COVID-19 and Cognitive Function: Evidence for Increased Processing Speed Variability in COVID-19 Survivors and Multifaceted Impairment with Long-COVID Symptoms

Abstract

Copyright © The Author(s), 2023. Background: There is increasing evidence for cognitive function to be negatively impacted by COVID-19. There is, however, limited research evaluating cognitive function pre- and post-COVID-19 using objective measures. Methods: We examined processing speed, attention, working memory, executive function and memory in adults (≤69 years) with a history of COVID-19 (n=129; assessed ≥20 days after diagnosis, none acutely unwell), compared to those with no known history of COVID-19 (n=93). We also examined cognitive changes in a sub-group of COVID (n=30) and non-COVID (n=33) participants, compared to their pre-COVID-19 pandemic level (data available through the MyCognition database). Results: Cross-sectionally, the COVID group showed significantly larger intra-individual variability in processing speed, compared to the non-COVID group. The COVID sub-group also showed significantly larger intra-individual variability in processing speed, compared to their pre-COVID level; no significant change occurred in non-COVID participants over the same time scale. Other cognitive indices were not significantly impacted in the cross-sectional or within subjects investigations, but participants (n=20) who had needed hospitalisation due to COVID-19 showed poor attention and executive function relative to those who had not required hospitalisation (n=109). Poor health and long-COVID symptoms correlated with poor cognitive function across domains in the COVID group. Conclusions: The findings indicate a limited cognitive impact of COVID-19 with only intraindividual variability in processing speed being significantly impacted in an adult UK sample. However, those who required hospitalisation due to COVID-19 severity and/or experience long-COVID symptoms display multifaceted cognitive impairment and may benefit from repeated cognitive assessments and remediation efforts.