Table 2.

Summary of the main results of AD studies reported in the present review.

Authors	Recording Type	Graph Parameters	Main Results (All Results Refer to AD vs. Healthy)
Stam et al., 2007 [29]	EEG	PL C	Beta PL ↑ Beta C ↓ Pearson’s correlation: Beta PL ↑ MMSE ↓
Stam et al., 2009 [39]	MEG	PL C	Alpha 1 PL↓ Alpha 1 C ↓ Pearson’s correlation: Alpha 1 C ↓ MMSE ↓
de Haan et al., 2009 [38]	EEG	PL C	Alpha-1 and beta C ↓ Alpha 1 and gamma PL ↓
Poza et al., 2013 [41]	EEG	PL C	Delta e theta PL ↑ Alpha 2 and beta PL ↓ Delta and theta C ↓ Alpha 2 and beta C ↑
Wang et al., 2014 [25]	EEG	PL C Global Efficiency Local Efficiency SW	PL↑ in all frequency bands (except delta) C ↓ in all frequency bands (except delta) Global Efficiency ↓ in all frequency bands Local Efficiency ↓ in all frequency bands SW ↓ in all frequency bands
Vecchio et al., 2014 [40]	EEG	PL C	Theta PL ↑ Delta, theta and alpha-1 C ↑
Frantzidis et al., 2014 [44]	EEG	SW	SW ↓ Pearson’s correlation: -SW ↓ MMSE ↓; SW ↓ MoCA ↓
Vecchio et al., 2016 [42]	EEG	SW	Pearson’s correlation: Gamma SW ↓ Digit Span Test ↓
Miraglia et al., 2017 [33]	EEG	SW	EO: delta and theta SW Nold>MCI>AD EC: delta SW Nold and MCI > AD
Vecchio et al., 2017 [34]	EEG	SW	Pearson’s correlations: Alpha SW ↓ hippocampal volume ↑ Delta, beta, and gamma SW ↑ hippocampal volume ↑
Saeedeh Afshari and Mahdi Jalili, 2017 [24]	EEG	Global efficiency Local efficiency	Beta global efficiency ↓ Alpha local efficiency↑
Vecchio et al., 2018 [45]	EEG	SW	ROC curve accuracy 97%
Franciotti et al., 2019 [27]	EEG	Degree In-degree Out-degree Assortative Coefficient	Degree, in-degree, out-degree ↓
Li et al., 2019 [54]	EEG	Degree C Centrality	Alpha 2 and beta degree, C, centrality ↓ in orbitofrontal and parietal regions All frequency degree, C, centrality ↓ in frontal pole and medial orbitofrontal regions All frequency degree, C, centrality ↑ in the temporal sulcus
Vecchio et al., 2020 [55]	EEG	SW	ROC curve accuracy 95%
Miraglia et al., 2020 [46]	EEG	SW	Gamma SW ↓ in converted MCI vs. stable MCI Delta SW ↓ in converted MCI in linguistic domain Delta and gamma SW ↓ and alpha 1 SW ↑ in converted MCI in executive domain
Cecchetti et al., 2021 [47]	EEG	PL C	Theta PL ↓ Alpha 2 PL ↑ Theta C ↑ Alpha 2 C ↓
Majd Abazid et al., 2021 [49]	EEG	PL C Degree Efficiency Betweenness	Higher accuracy of classification of AD for the graph parameters
Kocagoncu 2020 [50]	E/MEG	SW	Pearson’s correlation: Beta and gamma SW ↑protein Tau ↑
Tait et al., 2019 [51]	EEG	SW	Pearson’s correlation: Temporal lobe SW ↑ language sub-score ↑
Vecchio et al., 2021 [52]	EEG	SW	Pearson’s correlations: Delta SW ↓ ADAS-Cog ↑ Alpha 1 ↑ ADAS-Cog ↑
Vecchio et al., 2021 [53]	EEG	SW	Delta and theta SW ↓ Alpha 2 SW↑

The arrows refer to an increase (↑) or a decrease (↓) of the indicated parameters in AD patients. All results in the table refer to AD patients compared to elderly healthy controls, except when differently indicated. Abbreviations: EEG: electroencephalography; MEG: magnetoencephalography; PL: path length; C: clustering coefficient; SW: small-world index; MMSE: mini-mental state examination; MoCA: Montreal Cognitive Assessment; EO: eyes open; EC: eyes closed; NOLD: NOrmal eLDerly; MCI: Mild Cognitive Impairment; ROC: received operating characteristics.