Unconscious (Psychology)NCT03727464
Memory Priming in General Anesthesia
A study testing Abstract priming, Concrete priming and Propofol in people with Unconscious (Psychology), run by Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta at 1 site in Italy.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Unconscious (Psychology)
- What is being tested?
- Abstract priming, Concrete priming and Propofol
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 102 participants
- Where
- 1 siteItaly
- Study dates
- 7 Jan 2013to 15 Sep 2016
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Memory Priming for Abstract and Concrete Words in General BIS Guided Propofol vs. Sevoflurane Anesthesia
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.
Read the 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.
- Conditions
- Unconscious (Psychology)
- Being tested
- Abstract priming, Concrete priming, Controls, Propofol, Sevoflurane
- Keywords
- Memory priming, Anesthesia, Language processing, Abstract and Concrete words, Neural correlates
- Medical subject headings
- Unconsciousness
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Abstract primingBehavioural
Patients were primed with a list of abstract during their general anesthesia
Concrete primingBehavioural
Patients were primed with a list of concrete during their general anesthesia
ControlsBehavioural
Patients did not receive any specific stimulation with words during their general anesthesia
PropofolDrug
Propofol general anesthesia
SevofluraneDrug
Sevoflurane general anesthesia
| Study group | Role | What they receive |
|---|---|---|
| Propofol Abstract Priming | Experimental | Patients undergoing propofol general anesthesia and stimulation with a list of abstract words Receives: Behavioral: Abstract priming; Drug: Propofol |
| Propofol Concrete Priming | Experimental | Patients undergoing propofol general anesthesia and stimulation with a list of concrete words Receives: Behavioral: Concrete priming; Drug: Propofol |
| Propofol Controls | Active comparator | Patients undergoing propofol anesthesia without any intraoperative priming Receives: Behavioral: Controls; Drug: Propofol |
| Sevoflurane Abstract Priming | Experimental | Patients undergoing sevoflurane general anesthesia and stimulation with a list of abstract words Receives: Behavioral: Abstract priming; Drug: Sevoflurane |
| Sevoflurane Concrete Priming | Experimental | Patients undergoing sevoflurane general anesthesia and stimulation with a list of concrete words Receives: Behavioral: Concrete priming; Drug: Sevoflurane |
| Sevoflurane Controls | Active comparator | Patients undergoing sevoflurane general anesthesia without any intraoperative priming Receives: Behavioral: Controls; Drug: Sevoflurane |
What is being measured
The primary outcome is the main question the study is designed to answer.
Implicit score
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.
Measured: 24 hours
Secondary outcomes (4)
Explicit recall of intraoperative words
The number of intraoperative primed words that the patient is able to recall without any cue
Measured: before discharge from the Recovery Room and at 24 hours
Explicit recall of intraoperative events
The explicit recall of intraoperative events assessed with the Brice Interview
Measured: before discharge from the Recovery Room and at 24 hours
Target hits
The number of correct stem completions (hits) with target words (i.e. words heard intraoperatively)
Measured: 24 hours
Nontarget hits
The number of correct stem completions (hits) with nontarget words (i.e. words not heard intraoperatively)
Measured: 24 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Nov 2018
- Study start7 Jan 2013
- Primary completion15 Sep 2016
- Study completion15 Sep 2016
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Unconscious (Psychology)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 102 participants (actual)
Sponsor and investigators
- Lead sponsor
- Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta
- Sponsor type
- University, hospital or other
- Collaborators
- University of Milano Bicocca
- Responsible party
- Principal investigator, Eleonora Orena, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta
- Investigators
- Eleonora F Orena, PhD, Principal investigator, Fondazione IRCCS Istituto Neurologico Carlo Besta
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03727464
- Sponsor's protocol ID
- AR-INNCB-PRIMING-2012
- Status last verified
- Sep 2019
- First submitted
- 30 Oct 2018
- Last updated
- 6 Sep 2019
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Orena EF, Landucci F, Ayadi R, Caldiroli D, Papagno C. Propofol and sevoflurane affect intra-operative memory formation of words differently: A prospective cohort study. Eur J Anaesthesiol. 2021 Mar 1;38(Suppl 1):S50-S57. doi: 10.1097/EJA.0000000000001417.
