EEG Signal Correlates During Anesthesia and Sedation in Adults and Children (SPECTRALADUPED)

Study of Pharmacological and Clinical Correlates of the Electroencephalographic Signal During Induction, Maintenance and Emergence Phases of General Anesthesia or Procedural Sedation in Adults and General Anesthesia in Children

This prospective, multicenter, non-interventional observational study investigates the correlates between electroencephalographic (EEG) signals and pharmacological/clinical parameters during general anesthesia and procedural sedation. The study will enroll 330 participants across three distinct populations at two AP-HP sites (Bichat-Claude Bernard Hospital and Louis Mourier Hospital):

1. Pediatric cohort (n=110): Children aged 1-17 years undergoing general anesthesia, including 55 with autism spectrum disorder (ASD) and 55 without ASD.
2. Elderly adult cohort (n=110): Patients over 70 years undergoing scheduled surgery under general anesthesia.
3. Procedural sedation cohort (n=110): Adults ≥18 years undergoing procedural sedation for digestive endoscopy.

EEG data will be collected using BIS and SedLine monitors during routine anesthetic care with no modifications to standard practice. The primary objective is to identify EEG signal features correlating with clinical and pharmacological parameters during induction, maintenance, and emergence phases.

Secondary objectives include developing predictive models for anesthetic depth, analyzing age-related differences, comparing effects of different anesthetic agents, and investigating specific EEG patterns in children with ASD. This study will enhance understanding of brain responses to anesthesia across different age groups and clinical contexts, potentially improving anesthetic monitoring algorithms and management strategies.

Study Overview

• Status: Not yet recruiting
• Conditions: Anesthesia; Sedation; Consciousness Monitors

Detailed Description

BACKGROUND AND RATIONALE:

Monitoring depth of anesthesia using electroencephalography (EEG) has become standard clinical practice, particularly through processed indices like the Bispectral Index (BIS). However, the underlying neurophysiological mechanisms and relationships between raw EEG signals and clinical/pharmacological parameters remain incompletely understood. Current monitoring systems provide processed indices but limited insight into raw multi-channel EEG signal characteristics. Systematic analysis of EEG data across different patient populations, age groups, and anesthetic contexts is needed to advance our understanding of brain responses to anesthesia and improve monitoring strategies.

STUDY DESIGN:

This is a prospective, multicenter, non-interventional, observational cohort study conducted at two sites of the Assistance Publique - Hôpitaux de Paris (AP-HP): Bichat-Claude Bernard Hospital and Louis Mourier Hospital. The study involves no modifications to routine anesthetic care - only collection and analysis of EEG data during standard clinical practice.

STUDY POPULATIONS:

The study will enroll 330 participants across three distinct cohorts:

Cohort 1 - Pediatric Population (n=110):

Children aged 1-17 years undergoing general anesthesia for scheduled surgical procedures. This cohort specifically includes:

• 55 children with autism spectrum disorder (ASD) diagnosed according to DSM-5 criteria
• 55 children without ASD (matched controls) This unique population allows investigation of potential neurodevelopmental differences in anesthetic response and EEG patterns in children with ASD.

Cohort 2 - Elderly Adult Population (n=110):

Patients aged >70 years undergoing scheduled surgery under general anesthesia at Bichat-Claude Bernard Hospital. This elderly population is important for studying age-related physiological changes affecting EEG patterns during anesthesia and potential increased sensitivity to anesthetic agents.

Cohort 3 - Procedural Sedation Population (n=110):

Adults (≥18 years) undergoing procedural sedation for diagnostic or therapeutic digestive endoscopy procedures at Louis Mourier Hospital. This cohort provides comparative data on lighter levels of sedation versus general anesthesia.

