Across studies, spectral features such as delta, theta, alpha, and beta band powers, combined with advanced metrics including GFS, GFP, SL, complexity measures (Omega-complexity, Cross-ApEn, Cross-SampEn), and entropy-based connectivity indices, have shown meaningful associations with cognitive decline, disease severity, and biological markers like CSF tau, Aβ42, and neurogranin. This evidence concerns the gene NRGN and Mental deterioration.