Bayesian Network Modeling of Causal Influence within Cognitive Domains and Clinical Dementia Severity Ratings for Western and Indian Cohorts
Wupadrasta Santosh Kumar, Sayali Rajendra Bhutare, Neelam Sinha, Thomas Gregor Issac
TL;DR
The paper addresses how six cognitive-domain scores causally influence the global Clinical Dementia Rating ($CDR$) across Western (ADNI) and Indian (LASI) cohorts. It employs seven-node directed acyclic graphs learned with the Peter–Clark (PC) algorithm, quantifying edge strengths via a normalized chi-square metric to compare causal structures between populations. A key finding is that memory ($M$) exerts the strongest influence on $CDR$ in both datasets, but the overall DAG connectivity and edge strengths differ—ADNI is denser with high-strength edges, while LASI is sparser with variable weights—reflecting population-specific dementia pathways. The work demonstrates the value of causal DAGs for understanding domain-specific contributions to dementia severity in diverse populations and highlights the PC algorithm’s suitability for categorical clinical data, informing targeted interventions and field validation with clinicians.
Abstract
This study investigates the causal relationships between Clinical Dementia Ratings (CDR) and its six domain scores across two distinct aging datasets: the Alzheimer's Disease Neuroimaging Initiative (ADNI) and the Longitudinal Aging Study of India (LASI). Using Directed Acyclic Graphs (DAGs) derived from Bayesian network models, we analyze the dependencies among domain scores and their influence on the global CDR. Our approach leverages the PC algorithm to estimate the DAG structures for both datasets, revealing notable differences in causal relationships and edge strengths between the Western and Indian populations. The analysis highlights a stronger dependency of CDR scores on memory functions in both datasets, but with significant variations in edge strengths and node degrees. By contrasting these findings, we aim to elucidate population-specific differences and similarities in dementia progression, providing insights that could inform targeted interventions and improve understanding of dementia across diverse demographic contexts.
