Table 1.

Search syntax.

Database	Key words	Restrictions	N. of articles	Duplicates	Total
PubMed	(((Mild Cognitive Impairment[Title/Abstract]) OR (MCI[Title/Abstract])) AND (Prevalence[Title/Abstract])) NOT ((Parkinson[Title/Abstract] OR Parkinson's disease[Title/Abstract] OR frontotemporal dementia[Title/Abstract] OR FTD[Title/Abstract] OR vascular dementia[Title/Abstract] OR VaD[Title/Abstract] OR Lewy body[Title/Abstract] OR Multiple Sclerosis[Title/Abstract]))	Publication years; 1999–2022; Languages: English, Italian; Species: Human; Age: Middle Aged (45–64 yrs), Aged (65+ yrs), 80 and over.	1,191
Web of Science	(Mild Cognitive Impairment OR MCI) AND (prevalence) NOT (Parkinson OR Parkinson's disease OR frontotemporal dementia OR FTD OR vascular dementia OR VaD OR Lewy body OR Multiple Sclerosis)	Publication years: 1999–2022; Document type: Articles; Languages: English, Italian.	2,942
Scopus	(Mild Cognitive Impairment OR MCI) AND (prevalence) AND NOT (Parkinson OR Parkinson's disease OR frontotemporal dementia OR FTD OR vascular dementia OR VaD OR Lewy body OR Multiple Sclerosis)	TITLE-ABS-KEY; DOCTYPE (ar); PUBYEAR > 1999; LANGUAGE “English” and “Italian”.	2,101
PsycInfo	(Mild Cognitive Impairment OR MCI) AND (prevalence) NOT (Parkinson OR Parkinson's disease OR frontotemporal dementia OR FTD OR vascular dementia OR VaD OR Lewy body OR Multiple Sclerosis)	Publication years: 1999–2022; Reviewed by experts; Peer Reviewed Journal; English and Italian; Middle age (40–64 yrs), Aged (65 yrs and older), Very Old (85 yrs and older); Human; Journal Article; Exclude thesis.	461
		Total	6,695	3,574	3,121