Vagus Nerve Stimulation to Enhance Memory in Aging

The aim of this study is to determine whether non-invasive vagus nerve stimulation enhances memory formation in cognitively healthy older adults and whether the effects of stimulation depend on gut and brain health.

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Key information

Conditions

Alzheimer Disease Aging Brain Diseases Central Nervous System Diseases Dementia Mental Disorders Nervous System Diseases Neurocognitive Disorders Neurodegenerative Diseases Tauopathies

Age range

18 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Stanford University

Stanford, California, 94305, United States

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

Ages 18-30 years or 65-80 years
Normal or corrected-to-normal vision (visual acuity)
Fluent in English

Exclusion criteria

Pregnant
Symptoms of memory loss
History of a neurological, psychiatric, or medical condition that could affect cognition or preclude MRI or pupillometry
Use of medications known to alter cognition
For older adults, neuropsychological performance that falls outside 1.5 standard deviations of age-adjusted norms and no self-reported memory or attention complaints

Treatment and study plan

Transcutaneous Auricular Vagus Nerve Stimulation (taVNS)

Device

Non-invasive vagus nerve stimulation will be delivered with a well-validated device. taVNS delivers stimulation on the left ear, with the placement of the stimulating electrode differing between the active and sham conditions. Stimulation will occur during each learning trial (total of 30 trials per phase).

Primary outcomes

Change in Recognition Memory (d-prime)

Time frame: post-active vs post-sham stimulation; up to 2 hours of task

d' is a signal-detection sensitivity index-how well participants discriminate old (studied) from new (unstudied) items, independent of response bias. Computed as d' = Z(hit rate) - Z(false-alarm rate) from the old/new recognition memory test. Primary analysis is within-person Δhigh-confidence d' (based on "sure old" responses in the 4-point "sure old", "unsure old", "unsure new", "sure new" scale, Δ = active - sham) and Δoverall d' (based on "sure old" and "unsure old" responses). Main comparison is older vs. young, and within the older group also testing moderation by gut-brain axis measures and interactions with preclinical Alzheimer's disease pathology (pTau217, pTau181, Aβ42:40).

Sponsors and collaborators

Lead sponsor

Stanford University

Other

Collaborators

National Institute on Aging (NIA)

Registry information

Acronym: VNS

Important dates

Study start: 2027
Primary completion: 2028
Study completion: 2028
First posted: Oct 9, 2025
Registry last updated: Oct 9, 2025

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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