Electrical Nerve Stimulation During Sleep for Memory Consolidation

NCT07658274 | Recruiting

• 1 other identifier: 20260615
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

The purpose of this study is to investigate the effects of transcutaneous electrical nerve stimulation (eTNS) applied during sleep on memory consolidation and brain-body physiological coupling. Healthy college students will participate in four overnight sleep sessions in a standard sleep laboratory. Before going to sleep, participants will learn and complete two cognitive tasks: a motor sequence tapping task to assess procedural memory, and an N-back task to assess working memory. During the night, participants will receive either 2 Hz eTNS, 120 Hz eTNS, or a sham (placebo) stimulation on their forehead in a randomized order. Throughout the night, researchers will record their sleep using polysomnography (PSG), along with continuous monitoring of heart rate (ECG) and breathing (respiration). Upon waking the next morning, participants will be re-tested on both memory tasks. The primary objective is to determine whether eTNS during sleep can improve behavioral performance on procedural and working memory tasks overnight. Secondary objectives include analyzing the stimulation's effects on specific sleep brain wave patterns (such as slow oscillations and sleep spindles) and exploring the coupling mechanisms between brain activity, heart rhythms (Heartbeat Evoked Potentials), and respiration during sleep.

Conditions

Healthy Volunteers (HV)

Keywords

Transcutaneous Electrical Nerve Stimulation; eTNS; Procedural Memory; Working Memory; Slow Oscillations; Sleep Spindles; Heartbeat Evoked Potentials; Polysomnography

Outcome Measures

Primary Outcomes (1)

• Change in Procedural Memory Performance

  Procedural memory consolidation will be assessed using the classic sequential finger-tapping task (SFTT). Performance improvement is calculated as the difference in speed (number of correct sequences typed) and accuracy between the pre-sleep training/testing session and the post-sleep testing session. A larger positive difference indicates better procedural memory consolidation overnight.

  Assessed pre-sleep (approx. 21:00-22:00) and post-sleep (approx. 07:00-08:00 the following morning), representing an overnight interval of approximately 10 hours.

Secondary Outcomes (2)

• Change in Working Memory Performance

  Assessed pre-sleep (approx. 21:00-22:00) and post-sleep (approx. 07:00-08:00 the following morning), representing an overnight interval of approximately 10 hours.

• Sleep Architecture and Sleep Efficiency

  Continuously recorded during the 8-hour nighttime sleep period.

Other Outcomes (5)

• Sleep Slow Oscillation (SO) Density and Amplitude

  Continuously recorded during the 8-hour nighttime sleep period (from lights out at 23:00 to waking up between 07:00 and 08:00).

• Sleep Spindle Density and Amplitude

  Continuously recorded during the 8-hour nighttime sleep period.

• Slow Oscillation-Spindle Coupling

  Continuously recorded during the 8-hour nighttime sleep period.

Study Arms (3)

120 Hz Transcutaneous Electrical Nerve Stimulation

EXPERIMENTAL

Device: 120 Hz Transcutaneous Electrical Nerve Stimulation

2 Hz Transcutaneous Electrical Nerve Stimulation

EXPERIMENTAL

Device: 2 Hz Transcutaneous Electrical Nerve Stimulation

Sham Stimulation (Placebo)

PLACEBO COMPARATOR

Device: Sham Stimulation (Placebo)

Interventions

120 Hz Transcutaneous Electrical Nerve Stimulation DEVICE

Participants will receive 120 Hz transcutaneous electrical nerve stimulation (eTNS) during nighttime sleep. The stimulation is delivered via a current source stimulator connected to self-adhesive silicone electrodes placed above the left and right eyebrows. The stimulation consists of biphasic rectangular pulses with a 250 μs pulse width at a frequency of 120 Hz. It is delivered in continuous cycles of 30 seconds on and 30 seconds off. Before sleep, the current intensity is individually titrated to elicit a mild tingling sensation (corresponding to a score of 3-4 on a numerical rating scale) that will not disrupt the participant's sleep. The stimulation protocol automatically terminates after a duration of 8 hours.

120 Hz Transcutaneous Electrical Nerve Stimulation

2 Hz Transcutaneous Electrical Nerve Stimulation DEVICE

Participants will receive 2 Hz transcutaneous electrical nerve stimulation (eTNS) during nighttime sleep. The stimulation is delivered via a current source stimulator connected to self-adhesive silicone electrodes placed above the left and right eyebrows. The stimulation consists of biphasic rectangular pulses with a 250 μs pulse width at a frequency of 2 Hz. It is delivered in continuous cycles of 30 seconds on and 30 seconds off. Before sleep, the current intensity is individually titrated to elicit a mild tingling sensation (corresponding to a score of 3-4 on a numerical rating scale) that will not disrupt the participant's sleep. The stimulation protocol automatically terminates after a duration of 8 hours.

2 Hz Transcutaneous Electrical Nerve Stimulation

Sham Stimulation (Placebo) DEVICE

Participants will receive a sham stimulation designed to serve as a placebo control. The equipment setup, including the placement of self-adhesive silicone electrodes above the left and right eyebrows, is identical to the active eTNS conditions. The current intensity is initially adjusted before sleep to elicit the same mild tingling sensation (a score of 3-4 on a numerical rating scale). However, to maintain double-blinding without providing a therapeutic dose, the stimulator only delivers current output during the first 2 minutes of the night (i.e., exactly two cycles of 30 seconds on and 30 seconds off). After these initial 2 minutes, the current output ceases entirely for the remainder of the 8-hour sleep period.

Sham Stimulation (Placebo)

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Healthy young adults (e.g., college students), aged generally between 18 and 30 years.
• Right-handed.
• Body Mass Index (BMI) ≤ 30 kg/m\^2.
• Capable of fully comprehending the experimental procedures and voluntarily signing the informed consent form.

You may not qualify if:

• History or current presence of neurological disorders, psychiatric disorders, or brain damage.
• History or current presence of cardiovascular diseases (e.g., arrhythmias or abnormal nocturnal heart rate).
• Presence of depressive or anxiety symptoms (assessed by Patient Health Questionnaire-9 \[PHQ-9\] score \> 9, or Generalized Anxiety Disorder-7 \[GAD-7\] score \> 9).
• Presence of sleep disturbances or poor sleep quality (assessed by Insomnia Severity Index \[ISI\] score \> 8, or Pittsburgh Sleep Quality Index \[PSQI\] score \> 10).
• Any medication use within the past six months that could affect stress responses, cognitive abilities, or sleep architecture.
• History of smoking or alcohol abuse.
• Known skin allergies to conductive paste, medical tape, or silicone electrodes.
• Female participants who are in their menstrual period during the scheduled experimental sessions (sessions must be strategically scheduled to avoid this period).
• Inability or refusal to abstain from caffeine, tea, and alcohol for at least 24 hours prior to and during the experimental sessions.

Sponsors & Collaborators

• Xidian University: lead

Study Sites (1)

Xidian University

Xi'an, Shaanxi, 71000, China

RECRUITING

Central Study Contacts

Xue-Juan Yang

CONTACT

13227038185; xjyang@xidian.edu.cn

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: June 14, 2026
• First Posted: June 18, 2026
• Study Start: June 16, 2026
• Primary Completion: July 30, 2026
• Study Completion: July 31, 2026
• Last Updated: June 24, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

CN (1)