Post-Covid cognitive impairment affects daily function and quality of life.•ACE-III fails to detect cognitive impairment in most post-Covid patients.•89% of patients have impaired attention, executive function, processing speed on novel tests.•New tests are needed for post-Covid cognitive assessment in clinical practice.

11 studies (involving 939,824 post-COVID-19 survivors and 6,765,117 controls) were included in the review. Across a median observation period of 12 months post-COVID, the overall incidence of NOD was about 1.82% in the COVID-infected group, compared to 0.35% in the non-COVID-infected group. The overall pooled meta-analysis showed a significantly increased NOD risk among COVID-19 older adult survivors compared to non-COVID-19 controls

The study shows that the SARS-CoV-2 spike protein remains in the brain's protective layers, the meninges, and the skull's bone marrow for up to four years after infection. This persistent presence of the spike protein could trigger chronic inflammation in affected individuals and increase the risk of neurodegenerative diseases.