New Data on COVID-19's Cognitive Fallout

Pauline Anderson

June 21, 2021

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

Patients hospitalized with COVID-19 experience cognitive and behavioral problems post-discharge, new research shows.

Investigators found cognitive changes, depression, and posttraumatic stress disorder (PTSD) in infected patients, both in the subacute phase and 10 months after hospital discharge.

"We showed that cognitive and behavioral alterations are associated with COVID-19 infection within 2 months from hospital discharge and that they partially persist in the post-COVID phase," study investigator Elisa Canu, PhD, Neuroimaging Research Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy, told a press briefing.

The findings were presented at the virtual Congress of the European Academy of Neurology (EAN) 2021.

Executive Dysfunction

Previous research suggests about 30% of COVID-19 survivors have cognitive disturbances and 30%-40% have psychopathological disorders including anxiety and depression, said Canu.

These disturbances have been associated with the severity of acute-phase respiratory symptoms, infection-triggered neuroinflammation, cerebrovascular alterations, and/or neurodegeneration.

However, it's unclear whether these disturbances persist in the post-COVID phase.

To investigate, the researchers explored cognitive and psychopathological features in 49 patients with confirmed COVID-19 admitted to a hospital emergency department. They examined these factors at 2 months (sub-acute phase) and at 10 months (post-COVID phase).

Participants had an average age of 61 years (age range 40-75) and 73% were men. Most had at least one cardiovascular risk factor such as hypertension (55%), smoking (22%), and dyslipidemia (18%).

At hospital admission, 71% had an abnormal neurologic exam, 59% had hypogeusia (reduced sense of taste), 45% hyposmia (reduced sense of smell), 39% headache, and 20% confusion or drowsiness. During hospitalization, 27% had noninvasive ventilation.

In addition to cognitive and neurologic assessments, participants underwent MRI 2 months after hospital discharge. Researchers obtained data on gray matter, white matter, and total brain volume.

At 2 months post-discharge, 53% of patients presented with at least one cognitive deficit. Many deficits related to executive function including difficulty planning, attention, and problem-solving (16%).

However, some participants had memory issues (6%) or visuospatial disturbances (6%). Almost a quarter (23%) presented with a combination of symptoms related to executive dysfunction.

Low Oxygen Tied to More Cognitive Deficits

More than one third of patients experienced symptoms of depression (16%) or PTSD (18%).

Patients younger than 50 years had more executive dysfunction, with these symptoms affecting 75% of younger patients. "Our explanation for that is that younger people had a milder clinical profile regarding COVID, so they were cared for at home," said Canu.

While in hospital, patients may be on "continued alert" and receive structured interventions for cognitive and behavioral issues, she said.

More severe respiratory symptoms at hospital admission were significantly associated with deficits during the subacute phase (P = .002 for information processing).

"Low levels of oxygen in the brain could lead to confusion, headache, and brain fog, and cause the cognitive disturbances that we see," said Canu.

White matter hyperintensities were linked to cognitive deficits during this phase (P < .001 for verbal memory and delayed recall).

"These white matter lesions are probably preexisting due to cardiovascular risk factors that were present in our population and may have amplified the memory disturbances we saw," commented Canu.

The investigators did not find a significant relationship between cognitive performance and brain volume. Canu noted that cognitive and psychopathological disturbances are linked. For instance, she said, a patient with PTSD or depression may also have problems with attention or memory.

In the post-COVID phase, cognitive symptoms were reduced from 53% to 36%; again, the most common deficit was combined executive dysfunction symptoms. Depression persisted in 15% of patients and PTSD in 18%.

"We still don't know if these alterations are a consequence of the infection," said Canu. "And we don't know whether the deficits are reversible or are part of a neurodegenerative process."

The researchers plan to follow these patients further. "We definitely need longer follow-up and bigger populations, if possible, to see if these cognitive and psychopathological disturbances can improve in some way," said Canu.

The study results underline the need for neuropsychological and neurologic monitoring in COVID patients. Cognitive stimulation training and physical activity, preferably outdoors, could be beneficial, Canu added.

Congress of the European Academy of Neurology (EAN) 2021: Session 110. Presented June 19, 2021.

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