Thanks to COVID, many of us have become familiar with quite a few terms we’ve not encountered before. We all now know what a rapid antigen test is, and ‘contact tracing’ became a regular part of the vernacular.
Another term that many would have heard but may not understand is ‘brain fog’. And you can certainly be forgiven for not understanding it because even scientists have been struggling to get a handle on the condition.
But with many COVID sufferers experiencing brain fog, during and/or after the illness, scientists have been taking a closer look at it, and are finally beginning to unlock its secrets. For those who suffered periods of brain fog before the pandemic, that is good news.
But what exactly is brain fog? That’s not an easy question to answer, because it’s not actually a defined medical condition. It has no diagnostic criteria.
That doesn’t make it any less real for those who have experienced it, though, and I can speak from experience here. Over the past few years I have experienced three episodes of vertigo, during which the world spins around in my eyes and then I’d vomit for an hour or so.
After each of those episodes (which I have been advised were probably migraines), I went through several weeks of what was described under an umbrella term of brain fog: a lack of mental clarity, memory problems and an inability to focus.
Before COVID, the phenomenon of brain fog had been associated with many conditions, including allergies, menopause, attention deficit hyperactivity disorder (ADHD) and kidney failure, as well as mental health conditions such as anxiety and depression.
The pandemic has led to a greater research focus on brain fog. Somewhere between 10 and 25 per cent of those infected with the SARS-CoV-2 coronavirus develop long COVID – a condition characterised by new, returning or ongoing health issues related to the infection. Long COVID symptoms vary, and can include fatigue, muscle pain and digestive problems. But among the top three most commonly reported issues is brain fog.
There are several theories as to what might be the root cause of the debilitating condition. One of those is brain inflammation. The theory is that inflammation in the brain, caused by a heightened immune reaction to COVID, gums up the neural works, leading to the kind of cell damage and death that makes it harder for brain cells to send signals to one another.
The evidence for this is currently inconclusive, though, and Anna Nordvig, a neurologist at Weill Cornell Medicine in New York, has an alternative suggestion. Dr Nordvig believes that the ‘nuts and bolts mechanisms’ of COVID-related brain fog are more complicated than inflammation alone.
Her research suggests that COVID may not always result in damage to areas of the brain, but may rather lead to “tissue at risk”. In basic terms this means there may be areas of the brain where cells are no longer able to get the nutrients or blood flow they require to work at their best.
“There have been a number of studies now that talk about the decreased ability of the brain to pick up nutrients,” she says. “It’s quite patchy, with different small areas affected.” This could explain why those who experience brain fog report a wide variety of ways in which it manifests.
And, says Dr Nordvig, it may well be a good thing from a recovery perspective: “It’s also actually good news. This tissue is still there and still is functioning, albeit not as well as it could. That means it’s recoverable and there’s the potential for people to get better.”
Those words will be music to the ears of those waiting for their own brain fog to lift.
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