Cognitive consequences of COVID-19: results of a cohort study from South America

Abstract

Background: Neurological and psychiatric manifestations associated with SARS-CoV-2 infection have been reported throughout the scientific literature. However, studies on post-COVID cognitive impairment in people with no previous cognitive complaint are scarce. Objective: We aim to investigate the impact of COVID-19 on cognitive functions in adults without cognitive complaints before infection and to study cognitive dysfunction according to disease severity and cognitive risk factors. Methods: Forty-five post-COVID-19 patients and forty-five controls underwent extensive neuropsychological evaluation, which assessed cognitive domains such as memory, language, attention, executive functions, and visuospatial skills, including psychiatric symptomatology scales. Data were collected on the severity of infection, premorbid medical conditions, and functionality for activities of daily living before and after COVID-19. Results: Significant differences between groups were found in cognitive composites of memory (p=0.016, Cohen’s d= 0.73), attention (p<0.001, Cohen’s d=1.2), executive functions (p<0.001, Cohen’s d=1.4), and language (p=0.002, Cohen’s d=0.87). The change from premorbid to post-infection functioning was significantly different between severity groups (WHODAS, p=0.037). Self-reported anxiety was associated with the presence of cognitive dysfunction in COVID-19 subjects (p=0.043). Conclusion: Our results suggest that the presence of cognitive symptoms in post-COVID-19 patients may persist for months after disease remission and argue for the inclusion of cognitive assessment as a protocolized stage of the post-COVID examination. Screening measures may not be sufficient to detect cognitive dysfunction in post-COVID-19 patients.

Changes in cognitive functioning after COVID‐19: A systematic review and meta‐analysis

“…Specifically, the cognitive domains mostly impaired were immediate verbal memory impairment (38% moderate, 11.2% severe) and semantic verbal fluency (34.6% moderate deficits and 8.4% severe). In addition, studies found cognitive deficits in verbal fluency, attention, executive functions, and delayed memory 12,15,27–29 . In a study by Hosp et al., 15 neurological symptoms and executive deficits correlated with frontoparietal hypometabolism in fluorodeoxyglucose (FDG)–positron emission tomography (PET).…”

“…The quality of case‐control and cohort studies was assessed judging three categories: the selection of the study groups, the comparability of the groups; and the ascertainment of either the exposure or outcome of interest for case‐control or cohort studies, respectively. In summary, when using the Agency for Health Research and Quality (AHRQ) threshold standards, 9 of the 20 studies were good, 15,23,25,27,29,32,33,36,31 1 was fair, 28 and 10 were poor 10–12,14,16,24,30,34,35,37 …”

“…In addition, studies found cognitive deficits in verbal fluency, attention, executive functions, and delayed memory. 12,15,[27][28][29] In a study by Hosp et al,15…”

“…A total of five studies reporting MoCA results, including COVID-19 patients versus a control group, 11,24,29,31,36 were included in the metaanalysis. There was evidence of an effect of COVID-19 infection on the total MoCA score (MD = −0.94, 95% CI −1.59, −0.29; P = .0049).…”

“…Research and Quality (AHRQ) threshold standards, 9 of the 20 studies were good, 15,23,25,27,29,32,33,36,31 1 was fair, 28 and 10 were poor. [10][11][12]14,16,24,30,34,35,37 4 DISCUSSION…”