A novel method for characterization of peripheral nerve fiber size distributions by group delay measurements and simulated annealing optimization

Szlavik, Robert B.; Turner, Galen E.

doi:10.1109/iembs.2008.4650339

Cited by 6 publications

(15 citation statements)

References 18 publications

(16 reference statements)

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“…The basis of this technique lies on the estimation of the group delay between two sets of recordings electrodes. This group delay is then associated with the individual fibers that contribute to the maximum compound evoked potential [8]. With the group delay information, an estimate of the fibers' diameters is then made and the propagation delay of each individual fiber's potential with respect to the reference electrode is estimated.…”

Section: Determining Fiber Size Distributionmentioning

confidence: 99%

“…In this study, Szlavik [8] presents a technique to estimate the size distribution of the nerve fibers which is linearly related to the conduction velocity distribution. The basis of this technique lies on the estimation of the group delay between two sets of recordings electrodes.…”

Section: Determining Fiber Size Distributionmentioning

confidence: 99%

“…Gaining a better understanding of the nerve fibers within a given nerve trunk have become a recent topic of interest so Szlavik [8] began investigating a technique that could characterize the population of nerve fibers within a nerve trunk in terms of the fiber diameter. Having this information could prove to be very valuable because there would be a better understanding of which fibers, in terms of size, were contributing to the evoked potential.…”

Section: Determining Fiber Size Distributionmentioning

confidence: 99%

“…In conducting the experiment, a random population of nerve fiber diameters were created using a technique used by Szlavik and de Bruin in their previous work [8]. This technique involved using the following equation:…”

Section: Determining Fiber Size Distributionmentioning

confidence: 99%

“…All values used for the dimensions between these electrodes were arbitrary and were chosen for convenience. Other assumptions that were made for this simulation included the following [8]:…”

Section: Determining Fiber Size Distributionmentioning

confidence: 99%

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Characterizing Nerve Fiber Activation By Varying Fiber Diameter And Depth Within a Conductive Medium: A Finite Element Approach

Soto¹

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In some instances neuropathies can be diagnosed through a conduction velocity test. However, not all neuropathies can be classified using this method.Gaining an understanding of how the stimulus level varies for different fiber sizes at different fiber depths within a conductive medium will provide useful information for simulation studies.Following a two-step approach using COMSOL and MATLAB, a simulation was implemented to investigate the stimulus necessary to activate different sized fibers at different depths. In this two-step approach, COMSOL was used to describe the voltage profile that would be present within a conductive medium after a stimulus was applied. This voltage profile could then be analyzed using a program written in MATLAB to determine if the applied stimulus was sufficient to activate a given fiber. The analysis was performed using a stimulus method using a constant DC source. Two finite element models were also used, one using a homogeneous medium and the other inhomogeneous.A three dimensional plot was created to describe the effect of both the depth and diameter of a fiber on the required stimulus for fiber activation. From this plot, an equation was fit to the data to represent the activation function of a nerve fiber at various diameters and depths.v CHAPTER 1 -IntroductionThe biomedical field has changed tremendously throughout the past 20 years. Complicated electrical and mechanical systems are now being implemented into medical devices, which are advancing the field at an extremely high rate. Some of the most significant changes can be seen in the area of neurology and integrating medical devices with the neurological systems of the body. Companies are creating a division to investigate medical devices that address the subject of neuromodulation and neurostimulation.Understanding the intricacies of the nervous system is very important in developing a device that neuromodulates or neurostimulates correctly. One such example can be seen in devices that target people with chronic back pain.Neurostimulation devices are currently being designed to stimulate specific nerve fiber bundles in an attempt to mask the chronic pain signal. During this stimulation a large group of nerve fibers are usually stimulated because current technology is not capable of controlling the stimulation of individual fibers.Although this lack of ability to control the stimulation of individual fibers has not hindered these devices from treating their patients, more knowledge of how different fibers are stimulated could offer great benefits to the future of these devices. Neuroprosthetics is one application that would greatly benefit from differentiating the stimulus required to activate various fiber types. Characterizing how individual fibers respond to a given stimulus would allow much finer control of the nerves being targeted in the neuroprosthetic device and could lead to a much more accurate human-computer interface in these devices. 2Understanding how different nerve fibers respond to a given stimulus is...

