitive function and ME/CFS
- ME Research UK – research into the brain and ME/CFS
- All in your head – an introduction to brain
- All in your head? Brain research in ME/CFS
- Is the answer to ME/CFS in the brain?
- Review on cognitive dysfunction in ME/CFS published
2. Completed research funded by ME Research UK relating to the brain and nervous system
3. Ongoing research funded by ME Research UK looking at:
- Neurocognitive impairment in ME/CFS – Prof. François Jérôme Authier
- Tracking changes in the structure and function of the brain over time in ME/CFS – Dr Leighton Barnden
- Using MRI to assess brain neuroinflammation and the lymphatic system in ME/CFS – Dr Zack Shan