INCLUSION CRITERIA:

For adult patients:

• Age ≥18 years (Cohort 2: >70 years; Cohort 3: ≥18 years)
• Scheduled for general anesthesia (Cohort 2) or procedural sedation (Cohort 3)
• Pre-anesthetic consultation completed
• Informed of the study and non-opposition obtained

For pediatric patients (Cohort 1):

• Age 1-17 years
• Scheduled for general anesthesia for surgical procedure
• For ASD subgroup: Confirmed DSM-5 diagnosis of autism spectrum disorder
• Parental authority holder informed and non-opposition obtained
• Child informed (if age-appropriate) and non-opposition obtained

EXCLUSION CRITERIA:

For adult patients:

• Documented cognitive impairment in medical record
• Patient refusal to participate
• Patient deprived of liberty or under legal protection
• Pregnant or breastfeeding women

For pediatric patients:

• Parental refusal of child's participation
• Child refusal (if age-appropriate to understand)

DATA COLLECTION:

During routine anesthetic care without any protocol-specific interventions, the following will be recorded:

EEG Monitoring:

• Continuous multi-channel EEG using BIS (Bispectral Index) monitor
• Continuous multi-channel EEG using SedLine monitor
• Processed parameters (BIS index, spectral edge frequency, suppression ratio, etc.)
• Raw EEG signals recorded in standard EDF format

Synchronized Clinical Annotations:

• Anesthetic drug administration (agent, dose, route, timing)
• Clinical events (intubation, surgical incision, emergence, etc.)
• Hemodynamic parameters (heart rate, blood pressure)
• Level of consciousness assessments (RASS, clinical signs)
• Surgical stimulation intensity
• Adverse events

Patient Characteristics:

• Demographics (age, sex, weight, height, BMI)
• Medical history and comorbidities
• Concomitant medications
• ASA physical status classification
• For pediatric cohort: ASD diagnosis and characteristics

All EEG recordings and multi-signal files will be pseudonymized using a unique study identifier before analysis. Data will be stored on secure servers compliant with GDPR regulations.

PRIMARY OBJECTIVE:

To identify features of the electroencephalographic (EEG) signal that significantly correlate with:

1. Pharmacological parameters: anesthetic drug type, concentration (estimated effect-site concentration), drug combinations, pharmacokinetic/pharmacodynamic properties
2. Clinical parameters: patient age, comorbidities, surgical stimulation intensity, hemodynamic changes, emergence characteristics

These correlations will be analyzed separately for the induction, maintenance, and emergence phases of general anesthesia and for procedural sedation.

SECONDARY OBJECTIVES:

1. Develop and validate predictive models using machine learning algorithms to link specific EEG features to anesthetic depth and level of consciousness
2. Compare EEG spectral and temporal characteristics between pediatric and adult populations during equivalent anesthetic states
3. Analyze differential effects of commonly used anesthetic agents (propofol, sevoflurane, desflurane, remifentanil) on multi-channel EEG patterns
4. Investigate specific EEG signatures and anesthetic responses in children with autism spectrum disorder compared to typically developing children
5. Characterize distinctive EEG patterns during procedural sedation versus general anesthesia
6. Evaluate inter-individual and intra-individual variability in EEG responses to anesthetic agents
7. Assess correlation between frontal EEG patterns and clinical signs of anesthetic depth

ENDPOINTS:

Primary Endpoint:

Correlation coefficients (Pearson or Spearman as appropriate) between extracted EEG features (spectral power in different frequency bands, coherence, entropy measures, burst suppression patterns) and pharmacological/clinical variables during different anesthetic phases.

Secondary Endpoints:

• Performance metrics (sensitivity, specificity, AUC) of predictive models for anesthetic depth
• Differences in EEG power spectral density between age groups
• Changes in EEG patterns associated with specific anesthetic agents
• Differences in EEG characteristics between children with/without ASD
• Comparison of EEG patterns between sedation and general anesthesia
• Variance components of inter- and intra-individual EEG variability

STATISTICAL ANALYSIS:

Sample size of 330 participants (110 per cohort) was calculated to provide:

• Adequate power (>80%) to detect medium effect sizes (r≥0.3) for correlation analyses
• Sufficient training and validation datasets for machine learning models
• Subgroup analyses within pediatric cohort (ASD vs non-ASD)

Advanced signal processing techniques will be applied including:

• Fast Fourier Transform for spectral analysis
• Wavelet decomposition for time-frequency analysis
• Entropy measures (spectral entropy, permutation entropy)
• Coherence and connectivity analyses
• Machine learning algorithms (random forests, support vector machines, neural networks)

Statistical analyses will use appropriate parametric or non-parametric tests depending on data distribution. Multiple comparison corrections will be applied when appropriate (Bonferroni, FDR). Mixed-effects models will account for repeated measures within individuals.

