COVID-19 and Cognition: Impact for the Medical SLP

Written by:
Caroline Gammill, SLPD, CCC-SLP, CBIS
Kelly Zarifa, MA, CCC-SLP
Caroline Tobias, MS, CCC-SLP
Kyomi Gregory, PhD, CCC-SLP
​Edited by:
Natalie Douglas, PhD, CCC-SLP
Meet our Team, here.

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Editor’s Note: I think I knew that I wanted to be a speech–language pathologist by the time I was 15 years old. Twenty-five years later, I have never been so proud of our profession. Thank you for risking the health and well-being of you and your family and for providing quality services in the face of the unknown. We see you. We love you and we want to support you. We hope these blogs help to clarify some of what you’ve been seeing in the media, and if there’s another area we can explore for you, please tell us! There’s honestly nothing else we’d rather do!  ~Natalie Douglas, PhD, CCC-SLP

And a disclaimer: While we’ve looked extensively for peer-reviewed, quality studies, much of our information at this point is from media reporting cases and stories—simply because the science just isn’t available yet. We link here to the original cases when possible, but it’s just too early at this point to have lots of high-quality studies! We’ll come back to insert addendums as they’re available.

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We’re sure you’ve seen no shortage of confusing and frankly dizzying news updates on COVID-19. It’s hard to keep up! While information is changing daily and there’s still a lot we don’t know, studies and cases are emerging that suggest some type of association between neurological symptoms and COVID-19. Symptoms like headache, stiff neck, and loss of taste and smell raise suspicion of central nervous system involvement, especially when considering what we know about other related viruses. And, respiratory failure in patients with COVID-19 could possibly mean the virus entered the brainstem through synaptic connections between it and the lungs. 

On the one hand, this is a novel virus, so it’s hard to know what we’re dealing with. On the other hand, we can make some predictions based on similar or related viruses that have come before. Based on genomic analysis, SARS-CoV-2, which causes COVID-19 or coronavirus, is very similar to MERS-CoV and SARS-CoV. (If you really want to know, COVID-19 is 88% similar to two bat-derived SARS-like coronaviruses, 79% similar to SARS-CoV, and 50% similar to MERS-CoV, according to this study. That’s right, we’re out here ready with genome studies for you!) So, COVID-19 shows similar symptoms to what’s seen in these viruses, with respiratory distress and pneumonia being hallmark characteristics.
 
In this post we want to round up what we know so far in the research across two main areas:

1. What is the relationship between COVID-19 and the nervous system?
2. What do we know about the cognitive outcomes of people who have already had COVID-19?

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What is the relationship between COVID-19 and the nervous system?

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​Studies are emerging that tell us that coronaviruses similar to COVID-19 may invade the central nervous system (CNS) and cause neurological disease. In this study by Mao et al., 36.4% of 214 patients with COVID-19 at one hospital in Wuhan had neurological manifestations that were divided into these types of injuries:

• Central nervous system: dizziness, headache, acute impaired consciousness, acute cerebrovascular disease, ataxia, and seizure (24.8% of patients)
• Peripheral nervous system: impairments in taste, smell, or vision; nerve pain (8.9% of patients)
• Skeletal muscle (10.7% of patients)

It was also noted in this study that 38.8% of these patients had at least one underlying co-morbid disorder, including hypertension, diabetes, cardiovascular or cerebrovascular disease, or cancer.
 
There are four other potential reasons COVID-19 could be linked to neurological symptoms that we’ll discuss as well. First, the body’s immune system may overreact and cause a cytokine storm, which can cause inflammation and increase the risk for blood clots. It may be prolonged immobilization that leads to the blood clots, or, as we’ll mention below, something about COVID-19 itself. Physicians in Greece currently call for all hospitalized patients with COVID-19 to receive prophylactic anticoagulation therapy, as preliminary evidence suggests this may result in lower mortality rates. Second, there is a call to investigate the possibility that COVID-19, like SARS-CoV, may enter the brain through the olfactory nerve and attach to neurons (or by entering the brainstem like we mentioned). 
 
Third, COVID-19 may be related to encephalopathy (successfully treated with steroids in one non-peer reviewed case), encephalitis, viral meningitis, and even Guillain–Barré syndrome. In case you need a quick refresher, encephalopathy isn’t just one disease, but an umbrella term for damage or disease that affects your brain leading to an altered mental state. But buyer beware: don’t get encephalopathy confused with encephalitis, or inflammation of the brain, which is often caused by... you guessed it, viruses.  Now, it’s important to note that encephalitis can often cause encephalopathy, but overall, the two are mutually exclusive terms.

Another case report from physicians in New Jersey found acute disseminated encephalomyelitis (ADEM; demyelinating inflammation of the brain and spinal cord from acute viral infection), in a woman in her forties with COVID-19. She went on to develop dysphagia and dysarthria. In this case, she was not treated with steroids, as the physicians reported this may be “detrimental,” but we don’t know why. So, in case you missed it, we are all scrambling to figure out the best treatment for COVID-19.
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Lastly, there may be something about the virus itself, or the systemic illness or inflammatory response it causes, that leads to neurological symptoms. Recall the disclaimer above, but based on what we know about other viruses, especially SARS, there is speculation of some type of neurological involvement related to COVID-19. More high-quality studies are needed.

