The cognitive impact of long COVID

Hannah Calkins (2022) published The cognitive impact of long COVID: What can psychologists do in the American Psychological Association’s “Six things psychologists are talking about.” I have edited the article because, though we all want COVID to go away, it isn’t cooperating. I found this information very helpful:
A substantial number of people who survived the acute phase of COVID-19 have never made a full recovery. Psychologists are breaking new research ground to understand the causes, effects, and possible treatments for so-called “long COVID,” particularly related to its impact on cognition and mental health. The perils of long COVID include fatigue, lowered endurance, reduced cognitive efficiency, and mental health effects, such as anxiety and depression.

 “Data from our racially and ethnically diverse group of patients, who are assessed approximately four months after acute illness, suggest that more than two thirds are continuing to experience cognitive dysfunction,” said Tracy Vannorsdall, PhD, ABPP-CN, a clinical neuropsychologist.

Research by Vannorsdall and other psychologists shows that patients who endured severe illness requiring a stay in the intensive care unit (ICU) display significant cognitive and neuropsychological deficits, which tracks with long-established research on the impact of ICU treatment on the brain. However, both psychologists and neuroscientists have detected measurable changes in the brains of people who had less-severe cases, and many long COVID sufferers who had mild illness report ongoing cognitive dysfunction and psychological distress. While some research indicates that people with a history of anxiety are at higher risk for developing long COVID, psychologists are learning that previous mental health issues cannot explain the myriad symptoms long COVID patients endure. Now, experts theorize that SARS-CoV-2, the virus that causes COVID, has some harmful effect on the brain, either directly through infection or through resulting inflammation. Additionally, emerging evidence suggests that there may be non-psychological factors that make some people more susceptible to developing long COVID, such as previous infection with a different virus.

According to the U.S. Centers for Disease Control and Prevention (CDC), long COVID symptoms may impact as many as 1 in 5 adult survivors of the illness, regardless of how mild their initial infection was. The CDC estimates that more than 200 million people in the United States have already been infected with COVID-19, and predicts 100 million new infections this fall. People with long COVID are frequently described as having “lingering symptoms,” but they often develop confounding new ones. Their experiences support the rapidly accumulating evidence that SARS-CoV-2 is not simply a respiratory virus, but one that takes a toll on nearly every major system and organ in the body, from the immune system, to the heart and vascular system, to the gastrointestinal tract, to the kidneys.

The brain and the nervous system are no exceptions—and in fact, some of the most pervasive symptoms of long COVID appear to be neurological, cognitive, or psychiatric in nature. In August, a study of more than 2.5 million people by researchers at the University of Oxford revealed that the neurological and psychiatric risks of COVID were significant and that the more severe outcomes—such as psychotic disorders, cognitive deficit, dementia, and epilepsy or seizures—may persist for years. Descriptions of “brain fog,” which is not a medical term, have been ubiquitous since the early days of the pandemic. Also common are reports of altered or lost sense of taste or smell, which signals that the virus has had some neurological impact and, similarly, is observed in patients with neurodegenerative diseases. Many long COVID sufferers also report intense anxiety, anhedonia, insomnia, and debilitating fatigue, as well as short-term memory loss, confusion, and problems with concentration and attention. The data bear this out. A recent meta-analysis found that up to 22% of people who have had COVID report persistent fatigue or cognitive impairment 12 weeks after infection.

Delia Silva, PsyD, ABPP-CN, a clinical neuropsychologist in San Diego has seen an increasing number of referrals for patients in need of neuropsychological evaluation because of long COVID. While a “small minority” of these patients’ COVID symptoms were severe enough to require oxygen therapy or mechanical ventilation in the ICU (which raises the risk for poor cognitive outcomes), “most of the patients I have seen had relatively mild cases of COVID,” she said. She has observed that “consistent with the literature thus far, it appears that the people who were not hospitalized or intubated due to COVID have generally performed within normal limits on neuropsychological testing.”

However, these patients may struggle with dysautonomia, which involves dysfunction of the nerves that regulate nonvoluntary body functions, such as heart rate, blood pressure, and sweating. This may lead to reduced cognitive efficiency related to their fatigue, she said. Some patients with persisting symptoms have also presented with clinically significant psychiatric symptoms. [A]nxiety can cause physical symptoms, such as heart palpitations, which may partially explain some of the issues that patients with long COVID are experiencing.

“We know that people with medical comorbidities or of older age are at higher risk of having more severe COVID cases and persisting symptoms. We also know that people who were intubated are at higher risk of experiencing neurological or pulmonary symptoms,” said Silva. “We’re also seeing that with milder cases, people with premorbid psychiatric histories (anxiety, in particular) tend to have subjective reports of persisting COVID symptoms.” At the same time, Silva said, “there are also people with mild COVID cases who seem to have persisting symptoms that might not be explained by psychiatric factors.”

Because of a presumed lower prevalence in children and subsequent lack of data, most research into how long COVID impacts the brain is focused on adults. Rowena Ng, PhD, said that patients in her [child] clinic report cognitive dysfunction, fatigue, sleep disturbance, headaches, and anxiety and depression symptoms. But they typically perform normally on cognitive tests, and many of them have histories of attention, anxiety, or mood concerns prior to infection.

