Correlate of Surface Electroencephalogram (EEG) With Implanted EEG Recordings (ECOG)

Improve understanding of the correlation between surface EEG and implanted EEG recordings

Study Overview

• Status: Completed
• Conditions: Anesthesia
• Intervention / Treatment: Device: EEG; Device: ECOG

• Study Type: Observational
• Enrollment (Actual): 20

Contacts and Locations

Study Locations

• United States
  • California
    • Stanford, California, United States, 94305
      • Stanford University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Stanford Health Care and Clinics

Description

Inclusion Criteria:

• Male or Female subjects 18 years of age or older.
• English or Spanish Speaking
• Subjects who have been previously diagnosed with intractable epilepsy and require implantation of invasive electrophysiological recordings as part of their routine clinical presurgical workup.

Exclusion Criteria:

• Patients with skin abnormalities at the planned application sites that would interfere with sensor or electrode applications.
• Patients with pre-existing conditions and/or co-morbidities that would prohibit them from participating in the study due to unacceptable risks to their health and well-being, as determined by the Principal Investigator (PI).
• Patients who the PI deems ineligible at the PI's discretion
• Pregnant patients

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
ECOG and EEG Sensor; Study subjects are neurosurgical patients with medically refractory epilepsy who will have implanted with intracranial ECoG electrodes. The electrodes will be used during a period of inpatient monitoring to identify resectable seizure foci.	Device: EEG; EEG will be collected with Brain Product's VAMP-16 channel EEG Monitor using the accompanying software. (Website with further specifications and product details: https://www.brainproducts.com/productdetails.php?id=15); Device: ECOG; ECOG will be collected with Nihon Kohden acquisition System and accompanying software and depth electrodes.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Electrocardiogram (EEG) change before, during, and after anesthesia.	Patient subjective level of consciousness during and after anesthesia administration will be assessed using response to verbal stimuli, response via button press, reported subjective level of consciousness, and/or response to memory tests (i.e. demonstration of explicit memory recall). Around loss and recovery of consciousness time points (e.g. induction or emergence from anesthesia or when patient falls asleep or wakes up during 24 hour postoperative time points) level of consciousness will be assessed in brief intervals (seconds) until patient no longer responds or begins to respond. Data collected before, after, and during seizure activity if a patient loses consciousness or has diminished consciousness may also be compared.	Up to 48 hours. Specific time points are dependent on patient clinical events.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Electrocardiogram (EEG) change during any seizures.	Scalp and cortical electrical activity collected using EEG and ECOG arrays respectively will be analyzed using standard frequency-derived measures (e.g. spectrograms, Fourier analysis), nonlinear dynamical analyses (e.g. correlation dimension, entropy), network dynamics (e.g. connectivity matrices, path length), and/or machine learning. Data collected before, after, and during seizure activity if a patient loses consciousness or has diminished consciousness may also be compared. Reports will include characterization and comparison of EEG and ECOG electrophysiological activity and analyses during consciousness transitions and significant time points.	Up to 48 hours. Specific time points are dependent on patient clinical events.
Electrocardiogram (EEG) change during any changes in consciousness.	Scalp and cortical electrical activity collected using EEG and ECOG arrays respectively will be analyzed using standard frequency-derived measures (e.g. spectrograms, Fourier analysis), nonlinear dynamical analyses (e.g. correlation dimension, entropy), network dynamics (e.g. connectivity matrices, path length), and/or machine learning. These measures will include all of the data collected from the start of the implant procedure until 24 hours after the implant procedure has ended. Data collected before, after, and during seizure activity if a patient loses consciousness or has diminished consciousness may also be compared. Reports will included characterization of electrophysiological activity before, during, and after variations in behavioral and subjectively reported consciousness.	Up to 48 hours. Specific time points are dependent on patient clinical events.

Collaborators and Investigators

• Sponsor: Stanford University
• Investigators: Principal Investigator: David Drover, MD, Stanford University

Publications and helpful links

General Publications

• Purdon PL, Sampson A, Pavone KJ, Brown EN. Clinical Electroencephalography for Anesthesiologists: Part I: Background and Basic Signatures. Anesthesiology. 2015 Oct;123(4):937-60. doi: 10.1097/ALN.0000000000000841.
• Hajat Z, Ahmad N, Andrzejowski J. The role and limitations of EEG-based depth of anaesthesia monitoring in theatres and intensive care. Anaesthesia. 2017 Jan;72 Suppl 1:38-47. doi: 10.1111/anae.13739.
• Fahy BG, Chau DF. The Technology of Processed Electroencephalogram Monitoring Devices for Assessment of Depth of Anesthesia. Anesth Analg. 2018 Jan;126(1):111-117. doi: 10.1213/ANE.0000000000002331.
• Hashiguchi K, Morioka T, Yoshida F, Miyagi Y, Nagata S, Sakata A, Sasaki T. Correlation between scalp-recorded electroencephalographic and electrocorticographic activities during ictal period. Seizure. 2007 Apr;16(3):238-47. doi: 10.1016/j.seizure.2006.12.010. Epub 2007 Jan 19.
• Asano E, Brown EC, Juhasz C. How to establish causality in epilepsy surgery. Brain Dev. 2013 Sep;35(8):706-20. doi: 10.1016/j.braindev.2013.04.004. Epub 2013 May 15.
• Smith EH, Liou JY, Davis TS, Merricks EM, Kellis SS, Weiss SA, Greger B, House PA, McKhann GM 2nd, Goodman RR, Emerson RG, Bateman LM, Trevelyan AJ, Schevon CA. The ictal wavefront is the spatiotemporal source of discharges during spontaneous human seizures. Nat Commun. 2016 Mar 29;7:11098. doi: 10.1038/ncomms11098.
• Ramantani G, Maillard L, Koessler L. Correlation of invasive EEG and scalp EEG. Seizure. 2016 Oct;41:196-200. doi: 10.1016/j.seizure.2016.05.018. Epub 2016 Jun 10.

Study record dates

Study Major Dates

• Study Start (Actual): November 11, 2019
• Primary Completion (Actual): August 9, 2026
• Study Completion (Actual): August 9, 2026

Study Registration Dates

• First Submitted: May 29, 2018
• First Submitted That Met QC Criteria: August 12, 2018
• First Posted (Actual): August 14, 2018

Study Record Updates

• Last Update Posted (Actual): August 11, 2026
• Last Update Submitted That Met QC Criteria: August 9, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Diagnostic Techniques and Procedures; Diagnosis; Diagnostic Techniques, Neurological; Electrodiagnosis; Electroencephalography
• Other Study ID Numbers: 45987

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: Yes
• product manufactured in and exported from the U.S.: Yes