Changes in cognitive functioning after COVID-19: a systematic review and meta-analysis

Abstract

With an increasing number of individuals recovering from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, there is an urgent need to study the medium- and long-term consequences of the disease. Growing evidence suggests that some patients exhibit symptoms such as fatigue, “brain fog,” or cognitive complaints after the acute infection stage, commonly referred to as “Long COVID.”1 A 6-month study using multidimensional data from the medical records of 73,435 coronavirus disease 2019 (COVID-19) patients showed that, after the first 30 days of illness, individuals have an increased risk of death, higher health resource utilization, and an increased burden from neurocognitive disorders.1 Indeed, evidence from previous epidemics shows that subsequent neurological and, particularly, cognitive complications can occur, such as in the severe influenza epidemic from 1918 to 1921 (also known as the Spanish flu).2 More recently, cases of encephalitis, sensory impairment, coma, and severe neurological damage were reported during the Middle East respiratory syndrome coronavirus (MERS-CoV) outbreak in 20123 and vascular or inflammatory damage of the brain and central nervous system in people affected by the severe acute respiratory syndrome coronavirus (SARS-CoV) outbreak in 2003.4

Cognitive dysfunction has a significant impact on functionality and quality of life.5 Given the high incidence of COVID-19 and the associated economic, health, and social burden of the epidemic, studying its occurrence and underlying mechanisms is crucial. In the current systematic review, we assess whether there is an increased occurrence of cognitive deficits in adult patients with COVID-19 who previously had no cognitive impairment.