Structural analysis of Alzheimer's disease brain networks based on fractal features

It had been demonstrated that the functional brain networks of Alzheimer’s patients exhibit topological properties distinct from those of cognitively normal individuals, including small-world and clustering coefficients. To further elucidate the structural characteristics of the brain networks of Alzheimer’s patients and their differences in brain network structure with cognitively normal individuals, fractal features were introduced for comparative analysis. Experimental results demonstrated a significant difference in the minimum number of boxes and connection ratio between brain networks of Alzheimer’s patients and cognitively normal individuals at the same box-covering radius. At the brain network threshold of 0.4, the connection ratio values of cognitively normal individuals’ brain networks were distributed in the [0,1] interval, while the connection ratio values of Alzheimer’s patients’ brain networks were distributed in the (0.5,1) interval. Furthermore, the average connection ratio of Alzheimer’s patients’ brain networks was found to be higher than that of cognitively normal individuals at different thresholds. These differences in network structure provide a new reference for the diagnosis of Alzheimer’s disease.