Modulation of Working Memory by an Alternating Magnetic Field in Humans (MEMOCHAM)

Many studies have examined the effects of transcranial alternating current stimulation (tACS) on working memory, showing that low-intensity stimulation can enhance cognitive performance by modulating neuronal activity, particularly in the frontal cortex and the parietal lobule. Specific frequencies, such as the gamma frequency, have demonstrated beneficial effects on memory under high cognitive load. However, tACS has technical limitations, including uncomfortable sensations and uneven diffusion of electrical currents within the brain, which restrict its effectiveness in deeper brain regions.

Transcranial alternating magnetic stimulation (tAMS) is emerging as a potentially more precise and comfortable method. Unlike tACS, tAMS uses magnetic fields that penetrate more deeply into the brain and provide a more homogeneous distribution of induced electrical currents, allowing for more targeted stimulation. This study compares the effects of tACS and tAMS on working memory, with the hypothesis that tAMS will offer additional advantages in terms of comfort and efficacy. Cognitive performance will be assessed using working memory tasks, along with EEG signals to analyze neuronal modulations. The objective is to demonstrate that tAMS more effectively reaches deep brain regions and improves cognitive functions.

Study Overview

• Status: Not yet recruiting
• Conditions: Healthy
• Intervention / Treatment: Other: Electrical stimulation; Other: Magnetic stimulation; Other: No stimulation

• Study Type: Interventional
• Enrollment (Estimated): 102
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Alice Bourdon, Dr; Phone Number: +33 6 95 25 13 98; Email: alice.bourdon@hotmail.com

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Written, voluntary, and informed consent to participate in the study
• Fluent French speaker (task instructions are provided in French)
• Normal or corrected-to-normal vision using contact lenses only

Non inclusion Criteria:

• Individuals deprived of liberty by law
• Individuals under legal guardianship or curatorship
• Pregnant or breastfeeding women
• Presence of metallic implants in the head, implanted electronic devices, or any other metallic object that cannot be removed for the experiment (e.g. dental fillings)
• History of neurological or psychiatric disorders according to the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition)
• History of pathology or chronic disease affecting memory or attention
• Drug or alcohol consumption within the previous 24 hours

