Conference hydra::dejavu

    I was going to add:
    
    Has anybody got any ideas as to how to recieve & detech the various
    brain waves mentioned previously. I know the medical profession
    use a special machine(the name of which I can't remember!) but it
    is horrenduosly expensive... 
    
    I was thinking that if it were possible to detect brain waves via analogue 
    means(via very sensitive equipment!!) and then to digitise this,
    using sampler type software into a Personal Computer, it is possible to 
    provide feedback to the originator.... who can then learn to alter her/his
    state of mind to generate that type of brainwave.....
    nirvana/enlightenment may not be that far off....
    
    The above idea would be user_motivated and hence less dangerous
    then having an external factor(e.g expensive little boxes with loads of 
    buttons, drugs etc) meddling/inducing the beta(meditative) state....
    also it would be quicker then just mumbling mantras.   

    Dave.
    P.S  This is the first time I've written a topic, as I am fresh
    to Digital....I am a placement student(3rd Year), working in Digital,
    Solent Business Park, Fareham, UK.
    The majority of noters in this conference seen to be in the good
    old U S of A....anybody else out there in the UK??

    And there is THETA waves for the excited or angry state.  The
    frequencies of these waves lie in the range of about 3 hertz to 20
    hertz. I have (or had a text of biofeedback equipment, but I'm not sure
    if I still do.  These frequencies cannot be heard by the human under
    normal conditions.  The frequency for each type of "wave" is tuned via
    sensitive mechanical or electrical filters amplified and used to
    interact with a tone that we are able to hear.  As the desired
    frequency is approached by the brain, the increase in amplitude of the
    signal either heterodynes with the audible sound and nulls out the
    audible sound or the level of the selected "wave" is adjusted so that
    when the mind is able to produce the desired frequency, the audible
    sound gets softer until it entirely disappears.  The most expensive
    parts of the apparatus, if I remember correctly, are the sensors and
    the filter circuits.  Since the various alpha, beta, delta, and theta
    waves lie so very close together with respect to their actual
    frequencies, very high Q (very selective) circuits are needed to separate
    the various "waves."   Also, differential (balanced) circuits are
    reuired to help reduce atmospheric and other man made noise that will
    creep in via the leads and exposed circuitry;  THis reqirement also
    tends to increas the cost of design somewhat.
    
    I will look for that text, although it has been a along time since I
    have seen it around my house.
    
    
    Ernie 
    

    I don't think its dangerous, rubbish or brainwashing. :-)
    
    If I could get my hands on a machine, I'd love to play around with it
    myself.
    
    I've used the hemi-sync tapes myself and found them to be a fairly 
    effective training tool.
    
    Mary

    Shamans use drum beats of 200 to 220 per minute to help induce altered
    states. This translates to a theta frequency of 3.4 hertz. Strobe
    flashes are well known for their ability to "drive brain wave
    frequencies.  People who meditate successfully tend to have symmetrical
    brain waves with both alpha and theta present. I have entered some
    more about this in psychology 150.0, but have received no replies
    as yet.
    
    	Suppliers of Biofeedback Equipment;
    
    		In the UK;  Audio Ldt.
    			   26-28 Wendell Rd.
  			   London W129RT
                          
    
    		In the USA;  MOE
    			     5044 Wilder Drive
    			     Soquel CA 95073
    
    MOE sells a basic biofeedback monitor for brainwaves for about $180.
    
    					john turner
    o	W
      				 ats

  I agree it's definitely not rubbish. The fact that the brain does
  exhibit states which are detectable as patterns in electrical activity
  which is measurable at the skin has been well-documented. It's also
  true that people can learn to control these states to some extent by
  observing a display of this activity. And it's known that these
  physiological states correlate reasonably well with certain subjective
  states.

  What's not so clear is exactly what the benefits are to being able to
  control which waves your brain is generating. There would seem to be
  some benefits, but I suppose some people have gotten a little carried
  away and are claiming everything from being able to remove warts to
  healing congenital diseases to achieving Nirvana. If it sounds too
  good to be true ...

  Regarding any danger, as far as I know, there's no more danger than
  that posed by any mind-altering substance or technique. People with
  addictive or obsessive personalities should be cautious, but people
  who don't have such personalities may safely try it out of curiosity,
  because they won't become pathologically dependent on it for coping
  with their lives.

  I think that Radio Shack (Tandy) carries a product which does some
  fairly simple sort of brainwave detection and display. I don't know
  exactly what it does, but it would be an inexpensive way to
  experiment. Whatever else you might be able to do to yourself, the
  device itself should be completely harmless, as it's totally passive
  (i.e., doesn't send any electricity into your body).

