Towards normalization of cognitive function and psychiatric morbidity in patients with neurological symptoms post COVID-19: a longitudinal study

INTRODUCTION: Few studies of cognitive impairment in COVID-19 convalescents have assessed patients longitudinally. The aim of this study was to examine the course of performance-based cognitive functions from 6 (T1) to 12 (T2) months after COVID-19 in patients compared with healthy controls, and to investigate the effect of psychiatric diagnosis and fatigue on cognitive function trajectories. METHODS: Eighty-one patients with confirmed SARS-CoV-2 infection reporting neurological symptoms were assessed at T1 and 67 patients at T2 with neuropsychological assessment and a semi-structured psychiatric interview. Fatigue was assessed using the Giessener Beschwerdebogen questionnaire (GBB). Sixty-one, confirmed SARS-CoV-2 antibody negative, healthy controls underwent neuropsychological assessment and completed GBB. RESULTS: At T1, patients performed significantly (p < 0.001 to 0.031) worse across the different cognitive domains, except for verbal fluency, than healthy controls. At T2, there were no significant differences between the two groups in either cognitive domain. Patients improved significantly from T1 to T2 on 7 of 8 domain scores (p < 0.001 to 0.033) and fatigue scores (p = 0.003). The frequency of psychiatric disorders decreased from 40% to 21%. Having a psychiatric diagnosis at T2 and/or delirium during acute COVID-19 significantly predicted a less favourable cognitive function course. CONCLUSION: These results suggest cognitive function, psychiatric morbidity and fatigue improve one year after COVID-19. Patients with ongoing psychiatric disorder and/or sequela following COVID-19-related delirium may constitute a vulnerable subgroup for non-improvement of cognitive function and should be specifically targeted for rehabilitation and treatment. TRIAL REGISTRATION: The study was registered the 09th of October 2020 at clinicaltrials.gov (NCT04576351).