What We Know About Neurocognitive Outcomes in Long-/Post-COVID-19 Adults

Abstract: This review assesses neurocognitive studies on long-/post-COVID-19 adult patients, highlighting the research gaps. We categorize populations by infection severity, demographics, inclusion of controls, and psychological/biological factors. Methodologically, we analyzed 73 studies (95,600 subjects) from December 2019 to October 2022 using PRISMA-ScR guidelines and the PICO framework. Our findings revealed that most studies lacked control groups (88 %) and reported unclear overall cognitive outcomes (73 %). While the studies frequently assessed executive functions (86 %) and attention (85 %), there were few longitudinal studies. Varied reporting on sample sizes further complicated the analysis. The identified gaps encompass convenience sampling, limited longitudinal studies, and inadequate use of cognitive test batteries, leading to a discrepancy between expected and reported outcomes. The absence of standardized comparisons and inconsistent statistical methods exacerbated these gaps.