STUDY DURATION:

• Recruitment period: 12 months
• Individual patient participation: Approximately 1 month (interval between pre-anesthetic consultation and surgical procedure/endoscopy)
• Total study duration: 13 months including data analysis

ETHICAL AND REGULATORY CONSIDERATIONS:

This non-interventional study involves no modifications to standard clinical care, no additional risk to participants, and no experimental interventions. The study has been submitted to the Comité de Protection des Personnes (CPP) for ethical approval and will be registered with the ANSM. Participants (or parents for minors) will receive written information and provide non-opposition for data use. All data management complies with GDPR regulations (MR-003 reference methodology).

EXPECTED OUTCOMES AND IMPACT:

This comprehensive study will provide rich datasets on EEG signal characteristics across diverse anesthetic contexts and patient populations. Results may lead to:

• Improved algorithms for real-time anesthetic depth monitoring
• Better understanding of age-related and neurodevelopmental differences in anesthetic response
• Optimization of anesthetic agent selection and dosing strategies
• Enhanced safety through more accurate consciousness monitoring
• New insights into neurophysiological mechanisms of anesthesia
• Foundation for future development of personalized anesthetic management approaches

The purely observational design ensures maximal safety while generating clinically relevant data to advance the field of neuromonitoring in anesthesia.

• Study Type: Observational
• Enrollment (Estimated): 330

Contacts and Locations

• Study Contact: Name: Dan Longrois, MD, PHD; Phone Number: 01 47 60 61 35; Email: dan.longrois@aphp.fr
• Study Contact Backup: Name: David Holcman, MD, PHD; Phone Number: 01 44 32 36 61; Email: holcman.david@gmail.com

Study Locations

• France
  • Colombes, France, 92700
    • Hopital Louis Mourier
    • Contact: Dan Longrois, MD, PHD; Phone Number: 01 47 60 61 35; Email: dan.longrois@aphp.fr
    • Contact: David Holcman, MD, PHD; Phone Number: 01 44 32 36 61; Email: holcman.david@gmail.com
  • Ap-hp DRCI
    • Paris, Ap-hp DRCI, France, 75010
      • Hopital Bichat-Claude Bernard
      • Contact: Dan Longrois, MD, PHD; Phone Number: 01 47 60 61 35; Email: dan.longrois@aphp.fr
      • Contact: David Holcman, MD, PHD; Phone Number: 01 44 32 36 61; Email: holcman.david@gmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

For adults:

Patients over 70 years of age who need to benefit from general anesthesia for surgery (Bichat-Claude Bernard or Louis Mourier).

Adult patients (> 18 years old) who should benefit from procedural sedation for digestive endoscopies (Louis Mourier).

For children:

Children over 1 year of age (and weighing > 10 kg) who need to benefit from general anesthesia for dental or ENT surgery at the Louis Mourier Hospital (including children with autism spectrum disorder)

Description

INCLUSION CRITERIA:

For adult patients:

• Age ≥18 years (Cohort 2: >70 years; Cohort 3: ≥18 years)
• Scheduled for general anesthesia (Cohort 2) or procedural sedation (Cohort 3)
• Pre-anesthetic consultation completed
• Informed of the study and non-opposition obtained

For pediatric patients (Cohort 1):

• Age 1-17 years
• Scheduled for general anesthesia for surgical procedure
• For ASD subgroup: Confirmed DSM-5 diagnosis of autism spectrum disorder
• Parental authority holder informed and non-opposition obtained
• Child informed (if age-appropriate) and non-opposition obtained

EXCLUSION CRITERIA:

For adult patients:

