Brain Activity and Changes in Consciousness During General Anesthesia

September 19, 2026 updated by: Beijing Chao Yang Hospital

Mechanism Exploration of General Anesthesia-Induced Altered Consciousness Via Cortical-Thalamic Network Modulation and Development of a Precision Anesthesia Depth Monitoring Device

This study aims to investigate how general anesthetics alter brain activity and consciousness across different age groups. The study will evaluate four anesthetic agents with different mechanisms of action: propofol, remimazolam, esketamine, and dexmedetomidine. Electroencephalography (EEG) will be recorded during wakefulness, anesthetic induction, loss of responsiveness, and recovery of responsiveness to characterize changes in brain activity and brain network dynamics.

The study includes children aged 6-12 years undergoing surgery, healthy young adults aged 20-40 years, and healthy older adults aged 65-80 years. Resting-state EEG will be used to examine changes in brain rhythms, temporal and spatial brain dynamics, and network organization across different levels of consciousness. In a subgroup of young adult participants, auditory stimuli will also be presented continuously to investigate how the brain processes sounds and meaningful information as consciousness decreases and subsequently recovers.

The study will compare EEG changes across anesthetic agents, age groups, and states of consciousness. It will also evaluate the timing of loss and recovery of responsiveness, anesthetic dose-response relationships, and adverse events. The overall goal is to identify brain activity patterns associated with anesthesia-induced changes in consciousness and to provide a scientific basis for improved monitoring of consciousness and anesthetic depth.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

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Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
320

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • China
      • Beijing, China, 100020
        • Affiliated Beijing Chaoyang Hospital of Capital Medical University
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

6 years to 80 years (Child, Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  1. Participants must belong to one of the following prespecified age groups: children aged 6-12 years, young adults aged 20-40 years, or older adults aged 65-80 years.
  2. Children must be surgical patients undergoing general anesthesia. Young adult and older adult participants will be healthy volunteers.
  3. American Society of Anesthesiologists (ASA) physical status I; older adult participants may have ASA physical status II.
  4. Written informed consent must be obtained from all adult participants and surgical patients as applicable. For pediatric participants, written informed consent must be provided by a parent or legal guardian.

Exclusion Criteria:

  1. History of neuropsychiatric disorders, including epilepsy, dementia, or other relevant neurological or psychiatric diseases.
  2. Known hearing impairment or physical impairment that may interfere with completion of the study procedures or tasks.
  3. History of allergy to propofol, benzodiazepines, or other anesthetic agents used in the study.
  4. Long-term use of sedative or analgesic medications for more than 1 month. Disturbed sleep pattern within 14 days before the study, including shift work or insomnia.
  5. Communication difficulties or inability to cooperate with EEG data acquisition.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Propofol Group

Participants in this arm will receive propofol. In young and older healthy volunteers, propofol will be administered by target-controlled infusion, with the plasma target concentration increased by 0.5 μg/mL every 5 minutes up to a maximum of 5 μg/mL to induce loss of responsiveness. EEG will be recorded during wakefulness, anesthetic induction, loss of responsiveness, and recovery. Pediatric surgical participants in this group will undergo EEG recording during anesthesia in the operating room.
Drug: Propofol (Group P)

Propofol will be administered by target-controlled infusion in young and older healthy volunteers. The plasma target concentration will be increased by 0.5 μg/mL every 5 minutes, up to a maximum of 5 μg/mL, until protocol-defined loss of responsiveness is achieved. Consciousness will be assessed every minute using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale, and EEG will be recorded throughout anesthetic induction and recovery.
Experimental: Remimazolam Group

Participants in this arm will receive remimazolam. In young and older healthy volunteers, remimazolam will be administered intravenously at sequential infusion rates of 0.5, 1.0, 1.5, and 2.0 mg/kg/h, with each level maintained for 5 minutes, until loss of responsiveness is achieved. EEG will be recorded during wakefulness, anesthetic induction, loss of responsiveness, and recovery. Pediatric surgical participants in this group will undergo EEG recording during anesthesia in the operating room.
Drug: Remimazolam group

