Modeling and simulation methodologies for spinal cord stimulation.

neuron;simulation;genetic algorithm;spinal cord stimulation;pulse position optimization;electric field modeling

Saliya Kumara Kirigeeganage

University:University of Louisville

Department:Electrical and Computer Engineering

关键词: neuron;    simulation;    genetic algorithm;    spinal cord stimulation;    pulse position optimization;    electric field modeling;   

Others  :  https://ir.library.louisville.edu/cgi/viewcontent.cgi?article=4289&context=etd

美国|英语

来源: The Universite of Louisville's Institutional Repository

【 摘 要 】

The use of neural prostheses to improve health of paraplegics has been a prime interest of neuroscientists over the last few decades. Scientists have performed experiments with spinal cord stimulation (SCS) to enable voluntary motor function of paralyzed patients. However, the experimentation on the human spinal cord is not a trivial task. Therefore, modeling and simulation techniques play a significant role in understanding the underlying concepts and mechanics of the spinal cord stimulation. In this work, simulation and modeling techniques related to spinal cord stimulation were investigated. The initial work was intended to visualize the electric field distribution patterns in the spinal cord. A system consisting a set of stimulating electrodes with a model of the spinal cord was built and simulations were performed by applying different stimuli to the electrodes. Depending on the complexity of the model, the simulation times can be varying. However, the system demonstrated the ability to visualize the field distributions inside the spinal cord for static and transient stimuli. This data can be used to aid experimental studies and to better understand the results of the spinal cord stimulation by mapping known experimental results to the simulation results. The stimulation of biological tissue raises safety concerns. Therefore, a methodology utilizes in electrical stimulation of biological systems known as charge balancing was studied. The importance of charge balancing and the effects of using charge balancing was studied with simulation studies. The simulation results showed extensive charge accumulation in the biological tissue, around the stimulation sites, when charge balancing was not utilized. Hence, the studies showed the importance of using charge balancing and the importance of avoiding pulse collisions. Stimulation sequences that utilizes different stimuli with different frequencies results in a phenomenon known as pulse collision. Pulse collisions cause complications in charge balancing and should be avoided or reduced in stimulation procedures. An algorithm and a software based on the algorithm was developed to reduce pulse collisions by optimizing pulse positioning. The tool showed significant reduction in pulse collisions for simulation sequences that were used in experimental settings. The current version of the software is capable of optimizing up to five different pulses. Coupling the electric fields and action potentials generated in neurons due to the electric fields can lead to significant discoveries on the mechanics of the SCS. Therefore, the investigation of bi-domain models has valuable implications. Bi-domain models were built by combining different neural models