Abstract:
Covid-19 is associated with cognitive impairment despite resolution of the acute infection.
Our objective was to conduct a meta-analysis to quantify the proportion of individuals
experiencing cognitive impairment after recovering from Covid-19. We performed a
literature search completed on 31 August 2021, based on our pre-registered PRISMA
protocol. Searches were conducted without language restrictions on Google Scholar,
PsychINFO, Scopus, PubMed, Science Direct, Web of Science, and ProQuest Dissertations
& Theses Global. Primary research articles which evaluated individuals with a negative PCR
test after recovery from confirmed Covid-19 diagnosis and specifically reported cognitive
impairment were selected. One reviewer independently extracted published data and assessed
methodological quality and risk of bias. A meta-analysis was conducted using the randomeffects
model. The primary outcomes were the proportions of individuals reporting cognitive
impairment after recovering from Covid-19 infection. The literature search yielded 79,200,
excluding duplicates, and ten studies were selected for inclusion. The meta-analysis revealed
cognitive impairment in individuals recovered from Covid-19 with an effect of g = -.53, 95%
CI [-0.75, -0.31], p = 0.0000019, k = 10, I2 = 57.69%. We included various moderating
variables, including race/ethnicity, regional differences, sex, age, disease severity, strain
variants, genetic variants, treatments and comorbidities. These results indicated a proportion
of individuals experience cognitive impairment after recovering from Covid-19. The
frequency and nature of the prevailing symptoms indicate the need for more studies with
larger samples and control groups to understand the underlying mechanisms that cause
cognitive impairment.