.jpg) |
| A small device worn on the body can stimulate the nervous system via electrodes on the ear. Image Credit: Courtesy of Technische Universität Wien |
Scientific Frontline: Extended "At a Glance" Summary: Vagus Nerve Stimulation
The Core Concept: Vagus nerve stimulation (VNS) is a therapeutic technique that uses electrical impulses delivered via electrodes to modulate the parasympathetic nervous system, influencing internal organ function and blood circulation. It acts as an "electric pill" for treating chronic pain, inflammation, and neurological conditions.
Key Distinction/Mechanism: While traditional VNS is constant, this research highlights that the brain does not respond uniformly to electrical input. Effectiveness is significantly heightened when stimulation is synchronized with the body's natural rhythms—specifically applying pulses during the cardiac systole (heart contraction) and the inspiratory phase of breathing.
Major Frameworks/Components:
- Auricular Vagus Nerve Stimulation (aVNS): Delivering stimulation through electrodes placed on the ear.
- Cardiac Synchronization: Coordinating electrical pulses with the systole phase of the heartbeat.
- Respiratory Synchronization: Coordinating electrical pulses with the inhalation phase.
- Parasympathetic Modulation: Targeting the longest nerve of the parasympathetic nervous system to promote recovery and organ control.
Branch of Science: Biomedical, Physiology, and Neuroscience.
Future Application: The development of personalized, rhythm-aware algorithms for medical devices, potentially offering a non-invasive, targeted therapy for chronic diseases that previously failed to respond to static nerve stimulation protocols.
Why It Matters: By tailoring neurostimulation to the individual's physiological cycles, researchers can bypass the limitations of current devices and improve the success rates of neuromodulatory treatments for a variety of intractable illnesses.
.jpg) |
| The device in the lab at TU Wien. Photo Credit: Courtesy of Technische Universität Wien |
Nerve stimulation can help with various diseases. However, this only works well if the body's own rhythms are taken into account, says a study by TU Wien (Vienna).
It doesn't always have to be medication. Some health problems, from chronic pain and inflammation to neurological diseases, can also be treated by nerve stimulation, for example with the help of electrodes that are attached to the ear and activate the vagus nerve. This method is sometimes referred to as an ‘electric pill’.
However, vagus nerve stimulation does not always work the way it is supposed to. A study conducted by TU Wien (Vienna) in cooperation with the Vienna Private Clinic now shows how this can be improved: Experiments demonstrate that the effect is very good when the electrical stimulation is synchronized with the body's natural rhythms – the actual heartbeat and breathing.
The ‘electric pill’ for the parasympathetic nervous system
The vagus nerve plays an important role in our body: it is the longest nerve of the parasympathetic nervous system, the part of the nervous system that is significantly involved in the precise control of the internal organs and blood circulation, and is responsible for recovery and building up the body's own reserves. A branch of the vagus nerve also leads from the brain directly into the ear, which is why small electrodes in the ear can be used to activate the vagus nerve, stimulate the brain and thus influence various functions of the body.
“However, it turns out that this stimulation does not always produce the expected results,” says Prof Eugenijus Kaniusas from the Institute of Biomedical Electronics at TU Wien. "The electrical stimulation does not have an effect on the nervous system at all times. You could say that the brain is just not always listening. It's as if there is a gate to the control center of the nervous system that is sometimes open and then closed again, and this can change in less than a second."
Five people have now been examined in a pilot study. Their vagus nerve was electrically activated to lower their heart rate. It is already known from previous studies that heart rate is a potential indicator of whether stimulation therapy is beneficial or not.
It was shown that the temporal connection between stimulation and heartbeat plays a decisive role. If the vagus nerve is stimulated at a rhythm that is not synchronized with the heartbeat, hardly any effect can be observed. However, if the stimulation signals are always applied when the heart is contracting (during systole), a strong effect can be observed – much stronger than if stimulation is applied during the relaxation phase of the heart, diastole.
Breathing is also important in this context: the stimulation was significantly more effective during the inhalation phase than during the exhalation phase.
“Our results show that synchronizing vagus nerve stimulation with the heartbeat and breathing rhythm significantly increases effectiveness. This could help to improve the success of treatment for chronic illnesses, especially for those who have not previously responded to this therapy for reasons that are as yet unexplained,” says Eugenijus Kaniusas.
Larger clinical studies to follow
If nerve stimulation can be customized electronically so that it is tailored to the body's own individual rhythms at any given time, it should be possible to achieve significantly greater successes than has been possible to date. Future studies should examine larger and clinically relevant patient groups and develop even more precise algorithms in order to be able to tailor the stimulation even more precisely to individual needs.
“This technology could be an effective and non-invasive way of modulating the autonomic nervous system in a targeted and gentle manner - a potential milestone in the neuromodulatory treatment of various chronic diseases,” believes Dr Joszef Constantin Szeles from the Vienna Private Clinic.
Reference material: What Is: The Vagus Nerve
Published in journal: Frontiers in Physiology
Authors: Johannes Tischer, Jozsef Constantin Szeles, and Eugenijus Kaniusas
Source/Credit: Technische Universität Wien
Edited by: Scientific Frontline
Reference Number: bmed012725_01
.jpg)