Clinical relevance of automated cerebrospinal fluid amyloid and tau biomarkers in Indian patients with early onset cognitive decline: Insights from the AIIMS-Delhi Study Cohort of Early/late oNset Dementia (ASCEND).

Automated cerebrospinal fluid (CSF) biomarkers have been underexplored in early onset dementias (EOD) within the South-Asian context. In our ongoing ASCEND cohort (tertiary care center in India), we evaluated the added value of incorporating CSF amyloid-β 1-42 (Aβ42) and phosphorylated tau 181 (p-Tau181) (Elecsys immunoassay) into existing clinical diagnostic algorithms for EOD. Among 61 participants (mean age: 56.3 ± 5.8 years; 55.7% females), the CSF p-Tau181/Aβ42 ratio revealed alternative etiology in 16% of cases [5/37 (13.5%) clinically probable AD were reclassified as non-AD after CSF, while 5/24 (20.8%) clinically non-AD dementias were reclassified as AD]. Notably, clinico-biological concordance varied across different phenotypic presentations.