Background

Evidence-based data are still lacking to define de characteristics of cognitive impairment after COVI-19. Previous findings suggest that Covid-19 sequelae may resemble early Alzheimer’s disease (AD). In this abstract, our team present data from Argentina, Canada, Russia, Greece, and the UK including 1919 patients and 1031 controls.

Method

Participants were 18 to 97 years old. Neuropsychological evaluation included Montreal Cognitive Assessment – MoCA, Toronto Cognitive Assessment- TORCA, and/or batteries specially built for the evaluation of cognitive dimensions. Some cohorts included the anosmia. Participants were evaluated at a maximum of 6 months after discharge. A factorial analysis was performed on each country identifying 3 factors that could be compared between countries: one accounting for memory and language, the second is an attentional factor, and the last is a working memory factor. Between countries that have young population, there was a fourth factor accounting for executive functioning (planning and inhibition). We carried out meta-analysis of common factors and co-variates.

Result

Average duration of formal learning is 11.06 ± 5.11 years, and the mean age is 52.61 ± 15.87 years. Meta-analysis revealed an impairment in language (verbal fluency) for all patients vs controls. Factorial scores revealed that all the participants were impaired in attentional tasks but those over 60 years old were impaired also in working memory and the youngest participants in executive functioning. Significant differences between cases and controls in attentional, memory, and language tasks identified 4 different groups: normal cognition (71%); one dimension impaired (20.5%); two dimensions impaired (6.5%); and three dimensions impaired (2%). In older adults, these proportions rise to 28% for the impairment in one dimension; 11.5% for two dimensions, and 3.5% for three dimensions and is significantly associated with the infection diagnoses (p = 0.013) and with presence and severity of anosmia (p = 0,000).

Conclusion

Older adults are at greater risk of suffering persistent cognitive impairment after recovery from SARS-CoV-2 infection and cognitive impairment is correlated with the presence and severity of anosmia.