Neuropsychological functioning and its correlates at 1 year follow-up of severe COVID-19

Background: Short-term cognitive impairment is associated with SARS-CoV-2 infection but the long-term impact is yet to be examined in detail. We aim to study the evolution of these symptoms in severe COVID-19 patients admitted to the intensive care unit (ICU) between April and December 2020 1 year after hospital discharge and to analyze its clinical correlates.

Method: A total of 58 patients agreed to participate in the 6 months follow-up and 30 at 1 year after hospital discharge. Demographic, clinical and laboratory data were collected and a comprehensive neuropsychological battery including validated tests for the main cognitive domains was administered. To test the magnitude of neurocognitive sequelae, two standard deviations below normative group were considered. To compare the neuropsychological performance at 6 and 12 months follow-up we used repeated measures tests. Finally, regression analyses were performed to test the main effects of medical and psychological factors on multiple cognition.

Results: Almost half of the sample continued to have impaired performance on neuropsychological tests at 12 months follow-up. In comparison with the results obtained at 6 months, significant improvements were found in immediate recall (d = 0.49), delayed recall (d = 0.45), and inhibitory control (d = 0.53). Medical variables predicted cognitive performance at 6 months but not at 12 months follow-up, while anxiety and depression predicted cognitive deficits in the long-term.

Conclusions: A generalised improvement was observed in severe COVID-19 patients at follow-up. This improvement was particularly notable in verbal memory and executive functioning. However, a considerable proportion of the sample continued to present deficits at 1 year follow-up.