Aberrant brain functional connectome in patients with obstructive sleep apnea

Figures & data

Table 1 Demographic and clinical data comparisons between the patients with OSA and the GSs

Characteristics	Patients with OSA (n=45)	GSs (n=45)	t-value	P-value
Age (years)	37.56±8.86	37.84±11.38	−0.134	0.893
Education (years)	12.31±2.75	12.18±2.71	0.232	0.817
BMI (kg/m^2)	27.53±3.33	23.10±1.98	7.656	<0.001*
AHI	58.7±20.38	2.50±1.22	18.468	<0.001*
Nadir SaO2 (%)	66.4±12.56	90.27±2.89	−12.422	<0.001*
Average SaO2 (%)	90.62±4.48	95.53±2.41	−6.477	<0.001*
N1	31.16±17.56	10.09±3.66	7.885	<0.001*
N2	39.00±14.93	40.71±7.12	−0.693	0.490
N3	22.96±18.14	21.16±4.59	0.645	0.520
REM	7.04±7.87	21.73±7.48	−9.076	<0.001*
SaO2<90 (%)	30.89±21.51	0.354±0.20	9.522	<0.001*
Arousal index/hour	41.01±23.49	11.96±2.75	8.241	<0.001*
Oxygen desaturation index	55.38±24.94	2.95±1.28	14.083	<0.001*
Sleep efficiency	85.12±18.26	92.24±6.24	−2.613	0.011*
MoCA, score	25.18±2.13	27.73±1.40	−6.708	<0.001*
ESS, score	12.27±3.73	4.22±1.55	13.372	<0.001*

Note:

* P<0.05, which was considered statistically significant.

Abbreviations: OSA, obstructive sleep apnea; GSs, good sleepers; BMI, body mass index; AHI, apnea–hypopnea index; REM, rapid eye movement; SaO₂<90%, percentage of total sleep time spent at an oxygen saturation less than 90%; MoCA, Montreal Cognitive Assessment; ESS, Epworth Sleepiness Scale; n, numbers.

Figure 1 The small-world parameters and network efficiency parameters comparisons in patients with OSA and GSs.

Notes: Both the OSA and GSs exhibited small-world attribute. Compared to GSs, patients with OSA exhibited increased Lp, λ, and decreased γ, σ, and E_glob.
Abbreviations: σ, small-worldness; γ, normalized clustering coefficient; λ, normalized characteristic path length; OSA, obstructive sleep apnea; GSs, good sleepers.

Table 2 Between-group differences in nodal characteristics in patients with OSA and GSs

Brain region	Abbreviation	Nodal degree		Nodal efficiency
		t-value	P-value	t-value	P-value
OSA>GSs
Left insula	INS.L	2.710	0.008	2.185	0.031
Left heschl gyrus	HES.L	3.174	0.002	2.693	0.008
Left cerebellum crus I	CRBLCrus-I.L	3.326	0.001	2.734	0.008
Left cerebellum VIII	CRBL-VIII.L	4.119	<0.001	3.535	0.001
Vermis VII	Vermis-VII	2.851	0.005	2.443	0.017
Vermis VIII	Vermis-VIII	3.089	0.003	2.525	0.013
OSA<GSs
Left posterior cingulate cortex	PCC.L	−2.511	0.014	−2.936	0.004
Right posterior cingulate cortex	PCC.R	−2.620	0.010	−3.019	0.003
Left inferior parietal, but supramarginal and angular gyri	IPL.L	−2.868	0.005	−3.195	0.002
Right inferior parietal, but supramarginal and angular gyri	IPL.R	−3.463	0.001	−3.928	<0.001
Right inferior frontal gyrus, opercular part	IFGoperc.R	−3.992	<0.001	−4.250	<0.001
Left middle frontal gyrus, orbital part	ORBmid.L	−2.318	0.023	−2.986	0.004
Rightmiddle frontal gyrus, orbital part	ORBmid.R	−2.834	0.006	−3.288	0.001
Left angular gyrus	ANG.L	−2.929	0.004	−3.492	0.001

Note: The FDR correction was applied to each nodal characteristic, the P-value thresholds for both nodal degree and efficiency were 0.01, and none survived the correction for betweenness.