Right now, we’re experiencing the tension between how long good science can take and how much we need that good science yesterday. The struggle is real.    
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What do we know about the cognitive outcomes of people who have already had COVID-19?

​First, one of the main studies people are referencing came directly out of Wuhan, China. This study, published March 21 by Chen et al., examined clinical characteristics of COVID-19 from 113 deceased patients and 162 patients who recovered in 2019. The data showed that the symptoms of COVID-19 varied widely; however, disorders of consciousness were more common among deceased patients than in recovered patients (22% vs. 1%). Note that it’s possible that the disorders of consciousness were due to the severity of the illness itself, and we can’t necessarily link disordered consciousness here with neurological infection. These patients presented with various forms of disorders of consciousness upon hospital admission. The symptoms ranged from drowsiness to a deep state of prolonged unconsciousness. This finding is significant for SLPs since it provides us with a need to be aware of symptoms of cognition as patients that present with impaired cognition may have a poorer outcome. This study also raises awareness for the need for earlier monitoring of cognition in patients with COVID-19 as well as the need for prompt medical care if confusion is seen as a symptom upon hospital admission.  
 
Next, this open access article by Filatov et al. also from March 21 reports on one man who arrived at the hospital due to respiratory symptoms and fever, but was sent home as symptoms were thought to be an exacerbation of the patient’s underlying Chronic Obstructive Pulmonary Disease (COPD). Unfortunately, he returned to the hospital a day later as his symptoms became worse. He went through a gamut of tests, until he was eventually tested for COVID-19 and was found to be positive. Over the course of his illness, he eventually presented with altered mental status. The authors of this study describe him as “encephalopathic, nonverbal, and unable to follow any commands; however, he was able to move all his extremities and was reacting to noxious stimuli.” The main takeaway from this paper was that health care providers should be aware that neurological symptoms may accompany the presence of COVID-19. 

Physicians in France also reported on neurologic features in severe cases of COVID-19. Twenty-six of 40 patients had confusion, measured by the Confusion Assessment Method for the ICU. Two-thirds of patients had corticospinal tract signs, like enhanced reflexes and clonus. And, upon discharge, 33% of patients “had had” a dysexecutive syndrome with inattention and disorientation (it’s unclear if this wording meant the patients had presented with dysexecutive syndrome during their hospital stay and it had resolved, or if it was still present at discharge). A small number of the 58 patients included in the report had MRIs or EEGs that showed evidence of encephalopathy (1 patient) or ischemic strokes (2 patients).

As you can see, there are still a lot unknowns! Just as we were wrapping up writing this blog post, The Washington Times reported on the occurrence of strokes due to large blood clots in the middle cerebral artery (the artery often implicated in aphasia!) in young patients (in their 30s and 40s) with mild symptoms of COVID-19. That article also reported that three large U.S. medical centers are working on publishing data related to this stroke phenomenon. We’ll come back and insert addendums to this blog post as the data becomes clearer!

As SLPs, we may expect an increasing number of patients recovered from COVID-19 with lingering cognitive symptoms, including confusion and impaired executive functions, short-term memory issues, and learning difficulties. This open access article describes this mash-up of cognitive symptoms after acute respiratory distress syndrome. It’s unclear if we can expect stability or deterioration of cognition in COVID-19 survivors at this point, but for those who had compromised cognitive–communication status before COVID-19, we should be ready for a possible exacerbation of symptoms.

​We’re certain more research will emerge in this area, and we as SLPs will have a crucial role in documenting these cognitive symptoms, contributing to the research, and of course, managing their status to support functional communication and quality of life.

Update, Summer 2020:

• Note that we're continuing to provide updates on the neurological symptoms and outcomes from COVID-19 in our membership site, every single month! If you'd like to stay in-the-know on this topic, join here.  

 
Chen, T., Wu, D., Chen, H., Yan, W., Yang, D. Chen, G... & Ning, J. (2020). Clinical characteristics of 113 deceased patients with coronavirus disease 2019: retrospective study. The BMJ. https://doi.org/10.1136/bmj.m1091
 
Filatov, A., Sharma, P., Hindi, F., & Espinosa, P. (2020). Neurological complications of Coronavirus Disease (Covid-19): Encephalopathy. Cureus. 
http://doi.org/10.7759/cureus.7352
 
Li, Y., Bai, W., & Hashikawa, T. (2020). The neuroinvasive potential of SARS‐CoV2 may play a role in the respiratory failure of COVID‐19 patients. Journal of Medical Virology. https://doi.org/10.1002/jmv.25728
 
Mao, L., Jin, H., Wang, M., Hu, Y., Chen, S., He, Q... & Hu, B., (2020). Neurologic manifestations of hospitalized patients with coronavirus disease 2019 in Wuhan, China. Journal of the American Medical Association Neurology. 
​https://doi.org/10.1001/jamaneurol.2020.1127
 
Sasannejad, C., Wesley Ely, E., & Lahiri, S. (2019). Long-term cognitive impairment after acute respiratory distress syndrome: a review of clinical impact and pathophysiological mechanisms. Critical Care. https://doi.org/10.1186/s13054-019-2626-z