COVID-19 Impacts on Cognition and Quality of Life
(Long COVID part 2/4)
This week’s article continuous the discussion of the long-term consequences of being infected with SARS-CoV-2. Knowledge about the long-term effects of this virus is accumulating with study ongoing. Next week I will discuss more of this accumulated information and will continue to keep an eye out for new developments to share. Information presented is intended to provide a medical perspective - the articles are not intended as a political statement for or against any public policy. Statements in these articles should be considered coming from myself, not from any organization I represent or my employer.
Disturbances of taste and smell are two of the most common persistent neurological symptoms reported by people with COVID-19. While nasal congestion with other viral infections can cause problems with taste and smell there appears to be a neurological mechanism for this occurrence in some people with COVID-19.
Several different mechanisms have been proposed to account for the loss of taste and smell. In autopsy cases evidence of inflammation has been seen along the nerves that transmit information from the cells that detect odors to the parts of our brain that process these signals. MRI and PET scan abnormalities have been noted in the cells that sense odors and areas of the brain responsible for processing this information.
Some scientists have proposed that the virus directly invades the nervous system through the cells that sense odors. Viral particles have been found in the brain on some autopsies, however studies have failed to show that direct viral infection of the brain is the primary way in which most people lose their sense of smell. Studies are pointing to inflammatory or immune processes involving nerve cells, the cells that sense odors, and cells supporting the nervous system as the mechanisms for how people lose their sense of smell.
Loss of sense of smell has a significant impact on not just a person’s quality of life but on overall health and safety. Our sense of smell can affect our appetite and loss of sense of smell can lead to malnutrition especially in older people. Those with loss of the sense of smell may also be unaware when they are breathing toxic, polluted or smoke-filled air or eating spoiled food.
Fortunately, most people who lose their sense of smell from COVID-19 will eventually have partial or full return of their ability to sense odors. However, some may not recover for months and there are people who were ill early in the pandemic who still do not have full recovery of their sense of smell.
For those with persistent loss of the sense of smell there are treatments being studied showing some promise. For example, study participants using a combination of saline-steroid irrigation and “olfactory training” for 12 weeks had significant improvement in some (but not all) of the testing parameters being studied.
Loss of sense of smell is not the only long-term consequence of being infected with SARS-CoV-2 that has been shown to have a major impact on quality of life. Studies have shown that even people who experienced only mild to moderate initial illness had significant ongoing problems. For example, in a study of Swedish health care workers, 15% had at least 1 moderate to severe symptom that persisted for at least 8 months. This study excluded those how had severe acute COVID-19. The range of the health care workers' age was 33 to 52. 8% of these health care workers reported that their long-term symptoms moderately to markedly disrupted their work life. 15% reported their long-term symptoms moderately to markedly disrupted their social life, and 12% reported that their long-term symptoms moderately to markedly disrupted their home life.
A large study done primarily in the UK took advantage of a study was getting set up to use a web based cognitive test. The original aim of the study developed in December of 2019 was to develop a test that could screen large numbers of people for cognitive problems.
Researchers administered this test in 2020. Over eighty thousand people took the set of tests that measured different aspects of cognition. Data was also collected on if the person had COVID-19, as well as when and what symptoms they experienced. This study was published in the medical journal Lancet and is available online for anyone interested in the details (search “Cognitive deficits in people who have recovered from COVID-19”). In brief the researchers found evidence that many people - even those how had mild COVID-19 experienced significant long lasting cognitive problems.
Other studies have also been able to objectively show long term cognitive and functional problems in people who have had COVID-19. Numerous studies have looked at different mechanisms for why the brain and nervous system has these long-term problems. Studies have pointed to the finding of autoantibodies in the spinal fluid of some patients. Abnormal amounts of certain chemicals involved in the immune system have been found and there is evidence of impaired blood supply to the nervous system being a major factor.
Study is also ongoing into how we might treat people with long term neurological consequences. One of those studies made public this month has brain stimulation with alternating electrical microcurrents. This study was very small but produced promising results.
Next week I will continue to share with you information about the long term effects of COVID-19 including discussing a new study on the risk of cardiovascular problem following COVID-19.
Russ Coash, PA-C
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