Abstract
Objectives To characterise cognitive performance and olfaction in recovered COVID-19 patients.
Methods Patients underwent cognitive, olfaction and mental health assessments 2 months after initial SARS-CoV-2 infection as part of the Sydney St. Vincent’s Hospital ADAPT study, a prospective cohort study. Cognition was assessed with the Cogstate computerised battery and expressed as a demographically-corrected composite z-score and clinically classified as impaired/borderline/unimpaired. Anxio-depressive symptoms were assessed with the Depression in the Medical ill scale-10 (DMI-10), the Somatic and Psychological HEalth Report-34 (SPHERE) Psych sub-scale, and the Impact of Events Scale-Revised (IESR) and reduced into single Principal Component explaining 80% of the variance. Olfaction was assessed with the NIH Toolbox Odor Identification test and expressed as demographically-corrected T-scores, and impaired/unimpaired. Disease severity was classified as mild (40%), moderate (50%) or hospitalised (10%).
Results 132 patients (mean age=46±15; 40% women, median education=16 years, 10% Non-English-Speaking Background-NESB) were included. 17% had impaired cognition, 10% had borderline deficits, 25% has impaired olfaction. 25% had clinically elevated symptoms on the DMI-10, 13% on the IESR, and 35% on the SPHERE. Regression analyses showed that anxio-depression was not associated with cognitive performance (unadjusted p=.43; adjusted for sex & NESB p=.98) nor impaired/unimpaired status (unadjusted p=.50; adjusted for sex & NESB p=.78). Cognitively impaired patients were more likely to have impaired olfaction (p<.009). Results were independent of disease severity.
Conclusions Cognitive impairment is common and not related to psychological factors, may occur independent of disease severity and is associated with anosmia. These point to direct brain effects of COVID-19.
