highly significantP < 0.001
For example, the third basis function (bs3) was highly significant for ADAS‐Cog13 (β = 0.344, P < 0.001), CDR‐SB (β = 0.287, P = 0.005), and FAQ (β = 0.356, P < 0.001), confirming distinct nonlinear patterns in these measures.