GFAP and Atrophy: Elevated GFAP levels were correlated with reduced cortical thickness and poorer cognitive performance in the CL ≤ 10 group, while increased P-tau217 levels were associated with atrophy and non-executive cognitive deficits in the CL > 10 group.<h4>Interpretation</h4>Plasma P-tau217 and GFAP track early Aβ accumulation, downstream Tau pathology, neurodegeneration, and cognitive deterioration across different CL scales.