Remimazolam will be administered intravenously in young and older healthy volunteers at sequential infusion rates of 0.5, 1.0, 1.5, and 2.0 mg/kg/h, with each level maintained for 5 minutes, until protocol-defined loss of responsiveness is achieved. Consciousness will be assessed every minute using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale, and EEG will be recorded throughout anesthetic induction and recovery.
Experimental: Esketamine Group

Participants in this arm will receive esketamine. In young and older healthy volunteers, esketamine will be administered intravenously with the infusion rate increased by 0.10 mg/kg/h every 5 minutes, up to a maximum of 0.50 mg/kg/h, to induce loss of responsiveness. EEG will be recorded during wakefulness, anesthetic induction, loss of responsiveness, and recovery. Pediatric surgical participants in this group will undergo EEG recording during anesthesia in the operating room.
Drug: Esketamine group

Esketamine will be administered intravenously in young and older healthy volunteers. The infusion rate will be increased by 0.10 mg/kg/h every 5 minutes, up to a maximum of 0.50 mg/kg/h, until protocol-defined loss of responsiveness is achieved. Consciousness will be assessed every minute using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale, and EEG will be recorded throughout anesthetic induction and recovery.
Experimental: Dexmedetomidine Group

Participants in this arm will receive dexmedetomidine. In young and older healthy volunteers, dexmedetomidine will be administered intravenously with stepwise increases of 0.1 μg/kg/h, up to a maximum of 0.7 μg/kg/h, to induce loss of responsiveness. EEG will be recorded during wakefulness, anesthetic induction, loss of responsiveness, and recovery. Pediatric surgical participants in this group will undergo EEG recording during anesthesia in the operating room.
Drug: Dexmedetomidine group

Dexmedetomidine will be administered intravenously in young and older healthy volunteers with stepwise increases in the infusion rate of 0.1 μg/kg/h, up to a maximum of 0.7 μg/kg/h, until protocol-defined loss of responsiveness is achieved. Consciousness will be assessed every minute using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale, and EEG will be recorded throughout anesthetic induction and recovery.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Changes in Resting-State Quantitative EEG Measures Across Behavioral Responsiveness States
Time Frame: From the start of the 10-minute awake baseline through anesthetic induction, loss-of-responsiveness maintenance, emergence, and 30 minutes after recovery of responsiveness

Continuous resting-state EEG will be quantified across awake baseline, anesthetic induction, loss of responsiveness, maintenance, emergence, and recovery. Prespecified measures include delta power (0.5-4 Hz), alpha power (8-12 Hz), theta/alpha power ratio, slow-wave index (SWI), burst suppression ratio (BSR), autocorrelation window at the first zero crossing (ACW-0), EEG complexity (gMLZC), and alpha-band (8-13 Hz) functional connectivity/network measures, including wPLI/dwPLI² and weighted global efficiency. Each measure will be analyzed separately.
From the start of the 10-minute awake baseline through anesthetic induction, loss-of-responsiveness maintenance, emergence, and 30 minutes after recovery of responsiveness
Changes in Auditory-Evoked ERP and Time-Frequency EEG Measures Across Behavioral Responsiveness States
Time Frame: From the start of the 10-minute awake baseline through anesthetic induction, loss of responsiveness, maintenance, emergence, and at least 10 minutes after recovery of responsiveness

Auditory-evoked EEG will be quantified across awake baseline, anesthetic induction, loss of responsiveness, maintenance, emergence, and recovery. Event-related potential (ERP) measures include N100, mismatch negativity (MMN), N400, and P300 amplitudes and their state-related temporal dynamics. Stimuli include pure tones, white noise, characters, words, sentences, another person's name, and the participant's own name. Time-frequency measures include event-related theta-band activity (4-8 Hz), alpha-band activity (8-12 Hz), and intertrial phase coherence. Source-space analyses will localize N400 and P300 generators, and single-trial ERP amplitudes will be analyzed in relation to behavioral responsiveness. Each measure will be analyzed separately.
From the start of the 10-minute awake baseline through anesthetic induction, loss of responsiveness, maintenance, emergence, and at least 10 minutes after recovery of responsiveness

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Beijing Chao Yang Hospital

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 1, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 4, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 19, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 23, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
September 23, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 19, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2026-ke-429
  • L2510005 (Other Grant/Funding Number: Beijing Natural Science Foundation - Capital Clinical Medical Innovation Joint Fund)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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