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

Objective To explore the small-world properties of brain functional networks in patients with obstructive sleep apnea−hypopnea syndrome (OSAHS) to aid diagnosis. Methods 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 Eglobal, Elocal, and small-world parameters Lp, Cp, γ, λ, and σ. Results 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 Cp, Elocal, and Eglobal (p Conclusion 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.