PubMed 33399379
Study at a glance
From the registry record, last updated by the sponsor on 6 Sep 2019. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Memory Priming for Abstract and Concrete Words in General BIS Guided Propofol vs. Sevoflurane Anesthesia
- ClinicalTrials.gov ID
- NCT03727464
- Acronym / sponsor ID
- AR-INNCB-PRIMING-2012
- Conditions
- Unconscious (Psychology)
- Keywords
- Memory priming, Anesthesia, Language processing, Abstract and Concrete words, Neural correlates
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 102 participants (actual)
- Lead sponsor
- Fondazione I.R.C.C.S. Istituto Neurologico Carlo BestaUniversity, hospital or other
- Collaborators
- University of Milano Bicocca
- Study start
- 7 Jan 2013 (actual)
- Primary completion
- 15 Sep 2016 (actual)
- Study completion
- 15 Sep 2016 (actual)
- First posted
- 1 Nov 2018 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
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.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 6
| Arm | Type | Receives |
|---|---|---|
| Propofol Abstract Priming | Experimental | Behavioral: Abstract priming, Drug: PropofolPatients undergoing propofol general anesthesia and stimulation with a list of abstract words |
| Propofol Concrete Priming | Experimental | Behavioral: Concrete priming, Drug: PropofolPatients undergoing propofol general anesthesia and stimulation with a list of concrete words |
| Propofol Controls | Active comparator | Behavioral: Controls, Drug: PropofolPatients undergoing propofol anesthesia without any intraoperative priming |
| Sevoflurane Abstract Priming | Experimental | Behavioral: Abstract priming, Drug: SevofluranePatients undergoing sevoflurane general anesthesia and stimulation with a list of abstract words |
| Sevoflurane Concrete Priming | Experimental | Behavioral: Concrete priming, Drug: SevofluranePatients undergoing sevoflurane general anesthesia and stimulation with a list of concrete words |
| Sevoflurane Controls | Active comparator | Behavioral: Controls, Drug: SevofluranePatients undergoing sevoflurane general anesthesia without any intraoperative priming |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- 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
Key exclusion criteria (1 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Abstract primingPatients were primed with a list of abstract during their general anesthesia | Behavioural | Propofol Abstract Priming, Sevoflurane Abstract Priming |
| Concrete primingPatients were primed with a list of concrete during their general anesthesia | Behavioural | Propofol Concrete Priming, Sevoflurane Concrete Priming |
| ControlsPatients did not receive any specific stimulation with words during their general anesthesia | Behavioural | Propofol Controls, Sevoflurane Controls |
| PropofolPropofol general anesthesia | Drug | Propofol Abstract Priming, Propofol Concrete Priming, Propofol Controls |
| SevofluraneSevoflurane general anesthesia | Drug | Sevoflurane Abstract Priming, Sevoflurane Concrete Priming, Sevoflurane Controls |
Primary outcome
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.
4 secondary outcomes
Explicit recall of intraoperative words
Time frame: before discharge from the Recovery Room and at 24 hours
Explicit recall of intraoperative events
Time frame: before discharge from the Recovery Room and at 24 hours
Target hits
Time frame: 24 hours
Nontarget hits
Time frame: 24 hours
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Sep 2019.
- Derived from this study: PubMed 33399379Orena EF, Landucci F, Ayadi R, Caldiroli D, Papagno C. Propofol and sevoflurane affect intra-operative memory formation of words differently: A prospective cohort study. Eur J Anaesthesiol. 2021 Mar 1;38(Suppl 1):S50-S57. doi: 10.1097/EJA.0000000000001417.
- Individual participant dataSharing planned: No
Related trials for Unconscious (Psychology)
Active, not recruitingPhase 2
Calcineurin Inhibitor in NEuRoloGically Deceased Donors to Decrease Kidney delaYed Graft Function (CINERGY)
Organ Transplant Failure or Rejection, Brain Death
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Eleonora F Orena, PhD principal investigator
Fondazione IRCCS Istituto Neurologico Carlo Besta
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Abstract priming, Concrete priming and Propofol in people with Unconscious (Psychology), run by Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta at 1 site in Italy.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 6 Sep 2019. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Italy. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Implicit score (time frame: 24 hours). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03727464, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 Sep 2019.