The data economy: The future of health care is data based - VII

Implantable device to stimulate the Vagus Nerve to control epilepsy. Credit: Cyberonics

Biocompatible maleic-chitosan nanofibers (yellow) embedded in a field effect transistor. A potential difference applied across source and drain generates a proton current to flow along the maleic chitosan. A potential applied onto the gate modulates the proton current. This modulation occurs by inducing more or fewer protons onto the maleic chitosan via capacitive coupling. Credit: University of Washington

Continuing the exploration of turning knowledge into action, benefitting the individual and improving the economics of health care, I found the researches on electrical stimulation of our "body" quite interesting.

Fundamentally our body is a cluster of autonomous systems whose networking, scale and complexity give rise to the emergent property of “self”. Part of the networking is based on chemical diffused signals, part of electrical signals (ions, not electrons).  
 Drugs are affecting the chemical signals, changing, complementing and adding to them. Very little, so far, has been done in the area of electrical signals.

Possibly the first “cure” based on electrical signal is the pacemaker to provide an external “clock” to an electrically instable heart (although someone may wish to point out experiments carried out by Meucci in the 1860ies to use electricity as a form of anesthetic for dental surgery – it failed but a side effect was the invention of the telephone).

In the last twenty years electrical stimulation have been used to block epileptic seizures, to carry sensation to the brain from an artificial limb and a few more.

Technology has evolved fast and now we see a few companies, like CerbomedsCyberonics and Electrocore, proposing systems, the size of a small smart phone, to stimulate the Vagal Nerve (VNS – Vagal Nerve Stimulation).
 The vagal nerve has a role of general controller for many organs in the body and feedbacks from these organs have an impact on brain processing. There are some indications that the vagal nerve is also connected to migraine, at least in the sense that its stimulation can reduce migraine and in some cases stop it. This is a great news for the millions suffering from this debilitating condition but it is also a potentially good news from an economic standpoint: the cost of migraine is measured in tens of billions a year, worldwide, 27 billions in Europe alone.

The vagal nerve is actually a bunch of individual nerves, each one with a specific task and most often a specific signaling “protocol”. This is what is making selective VNS possible. What researchers are doing is to find our the signaling protocols of individual nerve and look for ways of altering the signals to achieve an intended result, like depressing the reactivity of an organ, masking some signals towards the brain that would result in unwanted behavior and so on.

The way signals are “injected” onto the vagal nerve is really amazing. Researchers are looking at specific frequencies that can affect the specific nerve within the vagal nerve. These frequencies have to go across the skin, reach the vagal nerve and affect only the desired one.  Stimulators, read the article on Spectrum, are usually placed on the side of the neck, since that is the place where the vagal nerve runs close to the skin (1-2 cm below), and a device can influence it. The first problem is that electrical signals affects all nerves, including the pain receptor. Hence, a stimulation might result in a very unpleasant experience. To avoid that the researchers are using higher frequencies that are not affecting pain receptors. The modulation of these high frequency signals is tailored to the specific nerve, within the vagal bunch, one wants to affect. 

Notice that VNS is another form of cure, and as any cure it works for certain patients pretty well but it does not work for others. The hope is that as more data are gathered and compared it would be possible to tailor the stimulation to each situation thus increasing its effectiveness.

As a last point, related to electrical communications, there have been important progresses in protonics. Electrical communications in nerves and between nerves termination and actuators (like muscle cells) is based on ions, that is protons (a H atom stripped by its electron, or in the case of cellular communications most often it is on K and Ca ions). This protonic communications is very selective, that is affects one and only one cell (whose membrane pores absorb the K/Ca ions) whilst electrical field spread around and affect many cells at the same time. Thus it has been impossible so far to re-establish a communication between fibers of a severed nerve. With the protonic chip it now becomes possible to have the same natural electrical communication and the hope is to be able to restore functionality to paralized persons by the end of the next decade. That would really be fantastic!

Author - Roberto Saracco

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