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

5

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Sham Comparator: No stimulation	Other: No stimulation; The experimental session lasts 2 hours and 30 minutes and includes four time points: Time 0, dedicated to training and adjustment of task difficulty, followed by Time 1, Time 2, and Time 3, corresponding respectively to assessments of working memory performance before, during, and after exposure to sham stimulation. Each time point includes blocks of the Sternberg task, for a total of 180 trials per session. Each block lasts 10 minutes.
Experimental: 40 Hz tACS stimulation	Other: Electrical stimulation; The experimental session lasts 2 hours and 30 minutes and includes four phases: Time 0, dedicated to training and adjustment of task difficulty, followed by Time 1, Time 2, and Time 3, corresponding respectively to assessments of working memory performance before, during, and after exposure to stimulation. Each phase includes blocks of the Sternberg task, for a total of 180 trials per session. Each block lasts 10 minutes.
Experimental: 60 Hz tACS stimulation	Other: Electrical stimulation; The experimental session lasts 2 hours and 30 minutes and includes four phases: Time 0, dedicated to training and adjustment of task difficulty, followed by Time 1, Time 2, and Time 3, corresponding respectively to assessments of working memory performance before, during, and after exposure to stimulation. Each phase includes blocks of the Sternberg task, for a total of 180 trials per session. Each block lasts 10 minutes.
Experimental: 40 Hz tAMS stimulation	Other: Magnetic stimulation; The experimental session lasts 2 hours and 30 minutes and includes four time points: Time 0, dedicated to training and adjustment of task difficulty, followed by Time 1, Time 2, and Time 3, corresponding respectively to assessments of working memory performance before, during, and after exposure to stimulation. Each time point includes blocks of the Sternberg task, for a total of 180 trials per session. Each block lasts 10 minutes.
Experimental: 60 Hz tAMS stimulation	Other: Magnetic stimulation; The experimental session lasts 2 hours and 30 minutes and includes four time points: Time 0, dedicated to training and adjustment of task difficulty, followed by Time 1, Time 2, and Time 3, corresponding respectively to assessments of working memory performance before, during, and after exposure to stimulation. Each time point includes blocks of the Sternberg task, for a total of 180 trials per session. Each block lasts 10 minutes.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sternberg task	During each trial, participants memorize a sequence of eight letters presented sequentially. They are then shown a probe letter displayed in blue and must indicate whether this letter was part of the memorized sequence. Participant performance will be evaluated based on two behavioral measures: accuracy (proportions of correct and incorrect responses) and reaction time in milliseconds.	Baseline (Day 1, before exposure), periprocedural (Day 1, during exposure), and post-intervention (Day 1, immediately after exposure)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
EEG Power Outcomes	Absolute power of EEG frequency bands will be measured using power spectral density analysis to quantify the energy within each frequency band associated with working memory.	Baseline (Day 1, before exposure), periprocedural (Day 1, during exposure), and post-intervention (Day 1, immediately after exposure)
EEG Power Outcomes	Relative power of EEG frequency bands will be calculated as the proportion of power in each frequency band relative to the total EEG signal power.	Baseline (Day 1, before exposure), periprocedural (Day 1, during exposure), and post-intervention (Day 1, immediately after exposure)
EEG Power Outcomes	Mean frequency of the EEG signal will be calculated from the power spectral density to characterize frequency distribution related to working memory processes.	Baseline (Day 1, before exposure), periprocedural (Day 1, during exposure), and post-intervention (Day 1, immediately after exposure)
EEG Power Outcomes	Median frequency of the EEG signal will be derived from the power spectral density as an indicator of the central tendency of EEG frequency content.	Baseline (Day 1, before exposure), periprocedural (Day 1, during exposure), and post-intervention (Day 1, immediately after exposure)
EEG Power Outcomes	Peak power frequency of the EEG signal will be identified as the frequency at which maximum power occurs.	Baseline (Day 1, before exposure), periprocedural (Day 1, during exposure), and post-intervention (Day 1, immediately after exposure)
EEG Signal Regularity Outcomes (RQA)	Recurrence rate derived from recurrence quantification analysis will be used to quantify the proportion of recurrent patterns in the EEG signal.	Baseline (Day 1, before exposure), periprocedural (Day 1, during exposure), and post-intervention (Day 1, immediately after exposure)
EEG Signal Regularity Outcomes (RQA)	Determinism derived from recurrence quantification analysis will be used to assess the temporal organization and regularity of EEG signal dynamics.	Baseline (Day 1, before exposure), periprocedural (Day 1, during exposure), and post-intervention (Day 1, immediately after exposure)
Neuropsychological data	Score from the Multidimensional Fatigue Inventory (MFI-20) will be used to assess fatigue. The Multidimensional Fatigue Inventory is a self-reported questionnaire with total scores ranging from 20 to 100. Higher scores reflect higher levels of fatigue.	Baseline (Day 1, before exposure)
Neuropsychological data	Score from the State-Trait Anxiety Inventory (STAI) will be used to assess anxiety. The State-Trait Anxiety Inventory is a self-reported questionnaire with scores ranging from 20 to 80. Higher scores reflect higher levels of anxiety.	Baseline (Day 1, before exposure)

Collaborators and Investigators

• Sponsor: Clinique Beau Soleil

Study record dates

Study Major Dates

• Study Start (Estimated): April 1, 2026
• Primary Completion (Estimated): April 1, 2028
• Study Completion (Estimated): September 1, 2028

Study Registration Dates

• First Submitted: December 8, 2025
• First Submitted That Met QC Criteria: February 2, 2026
• First Posted (Actual): February 10, 2026

Study Record Updates

• Last Update Posted (Actual): March 17, 2026
• Last Update Submitted That Met QC Criteria: March 16, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Investigative Techniques; Physical Stimulation; Electric Stimulation
• Other Study ID Numbers: 2025-A00296-43

Drug and device information, study documents

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