Cognitive Impairment in Post-COVID-19 Patients: A Prospective Neuropsychological Evaluation Study

Cognitive impairments, often termed "brain fog," have emerged as prevalent sequelae among individuals recovering from COVID-19. Despite increasing recognition, systematic neuropsychological evaluation data remain limited.

A prospective observational study was conducted between February 2023 and December 2024 in a tertiary care neurorehabilitation center. One hundred twenty post-COVID-19 patients (mean age 44.6 ± 11.3 years; 58.3% male) presenting with cognitive complaints at least 3 months after recovery were recruited. Patients underwent evaluation using the Montreal Cognitive Assessment (MoCA), Trail Making Test A and B (TMT-A, TMT-B), and Digit Span Test. A control group of 60 age- and education-matched individuals without prior COVID-19 served as comparison. Statistical analysis included independent t-tests, chi-square tests, and multivariate logistic regression (P < 0.05).

Cognitive impairment (MoCA score <26) was observed in 66.7% of post-COVID-19 participants compared to 15.0% of controls (P < 0.001). Post-COVID patients showed significantly slower TMT-A (43.7 ± 12.9 vs 31.2 ± 9.6 sec; P < 0.001) and TMT-B times (95.8 ± 22.4 vs 76.5 ± 17.8 sec; P < 0.001). Working memory (Digit Span backward) was also impaired (mean score: 4.2 ± 0.9 vs 5.3 ± 0.8; P < 0.001). Severity of initial infection (hospitalized vs non-hospitalized) was associated with increased odds of impairment (OR: 2.87; 95% CI: 1.22-6.74; P = 0.015).

Cognitive deficits are common in post-COVID-19 patients, particularly affecting attention, processing speed, and working memory. Structured cognitive screening and rehabilitation may be essential components of long-term COVID-19 care.