cognitiveTree creates an interpretable lifespan “tree” where each branch represents a distinct neurodegenerative condition, enabling differential diagnosis based on a subject’s proximity to these patterns in 3D space. Validated on independent external cohorts, the CognitiveTree outperformed traditional machine learning approaches, offering enhanced sensitivity and clearer visualization of disease-specific atrophy progression. With its ability to provide probability scores for each condition and highlight structural deviations from normal aging, this tool holds promise to support more accurate and interpretable clinical decision-making in cognitive neurology