title: Abnormal resting-state functional connectivity within the default mode network subregions in male patients with obstructive sleep apnea.
abstract: OBJECTIVE
  Abnormal resting-state functional connectivity (rs-FC) between the central executive network and the default mode network (DMN) in patients with obstructive sleep apnea (OSA) has been reported. However, the effect of OSA on rs-FC within the DMN subregions remains uncertain. This study was designed to investigate whether the rs-FC within the DMN subregions was disrupted and determine its relationship with clinical symptoms in patients with OSA.
  
  
  METHODS
  Forty male patients newly diagnosed with severe OSA and 40 male education- and age-matched good sleepers (GSs) underwent functional magnetic resonance imaging (fMRI) examinations and clinical and neuropsychologic assessments. Seed-based region of interest rs-FC method was used to analyze the connectivity between each pair of subregions within the DMN, including the medial prefrontal cortex (MPFC), posterior cingulate cortex (PCC), hippocampus formation (HF), inferior parietal cortices (IPC), and medial temporal lobe (MTL). The abnormal rs-FC strength within the DMN subregions was correlated with clinical and neuropsychologic assessments using Pearson correlation analysis in patients with OSA.
  
  
  RESULTS
  Compared with GSs, patients with OSA had significantly decreased rs-FC between the right HF and the PCC, MPFC, and left MTL. However, patients with OSA had significantly increased rs-FC between the MPFC and left and right IPC, and between the left IPC and right IPC. The rs-FC between the right HF and left MTL was positively correlated with rapid eye movement (r=0.335, P=0.035). The rs-FC between the PCC and right HF was negatively correlated with delayed memory (r=-0.338, P=0.033).
  
  
  CONCLUSIONS
  OSA selectively impairs the rs-FC between right HF and PCC, MPFC, and left MTL within the DMN subregions, and provides an imaging indicator for assessment of cognitive dysfunction in OSA patients.
authors: Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China.
authors: Hai-Jun
authors: HJ
authors: Li
authors: Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China.
authors: Xiao
authors: X
authors: Nie
authors: Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China.
authors: Hong-Han
authors: HH
authors: Gong
authors: Department of Pneumology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China.
authors: Wei
authors: W
authors: Zhang
authors: Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China.
authors: Si
authors: S
authors: Nie
authors: Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People's Republic of China.
authors: De-Chang
authors: DC
authors: Peng
keywords: cognitive impairment; default mode network; functional MRI; functional connectivity; obstructive sleep apnea