    
    Thanks to both Mike and John.  I love playing around with stuff like
    this and will see if I can't get ahold of one of these machines.
    
    Mary

  If you manage to get one from Radio Shack, please let us know what you
  think of it. I've been meaning to check it out for a long time, but
  keep forgetting.

    I'm afraid I'll probably have to wait for a more opportune time
    (meaning... I'm broke as usual :-).
    
    But one of these days, (when my ship comes in), I'll DEFINITELY get one
    because these types of games are so much fun to play and I'd really
    like to be able to alter my brain waves at will or to know if I am
    doing it already.
    
    	... of course... school starts soon and the kids need clothes and
    books (as usual) so... this may take awhile. :-}
    
    Mary

    First time entry, sorry about the mess-up
    
    For those who might want to build this brainwave monitor, I have an
    rather old 1975 electronic experimenter's handbook, in which there
    is given the information, how this monitor works, the electronic-
    circuit, parts list {approx. 28 different types of components mostly
    commen, 9 volt battery, 3 switches, and a speaker.} nothing complexed.
    
    	If interested, I would send the information to you.
    best regards, from a usually silent reader
    Thea
    

    re: .0
    
    Hello Dave - welcome to Dejavu - I enjoyed reading your entries.
    
    You said you've "...read somewhere that the Brain generates 3 types
    of waves...Alpha, Beta & Delta(REM).  Alpha being the awake state,
    beta - the meditative state & delta - the sleeping state(REM)."
    
    I think that your reading source gave you correct names - alpha, beta,
    and delta (REM) - but incorrect descriptions.  Most authors seem to
    agree that our brains produce predominately "beta" waves during ordi-
    nary waking consciousness; "alpha" waves during states of wakeful re-
    laxation; and "delta" or slow waves during sleep stages 3 and 4.  REM
    isn't the name of a brain wave, but of a stage of sleep characterized
    by fast brain waves, selective muscular paralysis, rapid eye movements,
    and dreaming.  The sequence of sleep stages is 1-2-3-4-3-2-REM-2-3-4-3-
    2-REM...etc.  REM sleep is light; stage 3 delta sleep is deep (20%
    delta waves,) and stage 4 is even deeper (50% delta.)  These slow wave
    stages are thought to have evolved about 180 million years ago, whereas
    REM is believed to have appeared about 50 million years later. 
    
    Virginia
    
    

    the monitor from Radio Shack is not for Brain waves. It is a GSR
    (galvanic skin response)monitor that sells for about 14.95. There
    is a relationship between emotions, arousal and the conductivity
    of the skin that is amplified and made audible. This is the type of
     monitor that Scientology  uses in auditing.
       There seems to be more excitement now about various schemes to
    drive brain waves rather than change them by feedback. Hemisync
    works on this principle. By apply two slightly different frequencies
    to each ear, the beat(difference)  between the two is supposed to
    entrain the brain waves. I tried them with no effect. At certain
    frequencies of strobe flashes I have found a slight enhancement
    of imagery. The basic circuitry for brain wave biofeedback is actually
    pretty straight  forward, I put one together out of radio shack
    parts once. The biggest problem I had was with electrodes. The
    slightest shift causes it to go out of range. I eventually gave
    up. 
    
    	Is there anyone out there who can help me with a question?
    Is it possible to find software to do real time frequency analysis
    of brain waves? I would like to use the output of an a/d converter
    and analyze the result by amplitude at various frequencies between
    1 and 30 hertz. I vaguely remember something about Fourier transforms,
    but I'm not that competent mathematically. Years ago I'm sure that
    it was cheaper to build umpteen high Q bandpass filters, but the
    resulting equipment  is very expensive-- $4000+. It seems that it
    might be possible to be make a really useful biofeedback machine
    using an expensive(but widely availabel) PC to do the signal
    processing.
    
    					john turner

    I think it might also be helpful if we 
    mention that there are at least two different applications of
    biofeedback :
    
    (1) the research applications (how does the mind and body operate,
    and what kind of interesting predictions and extrapolations can we make
    ?); and 
    
    (2) the clinical therapeutic applications (teaching people how 
    to lower their blood pressure, manage stress, and so on).
    
    	Some of the interesting classics in this field dealing with
    	the first application include :
    
    		Elmer and Alyce Green's "Beyond Biofeedback," 
    		Barbara Brown's "SuperMind," and "The Awakened Mind,"
    		by Coxhead and Cade.   
    