• Documented cognitive impairment in medical record
• Patient refusal to participate
• Patient deprived of liberty or under legal protection
• Pregnant or breastfeeding women

For pediatric patients:

• Parental refusal of child's participation
• Child refusal (if age-appropriate to understand)

Study Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort
COHORT 1 - Pediatric (n=110); Children aged 1-17 years undergoing general anesthesia, including 55 with ASD and 55 without ASD.
COHORT 2 - Elderly Adults (n=110); Patients over 70 years undergoing scheduled surgery under general anesthesia at Bichat-Claude Bernard Hospital.
COHORT 3 - Procedural Sedation (n=110); Adults ≥18 years undergoing procedural sedation for digestive endoscopy at Louis Mourier Hospital.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Correlation of EEG features with pharmacological and clinical parameters during anesthesia	Identification of electroencephalographic (EEG) signal features (spectral power in delta, theta, alpha, beta, gamma bands; coherence; entropy measures; burst suppression patterns) that demonstrate statistically significant correlation with: Pharmacological parameters including anesthetic drug type, estimated effect-site concentration, drug combinations, and pharmacokinetic/pharmacodynamic properties; Clinical parameters including patient age, comorbidities, surgical stimulation intensity, hemodynamic changes, and clinical signs of consciousness level Correlations will be quantified using Pearson or Spearman correlation coefficients (as appropriate) and analyzed separately for induction, maintenance, and emergence phases. Features will be extracted from multi-channel EEG recordings using advanced signal processing and machine learning techniques.	During anesthesia/sedation procedure (typically 1-6 hours per participant)
Development of mathematical tools for EEG analysis during maintenance phase	Development of new mathematical descriptors to quantify spectral density matrix (SDM) EEG profiles during anesthesia maintenance in adults and children, distinguishing stationary phases from transitions between states. Collaboration with mathematical team at ENS (Prof. David Holcman). Measured variables: Novel mathematical descriptors quantifying SDM EEG profiles during anesthetic maintenance. Outcome: Linearity of relationship between quantitative descriptors and clinical anesthesia phase, measured by R² correlation coefficient between new descriptors and clinical classification (awake, induction, light/medium/deep maintenance, emergence).	During anesthesia maintenance phase (varies per participant, typically 1-5 hours)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Development of mathematical tools for induction phases	Development of mathematical analysis tools specific to induction and emergence phases (adults and children). These phases involve much more rapid changes (seconds for induction, tens of seconds for emergence) compared to maintenance (minutes to hours) in both drug doses/concentrations and EEG profiles. Measured variables: New mathematical descriptors specific to induction and emergence phases. Outcome: Linearity of relationship between new descriptors and hypnotic drug doses/concentrations, measured by R² correlation coefficient and slope of dose-descriptor relationship during transition phases.	During induction (typically 2-5 minutes) and emergence (typically 5-20 minutes)
Development of mathematical tools for emergence phases	Development of mathematical analysis tools specific to induction and emergence phases (adults and children). These phases involve much more rapid changes (seconds for induction, tens of seconds for emergence) compared to maintenance (minutes to hours) in both drug doses/concentrations and EEG profiles. Measured variables: New mathematical descriptors specific to induction and emergence phases. Outcome: Linearity of relationship between new descriptors and hypnotic drug doses/concentrations, measured by R² correlation coefficient and slope of dose-descriptor relationship during transition phases.	During induction (typically 2-5 minutes) and emergence (typically 5-20 minutes)
Analysis of individual sensitivity to anesthetic drugs during induction	Test the hypothesis that individual sensitivity to anesthetic drugs can be analyzed in the first minutes of anesthetic induction. Outcome measure: Slope of the linear relationship (established in SO2) between hypnotic dose/concentration and numerical descriptor obtained in SO2. A slope closer to 1 indicates increased sensitivity. Applies to induction protocols used in adults (intravenous propofol injection) and children (sevoflurane inhalation).	During induction phase (first 2-5 minutes of anesthetic exposure)