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Section: Determining Fiber Size Distributionmentioning

confidence: 99%

Section: Determining Fiber Size Distributionmentioning

confidence: 99%

Section: Determining Fiber Size Distributionmentioning

confidence: 99%

Section: Determining Fiber Size Distributionmentioning

confidence: 99%

Section: Determining Fiber Size Distributionmentioning

confidence: 99%

See 3 more Smart Citations

Characterizing Nerve Fiber Activation By Varying Fiber Diameter And Depth Within a Conductive Medium: A Finite Element Approach

Soto¹

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A modification to the group delay and simulated annealing technique for characterization of peripheral nerve fiber size distributions for non-deterministic sampled data

Szlavik

2009

2009 Annual International Conference of the IEEE Engineering in Medicine and Biology Society

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Abstract-The ability to determine the characteristics of peripheral nerve fiber size distributions would provide additional information to clinicians for the diagnosis of specific pathologies of the peripheral nervous system. Investigation of these conditions, using electro-diagnostic techniques, is advantageous in the sense that such techniques tend to be minimally invasive yet provide valuable diagnostic information. One of the principal electro-diagnostic tools available to the clinician is the nerve conduction velocity test. While the peripheral nerve conduction velocity test can provide useful information to the clinician regarding the viability of the nerve under study, it is a single parameter test that yields no detailed information about the characteristics of the functioning nerve fibers within the nerve trunk. In previous work, the efficacy of the group delay and simulated annealing approach was demonstrated in the context of a simulation study where deterministic functions were used to represent the single fiber evoked potentials. In this study we present a modification to the approach discussed previously that is applicable to nondeterministic functions of sampled data.

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A Perturbation Based Decomposition of Compound-Evoked Potentials for Characterization of Nerve Fiber Size Distributions

Szlavik

2016

IEEE Trans. Neural Syst. Rehabil. Eng.

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The characterization of peripheral nerve fiber distributions, in terms of diameter or velocity, is of clinical significance because information associated with these distributions can be utilized in the differential diagnosis of peripheral neuropathies. Electro-diagnostic techniques can be applied to the investigation of peripheral neuropathies and can yield valuable diagnostic information while being minimally invasive. Nerve conduction velocity studies are single parameter tests that yield no detailed information regarding the characteristics of the population of nerve fibers that contribute to the compound-evoked potential. Decomposition of the compound-evoked potential, such that the velocity or diameter distribution of the contributing nerve fibers may be determined, is necessary if information regarding the population of contributing nerve fibers is to be ascertained from the electro-diagnostic study. In this work, a perturbation-based decomposition of compound-evoked potentials is proposed that facilitates determination of the fiber diameter distribution associated with the compound-evoked potential. The decomposition is based on representing the single fiber-evoked potential, associated with each diameter class, as being perturbed by contributions, of varying degree, from all the other diameter class single fiber-evoked potentials. The resultant estimator of the contributing nerve fiber diameter distribution is valid for relatively large separations in diameter classes. It is also useful in situations where the separation between diameter classes is small and the concomitant single fiber-evoked potentials are not orthogonal.

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A novel method for characterization of peripheral nerve fiber size distributions by group delay measurements and simulated annealing optimization

Cited by 6 publications

References 18 publications

Characterizing Nerve Fiber Activation By Varying Fiber Diameter And Depth Within a Conductive Medium: A Finite Element Approach

Characterizing Nerve Fiber Activation By Varying Fiber Diameter And Depth Within a Conductive Medium: A Finite Element Approach

A modification to the group delay and simulated annealing technique for characterization of peripheral nerve fiber size distributions for non-deterministic sampled data

A Perturbation Based Decomposition of Compound-Evoked Potentials for Characterization of Nerve Fiber Size Distributions

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