Abbreviations: OSA, obstructive sleep apnea; GSs, good sleepers; INS, insula; HES, heschl gyrus; CRBL, cerebellum; PCC, posterior cingulate cortex; IPL, inferior parietal, but supramarginal and angular gyri; IFGoperc, inferior frontal gyrus, opercular part; ORBmid, bilateral middle frontal gyrus, orbital part; ANG, angular gyrus; FDA, false discovery rate.

Figure 2 OSA-related alterations in FC.

Notes: A disconnected functional subnetwork with 14 nodes and 17 connections in the OSA group using a NBS approach (threshold, T=2.368, P<0.01). The OSA group exhibited abnormal long-distance and short-distance functional connections between/within DMN, SN, and CEN. The blue lines represent decreased rs-FC, and the red lines represent increased rs-FC in patients with OSA compared to GSs.
Abbreviations: OSA, obstructive sleep apnea; FC, functional connectivity; NBS, network-based statistics; DMN, default-mode network; SN, salience network; CEN, central executive network; rs-FC, resting state functional connectivity; GSs, good sleepers; ORBmid, middle frontal gyrus, orbital part; INS, insula; HES, heschl gyrus; IFGoperc, inferior frontal gyrus, opercular part; IPL, inferior parietal, but supramarginal and angular gyri; PCC, posterior cingulate cortex; CRBL-VIII, cerebellar lobule VIII; ANG, angular gyrus; CRBLCrus-I, cerebellum crus I.

Figure 3 The relationship between the mean FC and global network metrics.

Note: The mean functional connectivity was a positive correlation with σ, γ.
Abbreviation: FC, functional connectivity.

Table 3 OSA-related alterations in FC

Region 1	Category	Region 2	Category	t-value	P-value
PCC.L	Parietal	IFGoperc.R	Prefrontal	2.59	0.01
PCC.R	Parietal	IFGoperc.R	Prefrontal	2.27	0.03
PCC.L	Parietal	INS.L	Subcortical	2.2	0.03
IPL.L	Parietal	PCC.R	Parietal	2.47	0.02
IPL.L	Parietal	PCC.L	Parietal	3.04	<0.001
IPL.R	Parietal	PCC.L	Parietal	2.84	0.01
ANG.L	Parietal	ORBmid.L	Prefrontal	−2.14	0.04
IPL.R	Parietal	ORBmid.R	Prefrontal	−2.35	0.02
CRBLCrus-I.L	Cerebellum	ORBmid.L	Prefrontal	−3.34	<0.001
CRBLCrus-I.L	Cerebellum	ORBmid.R	Prefrontal	−3.43	<0.001
CRBL-VIII.L	Cerebellum	CRBLCrus-I.L	Cerebellum	2.18	0.03
Vermis-VII	Cerebellum	CRBL-VIII.L	Cerebellum	3.02	<0.001
Vermis-VII	Cerebellum	PCC.L	Parietal	2.18	0.03
Vermis-VIII	Cerebellum	IPL.R	Parietal	2.1	0.04
Vermis-VIII	Cerebellum	CRBLCrus-I.L	Cerebellum	2.94	<0.001
Vermis-VIII	Cerebellum	CRBL-VIII.L	Cerebellum	2.51	0.01
Vermis-VIII	Cerebellum	Vermis-VIII	Cerebellum	3.6	<0.001

Abbreviations: OSA, obstructive sleep apnea; FC, functional connectivity; PCC, posterior cingulate cortex; IFGoperc, inferior frontal gyrus, opercular part; INS, insula; IPL, inferior parietal, but supramarginal and angular gyri; ANG, angular gyrus; ORBmid, middle frontal gyrus, orbital part; CRBLCrus-I, cerebellum crus I; CRBL-VIII, cerebellar lobule VIII.