Functionally selective peripheral nerve stimulation
Tim Huggers (M-EE), Nicolò Rossetti (imec), Utku Yavuz (UT-BSS), Vojkan Mikhajlović, (imec), Ciska Heida (UT-BSS)
Abstract
Introduction
Peripheral nerve stimulation offers a sophisticated alternative to direct brain stimulation therapy, as it is clearer physiologically what pathways are stimulated and how the end-organs are influenced by the applied stimulation. Two of those important neural pathways of our (para)sympathetic nervous system are the vagus nerves: two semi-exposed nerves that run through the sides of our neck towards the major abdominal organs. They are a great candidate for placement of minimally invasive electrode cuffs that would allow us to treat any pathology related to sympathetic neural disorders such as rheumatoid arthritis, chronic pain and epilepsy.[Y(1]
Objective
In order to not stimulate the nerve fibers that innervate the neck muscle, which are also bundled into the vagus, a technique known as ‘anodal blocking’ is applied to the electrode cuff. Because of a local positive electric field close to the anodal electrode, we can selectively block an action potential from travelling further along the nerve depending on its fiber diameter.
Methods
Through a MRG double-cable axon model, it is observed that this mechanism can prevent specific fiber diameters that innervate the neck muscle from travelling further along the modelled nerve while it is stimulating the smaller sympathetic fibers. Designing the optimal electrode geometry is first understood through computational parameter space search and subsequently estimated through theoretical analysis.
Results
We present an approach for a design of an electrode cuff for a specific range of fiber diameters that are to be blocked - supported by neurophysiological- and electrode design theory and computational modelling.