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Finding the Nerve - 1st Edition - ISBN: 9780128141762, 9780128141779

Finding the Nerve

1st Edition

The Story of Impedance Neurography

Author: Philip Cory
eBook ISBN: 9780128141779
Paperback ISBN: 9780128141762
Imprint: Academic Press
Published Date: 26th September 2017
Page Count: 160
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Finding the Nerve: The Story of Impedance Neurography discusses research that elucidates the nature of nerve simulation via externally applied electrical fields, and how it has led to an entirely new understanding of neuronal cell membrane biophysics and defined a novel nerve imaging technology. It details how these discoveries came about and the nature of research that derives from unexplained clinical observations. The primary technology, impedance neurography, is a wholly new way of nerve-specific visualization in 2-D or 3-D, with the ability to define both normal and abnormal functioning of nerves, heretofore unavailable from techniques such as MRI neurography.

This is of particular importance with respect to the obesity epidemic where physicians performing nerve-related procedures cannot use ultrasound visualization due to the depth limitations of that technology.

Key Features

  • Focuses on nerve stimulation mechanics and neuronal cell membrane biophysics
  • Defines a nerve-specific imaging technology and issues with current nerve stimulation devices
  • Addresses inaccuracies in the understanding of nerve stimulation and provides a new understanding of neuronal cell membrane biophysics
  • Provides for nerve-specific visualization in 2-D or 3-D, with the novel ability to define both normal and abnormal functioning of nerves


Neuroscientists, neurophysiologists, neurosurgeons, electrical engineers, researchers in the areas of neurophysiology, neurology, pain management, and anaesthesiology

Table of Contents



1. Initial Impedance Neurography Findings: The TENS Technique and Nerve Stimulation Observations

Impedance Neurography Reveals Myofascial

Trigger Points

Confusing Results Regarding the Roles of Voltage and

Current in Effecting Action Potential Development

Getting Back to Current and Voltage Basics

Electric Fields in Non-Homogenous Material

Application of Electric Field Theory to Nerve Stimulation

Examples from the Clinical Realm

Stimulating Needles are Not Point Sources in Space

2. Skin Surface Impedance

The Nature of Skin Contact Systems

Skin Surface Contact Area

The Roles of

Contact Impedance and Skin Surface

Impedance Integration

Contact Impedance

Skin Surface Impedance Integration

A Final Observation for Consideration

3. The Varieties of Neuronal Cell Membrane Reactance: Nerves as RLC circuits

Electrical Modeling of Neuronal Cell Membranes

A Brief History of Electrotonics

Discordant Data Emerges

A Hard Lesson

Mystery solved: The Eureka Observation

The Nature of a Charged-DC Offset

Consequences of Applying a Periodic Waveform on a Constant Current Flow Caused by a c-DC Offset

Improvements to High Frequency Stimulation

Discriminating Neuronal Subpopulations

The Relationship of the Time Constant to the Apparent Impedance

Neuronal Membrane Electrical Circuit Characteristics and Anisotropicity

The Strength-Duration Relationship

Informed Nerve Stimulator Design

Extracting Tissue Time Constants

4. Anisotropicity

The Importance of Assumptions

A Revelation

Nerves Alone are Imaged

The Hierarchy of Nerve Structures Imaged

5. Depth Determination of Peripheral Nerves using Impedance Neurography

Electrode Separation Distance Considerations

Dimension Factors in Axon Impedance

Fusion Technologies



No. of pages:
© Academic Press 2017
26th September 2017
Academic Press
eBook ISBN:
Paperback ISBN:

About the Author

Philip Cory

Philip Cory is a retired anesthesiologist/pain management specialist living in Bozeman, MT. After receiving his undergraduate degree in chemistry with a physics minor, he attended the University of Washington School of Medicine. Noting that anesthesiologists actually worked on a daily basis with his interests in clinical pharmacology and physiology, plus being the main patient advocate in the operating room, he completed an anesthesiology residency (specializing in regional anesthesia) and fellowship at Virginia Mason Hospital in Seattle, WA. While searching locations for private practice, Phil and Joan fell in love with Montana which has never changed. An interest in post-herpetic neuralgia prompted a move to Penn State University’s Milton S. Hershey Medical Center where Phil joined the anesthesiology faculty and became Director of the Department’s Chronic Pain Management Clinic. But the allure of the mountains remained compelling, and they moved back to Bozeman where Phil pursued observations from treating people suffering chronic pain conditions. His urge to improve pain diagnosis and treatment led to the development of Impedance Neurography. This was the classic “basement” science endeavor, carved out of spare time, helped by corporate and State grants, a small group of investors, with additional basic science knowledge, invention ideas, and business acumen from Dr. Joan Cory. It wasn’t until Phil was literally knocked out of medical practice by his own medical issues, that he had time to finally pull twenty years’ worth of research together and determine the underlying electrophysiology of Impedance Neurography. The personal intersection of a background in basic science, clinical experience, and fortuitous observation led Phil to this new understanding of neuronal membrane biophysics while answering long standing questions regarding electrical nerve stimulation.

Affiliations and Expertise

Beargrass Patient Partners, USA

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