Disrupted functional brain network organization in patients with obstructive sleep apnea.
Obstructive sleep apnea (OSA) subjects show impaired autonomic, affective, executive, sensorimotor, and cognitive functions. Brain injury in OSA subjects appears in multiple sites regulating these functions, but the integrity of functional networks within the regulatory sites remains unclear. Our aim was to examine the functional interactions and the complex network organization of these interactions across the whole brain in OSA, using regional functional connectivity (FC) and brain network topological properties.



We collected resting-state functional magnetic resonance imaging (MRI) data, using a 3.0-Tesla MRI scanner, from 69 newly diagnosed, treatment-naïve, moderate-to-severe OSA (age, 48.3 ± 9.2 years; body mass index, 31 ± 6.2 kg/m(2); apnea-hypopnea index (AHI), 35.6 ± 23.3 events/h) and 82 control subjects (47.6 ± 9.1 years; body mass index, 25.1 ± 3.5 kg/m(2)). Data were analyzed to examine FC in OSA over controls as interregional correlations and brain network topological properties.



Obstructive sleep apnea subjects showed significantly altered FC in the cerebellar, frontal, parietal, temporal, occipital, limbic, and basal ganglia regions (FDR, P < 0.05). Entire functional brain networks in OSA subjects showed significantly less efficient integration, and their regional topological properties of functional integration and specialization characteristics also showed declined trends in areas showing altered FC, an outcome which would interfere with brain network organization (P < 0.05; 10,000 permutations). Brain sites with abnormal topological properties in OSA showed significant relationships with AHI scores.



Our findings suggest that the dysfunction extends to resting conditions, and the altered FC and impaired network organization may underlie the impaired responses in autonomic, cognitive, and sensorimotor functions. The outcomes likely result from the prominent structural changes in both axons and nuclear structures, which occur in the condition.
Department of Anesthesiology University of California at Los Angeles Los Angeles CA 90095.
Bumhee
B
Park
Department of Anesthesiology University of California at Los Angeles Los Angeles CA 90095.
Jose A
JA
Palomares
UCLA School of Nursing University of California at Los Angeles Los Angeles CA 90095.
Mary A
MA
Woo
Department of Medicine University of California at Los Angeles Los Angeles California 90095.
Daniel W
DW
Kang
UCLA School of Nursing University of California at Los Angeles Los Angeles CA 90095; The Brain Research Institute University of California at Los Angeles Los Angeles California 90095.
Paul M
PM
Macey
Department of Neurology University of California at Los Angeles Los Angeles California 90095.
Frisca L
FL
Yan-Go
The Brain Research Institute University of California at Los Angeles Los Angeles California 90095; Department of Neurobiology University of California at Los Angeles Los Angeles California 90095.
Ronald M
RM
Harper
Department of Anesthesiology University of California at Los Angeles Los Angeles CA 90095; The Brain Research Institute University of California at Los Angeles Los Angeles California 90095; Department of Radiological Sciences University of California at Los Angeles Los Angeles California 90095; Department of Bioengineering University of California at Los Angeles Los Angeles California 90095.
Rajesh
R
Kumar
D000328:Adult; D000368:Aged; D001341:Autonomic Nervous System; D001921:Brain / Q000503:physiopathology; D001931:Brain Mapping; D002531:Cerebellum / Q000473:pathology; D003071:Cognition; D063132:Connectome; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D012146:Rest / Q000502:physiology; D066191:Sensorimotor Cortex; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000000981:diagnostic imaging* / Q000378:metabolism*
Functional magnetic resonance imaging; functional network; graph theory; spontaneous activity