From: peterson_at_d...
Date: 2001-02-07 03:32:01
Lieber Moritz--By way of brief reply to some of the questions you
raised, 1)Electrodes. I think the simplest approach is to use the
little (I think 7 mm) disk electrodes available from Grass & others
(e.g. Apache Distributing)with a conductive paste like 10-20. The
electrodes come in tin, silver or gold, with prices ascending in
accod with the value of the metal. Surprisingly, the tin ones work
reasonably well. Depending on electrode placement, you can secure it
with a Velcro strap encircling the head like a headband above the
ears & across the forehead (for example at O1, O2, F3, F4, etc.).
For other placements, like Cz, Pz, F1, F2 or whatever, I depend on
the mildly adhesive nature of 10-20 to hold the electrode in place &
maybe run the wire lead under the velcro headband for additional
security. You can also always use a small piece of masking tape over
the electrode, contacting as much scalp as you can among the client's
hair to help hold it on. Grass also makes a small plastic spring-
loaded clamp that looks like a tiny clothes pin. It receives one or
2 of the 7 mm electrode disks and is used for earlobe grounds or
reference electrodes. There is also another style of ear-clamping
electrode that looks somewhat like an oversized earring clasp for
unpierced ears. Lexicor ships these with their EEG equipment. They
also use the 7mm disks for their training montages--tin in both
cases, by the way, unless you order the fancier silver or gold ones.
I can get you more precise details on the electrodes, but suspect
that both Grass and Apache Distributing have web sites with
information.
Now, as to what I would like the software to do, this is a somewhat
more complex issue. I will just give the minimal desiderata for alpha-
theta training (Peniston addictions/PTSD protocol). The simplest
version would permit the user to set thresholds in the traditional
theta, alpha and beta bands and give the option of providing audio
feedback whenever a threshold is exceeded, maybe a different
frequency of tone for each band. It would be nice if one could change
thresholds on-the-fly without interrupting the session. It would also
be nice if data were accumulated across the session and printed out
in a nice graph of mean amplitude per band per 2-second epoch across
the training session. One distinctively-colored trend line per band.
And maybe calculate total time above threshold for each band.
Actually, some of the old non-computerized machines like Rex
Hartzell's Discovery Engineering International machines do most or
all of this perfectly well with 1970's technology.
Ultimately, it would be wonderful if software cold be written to do
much more, such as setting variable band widths down to 1 Hz width,
setting up multiple bands, derived bands (e.g. theta/beta ratio),
etc., with lots of different games for feedback for kids in ADHD
trtaining. Then there's synchrony, there's coherence . . .
realistically, the possibilities probably far exceed the programmer
time available.
--- In buildcheapeeg_at_yahoogroups.com, Moritz v. Buttlar <info_at_baltic-microsolutions.de> wrote:
> Am Die, 06 Feb 2001 schrieben Sie:
>
> Dear Jim !
>
> > Hello all--I just found you due to a message that Yaniv posted to
the
> > BrainMaster group. I'm a psychologist, member of AAPB and SNR, a
> > diplomate of the neurotherapy cert board and BCIAC certified in
EEG,
> > and been using neurotherapy in various clinical settings for
about 7
> > years. I'm also definitely not an electronics type. I'm very
> > intrigued by the idea of a cheap EEG device, and know how I could
put
> > about 20 cheap units into clinical service tomorrow if I had
them.
> > If I can be of any help in terms of specifiying what I would want
in
> > a clinical device or whatever, I'd be happy to contribute. Also,
> > does the problem become much simpler if you are willing to settle
for
> > a 1-channel device? That's all you really need for
addictions/PTSD
> > training. --Jim Peterson, PhD
>
> Great to have a specialist here :)
>
> Maybe you can give some recommendations on electrodes: which ones
are the
> best for biofeedback ? What do they cost ? Where can they be
ordered ?
> And you can suggest a list of useful options for the software.
>
> Moritz
>
>
> --
>
----------------------------------------------------------------------
---- > Baltic Microsolutions / Flash Microcontroller Custom-Development > http://www.baltic-microsolutions.de
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