Effects of Transcutaneous Auricular Vagus Nerve Stimulation on Cognitive Performance and Sex Differences

Официальное название

A Sham-Controlled Cross-Over Study Examining the Effects of Transcutaneous Auricular Vagus Nerve Stimulation (taVNS) on Cognitive Performance and Gender Differences in Healthy Adults

Обзор

This study investigates the effects of transcutaneous auricular vagus nerve stimulation (taVNS) on cognitive performance in healthy adults. The study uses a sham-controlled, cross-over design in which each participant receives both active taVNS and sham stimulation in separate sessions. Each participant completes both conditions (active and sham) in a randomized order using a crossover design. Cognitive performance will be assessed before and after each session using standardized tests. The study also explores whether males and females respond differently to taVNS, in order to identify potential sex-related differences in cognitive outcomes.

Подробное описание

This randomized, sham-controlled cross-over study investigates the effects of transcutaneous auricular vagus nerve stimulation (taVNS) on cognitive performance, autonomic activity, and psychological state in healthy young adults, with specific attention to sex differences. Because hormonal fluctuations may influence vagal tone and cognitive outcomes, female participants are required to complete their stimulation sessions during the follicular phase (Day 5-10) of the menstrual cycle. Male participants follow the same protocol without timing restrictions.

The study consists of three laboratory visits, scheduled one week apart.

Visit 1 (Baseline Assessments):

Participants provide informed consent and complete a demographic questionnaire, menstrual-cycle verification (for female participants), the Montreal Cognitive Assessment (MoCA), and baseline psychological questionnaires including the State-Trait Anxiety Inventory (STAI) and the Perceived Stress Scale (PSS). Baseline cognitive performance is measured using the CogniFit digital battery.

Visits 2 and 3 (Randomized Cross-Over Stimulation Sessions):

Participants undergo active taVNS and sham stimulation in randomized order. At the beginning of each visit, heart rate variability (HRV) is recorded for 5 minutes before stimulation to establish a resting baseline. Stimulation is applied for 20 minutes using the VaguStim device. Immediately after stimulation, HRV is recorded again for 5 additional minutes, followed by completion of a side-effect questionnaire documenting any sensations or adverse reactions. Following that, participants complete the STAI and PSS questionnaires to assess post-stimulation psychological state.Cognitive performance is then reassessed using the CogniFit digital battery.

This cross-over design enables within-subject comparison between active and sham stimulation and provides the structure needed to examine potential sex-related differences in autonomic, cognitive, and psychological responses to taVNS.

Вмешательства

• Устройство Active taVNS
  Active taVNS will be delivered bilaterally to the cymba conchae and tragus regions using the VaguStim device. Stimulation parameters follow cognitive-neuroscience standards to minimize cardiac side effects: biphasic waveform, 25 Hz frequency, 250 μs pulse width, and intensity individually adjusted below the sensory threshold (0.5-4 mA). Each stimulation session lasts 20 minutes. This intervention corresponds to the Active taVNS Stimulation arm.
• Устройство Sham Stimulation
  Sham stimulation will be delivered using the same VaguStim device, but electrodes will be placed bilaterally on the earlobe, an area not innervated by the vagus nerve. Device parameters will be set to match the active condition, but no true vagus nerve stimulation is delivered. This procedure controls for placebo and participant expectancy effects. This intervention corresponds to the Sham Stimulation arm.

Первичные конечные точки

• CogniFit Digital Battery [Срок оценки: Day 1 (Visit 1 baseline), Day 8 (Visit 2), and Day 15 (Visit 3) Cognitive testing will occur after stimulation on Day 8 and Day 15.]

Вторичные конечные точки (4)

• Heart Rate Variability (HRV) [Срок оценки: Day 8 (Visit 2): 5 minutes before stimulation and 5 minutes after stimulation. Day 15 (Visit 3): 5 minutes before stimulation and 5 minutes after stimulation.]
• Perceived Stress Levels (PSS) [Срок оценки: Day 1 (Visit 1 baseline), Day 8 (Visit 2 after stimulation), and Day 15 (Visit 3 after stimulation).]
• State and Trait Anxiety (STAI) [Срок оценки: Day 1 (Visit 1 baseline), Day 8 (Visit 2 after stimulation), and Day 15 (Visit 3 after stimulation).]
• Self-Reported Side Effects [Срок оценки: Day 8 (Visit 2 after stimulation) and Day 15 (Visit 3 after stimulation)]

Критерии участия

Критерии включения

• Healthy young adults aged 18-30 years
• Ability to provide informed consent
• Right-handed participants (to reduce variability in cognitive performance)
• Normal or corrected-to-normal vision and hearing
• Female participants tested during the follicular phase of the menstrual cycle (days 5-10) to minimize hormonal effects on cognition and vagal tone

Критерии исключения

• History of neurological or psychiatric disorders
• Cardiovascular disease
• Use of psychoactive medications
• Substance dependence, including alcohol, illicit drugs, or nicotine
• Pregnancy or breastfeeding
• Skin conditions or ear anomalies that interfere with electrode placement
• Metal implants in the head or neck region
• History of epilepsy or migraine

Критерии приведены из реестра в оригинале (на английском). Окончательную оценку соответствия проводит исследовательский центр.

Здоровые добровольцы: Да

Дизайн исследования

Распределение

Рандомизированное

Модель

Перекрёстный дизайн

Маскирование

Двойное слепое

Основная цель

Фундаментальное исследование

Центры проведения

Список центров уточняется — проверьте первичный протокол.

Идентификаторы

NCT: NCT07256080 · 61351342/020-93

Первоисточники (государственные реестры)

• ClinicalTrials.gov (NIH, США)

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