Consistency of individual anesthetic sensitivity across induction	Test the hypothesis that individual sensitivity to anesthetic drugs identified during induction (SO3) remains constant during maintenance and emergence phases. Outcome: Correlations between slopes of dose/concentration-descriptor relationships (obtained in SO1 and SO2) across the three phases (induction, maintenance, emergence). Assessment of repeatability over time of dose-response relationship, measured by geometric mean error of predicted versus observed transition duration, adjusted for relevant covariates (dose changes, etc.).	Throughout entire anesthesia procedure (induction through emergence, typically 1-6 hours)
Consistency of individual anesthetic sensitivity across maintenance	Test the hypothesis that individual sensitivity to anesthetic drugs identified during induction (SO3) remains constant during maintenance and emergence phases. Outcome: Correlations between slopes of dose/concentration-descriptor relationships (obtained in SO1 and SO2) across the three phases (induction, maintenance, emergence). Assessment of repeatability over time of dose-response relationship, measured by geometric mean error of predicted versus observed transition duration, adjusted for relevant covariates (dose changes, etc.).	Throughout entire anesthesia procedure (induction through emergence, typically 1-6 hours)
Consistency of individual anesthetic sensitivity across emergence	Test the hypothesis that individual sensitivity to anesthetic drugs identified during induction (SO3) remains constant during maintenance and emergence phases. Outcome: Correlations between slopes of dose/concentration-descriptor relationships (obtained in SO1 and SO2) across the three phases (induction, maintenance, emergence). Assessment of repeatability over time of dose-response relationship, measured by geometric mean error of predicted versus observed transition duration, adjusted for relevant covariates (dose changes, etc.).	Throughout entire anesthesia procedure (induction through emergence, typically 1-6 hours)
EEG correlates predicting complication-free tracheal extubation in children	Specific analysis in children of EEG correlates (those already available on SedLine monitor and new tools developed in SO2 for emergence phase) to improve EEG predictive criteria for complication-free tracheal extubation. Measured variable: Occurrence of extubation complications, stratified as: (1) No complication, (2) Minor: persistent cough, agitation, transient desaturation (SpO2 >92%), (3) Moderate: laryngospasm resolved by mask ventilation, desaturation <92% requiring intervention, (4) Severe: laryngospasm/bronchospasm requiring reintubation. Outcome: Association between pre-extubation EEG profiles and complication occurrence, analyzed by multinomial logistic regression.	During emergence phase preceding tracheal extubation (typically 10-30 minutes)
EEG profile analysis in children with autism spectrum disorder during anesthesia	Analysis of EEG traces from children with autism spectrum disorder (ASD) using tools described in SO1-SO4. Descriptive analysis as literature lacks data on per-anesthesia EEG profiles in children with ASD pathology. Tests hypothesis of differences in EEG profiles between children with/without ASD. Measured variables: Quantitative EEG descriptors (identified in objectives 1-4) measured in 55 children with ASD and 55 without ASD, adjusted for medication doses and clinical correlates. Outcome: Discrimination capacity between groups, measured by area under ROC curve of classification models (principal component analysis and machine learning methods), with blinded analysis by mathematicians.	Throughout entire anesthesia procedure (typically 1-6 hours per participant)

Collaborators and Investigators

• Sponsor: Assistance Publique - Hôpitaux de Paris
• Collaborators: Bichat Hospital; Hôpital Louis Mourier; Ecole Normale Supérieure de Paris
• Investigators: Principal Investigator: Dan Longrois, MD, PHD, Assistance Publique Hopitaux de Paris

Study record dates

Study Major Dates

• Study Start (Estimated): March 15, 2026
• Primary Completion (Estimated): April 15, 2027
• Study Completion (Estimated): May 15, 2027

Study Registration Dates

• First Submitted: March 4, 2026
• First Submitted That Met QC Criteria: March 4, 2026
• First Posted (Actual): March 10, 2026

Study Record Updates

• Last Update Posted (Actual): March 10, 2026
• Last Update Submitted That Met QC Criteria: March 4, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: general anesthesia
• Other Study ID Numbers: APHP250674; 2025-A01891-48 (Other Identifier: IDRCB)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No