Cognitive impairment in tuberculous meningitis: Systematic review & meta-analysis

Tuberculous Meningitis (TBM) is one of the severe forms of tuberculosis affecting the central nervous system, often leading to long-term cognitive impairment. Understanding these deficits is essential for improving treatment outcomes and guiding rehabilitation strategies. A systematic review and meta-analysis following PRISMA guidelines examined cognitive dysfunction in TBM, identifying affected domains and the need for standardized assessment. The study assessed the extent, pattern, and long-term impact of cognitive impairment in TBM survivors, providing recommendations for optimal assessment timing and domains. A comprehensive search was performed in "PubMed, Scopus, Web of Science, Embase, Google Scholar & CINAHL" identifying 144 records, of which seven studies (N = 7 studies) met the inclusion criteria. Cognitive function was assessed at different phases of TB treatment using various neuropsychological tools. Meta-analysis was conducted using R version 4.4.0, employing a random-effects model to compare cognitive function between individuals with TBM and its comparators (N = 2 studies). Subgroup analysis (N = 5 studies) examined cognitive function at different TBM stages. Risk of bias was evaluated using the Newcastle-Ottawa Case control, cross sectional and cohort bias assessment scales. Meta-analysis observed cognitive decline in individuals with TBM when compared to its comparators, with an overall cognitive score reduction of 11.72 (I² = 84 %, P = 0.00125). Subgroup analysis suggested partial cognitive recovery over time (RR = 0.74, 95 % CI: 0.59-0.93), though residual deficits persisted, particularly in executive function and verbal memory. Considerable heterogeneity (I² = 68 %) was noted due to variations in cognitive assessments. Despite some cognitive recovery, long-term deficits persist, emphasizing the need for standardized assessment protocols and targeted interventions. Periodic cognitive assessments using sensitive tools like Addenbrooke's Cognitive Examination-III (ACE-III) and the Trail Making Test (TMT-A & B) are recommended. Future research should adopt uniform cognitive testing methodologies and long-term follow-ups to improve cognitive management in individuals with TBM.