Re: Circuit that produces a tingling sensation in the fingers.

From: Bob Masta (NoSpam_at_daqarta.com)
Date: 12/13/04 

Date: Mon, 13 Dec 2004 14:20:28 GMT

On 12 Dec 2004 16:00:58 GMT, Hans-Bernhard Broeker
<broeker@physik.rwth-aachen.de> wrote:

>Seconded. Keeping in mind that our nerves themselves are operating
>based on electricity, I suspect that the basic rule of thumb is:
>there's no such thing as safe electrostimulation of sensory nerves.
>Your stimulus can either be too weak for anything to be registered at
>all, or too strong to be safe.
>
>The margin between these two thresholds on stimulus strength is
>probably too small to be safe for everyday usage other than in a
>*very* closely controlled environment (say, within shouting distance
>of an ICU, with trained medical personnel controlling the apparatus,
>given a rather specific medical indication for doing it).

I recall from my bioengineering neuroscience class a
discussion of touch-sensing neurons becoming desensitized
from overstimulation. The classic example was the "glass harmonica"
player of (I think) late 1800s. The device was a series of disks of
different diameters and/or thicknesses that rotated on a shaft.
There may have been some mechanism to keep the rims wetted.
The performer played this by lightly touching the rims with his
fingertips, producing sound like you get from running a wet finger
around the rim of a wineglass. The story is that the real virtuoso
perfomers, who played a lot, eventually lost sensation in their
fingertips. This was apparently only due to overstimulation, since
there was no obvious tissue damage at the surface.

On a personal note, I used a "cheater" method of wood carving
many years ago. I would put a rotary file bit in a high-speed
die grinder (like a Dremel on steroids, or a long skinny router)
and carve away. This made carving a breeze, but after a half
hour or so of carving, I found my fingertips had a very strange
sensation. Even with everything turned off, there was still
a tingling. The strangest part was that if I tapped on something,
it felt like my fingers were little tuning forks... they seemed to
"ring" for a few seconds afterward.

Probably just as well I never made a career of this!

Best regards,

Bob Masta
dqatechATdaqartaDOTcom
 
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