“Many of these patients also have emergent physical symptoms after the infection, including headaches, fatigue, dizziness, and gastrointestinal problems—all of which may contribute to attention and concentration difficulties,” she said. “This makes it challenging to fully differentiate whether the cognitive difficulties patients report, or that we observe on testing, are a direct result of COVID-19 infection, indirect outcomes from physical symptoms associated with COVID-19, worsened anxiety or mood, pandemic-related stress, or a combination of these.”

Additionally, social isolation during “lockdown” periods of the pandemic has been noted to have a serious impact on school performance, attention, and mood in children, particularly those who already had mental health conditions. These effects may have been even worse in children who had COVID or experienced ongoing problems related to their infection. [One] study also found that children with a previous COVID infection had an increased risk of psychotic disorders and seizures, though they have an overall lower risk profile than older adults. Ng pointed to emergent clinical case studies suggesting that pediatric patients show changes in the brain following COVID infection, similar to what has been found in older adults.

Presently, there are three leading theories for what causes post-COVID cognitive and psychiatric symptoms, according to Silva. The first is cerebrovascular ischemia, which occurs when the brain doesn’t receive adequate blood flow and is a precursor to a stroke. This could largely explain why patients who had severe acute disease display the most serious deficits. For those with moderate or mild acute disease, a second theory is that direct viral infection of the brain causes cognitive dysfunction and neurological problems, such as the hallmark loss of taste and smell experienced by many people with COVID. There is limited evidence for this theory, Silva wrote. A third theory involves neuroinflammation, which scientists theorize is the result of an immune system in overdrive. 

However, in May 2022, a longitudinal study led by Michael Sneller MD failed to identify a definitive cause of long COVID, and did not find evidence to support these theories. The study did, however, find that women with a history of anxiety were at greater risk for developing long COVID, a conclusion that many patient advocates (and even Sneller himself) were concerned would lead to further marginalization of post-COVID patients by the medical and scientific establishment. Nonetheless, “emotional trauma and posttraumatic stress disorder may play a role in creating or worsening symptoms,” Samton said.

Samton also pointed out that researchers have identified some additional possible risk factors for developing long COVID, including Type 2 diabetes, fragments of SARS-Cov-2 RNA in the blood, evidence of Epstein-Barr virus (EBV) in the blood, and an increase in autoimmune antibodies. There is also some evidence regarding the protective factor of vaccines, which provides some clues, although the results have been mixed. One study suggested vaccination lowered the risk of developing long COVID by half. But a later study concluded that vaccines had a much more limited effect, and only reduced risk by 15%.

[W]hile this particular virus is a novel one, its potential to cause chronic illness and other sequelae is not unique. There are many examples, but a significant one is the relationship between EBV infection and multiple sclerosis. Additionally, some researchers and many patients have noted similarities between long COVID and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), which is theorized to be a post-viral illness. Particularly relevant is the fact that some survivors of the first SARS epidemic became ill with a similar post-acute condition in 2002. Altogether, though, this existing body of knowledge and new research have not yet added up to definitive answers. Vannorsdall said, “I suspect that as our mechanistic studies evolve, we will begin to appreciate that there are multiple etiologic pathways contributing to persistent post-COVID symptoms, with vascular, inflammatory, and psychological pathways contributing to varying degrees in different patients.”

“As we work towards answering clinically important questions, there will continue to be an important role for psychologists in providing psychoeducation and setting appropriate expectations, while helping optimize health behaviors and coping strategies in order to improve patient well-being,” Vannorsdall said. Silva agreed, and said that a cognitive behavioral approach on how mood or anxiety disorders can contribute to reduced cognitive efficiency can be helpful. “We have seen improvement with many of these patients at this practice,” she said. She also encourages patients to continue following up with their medical doctors for further evaluation and treatment of their physical symptoms. Rehabilitation psychologists like Rahman also have an important role to play in helping long COVID patients manage their symptoms. At both traditional rehabilitation clinics and specialty long COVID clinics, they are helping long COVID patients recover or adapt to their new levels of function.

Rahman said some of her patients have had success with several different approaches. One is “pacing,” a strategy that helps patients put their limited energy toward tasks and activities that matter the most to them. Other organizational strategies like symptom tracking can help patients prioritize their daily tasks, improve their memory and attention, and show patterns over time. Speech and language pathologists can also help patients compensate for deficits by working with them to develop new ways of learning and communicating. At the same time, normalizing the situation is important, Rahman said. “We have to acknowledge that yes, this is a major change, and it has so much impact on the patient’s day-to-day,” she said. “We have to be honest that we might not fix the brain right away, but we have great tools to help. We can instill hope.”

“Until we develop a treatment specifically targeted to the neuropsychiatric effects of COVID, we should rely on established therapeutics to rehabilitate affected individuals,” Samton said. “A multidisciplinary team that works together to address the different components of long COVID can make all the difference in hope and physical progress.”

`While long, this post may help practitioners recognize some of the questions to explore in dealing with clients who may have long COVID, especially with children who “perform normally” on cognitive tests, but whose long COVID symptoms may well predict substantial difficulties both at home and at school.