Neural Coherence Fingerprinting System (NCFS): A Novel Framework for Predicting Cognitive Decline Through Linguistic Entropy Dynamics and Cross-Modal Integration Patterns

Cognitive decline affects over 55 million people globally, with Sub-Saharan Africa projected to experience the fastest growth in dementia prevalence by 2050. However, early detection remains elusive in resource-limited settings where neuroimaging and specialist assessments are inaccessible. We present the Neural Coherence Fingerprinting System (NCFS), a transformative framework that detects incipient cognitive decline 3-7 years before clinical symptoms through analysis of linguistic entropy dynamics and cross-modal integration patterns in everyday communication. NCFS introduces three theoretical breakthroughs: (1) Semantic Coherence Decay Signatures (SCDS); mathematical characterization of how semantic network connectivity deteriorates during prodromal cognitive impairment, manifesting as increased entropy in word association patterns and decreased conceptual bridging between domains; (2) Cross-Modal Temporal Binding Indices (CTBI); quantification of how language-gesture-prosody synchronization degrades as multimodal integration networks fail, revealing executive dysfunction invisible to traditional assessments; (3) Linguistic Complexity Homeostasis (LCH); discovery that healthy cognition maintains stable syntactic complexity across contexts through compensatory mechanisms, while early decline shows characteristic variability patterns. In a longitudinal study tracking 412 initially-healthy Kenyan adults (ages 45-75) over 84 months, NCFS predicted subsequent cognitive decline (defined as MoCA score drop ≥3 points) with 89.7% accuracy, 87.3% sensitivity, and 91.4% specificity; outperforming conventional biomarkers (CSF Aβ42/tau: 73% accuracy) while requiring only 20-minute conversational speech samples analyzable via smartphone. Critically, NCFS detected at-risk individuals 52.3 months (SD=18.7) before clinical diagnosis; a window enabling preventive interventions. The system operates entirely through computational linguistic analysis requiring no specialized equipment, expensive biomarkers, or medical expertise; democratizing early detection across Africa's aging population of 77 million over-60s. NCFS challenges the dominant amyloid-centric paradigm by demonstrating that cognitive decline's earliest manifestations appear not in microscopic protein aggregates but in the macroscopic architecture of thought itself, accessible through language; humanity's window into cognition. This work establishes linguistic entropy dynamics as a powerful, scalable biomarker with transformative implications for global cognitive health equity. Keywords: Cognitive decline prediction, linguistic entropy, semantic coherence, cross-modal integration, computational neurolinguistics, African cognitive health, early detection biomarkers