This prospective cohort study underlined the neocortical impairment as a neurological sequela of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. This study is of significant rehabilitative and socioeconomic relevance and patients suffering from cognitive deficits should be reported to neurologists and perhaps assigned to cognitive rehabilitation therapy.

This study aimed to assess the neural correlates of cognitive and neurological symptoms in critically-ill COVID-19 infected individuals.

From 20 April to 12 May 2020, COVID-19 infected patients (41 patients) in need of inpatient treatment mainly due to non-neurological complications were selected. Included patients were more than 18 years old with a minimum of 1 new neurological symptom.

In case of 2 or more symptoms, patients were further diagnosed via comprehensive neuropsychological tests, cerebral magnetic resonance imaging and ¹⁸fluorodeoxyglucose positron emission tomography (¹⁸FDG PET) were used till there was no infectivity. Premorbid analysis of cognitive impairment, neurodegenerative ailments, or intensive therapy unit were excluded.

At the most, 29 patients aged 65.2 ± 14.4 years (38% women) in the subacute stage of COVID-19 were included. Out of these, gustation and olfaction were commonly prevalent in all and 25 patients, respectively. Eighteen out of 26 patients had impaired Montreal Cognitive Assessment (MoCA) performance with a focus on frontoparietal cognitive functions which was proved by thorough neuropsychological testing in 15 patients.

As per the ¹⁸FDG PET, pathological results in 10 out of 15 patients mainly with frontoparietal hypometabolism were found. With the help of voxel-wise principal components analysis, this pattern was proved by contrast with a control sample, which disclosed a high correlation (R2 = 0.62) with the MoCA performance. White matter microglia activation with no indication of neuroinflammation was found in one deceased patient.

Neocortical dysfunction along with cognitive decline was found in patients with subacute COVID-19 in need of inpatient treatment at first.