Study Stopped
Record erroneously created as an updated trial was initiated \& performed in the same patient population.
Modulating Oscillations and Working Memory in Patients With Subdural Electrodes
2 other identifiers
interventional
N/A
0 countries
N/A
Brief Summary
Purpose: To investigate whether rhythmic direct electrical stimulation (DES) causes entrainment of endogenous neural oscillatory activity and whether such activity improve cognition. Participants: Drug-resistant epilepsy patients undergoing epilepsy surgery cortical mapping with continuous electrocorticography (ECoG) with intracranial electrodes. Procedures (methods): Rhythmic electrical stimulation will be delivered via intracranial electrodes during routine extra-operative cortical mapping. Long-term ECoG, Pre-stimulation ECoG, peri-stimulation ECoG, and post-stimulation ECoG data will be analyzed to assess for entrainment of neural oscillations.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
Started Jan 2014
Typical duration for not_applicable
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
Study Start
First participant enrolled
January 1, 2014
CompletedFirst Submitted
Initial submission to the registry
February 22, 2017
CompletedPrimary Completion
Last participant's last visit for primary outcome
March 15, 2017
CompletedStudy Completion
Last participant's last visit for all outcomes
March 15, 2017
CompletedFirst Posted
Study publicly available on registry
April 12, 2017
CompletedMarch 19, 2026
January 1, 2025
3.2 years
February 22, 2017
March 16, 2026
Conditions
Keywords
Outcome Measures
Primary Outcomes (2)
Working Memory Task Performance - Accuracy
In this task, a sequence of items (alphabets or numerals) is presented followed by a delay. Following this, a single item which may or may not have been in the sequence is presented and the subject will be asked to indicate whether the item was in the previously presented sequence. A total of 150 trials will be performed with randomly interleaved sham trials where no stimulation is applied. Accuracy will be quantified in percentage correct.
1 Hour
Working Memory Task Performance - Reaction Time
In this task, a sequence of items (alphabets or numerals) is presented followed by a delay. Following this, a single item which may or may not have been in the sequence is presented and the subject will be asked to indicate whether the item was in the previously presented sequence. A total of 150 trials will be performed with randomly interleaved sham trials where no stimulation is applied. Reaction times will be quantified in milliseconds.
1 Hour
Secondary Outcomes (1)
Intracranial EEG
Intracranial EEG will be collected simultaneously when the participants perform the task. 1 Hour
Other Outcomes (2)
Facial Recognition Task Performance - Accuracy
1 Hour
Facial Recognition Task Performance - Reaction Time
1 Hour
Study Arms (2)
Sham
SHAM COMPARATORDevice: Direct Cortical Stimulation Sham. Trials in which stimulation is not applied. These trials are initiated using a generic trigger generator.
Stimulation
ACTIVE COMPARATORDevice: Direct Cortical Stimulation. 150 stimulations with stimulations lasting 5 seconds at different target electrodes at two target frequencies (e.g. 5 Hz and 10 Hz) 2 milliampere in amplitude (Pulse shape - Biphasic square pulse 200 microsecond in duration per phase). Stimulation will be applied concurrently with the task and stimulation trials will be randomly interleaved with sham trials.
Interventions
A train of periodic electrical pulses is delivered between two local electrodes implanted in the brain
Eligibility Criteria
You may qualify if:
- History of medically intractable epilepsy
- Capable of giving informed consent
- Aged 18 - 80 years, either sex
You may not qualify if:
- Past or current history of other neurological illnesses including ischemic stroke, intracerebral hemorrhage, brain neoplasm.
- Major systemic illness
- Severe cognitive impairment defined as mini-mental state examination of less than 20
- Severe psychiatric illness
- Excessive use of alcohol or other substances
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Related Publications (1)
Alagapan S, Schmidt SL, Lefebvre J, Hadar E, Shin HW, Frӧhlich F. Modulation of Cortical Oscillations by Low-Frequency Direct Cortical Stimulation Is State-Dependent. PLoS Biol. 2016 Mar 29;14(3):e1002424. doi: 10.1371/journal.pbio.1002424. eCollection 2016 Mar.
PMID: 27023427BACKGROUND
MeSH Terms
Conditions
Condition Hierarchy (Ancestors)
Study Officials
- PRINCIPAL INVESTIGATOR
Flavio Frohlich, PhD
University of North Carolina, Chapel Hill
- PRINCIPAL INVESTIGATOR
Hae Won Shin, MD
University of North Carolina, Chapel Hill
Study Design
- Study Type
- interventional
- Phase
- not applicable
- Allocation
- NON RANDOMIZED
- Masking
- SINGLE
- Who Masked
- PARTICIPANT
- Purpose
- BASIC SCIENCE
- Intervention Model
- CROSSOVER
- Sponsor Type
- OTHER
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
February 22, 2017
First Posted
April 12, 2017
Study Start
January 1, 2014
Primary Completion
March 15, 2017
Study Completion
March 15, 2017
Last Updated
March 19, 2026
Record last verified: 2025-01
Data Sharing
- IPD Sharing
- Will share
De-identified electrophysiology data and task information (e.g. timing of each trial, timing of responses) will be shared at the end of the study in a central repository (e.g. zenodo)