BACKGROUND AND AIM:Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) is a new coronavirus that was detected in late 2019 in China. It resulted in a pandemic that persisted until 2023. The disease caused by SARS-CoV-2 was named as Coronavirus disease-2019 (COVID-19). Primary involvement sites of COVID-19 are upper airways and lungs, but various organs and systems are also affected. In addition to physical damage, impairment of cognitive functions was detected after COVID- 19. The aim of the study is to assess the impact of COVID-19 and its severity on cognitive functions and to document the relationship between cognitive functions and physical capacity.

METHODS:Adult patients with a history of COVID-19 and without prior known cognitive impairment were included. Age, gender, and educational level of the patients were recorded. Time since the positive reverse transcriptase-polymerase chain reaction (RT-PCR) test result for COVID-19 to the evaluation was calculated. COVID-19 disease severity was determined according to classification of World Health Organization. Montreal Cognitive Assessment (MoCA) was used to assess cognitive functions. MoCA assesses cognitive functions in six domains: 1. Short-term memory, 2. Visuospatial abilities, 3. Executive functions, 4. Attention-concentration-working memory 5. Language, 6. Orientation to time and place. A total MoCA score of less than 26 revealed cognitive impairment. Physical capacity was estimated with 6-minute walking test (6MWT). Mann-Whitney U test, Student’s t test, chi-square test and Spearman’s correlation were used for statistical analysis.

RESULTS:Fifty-nine patients were included. 50.8% of the group (n=30) were males. Mean age of the group was 43.0 ± 11.6 years. Mean time from positive RT-PCR test result to the evaluation was 82.1 ± 42.9 (min-max: 31-170) days. Mean MoCA score was 26.05 ± 2.79 (median: 27, min-max: 20-30). Twenty-one (35.6%) patients had cognitive impairment according to MoCA score. Disease severity was mild in 25, moderate in 20, severe in 11 and critical in 3 patients. Patients were divided into two groups according to disease severity (mild/moderate and severe/critical) and two groups were compared. There was no statistically significant difference between disease severity groups according to age (p=0.41), gender (p=0.59), and educational level (p=0.63). In severe-critical disease severity group, scores of domains of executive functions (p=0.04), language (p=0.00), and attention-concentration- working memory (p=0.01) were lower than in mild-moderate disease severity group and this difference was statistically significant. Total MoCA score was also significantly lower (p=0.01) in severe-critical disease severity group (Table 1). Mean walking distance in 6MWT was 570.14 ± 98.17 meters in the whole group. There was a weak positive (r=0.28) and statistically significant (p=0.03) correlation between walking distance and total MoCA score. The relationship between domains of MoCA and 6MWT revealed only weak positive (r=0.36) and statistically significant (p=0.01) correlation between walking distance and executive functions domain (Table 2).