Stress Response
Conditions
Keywords
transcutaneous vagus nerve stimulation tVNS, stress regulation state anxiety , Trier Social Stress Test, performance
Brief summary
This study examines how individuals respond to performance-related tasks and whether a non-invasive ear stimulation device influences stress responses during those tasks. Participants will be randomly assigned to use either an active or inactive (placebo) version of a transcutaneous vagus nerve stimulation (tVNS) device during a laboratory session. The study includes two task conditions. In one condition, participants will prepare a brief speech under evaluative conditions designed to induce stress. In the other condition, participants will complete a non-evaluative writing task. During the session, participants will wear a heart rate monitor and complete short questionnaires assessing their current feelings, including state anxiety. The primary objective is to determine whether active tVNS is associated with lower state anxiety during a performance-related stress task compared to placebo stimulation. Secondary outcomes include heart rate and task-related responses. The study will also examine whether individual differences in stress reactivity influence responses to stimulation. Participation involves one laboratory session lasting approximately 45 minutes.
Detailed description
This study is a laboratory-based, randomized, double-blind experiment designed to examine whether non-invasive transcutaneous vagus nerve stimulation (tVNS) influences state anxiety and physiological arousal during performance-related stress. Participants will be randomly assigned to one of four conditions in a 2 × 2 between-subjects factorial design: Device Condition: Active tVNS Placebo (inactive) tVNS Task Condition: Stress Task (Modified Trier Social Stress Test speech preparation) Control Task (Non-evaluative writing task) The device condition is double blind. Half of the devices are configured by the manufacturer to deliver active stimulation to the auricular branch of the vagus nerve via the left ear. The remaining devices are configured to deliver brief initial stimulation that ramps down to zero (placebo condition). Neither participants nor experimenters are aware of device assignment during the session. After informed consent and baseline measures, participants complete a quiet baseline period during which heart rate and state anxiety are assessed. Participants then wear the tVNS device during structured laboratory tasks. In the stress condition, participants are instructed to prepare a five-minute speech to be delivered before evaluators and recorded for assessment. The preparation phase is modeled after the Trier Social Stress Test and is designed to induce anticipatory evaluative stress. The speech is not ultimately delivered. State anxiety and heart rate are measured during preparation and immediately afterward. In the control condition, participants complete a non-evaluative writing task on the same topic without evaluative framing. Physiological and self-report measures are collected at matched time points. The primary outcome measure is state anxiety assessed using the short-form State-Trait Anxiety Inventory (STAI). Secondary outcomes include heart rate measured during baseline, task preparation, and recovery periods. Additional measures include dispositional stress reactivity, which will be examined as a potential moderator of stimulation effects. The study is designed to determine whether active tVNS reduces subjective anxiety and physiological arousal during evaluative stress compared to placebo stimulation and to assess whether effects differ as a function of individual differences in stress reactivity. Participation consists of a single laboratory session lasting approximately 45 minutes.
Interventions
Transcutaneous vagus nerve stimulation delivered via an auricular stimulation device. Participants receive either active stimulation or sham stimulation depending on random assignment
Participants complete either an evaluative stress-induction task involving social evaluation or a non-evaluative control task. Task condition is assigned as part of the factorial design.
Sponsors
Study design
Masking description
Participants are blinded to device condition (active vs sham stimulation). Study personnel interacting with participants and collecting outcome data are blinded to condition assignment. Devices are pre-programmed and coded to maintain masking throughout the study.
Intervention model description
Participants are randomly assigned in a 2 × 2 between-subjects factorial design crossing device condition (active vs placebo transcutaneous vagus nerve stimulation) and task condition (evaluative stress task vs non-evaluative control task).
Eligibility
Inclusion criteria
\- Adults aged 18 to 65 years Fluent in English Able to provide informed consent Able to complete study procedures during a single laboratory session
Exclusion criteria
\- History of neurological or psychiatric disorders Cardiovascular disease or uncontrolled hypertension Implanted electrical devices (e.g., pacemaker) Current pregnancy Contraindications to transcutaneous vagus nerve stimulation (tVNS) Current use of medications that significantly affect autonomic nervous system functioning
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Self-Reported Stress | Baseline (pre-task) and immediately post-task during a single laboratory session. | Self-reported stress assessed using a questionnaire/scale administered before and after the performance task to capture changes in perceived stress during the laboratory session. |
Countries
United States
Contacts
University of Florida
University of Florida