Electrotherapy, FES and it's historical roots
Functional Electrical Stimulation and its parent topic, Electrotherapy have been around a long time now but it seems to me are still not well-understood or embraced in the mainstream of healthcare in the UK. This is a shame and im not quite sure why the general level of understanding is still low. In a few articles im going to take a look at this topic from a number of points of view.
At Anatomical Concepts we have a few fantastic products in this space now - the Stimulette Den2x and Stimulette Edition 5 plus the RehaStim 2 and 3 and RehaMove versions from Hasomed. These are relatively “high end” products but a quick web search will show up many products from a few hundred pounds to several thousand.
Maybe that’s part of the problem, the knowledge is not out there to guide people to the right electrotherapy tools and practice for their clinical applications.
I first worked with FES as a PhD student in the late 1970’s. The technology available in those days was not so easy to use compared with the systems we have available today. Having said that, we have had a good grasp of the principles for decades and with the improvement of technology there is no doubt that some great tools are available now that are very easy to use (when you know how)
Whatever era we are in the fundamental questions of interest remain the same
What can FES do that is worth the trouble?
How does FES work?
Is it safe to use? Will it damage healthy nerves and muscles?
Can the central nervous system or a lower-motor neuron system be retrained or reorganised through FES?
How can we design FES systems for maximum benefit
We can start this exploration with a look at the history of electrotherapy
It all started with a frog’s leg
It was just prior to 1800 that Galvani discovered that electricity applied to the sciatic nerve of a frog would produce a contraction of the frog’s leg. These foundations and the controversy between Galvani and a scientist called Volta laid the foundations for what became electrotherapy.
Volta, was a professor of experimental physics and he was among the first to repeat Galvani’s experiments.
At first, he embraced the idea of “animal electricity”. However, Volta came to believe that the contractions depended on the metal cable Galvani had used to connect the nerves and muscles in his experiments. Galvani believed that the animal electricity came from the muscle in the frogs pelvis. Volta, in opposition, reasoned that the animal electricity was a physical phenomenon caused by rubbing frog skin and not a metallic electricity.
In fact every cell has a cell potential. Biological electricity has the same chemical underpinnings as the current between electrochemical cells, and thus can be duplicated outside the body.
Volta's intuition was correct. Volta, essentially, objected to Galvani’s conclusions about "animal electric fluid", but the two scientists disagreed respectfully and Volta coined the term "Galvanism" for a direct current of electricity produced by chemical action.
We can say that owing to an argument between the two in regard to the cause of the electricity, Volta built the first battery in order to specifically disprove his associate's theory. Volta's “pile” became known as a voltaic pile.
As we move further into the 1800’s there was a growing scientific interest in Galvanism.
Let me tell you a story…
The inside of the Glasgow University Anatomy theatre was crowded. After all, it wasn’t everyday that anatomists worked on a fresh corpse in full public view. Five minutes before Matthew Clydesdale’s corpse was brought from the gallows, Dr. Andrew Ure charged his galvanic battery. A series of experiments were then carried out on the recently hanged body.
The final experiment had spectators believing that Clydesdale had returned from the dead. Once the current was turned on, Clydesdale began to raise his hand and point to the people in the audience.
‘…At this spectacle several spectators were forced to leave the arena from terror or
sickness, and one gentleman fainted’.
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Glasgow University Anatomy department (I studied anatomy here - but much later than Andrew Ure
For more than 200 years we have known that electricity applied to the body can cause contraction of muscle. Over the last 50 years our understanding has improved and with it so has the technology to make FES one of the most powerful and flexible tools for rehabilitation.
By the 19th Century there was significant interest in electrotherapy. An electric bath was a medical treatment in which high-voltage electrical apparatus was used for electrifying patients by causing an electric charge to build up on their bodies.
In the USA this process was known as Franklinization after Benjamin Franklin. The process became widely known after Franklin described it in the mid-18th century, but after that it was mostly practiced by quacks.
Golding Bird brought it into the mainstream at Guy's Hospital in the mid-19th century and it fell into disuse in the early 20th century.
Perhaps this association with quackery has not served us well. In articles to come we will look at the underlying principles and modern practice of electotherapy.
Derek Jones PhD MBA