Introduction: Previous studies on the prognostic role of sex in post-COVID-associated brain fog have yielded divergent results. Moreover, limited evidence exists regarding the evolution of brain fog symptoms over time, especially in ambulatory patients and separately for women and men. Therefore, the aim of the current study was to assess brain fog symptoms in nonhospitalised patients with COVID-19, according to their sex.
Material and methods: We created a neuropsychological questionnaire including eight questions on the presence of brain fog symptoms in the following four time periods: before COVID-19, and 0-4, 4-12, and > 12 weeks post-infection. The validity and reliability of the questionnaire were assessed. In this cross-sectional study, questionnaires were filled out anonymously and retrospectively once only by patients or through a survey link posted online. Included were patients ≥ 18 years, with > 3 months since the SARS-CoV-2 infection onset confirmed by RT-PCR from a nasopharyngeal swab.
Results: The study included 303 patients (79.53% women, 47.52% medical personnel). Median time between COVID-19 onset and questionnaire completion was 208 (IQR 161-248) days. Women, compared to men, reported a higher prevalence of problems with writing, reading, and counting (< 4 weeks, OR 3.05, 95% CI: 1.38-6.72; 4-12 weeks, OR 2.51, 95% CI: 1.02-6.14; > 12 weeks, OR 3.74, 95% CI: 1.12-12.56) and thoughts communication (< 4 weeks, OR 2.53, 95% CI: 1.41-4.54; 4-12 weeks, OR 3.74, 95% CI: 1.93-7.24; > 12 weeks, OR 2.00, 95% CI: 1.01-3.99). The difference between the two sexes in answering questions in an understandable/unambiguous manner was statistically significant between four and 12 weeks after infection (OR 2.63, 95% CI: 1.36-5.10), while a sex difference in recalling new information was found below 12 weeks (OR 2.54, 95% CI: 1.44-4.48 and OR 2.43, 95% CI: 1.37-4.31 for < 4 and 4-12 weeks, respectively). No sex differences in reporting problems with multitasking, remembering information from the past, determining the current date, or field orientation were noted.
Conclusions: Non-hospitalised women and men retrospectively report a different course of COVID-19-associated brain fog.
Keywords: COVID-19; brain fog; course of COVID-19; long COVID; sex.