Cognitive and Electrophysiological Assessment of Non-Invasive Temporally-Interfering Electric Fields Stimulation (TIEFS) (TIEFS)

The goal of this clinical trial is to learn how a non-invasive brain stimulation method called Temporally Interfering Electric Fields Stimulation (TIEFS) affects brain activity and thinking in adults. TIEFS uses electrical currents applied to the scalp to influence brain activity without surgery.

The main questions this study aims to answer are:

• How does TIEFS change brain signals measured with brain recordings?
• Does TIEFS affect thinking abilities such as memory, language, movement, or perception?
• Is TIEFS safe and well tolerated when used in people?

This study includes two groups of participants. One group includes adults with epilepsy who are already undergoing specialized brain monitoring as part of their medical care. The other group includes healthy adults with no history of seizures.

Participants will:

• Receive brief sessions of TIEFS using electrodes placed on the scalp
• Complete computer-based tasks that test memory, attention, language, or movement. Answer questions about how the stimulation feels
• Have brain activity recorded during the study

Each study visit lasts up to three hours and may occur in one or two sessions. Information from this study may help researchers better understand the human brain and support the development of future non-invasive brain stimulation treatments.

Study Overview

• Status: Recruiting
• Conditions: Epilepsy
• Intervention / Treatment: Device: Temporal Interference Electrical Stimulation

• Study Type: Interventional
• Enrollment (Estimated): 15
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Nigel P Pedersen, MBBS; Phone Number: 617-462-8120; Email: nppedersen@health.ucdavis.edu
• Study Contact Backup: Name: Raul S Castillo-Astorga, MD; Phone Number: 530-220-0057; Email: rcastilloastorga@ucdavis.edu

Study Locations

• United States
  • California
    • Sacramento, California, United States, 95817
      • Recruiting
      • University of California Davis Medical Center
      • Contact: Nigel P Pedersen, MBBS; Phone Number: 617-462-8120; Email: nppedersen@health.ucdavis.edu
      • Principal Investigator: Nigel P Pedersen, MBBS

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Adult patients (age 18-65 years of age) undergoing an intracerebral electrophysiology study for epilepsy pre-surgical evaluation are eligible for inclusion.
• For healthy control subjects are also eligible for inclusion (Scalp EEG measurements).
• Participants must be able to sufficiently speak and understand English or Spanish for consent and be able to understand and complete cognitive tasks.
• All subjects must have the ability to give valid informed consent.

Exclusion Criteria:

• No pregnant women will be recruited.
• People with implanted electrical devices such as Deep Brain Stimulation devices or Pacemakers.
• No prisoners will be recruited.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Non-Randomized
• Interventional Model: Sequential Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Comparison of Active vs Sham TIEFS Stimulation in SEEG patients; This arm involves a within-subject comparison of different frequencies of active TIEFS stimulation and sham stimulation, all within the same session. Patients will already have been admitted to SEEG surgery, and will be approached while still having the electrodes implanted. Each participant will receive multiple types of stimulation at different envelope frequencies (ranging from 1-130 Hz). During the session, electrodes will be placed on the scalp to administer TIEFS at varying frequencies. Each frequency will be tested in separate trials within the session, with multiple trials per frequency. The results from these trials will be averaged to determine the overall impact of each frequency on brain activity (measured through SEEG) and/or cognitive functions (evaluated using tasks related to memory, language, motor function, and perception). Sham stimulation will also be delivered within the same session, and participants will be blinded to the type of stimulation (active vs sham).	Device: Temporal Interference Electrical Stimulation; Temporal Interference Electrical Stimulation (TIEFS) is a non-invasive brain stimulation technique that uses two high-frequency electrical fields (>1 kHz) to generate an interference pattern at a specific brain region, creating a low-frequency envelope (Δf = f2 - f1) at the target depth. Unlike traditional stimulation methods, which affect only superficial brain regions, TIEFS can reach deeper structures without the need for implanted electrodes. The stimulation is applied through scalp electrodes. It has the potential for targeted brain interventions in both functional studies and clinical applications for neurological conditions.
Experimental: Comparison of Active vs Sham TIEFS Stimulation in Healthy Subjects; This arm involves a within-subject comparison of active and sham TIEFS stimulation in healthy control subjects. Participants will receive both active and sham stimulation in a single session, with different frequencies of TIEFS applied during active stimulation. The goal is to measure the changes in brain activity using EEG and assess the impact of TIEFS on cognitive functions such as memory, motor function, language, and perception. Participants will be blinded to the type of stimulation they are receiving during the session.	Device: Temporal Interference Electrical Stimulation; Temporal Interference Electrical Stimulation (TIEFS) is a non-invasive brain stimulation technique that uses two high-frequency electrical fields (>1 kHz) to generate an interference pattern at a specific brain region, creating a low-frequency envelope (Δf = f2 - f1) at the target depth. Unlike traditional stimulation methods, which affect only superficial brain regions, TIEFS can reach deeper structures without the need for implanted electrodes. The stimulation is applied through scalp electrodes. It has the potential for targeted brain interventions in both functional studies and clinical applications for neurological conditions.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Brain activity changes during Stimulation	This outcome measures the changes in brain activity, either measured through scalp EEG electrodes (in Healthy Participant controls), or intracranial stereotaxic EEG electrodes (for SEEG pre-surgical evaluation epilepsy patients). Local field potential (LFP) power and EEG power in response to active TIEFS stimulation will be compared to sham stimulation. Electrical signals recorded from the brain reflect neural activity. Intracranial signals will be measured across different locations in the brain using implanted SEEG electrodes. Additionally, SEEG electrodes may have tetrodes tips to capture single neuron activity. We will compare how the brain's electrical activity changes during active TIEFS at various frequencies and during the sham stimulation to assess the impact on brain and neural function.	Measurements will be recorded throughout the stimulation session (lasting up to 90 minutes), with data collected before, during, and immediately after each stimulation.

Collaborators and Investigators

• Sponsor: University of California, Davis
• Investigators: Principal Investigator: Nigel P Pedersen, MBBS, University of California Davis, School of Medicine, Neurology Department

Study record dates

Study Major Dates

• Study Start (Actual): April 16, 2025
• Primary Completion (Estimated): April 15, 2027
• Study Completion (Estimated): April 15, 2027

Study Registration Dates

• First Submitted: June 16, 2026
• First Submitted That Met QC Criteria: June 16, 2026
• First Posted (Actual): June 23, 2026

Study Record Updates

• Last Update Posted (Actual): June 23, 2026
• Last Update Submitted That Met QC Criteria: June 16, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: Brain Stimulation
• Additional Relevant MeSH Terms: Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Epilepsy
• Other Study ID Numbers: 2226959

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Upon publication, anonymized individual participant data (IPD) will be shared as part of the supplementary materials. The shared data will include EEG recordings, cognitive task results (memory, language, motor, perception), and stimulation parameters (active vs sham, frequencies). All IPD will be de-identified, with personal identifiers removed to ensure confidentiality and compliance with HIPAA. The de-identified data will be made available through a repository or data-sharing platform, accessible to qualified researchers for scientific and educational use only.

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.: No