Covid impairs brain health, but not more than pneumonia, cardiac arrest, or critical illness: Study

New Delhi: Brain function is impaired in patients following severe Covid-19, but no more than that of people hospitalised with illnesses like pneumonia and cardiac arrest with similar severity, new research has found.

Researchers found that patients hospitalised due to Covid-19 had worse cognitive, neurological and psychiatric effects than healthy participants after an 18-month follow-up period.

However, the researchers at the University of Copenhagen, Denmark, also found that these deficits in brain function were not significantly different to those in 'carefully matched' patients requiring hospitalisation for pneumonia, myocardial infarction (cardiac arrest), or non-Covid-19, intensive care-requiring illness.

Thus, they say that long-term associations with brain health might not be specific to Covid-19 but associated with overall illness severity and hospitalisation.

They also said that this information was important for putting understandable concerns about brain health after Covid-19 into perspective. Their findings are published in the Journal of American Medical Association (JAMA) Network Open.

Previous studies have found Covid-19 to compromise brain function.

However, long-term prospective investigations with matched control cohorts and face-to-face assessments were lacking, the researchers said.

In this study, the team included 345 participants, including 120 patients with Covid-19, 125 patients hospitalised for non-COVID-19 pneumonia, myocardial infarction, or non-Covid-19, ICU-requiring illness and 100 healthy controls.

Over the follow-up period, the participants were evaluated for their cognition and executive function, along with depression and anxiety. They also underwent a neurological examination, which measured their sensorimotor and cerebellar functions and cranial nerves.

The team also conducted interviews with the patients to gather data on cognitive and neuropsychiatric symptoms they were experiencing, including fatigue. The symptoms attributable to the hospitalisation were included in the study, they said.

All the evaluations, except for executive function and impaired sense of smell, showed that patients hospitalised with Covid-19 performed worse than the healthy individuals, but no worse than those hospitalised with similarly severe illnesses, the researchers said.

They also found that patients with Covid-19 had a higher incidence of new psychiatric diagnoses - anxiety and depression - compared with healthy controls, but again, not more than the hospitalised control patients. They said this observation corroborated previous studies.

The researchers acknowledged that because healthy controls had fewer comorbidities than hospitalised individuals, thus multimorbidity could play a role in both hospitalisation and lasting associations with brain health.

Further, even as studies with broader cognitive test batteries are needed to confirm these findings, brain health after Covid-19 seems overall comparable to that after other diseases of similar severity, they said.