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Completed

NCT Number: NCT06680154

Induction and Stabilization of Gamma Oscillations With 40 Hz External Brain Stimulation

The goal of the present studies is to develop and validate novel stimulation protocols for the entrainment of gamma oscillations, which are associated with many cognitive functions and critically involved in cognitive impairment such as Alzheimer's disease. In this proposal, combination of repetitive transcranial magnetic stimulation (rTMS) and transcranial alternating current stimulation (tACS), which has been shown effective for the induction, and stabilisation of alpha and theta frequencies in our forgoing studies, will be adopted to the gamma frequency range and applied on prefrontal regions as well as model-based cortical areas to enhance and stabilize gamma oscillations, thereby facilitating cognition

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Key information

Conditions

Alzheimer Disease Brain Diseases Central Nervous System Diseases Dementia EEG Brain Oscillations Mental Disorders Nervous System Diseases Neurocognitive Disorders Neurodegenerative Diseases Tauopathies Working Memory

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Leibniz-Institut für Arbeitsforschung

Dortmund, North Rhine-Westphalia, 44139, Germany

About this study

Neuropsychiatric disorders are a leading cause of global disability-adjusted life years, and treatment solutions are lacking. Recent findings suggest that non-invasive brain stimulation may be a valuable option in conditions such as epilepsy or Alzheimer's disease (AD). Still, a better understanding of mechanisms and patient-specific factors is needed. Personalized hybrid brain models uniting the physics of electromagnetism with physiology - NeuroTwins (NeTs) - are poised to play a fundamental role in understanding and optimizing the effects of stimulation at the individual level. The purpose of this project is to deliver solutions through model-driven, individualized therapy. A computational framework - weaved and validated across scales and levels of detail - will be proposed to represent the mechanisms of interaction of electric fields with brain networks and assimilate neuroimaging data. This will allow us to characterize the dynamical landscape of the individual brain and define strategies to restore healthy dynamics. The work package, which will take place at IfADo, is part of the consortium collaborating with labs across Europe and USA, aiming to validate and optimize the realistic hybrid brain models developed by NeTs. The targeted subject groups of the IfADo project will be healthy young and old participants. Non-invasive brain stimulation including repetitive transcranial magnetic stimulation and transcranial alternating current stimulation will be applied with electroencephalography, and magnetic resonance spectroscopy as outcome measures. The results are to be translated into a technology pipeline for the design of new personalized neuromodulation protocols which will further be tested in a cohort of AD patients by another clinical consortium member, delivering model-driven breakthroughs in basic and clinical neuroscience, with patients ultimately benefiting from safe, individualized therapy solutions.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • normal or corrected to normal eye vision
  • right-handed
  • non-smokers
  • being 18-60 years old
  • providing written informed consent

Exclusion criteria

  • history of neurological or psychiatric disorders including seizures or epilepsy,
  • Taking CNS medication
  • having metal implants
  • current pregnancy

Treatment and study plan

Transcranial Alternating Current Stimulation

Device

Transcranial alternating current was delivered utilizing a Starstim 8-channel constant current, battery-powered electric stimulator (Neuroelectrics, Barcelona, Spain). Circular carbon rubber electrodes (2cm radius, 12,57 cm2) were used throughout the stimulation. Before placing the electrodes on the head, the subject's hair was moved to the side

Theta Burst Stimulation

Device

the intermittent theta burst stimulation (iTBS) which is regarded as safe for high-frequency neuromodulation. Compared to classical rTMS, where pulses are applied repeatedly at a fixed frequency, iTBS consists of bursts of pulse triplets. In the classical protocol, the bursts are applied for two seconds in 5Hz intervals followed by an eight-second break, before the next bursts are applied. This pattern is repeated for 190 seconds resulting in 600 pulses per protocol.

Sham (No Treatment)

Device

In the case of sham TMS, two different sham coils (double 70mm pCool-SHAM coil, Mag&More GmbH, Munich, Germany) will produce audible clicks at the decibel intensity corresponding to an active coil without the induction of an electromagnetic pulse. Sham tACS will be applied by only ramping the current for 15 seconds up and 15 seconds down at the beginning and end of the stimulation respectively.

Primary outcomes

  1. Working Memory behavioral performance

    Time frame: During procedure (20 minutes)

    Participants view a continuous sequence of alphabet letters, presented as stimuli in Arial font, size 120pt, on a tube screen positioned at 60cm eye distance. The stimuli are shown with a time interval of two seconds between them. The task consisted of six blocks with 70 stimuli, including 12 possible hit trials. Participants were instructed to press the left key on a response box if the presented stimulus matched either the one presented one trial prior (1-Back) or three trials prior (3-Back). In all other cases, participants press the right key. The left button is pressed with the index finger, while the right button is pressed with the middle finger of the right hand, with buttons aligned horizontally. The response condition varied by block, with three blocks for 3-Back and three for 1-Back, and the order was counterbalanced across participants and sessions.

  2. electroencephalogram (EEG) oscillatory power

    Time frame: up to 2 hours after the intervention

    Change in the EEG power in alpha, delta, theta and beta bands

  3. electroencephalogram (EEG) functional connectivity

    Time frame: up to 2 hours after the intervention

    Change in EEG functional connectivity, specifically global efficiency, coherence, and phase-locking value.

Sponsors and collaborators

Lead sponsor

The National Brain Mapping Laboratory (NBML)

Other

Collaborators

  • Leibniz Research Centre for Working Environment and Human Factors

Registry information

Official study title

Gamma Oscillations and Working Memory Following Combined 40Hz tACS and iTBS

Important dates

Study start
2021
Primary completion
2023
Study completion
2023
First posted
Nov 8, 2024
Registry last updated
Mar 18, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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