Stewart Forsyth: Brain fog - what is it and how do we clear it?

A UK study, including 12,869 who had experienced Covid symptoms, found that those hospitalised and on respirators lost an average of seven IQ points. Photo / 123rf, File

Opinion

OPINION

A 2020 story in the New York Times introduced people who were suffering the cognitive impacts of Covid, including, "a veteran nurse practitioner at an urgent care clinic who fell ill with the virus in July, finds herself forgetting routine treatments and lab tests, and has to ask colleagues about terminology she used to know automatically".

There is Covid, then for some, there is long-Covid. Symptoms can include brain fog.

A detailed follow-up of 181 Covid sufferers by Lucy Cheke of the Covid cognition study (COVCOG) at Cambridge University, indicated that 27 per cent experienced "semantic dysfluency" (mistakes in saying or typing a word) and up to 52 per cent had difficulty concentrating. Other distressingly common symptoms measured include memory loss, reduction in executive and visuospatial functioning, and in visual attention.

The research into the cognitive impacts of Covid is reasonably clear – the worse the Covid patient is, the bigger hit the brain and mental function takes. A July 2021 UK study (including 12,869 who had experienced Covid symptoms) found that those hospitalised and on respirators lost an average of seven IQ points.

Recent research indicates some key pathways to these nasty cognitive effects.

Stanford researcher Michelle Monje has been studying chemobrain for 20 years. There are the cognitive effects people experience when completing chemotherapy (and radiotherapy) for cancer. She spotted the similarities to Covid-induced brain fog, which she considered might indicate a similar cause – the inflammatory response as the body responds to insult (for example from chemotherapy) or invasion by the Covid virus.

Up to one-half of those treated with chemo or radiotherapy have difficulty paying attention, memory loss, impaired multi-tasking, and sometimes anxiety – a reasonable response to these issues. These are measurable impacts – for example, patients lose IQ points.

Monje's work has indicated the importance of glia cells in the brain, which facilitate communication between brain cells and regions of the brain. These cells are fundamental to the brain staying plastic and adaptable. Cognitive impairment is an indication of the brain losing plasticity. The fundamental cause appears to be the inflammation of the brain's immune cells and the production of cytokines

Working with Akiko Iwasaki (and others) Monje demonstrated compelling similarities between chemo- and radiotherapy-induced chemobrain and Covid-19-produced brain fog.

This was both complex and clever work. Iwasaki has developed a strain of mice that can be infected with respiratory Covid-19. Any brain effects are from the body's response to Covid, not from Covid in the brains of the mice.

Stewart Forsyth. Photo / Supplied

Inflammatory products, including cytokines, were tracked from the lungs of the mice into their brains. There was consequential damage to the hippocampus (memory central) and other brain structures. These are the same inflammatory products that are found in the brains of humans suffering cognitive issues after Covid.

There are some indications of what can help. Monje's group have a drug entering clinical trials. A follow-up study by Elizabeth Salerno and colleagues of women treated with chemotherapy for breast cancer found that exercise helped brain function. A third of the women were meeting the recommended minimum standard for exercise before treatment. Those who exercised in the moderate-to-vigorous range did better on cognitive tests and reported better cognitive function.

Just a reminder – the recommended weekly minimum is 2.5 hours of moderate-intensity exercise (brisk walking; you can chat) or 1.25 hours of vigorous exercise (running or a high-intensity session; it's hard to speak in full sentences).

Possibly brain exercise helps as well, although the research indicating improved cognitive function is with older people experiencing cognitive decline and not people who have been hit by inflammation-induced attacks on their brain's communication system.

Professor Cheke emphasises the importance of rest – the one behavioural factor that appears to indicate a better cognitive outcome. That includes taking time off work or school and limiting mental activities to easy (or 'over-learned') hobbies or chores. Further, avoiding activities making mental demands such as rapid reactions, use of memory, or multitasking.

In other words, press pause on cognitively demanding tasks such as online gaming, reading complicated books or solving demanding word puzzles or solving complex work issues.

What about our mind's inclination to find (complicated) stuff to think about? It can be hard to tell the mind to "turn off" and "stop thinking". Leo Tolstoy wrote a short story about a boy tasked to "not think of white bears." Of course, the paradox is that we immediately spend a huge amount of mental energy keeping those images out of consciousness.

An alternative, mindful approach is to accept the image of the polar bear (or distracting thought), thank our mind for reminding us, but reassure that mind that this is not on our agenda, and then turn our attention to an alternative, such as a sound or image around us, or coming back to the rhythm of our breath.

For those laid low by Covid – give yourself time to gently come back to your previous high level of functioning. Add both cognitive and physical activities gradually – one at a time, then see how you are doing 24 hours later.

If all is going well – add another task. If not, dial it back and take it more gradually.

• Stewart Forsyth is an organisational psychologist and executive coach.