Brain fog: Memory and attention after COVID-19
Brain fog: Memory and attention after COVID-19

Brain fog: Memory and attention after COVID-19

As a neurologist working in the COVID Survivorship Program at Beth Israel Deaconess Medical Center, I find that my patients all have similar problems. It’s hard to concentrate, they say. They can not think of a particular word they want to use and they are uncharacteristically forgetful.

Those who come to our cognitive clinic are among those estimated 22% to 32% of patients who recovered from COVID-19 but still experience brain haze as part of their experience of prolonged COVID, or post-acute sequelae of SARS CoV-2 infection (PASC), as experts call it .

What is brain fog?

Brain fog, a term used to describe slow or sluggish thinking, can occur in many different circumstances – for example, when someone has sleep deprivation or feels uncomfortable, or due to side effects from medications that cause drowsiness. Cerebral palsy can also occur after chemotherapy or concussion.

In many cases, brain fog is temporary and gets better on its own. But we do not really understand why brain fog occurs after COVID-19, or how long these symptoms are likely to last. But we know that this kind of brain fog can affect different aspects of cognition.

What is cognition?

Cognition refers to processes in the brain that we use to think, read, learn, remember, reason, and pay attention. Cognitive impairment is a reduction in your ability to perform one or more thinking skills.

Among people who were hospitalized due to COVID, a large number of problems with cognition have been reported. They include difficulties with

  • awareness, which allows our brains to actively process information happening around us while ignoring other details. Attention is like a spotlight on a stage during a show that allows artists to stand out from the background.
  • memory, the ability to learn, store, retain and later retrieve information.
  • executive function, which includes more complex skills such as planning, focusing attention, remembering instructions and juggling multiple tasks.

People who struggle with the effects of prolonged COVID may have noticeable problems with attention, memory and executive function. Studies report these issues both in persons who were not hospitalized with COVID and in those who were, as well as in persons who had serious cases. These results raise some important questions about how COVID-19 infection affects cognition.

Less obvious memory and attention loss may occur even with mild COVID

One recently examination published by a group of German researchers suggests that even people who do not notice signs of cognitive impairment may have problems with memory and attention after recovering from a mild case of COVID-19.

The study involved 136 participants, who were recruited from a website that advertised the study as a brain game to see how well people could perform. The average age was about 30 years. Almost 40% of the participants had recovered from COVID, which did not require hospitalization, while the rest had not had COVID. All participants reported that they had no problems with their memory or thinking.

Tests, however, showed that the performance on an attention task was not as good among the group that had COVID compared with those that did not. Likewise, participants who had COVID had significantly poorer performance on a memory task. Both of these effects seem to get better over time, with the memory problem getting better with six months and decreased attention no longer present after nine months.

This study suggests that memory and attention problems can occur not only in people who are sick enough with COVID to have been hospitalized, and in those who develop long-term COVID, but also to some extent in most people, who had COVID. However, these results should be interpreted with caution. The study mostly included young patients recruited through a website, no one had COVID for long, and participants’ cognitive abilities before COVID were not known.

What does this study tell us about cognition and COVID?

Further research is needed to confirm whether attention and memory disorders are widespread with COVID-19 infections – across all age groups and no matter how mild or severe the disease is – and to consider other factors that may affect cognition. Better understanding of why some people have noticeable problems with attention and memory after having COVID, and others do not, can ultimately help guide care.

Memory recovery within six months and improvement in attention within nine months of COVID infection were seen in this study, suggesting that some cognitive impairments with COVD, although prevalent, are potentially reversible.

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