Table 31.

Reported limitations.

Category	Description	Articles
Population	Small number of subjects in the study	[37, 58, 80, 83, 86, 99, 101, 109–111, 121, 124, 128, 135, 139, 140, 153, 159, 163, 164]
	Merged databases are different due to local implementations	[81]
	Lack of different stages in AD cohort	[86, 121, 135]
	AD cohort includes participants taking antidementia drugs	[81, 83, 163, 164]
	Lack of population matching, age, gender, and/or education	[66, 90, 99, 135]
	Possible preclinical AD in N cohort	[81]
	Prodromal AD was applied in aMCI with Aβ42	[150]
EEG experiment setup	No severe AD as hard to perform EEG recordings	[66]
	Presence of dominant alpha activity during EC condition	[80]
	Differences in datasets due manual artifact handling	[58, 81, 163]
	Low number of electrodes for source localization methods	[37, 82, 163]
	Low number of electrodes for connectivity analysis	[83, 145]
	Low number electrodes for advanced AAR methods	[84]
Reported results	Lack of research for other dementia types	[39, 109, 110, 139, 163]
	Lack of longitudinal approach for N, MCI, AD populations	[66, 128, 138, 155, 160, 170]