COVID-19
The COVID-19 pandemic is caused by a coronavirus, SARS-CoV-2. We know that similar viruses, including MERS and other strains of SARS, have caused very serious outbreaks in the past. The fatality rate of MERS in 2012 was about 34%, while that of SARS in 2003 was over 9%. The true fatality rate of the current coronavirus will not be known until the pandemic ends, but current estimates range from 1 and 3%. Doesn’t sound like much, right? Wrong. Because COVID-19 is so highly transmissible and does not kill its host quickly, it can spread farther, infecting more people. To date, COVID-19 is responsible for more than 100x more deaths than either SARS or MERS outbreak, and we’re not out of danger yet.
Researchers have already learned a great deal about COVID-19 prevention (please see our brief recommendations at the end of this article), infection, symptoms and associated disorders, and long-term effects of different severities. For the purposes of this article, we will focus on how COVID-19 affects the brain. COVID-19 infection in the brain seems to happen from one of two ways. The first route is by crossing the blood-brain barrier (a “wall” of blood vessels that protects the brain) through infected white blood cells or infected cells in blood vessel walls. The second way is breathing virus particles in through the nose, allowing them to go directly into the brain via the olfactory (sense of smell) nerve. That second route explains why people sometimes lose their sense of smell during the infection.
COVID in the Brain
Even when the COVID-19 infection doesn’t start in the brain, it can damage patients’ hearts and lungs, depriving their brains of oxygen and nutrients necessary for survival. When COVID-19 gets into the brain, it can impact many systems directly and indirectly. Generally, brain infections can cause changes in thinking, changes in control over one’s movement, confusion, high fevers, seizures, delirium, or even death. In the brainstem, where many of our body’s basic functions are regulated, COVID-19 can affect breathing, sleep, and alertness. In the blood supply, COVID-19 creates a hypercoagulant effect, thickening the blood more than normal, increasing the risk of stroke.
Neuroinflammation is caused by the body’s attempt to heal itself, otherwise known as the immune response, but it can also have destructive side effects. Mildly, this can be severe headaches that don’t respond well to over-the-counter medicines. In other cases, heightened immune response can cause braincell death and demyelination, which is when the substance encasing neural connections breaks down and the cells then cannot communicate properly. This can cause symptoms similar to autoimmune disorders, like Guillain-Barre syndrome (GBS) in peripheral nerves (outside the brain and spinal column), as well as change many thinking skills if central nerves (in the brain or spinal column) are affected.
Post-COVID Neuropsychological Symptoms
Given all of the above information, it’s not hard to understand why some patients who currently have or who recovered from a COVID-19 infection feel like their brains aren’t the same. Older adults and pregnant women are also at increased risk. Children are not immune and can spread the disease just as effectively as adults. Different hospitals and researchers report different rates of cognitive difficulties after with COVID-19 infection, but most are related to moderate to severe infections. During hospitalization, more than 80% of patients may show neurological symptoms and between 25% and 33% may show long-term effects. People have reported problems with:
- confusion,
- orientation,
- attention,
- concentration,
- memory,
- motor responses,
- visual-spatial skills (in part because of difficulties with the eyes),
- and emotional functioning:
- agitation
- anxiety
- depression
- Posttraumatic Stress Disorder (PTSD)
- If a patient has a stroke, damage to that area can cause specific difficulties in any cognitive domain.
Additional Risk Factors
The likelihood that severe infections, and subsequent neurological symptoms, will occur increase dramatically in people who have a history of:
- respiratory illness
- cardiac illness
- cancer
- seizure disorders
- blood disorders
- existing demyelinating disorders (e.g., multiple sclerosis, GBS)
- diabetes
- obesity
- nicotine users
Unfortunately, when the brain is impacted by lack of oxygen, problems getting nutrients, cell death, or any other insult, damage may be permanent. Some researchers believe that those who were infected with COVID-19 may be at increased risk for dementia later in their lives. However, as with most injuries to the brain, quick treatment and supporting the patient’s skill rehabilitation can improve symptoms and quality of life. For people experiencing post-COVID-19 cognitive problems, early intervention may be essential.
How Can SFN Help?
Neuropsychological evaluation is a procedure during which a highly-skilled professional collects a wide array of information about how a patient’s brain is functioning. This includes thinking skills but also how well a person is able to complete normal activities. Neuropsychologists help patients and their doctor understand what is happening with their brain. We identify strengths and weaknesses, as well as provide recommendations to better support areas of difficulty.
Although we know neuropsychological side effects were caused by SARS and MERS, we don’t yet fully understand how COVID-19 may impact people’s cognition. What we do know is there is hope. San Francisco Neuropsychology will continue to monitor emerging research in order to help people reach their potentials by helping them understand themselves and capitalize on their strengths.
PREVENTION
Please follow social distancing protocols, wash your hands regularly, and wear protective gear. We recommend becoming knowledgeable about your practices and improving in every way you can! Please see the guidance provided by the CDC and the Mayo Clinic, and many other sources. Protect yourself, your loved ones, and your community by being responsible and informed.