Aberrant brain functional connectome in patients with obstructive sleep apnea

Abstract

Objective

Obstructive sleep apnea (OSA) is accompanied by widespread abnormal spontaneous regional activity related to cognitive deficits. However, little is known about the topological properties of the functional brain connectome of patients with OSA. This study aimed to use the graph theory approaches to investigate the topological properties and functional connectivity (FC) of the functional connectome in patients with OSA, based on resting-state functional magnetic resonance imaging (rs-fMRI).

Methods

Forty-five male patients with newly diagnosed untreated severe OSA and 45 male good sleepers (GSs) underwent a polysomnography (PSG), clinical evaluations, and rs-fMRI scans. The automated anatomical labeling (AAL) atlas was used to construct the functional brain connectome. The topological organization and FC of brain functional networks in patients with OSA were characterized using graph theory methods and investigated the relationship between functional network topology and clinical variables.

Results

Both the patients with OSA and the GSs exhibited high-efficiency “small-world” network attributes. However, the patients with OSA exhibited decreased σ, γ, E_glob; increased Lp, λ; and abnormal nodal centralities in several default-mode network (DMN), salience network (SN), and central executive network (CEN) regions. However, the patients with OSA exhibited abnormal functional connections between the DMN, SN, and CEN. The disrupted FC was significantly positive correlations with the global network metrics γ and σ. The global network metrics were significantly correlated with the Epworth Sleepiness Scale (ESS) score, Montreal Cognitive Assessment (MoCA) score, and oxygen desaturation index.

Conclusion

The findings suggest that the functional connectome of patients with OSA exhibited disrupted functional integration and segregation, and functional disconnections of the DMN, SN, and CEN. The aberrant topological attributes may be associated with disrupted FC and cognitive functions. These topological abnormalities and disconnections might be potential biomarkers of cognitive impairments in patients with OSA.

Keywords:

• obstructive sleep apnea
• graph theory
• functional connectome
• cognitive function
• resting-state fMRI

Acknowledgments

This work was supported by grants from the Natural Science Foundation of China (Grant No 81560285), the Natural Science Foundation of Jiangxi, China (Grant No 20171BAB205070, 20132BAB205100), the Education Department Foundation of Jiangxi, China (Grant No 700544006), the Graduate Innovation Foundation of Jiangxi, China (Grant No YC2016-S100), the Science and Technology Support Program of Jiangxi, China (Grant No 20132BBG70061, 20141BBG70026), and the Doctoral Project Startup Fund (Grant No 700544005).

Disclosure

The authors report no conflicts of interest in this work.