Year: 2026
Type: dissertation
Study design: Observational Study
Abstract: SARS-CoV-2, the virus responsible for the Covid-19 pandemic, has been shown to have an impact on cognitive function and the brain, but the specific areas that are affected remain unclear, increasing the need for replication studies. We present findings from 3 datasets looking at this topic. In Chapter 2 we analysed online cognitive data from individuals with and without previous Covid-19 infection with the aim to replicate and extend previously found effect of Covid on specific long-term memory types. Using both Frequentist and Bayesian approaches, we confirmed an effect of Covid status on accuracy across long-term memory tasks, but not on reaction times. Contrary to predictions, the effect did not interact with memory type (associative vs. item) or stimulus type (verbal vs. nonverbal). In Chapters 3-5, we extended this work using the UK Biobank dataset, which includes cognitive and neuroimaging data collected both before and after the pandemic. Consistent with our preregistered hypotheses, we observed an effect of Covid-19 on associative memory and replicated previous reports of reduced global grey-matter volume in those who had recovered from infection. Diffusion MRI analyses revealed trajectories of increased mean fractional anisotropy and decreased mean diffusivity relative to controls tested before the pandemic, effects in opposite direction compared to our predictions. Canonical Correlation Analysis in Chapter 5 further indicated that although Covid-19 participants differed in their overall position within the joint cognitive–imaging latent space, the underlying relationship between cognitive and brain measures remained stable across groups. In Chapter 6 we examined longitudinal data from the CamCAN study to replicate the memory effect once more. However, power simulations based on prior effect sizes indicated insufficient statistical power (≈12%), and the predicted effect was not detected. Overall, these studies provide valuable insights into the effect of (or, in some cases, lack of) SARS-CoV-2 infection on cognition and the brain, and can inform further research, policy makers and healthcare services.
Author: Weinerova, Josefina
Language: English
Subfield: Clinical Neurology
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W7217851144