Understanding Non-invasive Vagus Nerve Stimulation Effects in PTSD
Trial statusNot yet recruiting
Trial phaseEarly Phase 1
Trial typeInterventional
Biological sexAll
Age18-80
SponsorWayne State University
About this trial
The goal of this study is to determine how non-invasive brain stimulation (delivered through the ear called vagus nerve stimulation) affects fear learning processes in people who have experienced psychological trauma. To answer these questions, we measure bodily responses (heart rate, sweat, startle) and questionnaires. The main questions it aims to answer are:
Does non-invasive vagus nerve stimulation help reduce anxious arousal? Does non-invasive vagus nerve stimulation help dampen learned fear?
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
Ages 18-80
Fluent in English
Experience with a DSM-5 Criterion A trauma (LEC-5)
Probable PTSD (PCL-5 ≥ 32)
Disqualifiers
Visual or Auditory impairment
Major injury at time of screen or study procedures
Taking ≥20 mg morphine per day
Current substance use or intoxication (12-panel drug test)
Trial design
Design model
Crossover
Treatments tested in this trial
transcutaneous auricular vagus nerve stimulation
DeviceFDA-cleared Digitimer DS7A Constant Current Stimulator (Digitimer Ltd., USA) will deliver electrical stimulation for 60 mins. Active stimulation will consist of direct electrical stimulation to the inner side of the left tragus (anode on the cymba concha, cathode on the surface of the tragus), thereby stimulating the ABVN. Stimulation parameters will consist of 500μs pulse width, 25Hz frequency, delivered at 200% of each participant's individual perceptual threshold (PT) in 60sec on/off trains.
sham transcutaneous auricular vagus nerve stimulation
DeviceFDA-cleared Digitimer DS7A Constant Current Stimulator (Digitimer Ltd., USA) will deliver electrical stimulation for 60 mins. Sham will be delivered to the ear lobe. Stimulation parameters will consist of 500μs pulse width, 25Hz frequency, delivered at 200% of each participant's individual perceptual threshold (PT) in 60sec on/off trains.
Treatment groups
60 Participants
are divided into 2 treatment groupsGroup A: Active taVNSExperimental treatment 1 intervention
Group B: Sham taVNSSham comparator 1 intervention
Trial outcomes
Primary outcomes
1
Fear potentiated startle (FPS)
FPS modulation, an objective behavioral indicator of defensive reactivity, is measured during acquisition and extinction, collected using electromyogram (EMG) of the right orbicularis oculi muscle with the EMG module of the Biopac MP160 for Windows.
Time frame
From enrollment to the end of the cross over visit at week 2Secondary outcomes
1
Skin Conductance (SC)
SC is measured using the electrodermal activity (EDA) module of the Biopac system. Two disposable pre-gelled Ag/AgCl electrodes are placed on the hypothenar surface of the non-dominant hand. SCR is defined as the increase from SC during a 1s pre-CS+ onset baseline to SC during the 3-6s post-CS+ onset.
Time frame
From enrollment to the end of the cross over visit at week 22
Heart Rate (HR)
HR is acquired via electrocardiogram (ECG) Biopac module. Three disposable pre-gelled Ag/AgCl electrodes are used: one each on the right and left sides of the torso, 1cm below the clavicle, and a third on the inside of the left wrist. The HR response is defined as the increase in HR from a 1m baseline prior to the first airblast to 1m after first airblast.
Time frame
From enrollment to the end of the cross over visit at week 23
Unconditioned Stimulus Expectancy Ratings
Identification of threat/conditioned stimulus with reinforcement (CS+) and safety/conditioned stimulus without reinforcement (CS-) is used to assess US expectancy during fear acquisition and extinction, consistent with mentors', Jovanovic and Norrholm's, research. Individuals respond on a keypad (Cedrus, Inc.) after each trial regarding CS-US contingencies. Responses consist of 3 button presses (Yes, No, I don't know) for whether participants believe a shape (CS+/CS-) will be followed by the US.
Time frame
From enrollment to the end of the cross over visit at week 24
Subjective Units of Distress (SUDS)
SUDS is recorded pre- and post- fear acquisition and extinction, and at baseline and recovery. Arousal measures will be evaluated individually and in combination to determine multivariate effects. SUDS and objective responses will be monitored, as investigations show discordance within and between objective and subjective measures of distress. SUDS are on a scale of 0 (no anxiety/distress, calm and relaxed) to 100 (extreme anxiety/distress, worst ever experienced).
Time frame
From enrollment to the end of the cross over visit at week 2Sponsors and contacts
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Source ClinicalTrials.gov
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