Long-COVID-19 cognitive disfunction: strain-specific effects on 452 subjects
Ítalo Karmann Aventurato1, Mateus Nogueira1, Lucas Scardua Silva1, Rafael Baptista João1, José Flávio Becchelli1, Alan Ferreira dos Santos1, Leila Camila Santos Silva1, Mariana Rabelo de Brito1, Fernando Cendes1, Clarissa Yasuda1
1Department of Neurology, UNICAMP
Objective:
Evaluate the effect of COVID-19 presumed viral strains on different cognitive domains.
Background:
Cognitive dysfunction (CD) is a frequent and debilitating symptom of long-COVID syndrome with a negative impact on survivors' productivity and quality of life. It is unknown whether there are strain-specific effects on cognition.
Design/Methods:
We used the Fiocruz database (http://www.genomahcov.fiocruz.br) to separate 452 subjects (15 years of education; 88 days after diagnosis) according to the prevalent viral strain at the time of the positive COVID-19 test.
Subjects completed a neuropsychological evaluation consisting of phonetic fluency (FAS), semantic fluency (SF: animals), logic memory (immediate and late recall), Rey-Osterrieth complex figure test (copy and recall), colored trails test A and B, 9-hole peg test (dominant and non-dominant hand) and the five digits test (reading, counting, choice, alternation, inhibition, and flexibility). Test scores were converted to Z-scores using normative Brazilian tables. Global strain effects were tested using MANOVA, followed by one-way ANOVAs for each test.
Results:
Subjects were classified into five presumed strain groups: original (247), original+P2 (36), P2 (86), gamma+P2 (50), and delta (6). Full testing data were available for 141 subjects. MANOVA showed significant strain effects (p=0.046). However, post-hoc tests showed no strain effects on any of the cognitive tests. SF showed a marginally significant effect (n=392, p=0.056) due to better performances in the original+P2 and P2 groups. FDT reading subtest was marginally significant (n=323, p=0.073) due to better test performances in the P2 and delta groups.
Conclusions:
Despite the small groups with non-original strains, we suppose neurotropism regardless of different strains. As millions of survivors may present CD, there is an urgent need for health policies to provide multidisciplinary treatment and rehabilitation to improve workability and quality of life. Further studies with larger samples may disclose the protective role of vaccination in preventing CD.