Stimulating the vagus nerve in the neck could help relieve the pain associated with PTSD

Post-traumatic stress disorder, or PTSD, is a mental condition caused by a traumatic event. People with PTSD may have pervasive memories, negative thoughts, anxiety, and chronic pain. The disease is usually treated with a combination of psychotherapy, antidepressants and anti-anxiety medications.

It is this link between mental health and pain that interests Imanuel Lerman, MD, badociate professor at the University of California San Diego School of Medicine, at the Jacobs Faculty of Engineering and at the University of California. 39 Qualcomm Institute, and specialist in pain management at the University of San Diego (San Diego). Health care system.

Lerman especially wants to know how the feeling of emotional pain can be influenced by the vagus nerve, which runs through both sides of the neck, from the brainstem to the abdomen. The vagus nerve also plays a vital role in maintaining heart rate, respiratory rate, digestive tract movement and many other basic bodily functions.

In a study published on February 13, 2019 in PLOS ONELerman and his colleagues tested non-invasive vagus nerve stimulation as a way to reduce the pain sensation.

"It's thought that people with differences in how their body – their autonomic and sympathetic nervous systems – treat pain may be more likely to suffer from PTSD," said Lerman. "And so we wanted to know if we could rewrite this" firing mistake "as a way to manage pain, especially for people with PTSD." Lerman led the study with Alan N. Simmons, PhD, director of the San Diego Veterans Affairs Health System's fMRI research laboratory and badociate professor of psychiatry at UC San Diego School of Medicine.

The team used functional magnetic resonance imaging (fMRI) to examine the brain of 30 healthy participants in the study after the application of a thermal stimulus painful on their legs. To determine how the sympathetic nervous system of the body reacts to pain, they also measured perspiration on participants' skin before applying heat and repeatedly, as the heat increased.

Half of the participants were treated with non-invasive vagus nerve stimulation for two minutes – via electrodes placed on the neck – approximately 10 minutes before the thermal stimulus. The other half received a stimulation simulation.

Lerman and his colleagues report three main findings of this study. First, vagus nerve stimulation attenuated the maximal response to the thermal stimulus in several areas of the brain recognized as important for the treatment of sensory and discriminative pain, as well as in the centers of emotional pain. The treatment also delayed the pain response in these areas of the brain – the pain-related areas of the brain were activated ten seconds later in participants pretreated with vagus nerve stimulation compared to participants treated in a simulated manner.

Second, sweat measurements revealed that vagus nerve stimulation altered autonomic responses to painful thermal stimulus. In participants pretreated with vagus nerve stimulation, the response to sweat decreased over time, in contrast to the group treated with simulated treatment.

Third, vagus nerve stimulation has amortized the usual brainstem centers essential for combat-or-flight responses, also known to control the response of sweat to pain.

"Not everyone is the same – some people may need more vagus nerve stimulation than others to get the same results and the necessary frequencies could change over time – so we will have to customize this approach, "said Lerman. "But we are hopeful and look forward to the next steps to evolve this approach to the clinic."

Then, Lerman and his colleagues will launch a clinical trial funded by the Veterans Affairs San Diego Health System with veterans, with and without PTSD. They want to determine if vagus nerve stimulation at home can reduce the emotional pain and underlying neural inflammation badociated with PTSD. To learn how to participate, please call 858-552-8585 or write to [email protected].

Stimulation of the vagus nerve is a form of neuromodulation, an approach to pain management that also includes the stimulation of the spinal cord and dorsal root ganglia. The US Food and Drug Administration (FDA) has approved a non-invasive vagus nerve stimulator for the treatment of episodic and chronic headaches and acute migraines, as well as an implantable device for epilepsy . An implanted vagus nerve stimulator is currently undergoing clinical trials in the treatment of rheumatoid arthritis. Side effects of implanted vagus nerve stimulation may include hoarseness, shortness of breath, and nausea.

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The co-authors of this study are: Bryan Davis, Linda Sorkin, James Proudfoot, Edward Zhong, Donald Kimball, Ramesh Rao, UC San Diego; Mingxiong Huang, Charles Huang, Andrea Spadoni, Dewleen G. Baker, UC San Diego and San Diego Veterans Health Care System; Bruce Simon, electroCore LLC; and Irina Strigo, San Francisco Veterans Health System.