Review Article

Complex Brain Network Analysis and Its Applications to Brain Disorders: A Survey

Table 2

Overview of structural brain network studies in AD.

StudyModalitySubjects Node definition Edge definition Network type Main findings

He et al., 2008 [95]sMRI92 AD
97 HC
54 regions in ANIMAL packagePartial correlation based on cortical thicknessBinary(1) Increased clustering coefficient and shortest paths in AD.
(2) Reduced betweenness centrality in the temporal and parietal regions and increased betweenness centrality in the occipital regions.

Yao et al., 2010 [83]sMRI91 AD
113 MCI
98 HC
90 regions in AAL atlasPearson correlation based on gray matter volumeBinary(1) The greatest clustering coefficient and the longest absolute path length in AD.
(2) The small-world index of the MCI network was between AD and HC networks.
(3) Compared with the HCs, the MCI and AD patients retained hub regions in the frontal lobe but lost hub regions in the temporal lobe.

Tijms et al., 2013 [96]sMRI38 AD
38 HC
8683 ± 545 cubesIntracortical similarityBinary(1) Decreased normalized clustering coefficient and normalized path length in AD.
(2) Decreased small-world index in AD.

Pereira et al., 2016 [97]sMRI282 AD
110 sMCI
71 lMCIc
87 eMCIc
301 HC
82 regions in FreeSurferPearson correlationBinary(1) Increased characteristic path length in sMCI, lMCIc, eMCIc, and AD compared with HC.
(2) Decreased clustering coefficient in lMCIc, eMCIc, and AD compared with HC.
(3) Decreased transitivity and increased modularity in patients compared with HCs.
(4) Decreased small-world index in patients compared with HCs.
(5) Decreased characteristic path length and clustering coefficient in lMCIc, eMCIc, and AD compared with sMCI.

Lo et al., 2010 [98]DTI25 AD
30 HC
78 regions in AAL atlasFN × FAWeighted(1) Increased shortest path length in AD.
(2) Decreased global efficiency and reduced nodal efficiency in the frontal regions in AD.

Bai et al., 2012 [99]DTI35 RGD
38 aMRI
30 HC
90 regions in AAL atlasFNWeighted(1) Reduced network strength, reduced global efficiency, and increased absolute path length in RGD and aMCI.
(2) Similar deficits of the regional and connectivity characteristics in the frontal brain regions in RGD and aMCI.
(3) Different nodal efficiency in the posterior cingulate cortex and several prefrontal brain regions between RGD and aMCI.

Daianu et al., 2015 [100]DTI42 AD
110 MCI
50 HC
68 regions in FreeSurferFNBinary(1) AD affected the low degree brain regions, rather than the rich club comprising the high degree brain regions.
(2) Global connectivity of AD was disrupted.
(3) Detecting network differences of MCI/HC and AD/HC using the normalized rich club coefficient.

Wang et al., 2016 [101]DTI26 AD
16 HC
90 regions in AAL atlasFNBinary(1) Higher small-world index in AD.
(2) Decreased global efficiency and local efficiency in AD.
(3) Increased normalized shortest path length and normalized clustering coefficient in AD.