The Fog Left by COVID-19
Written by Kristen Zeller
2020 was not a kind year.
The impact of COVID-19, either directly or indirectly, still affects the lives of many today. Even with the relief of vaccinations just on the horizon, unfortunately, we still have the lingering effects of the virus to worry about...
“Long-COVID” refers to persisting COVID-19 symptoms after the virus has wreaked havoc on a person’s body (Budson, 2021). One of these lasting symptoms is called “brain fog.” A brain fogged mind is bogged down by forgetfulness, feeling cloudy headed, and experiencing difficulty thinking, focusing, and communicating (Ross et al., 2013). You might be wondering, “Doesn’t everyone experience this from time to time?” We do, but brain fog is far more serious and prolonged than the occasional bouts of forgetfulness or mental fatigue. One in three individuals who contract COVID-19 ends up facing Long-COVID (Godlee, 2020). Long-COVID sufferers are not necessarily those who were ill enough to require hospitalization. Typically, these are younger, physically fit individuals who caught a mild case of COVID-19, but later go on to suffer prolonged symptoms of exercise intolerance, breathlessness, palpitations, headaches, and - you guessed it - brain fog. Given the prevalence of Long-COVID, let’s look at how COVID-19, a respiratory virus, results in the potential for so much cognitive impairment.
Some Long-COVID sufferers are developing conditions like Postural Orthostatic Tachycardia Syndrome (POTS; Miglis et al., 2020; Chung, n.d.), an autonomic nervous system condition that impacts our heart rate, body temperature, and blood pressure (see more details here; Johns Hopkins Medicine.org., n.d.; Dysautonomia International., n.d.). Research on POTS shows that physical stress from standing upright can negatively impact one’s cognition (Ross et al., 2013). It’s no wonder, then, that brain fog is commonly listed as a detrimental symptom of POTS. It is still unclear how COVID-19 triggers POTS or POTS-like symptoms; however, some research suggests that viral infection, an overactive inflammatory response to COVID-19, or an interaction between COVID-19 and the autonomic nervous system can trigger POTS (POTS UK, 2021).
Those are milder cases of long-COVID sufferers. So what about the serious ones?
While researchers are still trying to understand this complex virus (Heneka et al., 2020), something that is increasingly evident is the rippling damage COVID-19 can cause to the brain (Budson, 2021). The severe cases of COVID-19 can result in brain swelling (Budson, 2021), stroke, and Acute Respiratory Distress Syndrome (Lahiri & Ardila, 2020). Acute Respiratory Distress Syndrome is a condition in which fluid buildup in the lungs reduces the amount of oxygen reaching the bloodstream (Mayo Clinic, n.d.). A significant number of those with ARDS are suffering with potentially long-term cognitive impairments due to oxygen deprivation and blood-brain barrier damage. Cognitive impairments include confusion, agitation, altered consciousness, and delirium (Lahiri & Ardila, 2020). COVID-19 cases this severe may also require the use of mechanical ventilation to assist with breathing (Bilotta et al., 2019). Apart from the virus, mechanical ventilation is known to cause cognitive impairment with over a third of patients performing abnormally on cognitive tests (Sasannejad et al., 2019). These impairments can be in visual memory, psychomotor speed, verbal fluency, and visuo-construction. Many abilities make up visuo-construction such as visuospatial ability, fine motor skills, executive function and planning (Ahmed et al., 2016). Tasks like the Rey Osterreith Complex Figure Test help to assess visuo-construction. The Rey Osterrieth Complex Figure Test has participants copy a complex line drawing followed by having them attempt to redraw it from memory (Shin et al., 2006). Performance on this test can provide helpful information on how recognition, recall, visuospatial ability, attention, planning and executive function have been impacted.
There is still so much about the progression and long-term impacts of COVID-19 that is unknown. As research continues to grow, so will our understanding of the virus and how it affects cognition. Until then, stay safe and wear a mask.
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Disclaimer
The blog posts are for informational and educational purposes only. The posts should not be considered as any type of advice (medical, mental health, legal, and/or religious advice). All blog posts have been researched, written, and edited by the undergraduate students and alumni of the Lifespan Cognition Lab. As a teaching and research-based lab, we encourage all lab members to help make knowledge more accessible to all communities through these posts.
