Table 1.

Search strategy

Database	Search strategy
Pubmed	((“Electroencephalogram“[MeSH Terms] OR “Electroencephalogram” OR “EEG monitoring” OR “Intraoperative EEG” OR “processed EEG” OR “bispectral index” OR “BIS”) AND (“Anesthesia“[MeSH Terms] OR “Anesthesia” OR “Anaesthesia”) AND (“Cognitive Dysfunction“[MeSH Terms] OR “Cognitive Dysfunction” OR “Cognitive Decline” OR “Postoperative Cognitive Dysfunction” OR “POCD” OR “Postoperative Cognitive Impairment”) AND (“Aged“[MeSH Terms] OR “Elderly” OR “Older Adults” OR “Aged” OR “Geriatric”))
Embase	(‘electroencephalogram’/exp OR ‘EEG monitoring’ OR ‘intraoperative EEG’ OR ‘processed EEG’ OR ‘bispectral index’ OR ‘BIS’) AND (‘anesthesia’/exp OR ‘anaesthesia’) AND (‘cognitive dysfunction’/exp OR ‘cognitive decline’ OR ‘postoperative cognitive dysfunction’ OR ‘POCD’ OR ‘postoperative cognitive impairment’) AND (‘aged’/exp OR ‘elderly’ OR ‘older adults’ OR ‘geriatric’)
Cochrane	(“Electroencephalogram” OR “EEG monitoring” OR “Intraoperative EEG” OR “processed EEG” OR “bispectral index” OR “BIS”) AND (“Anesthesia” OR “Anaesthesia”) AND (“Cognitive Dysfunction” OR “Cognitive Decline” OR “Postoperative Cognitive Dysfunction” OR “POCD” OR “Postoperative Cognitive Impairment”) AND (“Elderly” OR “Older Adults” OR “Aged” OR “Geriatric”)
Web of Science	TS=(“Electroencephalogram” OR “EEG monitoring” OR “Intraoperative EEG” OR “processed EEG” OR “bispectral index” OR “BIS”) AND TS=(“Anesthesia” OR “Anaesthesia”) AND TS=(“Cognitive Dysfunction” OR “Cognitive Decline” OR “Postoperative Cognitive Dysfunction” OR “POCD” OR “Postoperative Cognitive Impairment”) AND TS=(“Elderly” OR “Older Adults” OR “Aged” OR “Geriatric”)