Re: Reverse EEG

Hi

You guys should perhaps read up on the LENS system as developed by Dr. Len
Ochs.  I first thought that the name LENS was taken from the developer's
first name, but I was mistaken.  LENS = Low Energy Neurofeedback System.

I don't know much about it... the system is based on a slightly modified
EEG amplifier - I think they are using a J&J amp.  Sold by Ochs Labs.  The
very same EEG cables that input the EEG signal to the amp, are somehow used
for an electrical feedback using some sort of conducted RF.  US patent
8082031 B2 (Dec. 20, 2011) gives some info.

LENS is not new, I think the above mentioned patent must be a follow up, or
update.  I wouldn't be surprised if LENS has been around for more than ten
years.

BTW.  In the last posts you where talking about currents.  EEG signals are
actually small voltages.  You could argue that it is impossible to measure
a voltage without some (measuring) current flowing, even if your EEG
amplifier has an input impedance of 100s of Megaohms.  But in practise,
these measurement currents are so small that they can be considered zero.

CES and tDCS instruments DO inject meaningful currents, typically in the
order of 100s of uA.

Alpha-Stims (CES) have been used for many, many years and there are many
fans.  Personally I would not use one, simply because I am too dumb to know
that I have a brain problem and believe in don't fixing something that
ain't broken.

The brain/skull is a complex electrical resistive network.  The skull
largely isolating, and the soft tissue mixing/bridging any electric
activity.  I always use the analogy of looking through a frosted shower
door.  You can see someone is standing in the shower, but you have a much
harder time determining the sex of the person, not to mention anything more
specific such as facial expression, etc.

DSP processing could "clean" a video image taken through frosted glass to a
limited extend (think Hubble telescope) but only up to a point.  Making
sense out of the EEG is as difficult.  The Hubble telescope is actually
quite successful, because the guys know EXACTLY how the optical signal was
distorted by the wrongly manufactured mirror/lens.  When your distortion is
more random, well then your options are not good.

I would guess that very little CES current would find it's way through the
grey matter itself, but would probably find lower impedance paths elsewhere
- but perhaps I am wrong.

Regards
Stefan

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