Transcutaneous Auricular Vagus Nerve Stimulation Effects on Attention and Working Memory: A Pilot Study
Trial Snapshot
- Phase
- Not Applicable
- Status
- Recruiting
- Sponsor
- Baylor College of Medicine
- Enrollment
- 30
- Locations
- 3
- Primary Endpoint
- Attention and working memory
Study Overview
Brief Summary
This clinical trial aims to evaluate whether transcutaneous auricular vagus nerve stimulation (taVNS), a non-invasive brain stimulation method, can improve attention and memory in veterans with traumatic brain injury (TBI) and depression and/or posttraumatic stress disorder (PTSD). The study seeks to answer two main questions:
- Can active taVNS improve attention and memory compared to sham (placebo) stimulation?
- Does taVNS affect heart rate variability (HRV)?
taVNS delivers a gentle electrical current to the vagus nerve through electrodes placed on the ear, targeting brain areas involved in attention and memory without requiring surgery.
This study uses a crossover design, meaning all participants will experience two sessions: one with active taVNS and one with sham stimulation. The sham session feels similar but does not deliver actual stimulation, allowing researchers to compare the two and understand taVNS's effects on the brain.
In a single visit, participants will:
- Complete eligibility screening (questionnaires and vital signs).
- Undergo two sessions (one active and one sham), randomly assigned.
- Perform attention tasks before and after each session.
- Have their heart rate monitored during the sessions.
The findings will help determine whether taVNS could be an effective treatment for improving attention and memory in veterans with TBI.
Detailed Description
Attention and memory problems are common in veterans with traumatic brain injuries (TBI), particularly when accompanied by depression and/or posttraumatic stress disorder (PTSD). Current treatments for these issues often have limited effectiveness or unwanted side effects. Transcutaneous auricular vagus nerve stimulation (taVNS) is a non-invasive technique that uses gentle electrical impulses delivered through electrodes placed on the ear. This stimulation targets the vagus nerve, which plays a key role in regulating brain areas involved in attention and memory. By enhancing the activity of these brain regions, taVNS shows potential as a novel treatment option for improving cognitive functions like attention and memory.
In this study, researchers aim to determine whether taVNS can enhance attention and memory in veterans with TBI. Participants will complete a single study visit lasting 2.5 to 3 hours. The visit includes two taVNS sessions, one active and one sham (placebo), to compare their effects. Sham stimulation mimics the sensation of taVNS but does not deliver electrical current to the vagus nerve. This design allows researchers to isolate the specific effects of taVNS.
Procedures:
- Screening (40 minutes):
Participants will begin by completing questionnaires about their medical history, memory concerns, alcohol and substance use, mood, and demographics. Vital signs (heart rate, blood pressure, and temperature) will also be measured to confirm eligibility. 2. Session 1 (approximately 40 minutes):
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Treatment
- Masking
- Single (Participant)
Eligibility Criteria
- Ages
- 25 Years to 64 Years (Adult)
- Sex
- All
- Accepts Healthy Volunteers
- No
Inclusion Criteria
- •Ages 25-64
- •Right-handedness
- •Veterans with a history of deployment to Operation Iraqi Freedom (OIF), Operation Enduring Freedom (OEF), Operation New Dawn (OND) or other post 9/11 war on terrorism
- •History of PTSD and/or depression
- •Military related mild traumatic brain injury
- •If taking psychotropic medication, demonstrate stability for 3 months
- •If taking stimulants, washout period of 12 hours
Exclusion Criteria
- •History of neurological, cardiovascular, or pulmonary disease
- •Cardiac arrhythmia (all types)
- •Active suicidal ideation
- •Visible wounds on skin of the left ear
- •Medical implants such as cardiac defibrillators, pacemakers, or deep brain stimulators
- •Pregnancy
- •Completed taVNS in the past 4 weeks
- •Current substance use disorder (exception: mild cannabis use disorder allowed)
- •Current moderate or severe alcohol use disorder
- •Major cognitive disorder
Arms & Interventions
taVNS active stimulation
Participants will receive transcutaneous auricular vagus nerve stimulation (taVNS) using electrodes placed on the left ear. A low-level electrical current will be delivered to stimulate the vagus nerve. This stimulation is designed to activate brain areas involved in attention and memory.
Intervention: Transcutaneous vagus nerve stimulation for attention in veterans with TBI (Other)
taVNS active stimulation
Participants will receive transcutaneous auricular vagus nerve stimulation (taVNS) using electrodes placed on the left ear. A low-level electrical current will be delivered to stimulate the vagus nerve. This stimulation is designed to activate brain areas involved in attention and memory.
Intervention: Soterix Medical Vagus Nerve Stimulation mini-CT (Device)
Sham (Placebo) taVNS
Participants will undergo sham stimulation, where electrodes are placed on the left ear to mimic the experience of active taVNS. However, no electrical current will be delivered to the vagus nerve. This sham condition enables a direct comparison with active taVNS, ensuring that any observed changes in working memory and attention can be attributed to the taVNS intervention.
Intervention: Transcutaneous vagus nerve stimulation for attention in veterans with TBI (Other)
Sham (Placebo) taVNS
Participants will undergo sham stimulation, where electrodes are placed on the left ear to mimic the experience of active taVNS. However, no electrical current will be delivered to the vagus nerve. This sham condition enables a direct comparison with active taVNS, ensuring that any observed changes in working memory and attention can be attributed to the taVNS intervention.
Intervention: Soterix Medical Vagus Nerve Stimulation mini-CT (Device)
Outcomes
Primary Outcomes
Attention and working memory
Time Frame: One day, one visit
Aim 1: To evaluate the effects of transcutaneous auricular vagus nerve stimulation (taVNS) on sustained attention and working memory. Attention and memory performance will be assessed using the Gradual Onset Continuous Performance Task (gradCPT), a validated computerized test that measures the ability to sustain attention and respond selectively to relevant stimuli. This cognitive test measures sustained attention and inhibitory control. During the test, subjects view a continuous stream of gradually fading images of cities and mountains on a computer screen. They are instructed to press the space bar when they see a city (target stimulus) and withhold responses when they see a mountain (non-target stimulus). Key performance metrics which collectively assess attention and working memory in this test include mean reaction time (response speed), omission errors (failure to respond to targets), and commission errors (responses to non-targets).
Secondary Outcomes
- Heart-rate variability(One day, one visit)
Investigators
Ricardo Jorge, MD
Professor
Baylor College of Medicine