Propofol and midazolam inhibit conscious memory processes very soon after encoding: An event-related potential study of familiarity and recollection in volunteers Journal Article

   

Authors:	Veselis, R. A.; Pryor, K. O.; Reinsel, R. A.; Li, Y.; Mehta, M.; Johnson, R.
Article Title:	Propofol and midazolam inhibit conscious memory processes very soon after encoding: An event-related potential study of familiarity and recollection in volunteers
Abstract:	BACKGROUND: Intravenous drugs active via γ3-aminobutyric acid receptors to produce memory impairment during conscious sedation. Memory function was assessed using event-related potentials (ERPs) while drug was present. METHODS: The continuous recognition task measured recognition of photographs from working (6 s) and long-term (27 s) memory while ERPs were recorded from Cz (familiarity recognition) and Pz electrodes (recollection recognition). Volunteer participants received sequential doses of one of placebo (n ≤ 11), 0.45 and 0.9 μg/ml propofol (n ≤ 10), 20 and 40 ng/ml midazolam (n ≤ 12), 1.5 and 3 μg/ml thiopental (n ≤ 11), or 0.25 and 0.4 ng/ml dexmedetomidine (n ≤ 11). End-of-day yes/no recognition 225 min after the end of drug infusion tested memory retention of pictures encoded on the continuous recognition tasks. RESULTS: Active drugs increased reaction times and impaired memory on the continuous recognition task equally, except for a greater effect of midazolam (P < 0.04). Forgetting from continuous recognition tasks to end of day was similar for all drugs (P ≤ 0.40), greater than placebo (P < 0.001). Propofol and midazolam decreased the area between first presentation (new) and recognized (old, 27 s later) ERP waveforms from long-term memory for familiarity (P ≤ 0.03) and possibly for recollection processes (P ≤ 0.12). Propofol shifted ERP amplitudes to smaller voltages (P < 0.002). Dexmedetomidine may have impaired familiarity more than recollection processes (P ≤ 0.10). Thiopental had no effect on ERPs. CONCLUSION: Propofol and midazolam impaired recognition ERPs from long-term memory but not working memory. ERP measures of memory revealed different pathways to end-of-day memory loss as early as 27 s after encoding. © 2009, the American Society of Anesthesiologists, Inc.
Keywords:	adolescent; adult; controlled study; middle aged; young adult; clinical trial; placebo; dose response; controlled clinical trial; randomized controlled trial; midazolam; propofol; drug effect; dose-response relationship, drug; psychological aspect; statistical analysis; data interpretation, statistical; measurement; memory disorder; memory; photic stimulation; psychomotor performance; recognition; task performance; event related potential; hypnotics and sedatives; electroencephalography; human experiment; dexmedetomidine; thiopental; hypnotic sedative agent; consciousness; memory consolidation; reaction time; working memory; conscious sedation; evoked response; photostimulation; recall; evoked potentials; mental recall
Journal Title:	Anesthesiology
Volume:	110
Issue:	2
ISSN:	0003-3022
Publisher:	Lippincott Williams & Wilkins
Date Published:	2009-02-01
Start Page:	295
End Page:	312
Language:	English
DOI:	10.1097/ALN.0b013e3181942ef0
PUBMED:	19194157
PROVIDER:	scopus
PMCID:	PMC2735240
DOI/URL:	http://www.scopus.com/inward/record.url?eid=2-s2.0-61549091526&partnerID=40&md5=7e29684ccebac1102608b497fa191ccd
Notes:	--- - "Cited By (since 1996): 2" - "Export Date: 30 November 2010" - "CODEN: ANESA" - "Source: Scopus"

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