University of Twente Student Theses


Nerve Fiber Modelling for Improved Understanding of the Electrocutaneous Interface in the Context of Pain Diagnostics

Togtema, M.H. (2021) Nerve Fiber Modelling for Improved Understanding of the Electrocutaneous Interface in the Context of Pain Diagnostics.

[img] PDF
Abstract:In order to understand chronic pain for possible treatment improvement or early detection, it is of importance to know the underlying structures and neural pathways involved. The nociceptive system regulates pain in the human body and can be (selectively) activated with the use of electrical stimuli given by electrodes attached on the skin. To give better insight in the electrocutaneous interface, nerve fiber modelling could be an option. This research aimed at validating a mathematical model of the skin-electrode interface containing touch related Aβ-fibers and nociceptive Aδ-fibers. The mathematical model consists of a 2D volume-conduction model in COMSOL using FEM and a stochastic branching fiber model in MATLAB. The model was validated using the results presented by Morch2011a. The mean threshold (± SEM) calculated by the model ranged between 2.0 ± 0.01 to 2.7 ± 0.01 mA for Aβ and 5.5 ± 0.04 to 7.6 ± 0.03 mA for Aδ for electrode diameter sizes ranging from 0.2 to 20 mm. These results were a factor 7 for Aβ and a factor 12 for Aδ higher compared to the article’s findings. All the (model) steps described in the article were checked and for parameters that were not described (in detail) the effect on the mean threshold was investigated. This concluded no clear source for the discrepancy in data. In addition, another 2D FE model of a single needle IES electrode was made and simulations were carried out to investigate whether penetration depth of the needle in the skin influenced Aβ and Aδ activation. Preferential activation of Aδ was observed where Aβ thresholds were 1.4 to 1.8 times higher when the needle tip resided in the epidermis, resembling results found in literature. Furthermore, an increase of needle depth in the skin model presented an increase in Aδ threshold. The results of this research taken together leads to a contradiction with respect to the validation of the mathematical model where it is concluded that more research is required, including other validation steps.
Item Type:Essay (Master)
Faculty:TNW: Science and Technology
Subject:30 exact sciences in general, 42 biology, 50 technical science in general, 53 electrotechnology
Programme:Biomedical Engineering MSc (66226)
Link to this item:
Export this item as:BibTeX
HTML Citation
Reference Manager


Repository Staff Only: item control page