Review Cognitive domains affected post-COVID-19; a systematic review and meta-analysis, 2024, Carson, David, Nicholson+

Cognitive domains affected post-COVID-19; a systematic review and meta-analysis
Jack B. Fanshawe; Brendan F. Sargent; James B. Badenoch; Aman Saini; Cameron J. Watson; Aleksandra Pokrovskaya; Daruj Aniwattanapong; Isabella Conti; Charles Nye; Ella Burchill; Zain U. Hussain; Khanafi Said; Elinda Kuhoga; Kukatharmini Tharmaratnam; Sophie Pendered; Bernard Mbwele; Maxime Taquet; Greta K. Wood; Jonathan P. Rogers; Adam Hampshire; Alan Carson; Anthony S. David; Benedict D. Michael; Timothy R. Nicholson; Stella-Maria Paddick; Charles E. Leek

BACKGROUND AND PURPOSE
This review aims to characterize the pattern of post-COVID-19 cognitive impairment, allowing better prediction of impact on daily function to inform clinical management and rehabilitation.

METHODS
A systematic review and meta-analysis of neurocognitive sequelae following COVID-19 was conducted, following PRISMA-S guidelines. Studies were included if they reported domain-specific cognitive assessment in patients with COVID-19 at >4 weeks post-infection. Studies were deemed high-quality if they had >40 participants, utilized healthy controls, had low attrition rates and mitigated for confounders.

RESULTS
Five of the seven primary Diagnostic and Statistical Manual of Mental Disorders (DSM-5) cognitive domains were assessed by enough high-quality studies to facilitate meta-analysis. Medium effect sizes indicating impairment in patients post-COVID-19 versus controls were seen across executive function (standardised mean difference (SMD) −0.45), learning and memory (SMD −0.55), complex attention (SMD −0.54) and language (SMD −0.54), with perceptual motor function appearing to be impacted to a greater degree (SMD −0.70). A narrative synthesis of the 56 low-quality studies also suggested no obvious pattern of impairment.

CONCLUSIONS
This review found moderate impairments across multiple domains of cognition in patients post-COVID-19, with no specific pattern. The reported literature was significantly heterogeneous, with a wide variety of cognitive tasks, small sample sizes and disparate initial disease severities limiting interpretability. The finding of consistent impairment across a range of cognitive tasks suggests broad, as opposed to domain-specific, brain dysfunction. Future studies should utilize a harmonized test battery to facilitate inter-study comparisons, whilst also accounting for the interactions between COVID-19, neurological sequelae and mental health, the interplay between which might explain cognitive impairment.

Link | PDF (European Journal of Neurology)