Published by the Students of Johns Hopkins since 1896
June 22, 2024

Seeing through the fog: cognitive impacts of long COVID

By DEANNA RAHMAN | September 26, 2022



Chief among the cognitive impacts of long COVID-19 is "brain fog," characterized by difficulty thinking clearly, concentrating, forgetfulness and memory loss.

Among the long-term symptoms associated with COVID-19 investigated by the Centers for Disease Control and Prevention (CDC), cognitive dysfunction has emerged as one of the most persistent. 

In April of 2021, a nonprobability-based internet panel was established by Porter Novelli Public Services and used by the CDC to compare the prevalence of long-term symptoms among persons who self-reported testing positive for COVID-19 with those who tested negative. 55.5% of respondents who tested positive experienced persistent cognitive dysfunction. The survey defined cognitive dysfunction as difficulty thinking clearly, concentrating, forgetfulness, memory loss or “brain fog” with persistent symptoms that lasted for more than four weeks. 

According to a 2021 study of patients from the Johns Hopkins Post-Acute COVID-19 Team (JH PACT) pulmonary clinic, cognitive dysfunction, emotional distress and functional decline were commonly found among the diverse clinical sample of COVID-19 survivors (varying in acute illness severity). 35% of patients demonstrated impaired processing speed, 26 – 32% had impaired verbal fluency and 27% suffered from learning and memory challenges — in addition to moderate symptoms of depression (23%), anxiety (15%) or functional decline (15%). Additionally, 25% of intensive care unit (ICU) patients reported trauma related distress.

With this in mind, I contacted Megan Hosey, an assistant professor in the Department of Physical Medicine and Rehabilitation at the School of Medicine and clinical psychologist in the Pulmonary and Critical Care division at Hopkins, for her insight into how post-COVID cognitive dysfunction is being investigated and treated.

The physical impacts of persistent long COVID symptoms might be more commonly considered by the public due to its physiological effects. However, COVID-19 is linked to cognitive and psychological issues in multiple ways. 

In an interview with The News-Letter, Hosey elaborated on this phenomenon. 

“We’re seeing fewer people with critical illness because of COVID, but [among] those who did require things like mechanical ventilation or hospitalization we see around 25 to 35 percent having a new incident mental health problem,“ she said. “That could include anxiety, depression or post traumatic stress disorder (PTSD). We also know that people may experience cognitive changes, such as changes in things like attention, memory and executive function.”

Hosey also discussed the risk factors for long term cognitive impairment among patients who were critically ill.

“For example, having reduced oxygen to the brain if there are periods of time where their lungs aren’t circulating enough oxygen, they might be experiencing exposure to new types of medications.” she said. “Many patients experience something called ICU delirium, which involves major problems with attention, that can lead to it being very tough to tell what’s a dream and what’s real. So this is another thing that we’ve associated with longer term, cognitive impairment.”

In addition to decreased oxygen circulation and exposure to new types of medications, Hosey mentioned the following risk factors for long term cognitive impairment: advanced age, the amount of time a patient had to be sedated and how many organs failed while they were in the ICU. According to Hosey, studies have shown that the presence of these risk factors can lead to changes in cognitive function that last as long as five years after the onset of an illness. 

Furthermore, Hosey offered insight into the causes of post-COVID psychological sequelae, such as anxiety and depression. 

“Some of these psychological sequelae might be because people had a fear of dying, they’ve had multiple changes in their medical status or they’re worried that this could happen to them again,“ she said. “Many people have a major change in their ability to function in their day to day, which is sometimes associated with increased rates of depression.”

While the breadth and severity of cognitive impairment is greater among patients requiring treatment in the ICU, post-COVID cognitive symptoms are not limited to this patient population. In fact, neuropsychiatric symptoms and functional decline did not differ by post-ICU versus non-ICU status based on the JH PACT study. 

Hosey noted that cognitive issues related to prolonged illness or care in the ICU have occurred prior to COVID-19, and disease treatments have allowed clinicians to reinstate or amplify programs that positively impact patient outcomes, such as the University’s early rehabilitation program in the ICU. 

“We know that [the early rehabilitation program] can help people get a sense of self efficacy and understanding of what’s happening in their critical illness,“ she said. “We think that it also reduces the harm of bedrest, and so giving people that early access to rehabilitation with those disciplines as early as the ICU was important prior to COVID.” 

Hosey also cited the presence of family or loved ones as an important aspect of patient recovery, which has been reflected in the transition from restricted visitation to more open ICUs and the use of telecommunications in the past decade.

She discussed her key takeaways from her experience working with critically ill patients as they recover, especially during the pandemic.  

“There are many, many illnesses that leave people with a longer tail of recovery,“ she said. “[Recovery] also involves things like anxiety, depression, PTSD and major disruptions in important life functions like sleep, eating and appetite. Bringing all of our attention to recovery, even if it’s recovery that takes longer than we expected, is something we should be doing for all patients with all types of medical conditions.”

Most importantly, Hosey shared an optimistic perspective of the pandemic. 

“There are things we can start doing to protect our mental and cognitive health; there are professionals that you can reach out to to help with these types of things,” she said. “I do have a lot of hope that we're in the process of recovery, as a group, as a society, from all that COVID entailed from grief and loss from people we lost to the virus to the ways that it shut us down.”

Deanna Rahman is a senior from Westchester, N.Y. majoring in Medicine, Science and the Humanities and minoring in Anthropology and Spanish for the Professions.In for the Long Haulaims to investigate and increase awareness about COVID-19’s impact on physical health, mental and emotional well-being and the functioning of society as a whole.

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