Biofeedback-based auricular vagus nerve stimulation
Auricular vagus nerve stimulation (aVNS) is a novel neuromodulatory therapy used for treatment of various chronic systemic disorders such as chronic back pain. Currently, aVNS is non-individualized, disregarding the physiological state of the patient and therefore making it difficult to reach optimum therapeutic outcomes.
A closed-loop aVNS system is required to avoid over-stimulation and under-stimulation of patients, leading to personalized, side-effects free and thus improved therapy. This can be achieved by continuous monitoring of individual physiological parameters that serve as a basis for the selection of optimal aVNS settings.
In this work we developed a novel aVNS hardware for closed-loop application, which utilizes cardiorespiratory sensing using embedded sensors (and/or external sensors), processes and analyzes the acquired data in real-time, and directly governs settings of aVNS. We show in-lab that aVNS stimulation can be arbitrarily synchronized with respiratory and cardiac phases (as derived from respiration belt, electrocardiography and/or photo plethysmography) while mimicking baroreceptor-related afferent input along the vagus nerve projecting into the brain. Our designed system identified >90% of all respiratory and cardiac cycles and activated stimulation at the target point with a precision of ± 100ms despite the intrinsic respiratory and heart rate variability, reducing the predictability.
The developed system offers a solid basis for future clinical research into closed-loop aVNS in clear favor of personalized therapy (https://doi.org/10.1007/s10470-022-02037-8, opens an external URL in a new window).
Percutaneous auricular vagus nerve stimulation reduces inflammation in critical Covid-19 patients
Covid-19 is an infectious disease associated with cytokine storms and derailed sympatho-vagal balance leading to respiratory distress, hypoxemia and cardiovascular damage.
We apply the auricular vagus nerve stimulation (aVNS) to modulate the parasympathetic nervous system, activate the associated anti-inflammatory pathways, and reestablish the abnormal sympatho-vagal balance. aVNS is performed percutaneously using miniature needle electrodes in ear regions innervated by the auricular vagus nerve.
In terms of a randomized prospective study, chronic aVNS is started in critical but not yet ventilated Covid-19 patients during their stay at the intensive care unit. The results show decreased pro-inflammatory, e.g. a reduction of CRP level by 32% after one day of VNS and 80% over 7 days or similar a reduction of TNFalpha level by 58.1% over 7 days and coagulation parameters and increased anti-inflammatory parameters, e.g. a decrease of IL-10 level by 66% over 7 days over the aVNS duration without collateral effects.
aVNS proved to be a safe clinical procedure and could effectively supplement treatment of critical Covid-19 patients while preventing devastating over-inflammation (https://doi.org/10.3389/fphys.2022.897257, opens an external URL in a new window).
Venue: TUtheSKY, opens an external URL in a new window, Getreidemarkt 9, 1060 Vienna
When: October 12, 2022