[Impairments in neurocognitive functions in patients with long COVID: A systematic review].

Background: Studies have shown impairments in neurocognitive functions which persist more than 3 months after COVID-19 (long COVID). It remains unclear what these impairments entail, how long they persist and what proportion of the patients exhibit them.

Aim: To define the specific neurocognitive profile and to determine the proportion of deficits in at least one cognitive domain in patients with long COVID.

Method: We conducted a systematic search in PubMed according to PRISMA 2020 guidelines with the following inclusion criteria: peer reviewed publications in which patients were assessed more than 3 months following acute COVID-19 by means of a test battery for different domains of neurocognition.

Results: We found a total of 1178 papers, of which 7 cohort studies and 1 case-control study were selected. The proportion of patients having deficits in at least one domain of neurocognition ranged from 23% to 100%. Most frequent impairments were found in attention and speed of information processing, anterograde memory, working memory and executive function. Quality of the included studies was moderate.

Conclusion: Impairments in neurocognitive functions are highly prevalent among patients with long COVID and include various cognitive domains. We encourage further research to continue studying the complex interaction of COVID-19, neurocognitive impairments and neuropsychiatric syndromes.