Hierarchical disruptions of white matter rich-club organization in comorbid insomnia with anxiety: a diffusion tensor...

Rich-club organization is a fundamental topological feature supporting global information integration in the brain. However, its hierarchical alterations in comorbid insomnia with anxiety (CI-A) remain poorly understood.

Diffusion tensor imaging was performed in 61 patients with CI-A and 35 matched healthy controls. Whole-brain structural networks were reconstructed and categorized into rich-club, feeder, and local connections. Group differences in diffusion metrics and connectivity strength were examined, and their associations with the Pittsburgh Sleep Quality Index (PSQI), Hamilton Anxiety Rating Scale (HAMA-14), Hyperarousal Scale (HAS), and Montreal Cognitive Assessment (MoCA) were evaluated.

In feeder connections, CI-A patients showed elevated radial diffusivity, which correlated with HAS (r = 0.304, p = 0.003), and higher fiber number was associated with PSQI (r = 0.335, p = 0.001). In local connections, increased radial diffusivity correlated with HAS (r = 0.308, p = 0.002), and heightened axial diffusivity was linked to PSQI (r = 0.299, p = 0.003).

These findings reveal a selective vulnerability pattern in CI-A, with peripheral connections showing more pronounced microstructural abnormalities than the rich-club connections, providing novel insights into the hierarchical disruption of white matter networks in this condition.