Friday, December 8, 2017

Shattered Nerves: How Science is Solving Modern Medicine's Most Perplexing Problem

In his book Shattered Nerves: How Science is Solving Modern Medicine’s Most Perplexing Problem, Victor Chase tells the story of neural prostheses. Russ Hobbie and I discuss neural stimulation in Section 7.10 of Intermediate Physics for Medicine and Biology.
“The information that has been developed in this chapter can also be used to understand some of the features of stimulating electrodes. These may be used for electromyographic studies; for stimulating muscle to contract called functional electrical stimulation (Peckham and Knutson 2005); for a cochlear implant to partially restore hearing (Zeng et al. 2008); deep brain stimulation for Parkinson’s disease (Perlmutter and Mink 2006); for cardiac pacing (Moses and Mullin 2007); and even for defibrillation (Dosdall et al. 2009).”
Chase begins by describing the cochlear implant. A common cause of deafness is the death of hair cells in the cochlea, leaving the auditory nerve intact but not activated by sound. A cochlear implant stimulates the auditory nerve using several electrodes, each corresponding to a different frequency. Chase often describes medical devices from the point of view of a patient, and in this case he tells the story of Michael Pierschalla, who not only benefited from this technology but contributed to its development.

I am fascinated by idiosyncratic inventors such as Giles Brindley. Chase writes
“An often-told tale about Giles Brindley might reveal something about the person referred to as the grandfather of neural prostheses. In 1983, the inveterate innovator and self-experimenter stood before a scientific audience and removed his pants. The venue was Las Vegas, Nevada, and the audience that witnessed this occurrence was the membership of the American Urological Association. Brindley was demonstrating, quite graphically, the success of an injection of phenoxybenzamine, a treatment he had developed for erectile dysfunction.”
Brindley developed one of the first visual prostheses that stimulated the brain. He also invented a musical instrument he called the "undilector," which is something like a computer-controlled bassoon.

One hero of Chase’s story is F. Terry Hambrecht, who led the National Institutes of Health Neural Prosthesis Program. When I was working at the NIH intramural program in the early 1990s, I often attended Hambrecht’s annual Neural Prosthesis Workshop. Sometimes I would submit a poster about magnetic stimulation. It was close enough to the workshop’s theme to be worth a poster, but far enough from its main thrust to be a little off-topic. At these workshops, held on the NIH campus, I met many of the scientists highlighted by Chase.

Shattered Nerves focuses on research performed at Case Western Reserve University. J. Thomas Mortimer founded the Applied Neural Control Laboratory there. His student P. Hunter Peckham developed a prosthetic device to restore function to a patient's paralyzed hand. Another Case researcher, Ronald Triolo, invented a stimulator that allowed a wheelchair-bound patient to stand and move around. Quadriplegics often have difficulty controlling their urination and bowel movements. Mortimer and Graham Creasey developed a prosthesis to control the bladder and bowel muscles.

Rather than summarizing Shattered Nerves myself, I will let Chase do so in his own words.
"Unfortunately, in some people, the circuitry that generates and conducts electrical signals goes bad, rendering them unable to fully partake of the miracle of the senses, as in the case of the blind, when the rod and cone photoreceptors inside the eye can no longer translate light into the electrical signals that send information to the brain. Or when the hair cells inside the cochlea of the inner ear, which process sound waves, die off, and a person loses the ability to hear. Failure of the body's electrical circuitry is also responsible for paralysis that occurs when spinal cord injuries damage the nerve cells that carry electrical signals from the brain's motor cortex to the muscles and from the skin's tactile receptors to the somatosensory portion of the brain. Until recently, these conditions were deemed irreversible. Now there is hope."
What did I gain from reading Shattered Nerves? First, I like to study the history of a field in order to better appreciate the current problems and future directions. Second, the researchers and patients that Chase describes are inspirational. Third, I was amazed at how these pioneers combined physics and engineering with medicine and biology, as Russ and I advocate in IPMB.

All books have advantages and disadvantages. One disadvantage is that Shattered Nerves was written in 2006. In a fast moving field like neural prostheses, I wish the book was up-to-date. An advantage is that you can read it for free through Project Muse.


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