Mechanisms of Sympathetic Overactivity in Post-traumatic Stress Disorder
Emory University
Summary
Post-traumatic stress disorder (PTSD) is a highly prevalent anxiety disorder that is associated with an increased risk of cardiovascular (CV) disease and hypertension. One potential mechanism is overactivation of the sympathetic nervous system (SNS), both at rest and particularly during stress. This study will evaluate whether 8 weeks of daily DGB therapy or transcutaneous vagus nerve stimulation (tVNS) therapy improves SNS activity at rest and during stress.
Description
PTSD is highly prevalent in both the military and general population. Because of the tremendous deleterious mental health and socioeconomic impact of PTSD, research to understand and treat all aspects of PTSD is vitally important. One less recognized but highly significant consequence of PTSD is an increased risk of hypertension, cardiovascular disease (CV) disease, and its risk factors. Despite the epidemiologic data demonstrating increased CV risk in PTSD, very little is known about underlying mechanisms. This project will help fill this gap by examining the mechanistic role of sympathetic o…
Eligibility
- Age range
- 18–65 years
- Sex
- All
- Healthy volunteers
- Yes
Inclusion Criteria: * prehypertensive and normotensive veterans with PTSD, and prehypertensive and normotensive veterans without PTSD (controls) Exclusion Criteria: * heart or vascular disease * illicit drug use within the last 6 months * excessive alcohol use (\>2 drinks per day) * pregnancy * autonomic dysfunction * medications known to affect SNS (clonidine) * treatment with monoamine oxidase (MAO) inhibitors within the last 14 days * any serious systemic disease
Interventions
- DeviceDevice-Guided Breathing (DGB)
The RESPeRATE device will be used for 15 minutes of device-guided breathing daily for 8 weeks. The participant places the elastic belt with a respiration sensor around the upper abdomen, and wears earbuds for audio feedback. The device monitors the breathing rate, calculates inspiration and expiration times, and generates a personalized melody of two distinct ascending and descending tones for inhalation versus exhalation. Users effortlessly entrain their breathing pattern with the tones, and the device gradually guides the user to a prolonged expiration time and slower respiratory rate (to \< 10 breaths/minute). The device automatically stores usage data, allowing for quantification of adherence and performance.
- DeviceSham DGB
The sham device is identical to the DGB device, except it does not guide respiratory rates to slow down and instead maintains a rate of 14 breaths per minute. The sham device is used for 15 minutes per day for 8 weeks.
- DeviceTranscutaneous Vagal Nerve Stimulation (tVNS)
tVNS is a noninvasive method that involves placing a device over the skin overlying the vagus nerve on the neck. The device delivers mild electrical stimulation, using transcutaneous electrical nerve stimulation (TENS) unit. The stimulation is increased until there is a vibration and slight muscle contraction in the lower face or neck. Then the stimulation is delivered for 2 minutes on the left side of the neck, and on the right side of the neck, for a total of 4 minutes. The tVNS device is used twice daily for 8 weeks.
- Device
Location
- Atlanta VA Medical CenterDecatur, Georgia