Small-world properties of the whole-brain functional networks in patients with obstructive sleep apnea-hypopnea...

To explore the small-world properties of brain functional networks in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) to aid diagnosis.

A total of 29 OSAHS patients and 26 matched healthy volunteers were scanned with blood oxygen level-dependent functional magnetic resonance imaging (BOLD-fMRI) separately, and the whole brain was divided into 90 districts via automated anatomical labeling. The matrix Z was then built through a Fisher Z transformation. Two-sample t tests were applied to evaluate the changes in small-world properties in OSAHS patients compared to the control group. The properties included E_global, E_local, and small-world parameters L_p, C_p, γ, λ, and σ.

Both groups satisfied the small-world properties (σ > 1) within the sparsity range of 0.1-0.2. However, compared with the control group, the OSAHS group performed significantly lower in C_p, E_local, and E_global (p < 0.05) and higher in L_p (p < 0.05). The γ, σ, and λ values were not significantly different between the two groups.

Both healthy and OSAHS patients exhibited small-world properties in functional networks, but a subset of these small-world properties in OSAHS patients performed differently. These changes will not only provide a new perspective for pathophysiological mechanisms of OSAHS but will also help in understanding the disease in terms of whole-brain functional networks.