Working…
ClinicalTrials.gov
ClinicalTrials.gov Menu

Memory Priming in General Anesthesia

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
 
ClinicalTrials.gov Identifier: NCT03727464
Recruitment Status : Completed
First Posted : November 1, 2018
Last Update Posted : September 5, 2019
Sponsor:
Collaborator:
University of Milano Bicocca
Information provided by (Responsible Party):
Eleonora Orena, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta

Brief Summary:

Memory priming under general anesthesia is a phenomenon of incredible interest in the study of consciousness and unconscious cognitive processing, and for clinical practice.

However results from anesthesiological literature are divergent and methodologies vary.

To overcome these limits, the present study aims at better defining the phenomenon of memory priming under general anesthesia, manipulating as experimental variables both the anesthetic drug used and the stimuli primed.


Condition or disease Intervention/treatment Phase
Unconscious (Psychology) Behavioral: Abstract priming Behavioral: Concrete priming Behavioral: Controls Drug: Propofol Drug: Sevoflurane Not Applicable

Detailed Description:

Some patients may develop serious psychological sequelae after surgical intervention under general anesthesia due to implicit memory formation of intraoperative events.

A number of studies in the field of anesthesiology have tried to better define the phenomenon of implicit memory in general anesthesia, with conflicting results. While some studies demonstrated the existence of unconscious memory formation also under adequate general anesthesia (BIS ranging 40-60), others state that implicit memory formation is possible only during light sedation, and that, therefore, traumatic disorders due to unconscious intraoperative memories are imputable to inadequate anesthesiological intraoperative management. The methodologies used by these studies, however, are very heterogeneous, and often inaccurate from a cognitive point of view. Data from cognitive neuroscience, in fact, demonstrate that different linguistic material, e.g. abstract and concrete words, are processed and retrieved via different networks in the brain. Then, since different anesthetics are known to target different areas of the brain, it is assumable that implicit memory formation is influenced both by the specific drug used and by the type of stimuli primed.

Therefore in this experiment, the investigators aim at testing implicit memory for different word category, abstract vs. concrete words, in patients undergoing either propofol or sevoflurane general anesthesia. Also, a very strict methodology was used both for the construction of the stimuli and the stimulation and testing procedure, in order to maximize the priming effect and exclude the risk of false positive results. The investigators hypothesize that, considering the existing data on propofol and sevoflurane effects on the brain, and the known neural correlates for abstract and concrete word processing, the priming effect would be different for abstract and concrete words between patients under propofol or sevoflurane anesthesia.


Layout table for study information
Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 102 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary Purpose: Basic Science
Official Title: Memory Priming for Abstract and Concrete Words in General BIS Guided Propofol vs. Sevoflurane Anesthesia
Actual Study Start Date : January 7, 2013
Actual Primary Completion Date : September 15, 2016
Actual Study Completion Date : September 15, 2016

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Memory

Arm Intervention/treatment
Experimental: Propofol Abstract Priming
Patients undergoing propofol general anesthesia and stimulation with a list of abstract words
Behavioral: Abstract priming
Patients were primed with a list of abstract during their general anesthesia

Drug: Propofol
Propofol general anesthesia

Experimental: Propofol Concrete Priming
Patients undergoing propofol general anesthesia and stimulation with a list of concrete words
Behavioral: Concrete priming
Patients were primed with a list of concrete during their general anesthesia

Drug: Propofol
Propofol general anesthesia

Active Comparator: Propofol Controls
Patients undergoing propofol anesthesia without any intraoperative priming
Behavioral: Controls
Patients did not receive any specific stimulation with words during their general anesthesia

Drug: Propofol
Propofol general anesthesia

Experimental: Sevoflurane Abstract Priming
Patients undergoing sevoflurane general anesthesia and stimulation with a list of abstract words
Behavioral: Abstract priming
Patients were primed with a list of abstract during their general anesthesia

Drug: Sevoflurane
Sevoflurane general anesthesia

Experimental: Sevoflurane Concrete Priming
Patients undergoing sevoflurane general anesthesia and stimulation with a list of concrete words
Behavioral: Concrete priming
Patients were primed with a list of concrete during their general anesthesia

Drug: Sevoflurane
Sevoflurane general anesthesia

Active Comparator: Sevoflurane Controls
Patients undergoing sevoflurane general anesthesia without any intraoperative priming
Behavioral: Controls
Patients did not receive any specific stimulation with words during their general anesthesia

Drug: Sevoflurane
Sevoflurane general anesthesia




Primary Outcome Measures :
  1. Implicit score [ Time Frame: 24 hours ]
    Implicit memory is tested through a word stem completion test, in which the participant has to complete a three-letter stem with the first word that comes to mind. The completion test comprises both target stems (stems of word primed intra-operatively) and foils. The number of correct completions of target stems and foils is recorded as target and non target hits. The implicit score is then calculated as (target hits - nontarget hits)/total target stimuli. The score can therefore range (absolute values) from -1 to +1, where a positive score indicates memory priming.


Secondary Outcome Measures :
  1. Explicit recall of intraoperative words [ Time Frame: before discharge from the Recovery Room and at 24 hours ]
    The number of intraoperative primed words that the patient is able to recall without any cue

  2. Explicit recall of intraoperative events [ Time Frame: before discharge from the Recovery Room and at 24 hours ]
    The explicit recall of intraoperative events assessed with the Brice Interview

  3. Target hits [ Time Frame: 24 hours ]
    The number of correct stem completions (hits) with target words (i.e. words heard intraoperatively)

  4. Nontarget hits [ Time Frame: 24 hours ]
    The number of correct stem completions (hits) with nontarget words (i.e. words not heard intraoperatively)



Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.


Layout table for eligibility information
Ages Eligible for Study:   18 Years to 65 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • patient undergoing general anesthesia for back surgery
  • American Society of Anesthesiology (ASA) physical status classification I or II
  • Italian native speaker
  • right handed (assessed with the Edinburgh Handedness Inventory)
  • not to suffer from memory deficits, hearing impairment or any other medical/psychiatric condition that could affect the memory performance or hearing

Exclusion Criteria:

  • to develop a postoperative cognitive dysfunction or delirium or any other medical complication that could prevent the memory testing or that could affect memory performance

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03727464


Locations
Layout table for location information
Italy
Fondazione IRCCS Istituto Neurologico Carlo Besta
Milan, Italy, 20133
Sponsors and Collaborators
Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta
University of Milano Bicocca
Investigators
Layout table for investigator information
Principal Investigator: Eleonora F Orena, PhD Fondazione IRCCS Istituto Neurologico Carlo Besta

Layout table for additonal information
Responsible Party: Eleonora Orena, PhD, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta
ClinicalTrials.gov Identifier: NCT03727464     History of Changes
Other Study ID Numbers: AR-INNCB-PRIMING-2012
First Posted: November 1, 2018    Key Record Dates
Last Update Posted: September 5, 2019
Last Verified: September 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

Layout table for additional information
Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by Eleonora Orena, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta:
Memory priming
Anesthesia
Language processing
Abstract and Concrete words
Neural correlates
Additional relevant MeSH terms:
Layout table for MeSH terms
Unconsciousness
Consciousness Disorders
Neurobehavioral Manifestations
Neurologic Manifestations
Nervous System Diseases
Signs and Symptoms
Anesthetics
Propofol
Sevoflurane
Central Nervous System Depressants
Physiological Effects of Drugs
Hypnotics and Sedatives
Anesthetics, Intravenous
Anesthetics, General
Platelet Aggregation Inhibitors
Anesthetics, Inhalation