Finding the Nerve

Finding the Nerve

The Story of Impedance Neurography

1st Edition - September 26, 2017

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  • Author: Philip Cory
  • eBook ISBN: 9780128141779
  • Paperback ISBN: 9780128141762

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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

  • Preface


    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


Product details

  • No. of pages: 160
  • Language: English
  • Copyright: © Academic Press 2017
  • Published: September 26, 2017
  • Imprint: Academic Press
  • eBook ISBN: 9780128141779
  • Paperback ISBN: 9780128141762

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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