COGNITIVE RESERVE IN PATIENTS AFTER CORONAVIRUS INFECTION.
Despite the growing evidence of persistent cognitive dysfunction after COVID-19, the role of cognitive reserve as a modifying factor of post-infectious neurocognitive outcomes remains insufficiently explored, particularly in relation to disease severity and premorbid lifestyle characteristics.
To analyze the characteristics of cognitive reserve in patients after SARS-CoV-2 infection and to assess its impact on the structure and severity of post-COVID cognitive impairments.
The study included 247 patients aged 31-67 years who had recovered from COVID-19 (93 hospitalized and 154 treated on an outpatient basis) and 50 age-matched controls without a history of COVID-19. Cognitive reserve and related factors were assessed using the Cognitive Reserve Questionnaire (CRQ), Test of Premorbid Functioning (TOPF), Montreal Cognitive Assessment (MoCA), Trail Making Test A/B, Digit Span Backward, and semantic verbal fluency test. Premorbid lifestyle characteristics, occupational cognitive complexity, physical activity, disease severity, body mass index, and inflammatory markers (peak C-reactive protein) were recorded. Multivariate linear regression models were constructed with global cognitive performance (MoCA score at 12 months) as the dependent variable.
Post-COVID patients demonstrated significantly lower CRQ total scores compared with controls (7.82±0.12 vs 9.41±0.15; p<0.001), with the lowest values observed in hospitalized patients. Educational level and premorbid intelligence (TOPF) did not differ between groups, indicating preserved premorbid cognitive capacity. Reduced CRQ scores were primarily driven by lower occupational cognitive complexity and diminished cognitively active lifestyle, suggesting impaired utilization of cognitive reserve rather than loss of reserve capacity. MoCA scores were significantly lower in post-COVID patients (25.4±0.19 vs 27.8±0.22; p<0.001), with predominant impairment of executive functions, attention, and processing speed. In multivariate analysis, better cognitive outcomes were independently associated with higher CRQ scores, greater occupational complexity, and higher premorbid physical activity, while disease severity, elevated inflammatory markers, and older age were associated with poorer MoCA performance (Adjusted R²=0.521; p<0.001).
Post-COVID cognitive impairment occurs despite preserved premorbid cognitive reserve and is characterized by reduced utilization and engagement of reserve mechanisms, particularly following severe disease.
To analyze the characteristics of cognitive reserve in patients after SARS-CoV-2 infection and to assess its impact on the structure and severity of post-COVID cognitive impairments.
The study included 247 patients aged 31-67 years who had recovered from COVID-19 (93 hospitalized and 154 treated on an outpatient basis) and 50 age-matched controls without a history of COVID-19. Cognitive reserve and related factors were assessed using the Cognitive Reserve Questionnaire (CRQ), Test of Premorbid Functioning (TOPF), Montreal Cognitive Assessment (MoCA), Trail Making Test A/B, Digit Span Backward, and semantic verbal fluency test. Premorbid lifestyle characteristics, occupational cognitive complexity, physical activity, disease severity, body mass index, and inflammatory markers (peak C-reactive protein) were recorded. Multivariate linear regression models were constructed with global cognitive performance (MoCA score at 12 months) as the dependent variable.
Post-COVID patients demonstrated significantly lower CRQ total scores compared with controls (7.82±0.12 vs 9.41±0.15; p<0.001), with the lowest values observed in hospitalized patients. Educational level and premorbid intelligence (TOPF) did not differ between groups, indicating preserved premorbid cognitive capacity. Reduced CRQ scores were primarily driven by lower occupational cognitive complexity and diminished cognitively active lifestyle, suggesting impaired utilization of cognitive reserve rather than loss of reserve capacity. MoCA scores were significantly lower in post-COVID patients (25.4±0.19 vs 27.8±0.22; p<0.001), with predominant impairment of executive functions, attention, and processing speed. In multivariate analysis, better cognitive outcomes were independently associated with higher CRQ scores, greater occupational complexity, and higher premorbid physical activity, while disease severity, elevated inflammatory markers, and older age were associated with poorer MoCA performance (Adjusted R²=0.521; p<0.001).
Post-COVID cognitive impairment occurs despite preserved premorbid cognitive reserve and is characterized by reduced utilization and engagement of reserve mechanisms, particularly following severe disease.
Authors
Khramtsov Khramtsov, Chernyshov Chernyshov, Stoyanov Stoyanov, Gryb Gryb, Vorokhta Vorokhta
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