    For the second type of application,
    any somatic process that can be measured continuously,
    accurately, and quickly can be used in
    biofeedback, but the ones that relate to overall stress level
    seem most useful.  The temperature of any surface part of the body,
    the resistance of the skin, the electrical currents in the 
    muscles, and the blood pressure are common examples.
    
    Various companies in the U.S. sell GSR and temperature measuring equipment 
    in the $50-$100 range, and even little business cards with LCD thermometers
    you can play with to try to lower your finger skin temperature (related
    to overall stress level due to constriction of capillaries under
    stress).   I used to sit with one in meetings just to watch
    my stress level rise and see if I could lower it.  Soon, everyone
    was holding them.  It's like group therapy :-) ....
    
    	warm regards,
    
    	>Todd>

    Digital Signal processing should be quite straight forward and well
    within the capabilities of modern micros.  You'll only need to sample
    at about 60 samples/second to accurately represent everything 30Hz
    and below.  Even pushing that up to 100 samples/sec so that you can
    use a cheaper filters.  I have programmed a real-time FFT for 20000
    samples a second -- it did use a special processor containing 9 micros
    but that was almost 20 years ago and 200 times the data rate.  Besides,
    a Fourier transform is probably overkill for this problem -- its quite
    likely that some simple digital filters would be all that you needed.

    I wouldn't dismiss analog solutions too quickly.  The guts of high-Q
    bandpass filters adequate for this purpose can be purchased for less
    than a dollar, or a few dollars at most.  Just add some caps, resistors
    and a powersupply, voila.  PLL (Phase-Locked Loop) chips might also
    be applicable -- they could be used to "track" the strength and
    principle frequency of the waves in each band, rather than simply
    indicating alpha/no-alpha.  The expense of commercial EEGs are to
    allow nuances which are not of interest here -- generally 16 or more
    channels for one thing.

    In my files at home I have plans for an EEG card for a PC.  It includes
    a BASIC program to display a two channel histogram of amplitude in
    various frequency bands.  I forget how much is done in software vs
    digital hardware vs analog hardware, but it appeared in one of the
    popular electronics hobby magazines not too long ago.  I'll try to
    remember to check tonight.  I also may have plans somewhere from a
    long time ago (late 60's, early 70's) for a "biofeedback brainwave
    monitor", I'll see if I can find it.

					    Topher

    	Thanks for the encouragement, Topher. The reason for the complexity
    that I envisioned, is probably better explained by Maxwell Cade
    in his book The Awakened Mind. He experimented for several years
    with standard biofeedback equipment with rather haphazard results.
    Eventually he came up with the Mind Mirror. This device consists
    of 12 channels for each side of the brain with outputs to bargraphs.
    Each channel had a bandpass of about 2 HZ. 
    This adds up to 384 LEDs and 24 4 pole filters. Its not hard to
    see why this device sells for $4000. From examining Cade's book,
    I suspect that 3 channels for each side would be sufficient to get a
     recognition of the target states.(Cade found that when there were
     symmetrical peaks in theta,alpha and beta people began to report a
    sort of training wheels effect or aha experience)
       Since Alpha, for example needs to be shifted down in frequency
    from 10-12 Hz to 7-8 Hz extra info would probably make it easier
    to use.
    Cade found that people who had meditated for 6 to 10 years were
    usually producing what he calls the 5th state, at least they were with
     they're eyes closed. With additional training  they learned to maintain
    this state during normal activities. Cade also found that many
    meditators were not getting the right idea and thus failing to make
    any progress at all, sometimes with knowing it. 
    
    	Anyhow, I hope that explains a little better the rationale for
    my requested complexity.
    I am intrigued by  the EEG project that you remember seeing, Topher, it
    sounds like it might be a ready made solution. I hope you can dig
    it out.
    						john
    

    Hi John T,

    I spent some time meditating with Max Cade and using
    a mind mirror. If there's any background I can fill in
    then please let me know.

    Apart from that, I think technology has moved on and that
    a common PC will do the job (and better). The main problem
    are the leads and attaching them to the scalp and the
    amplifier (which needs to be carefully isoalted from the
    leads because of risks to your health!). The programming
    would not be a significant problem. Micros go fast enough
    to FFT at the rate you'd need.

    If anyone finds something I'd be interested. I'm sure there's
    a slot in card out there somewhere.

John D.

    PS. I'm on holiday next week, so there'll be a delay in
    my responses.    

    Found it.

    The article in question appeared in two parts, in BYTE magazine, June
    and July, 1988.  It appeared in the column "Ciarcia's Circuit Cellar".
    I misfiled both of these and only have the second part, but apparently
    the hardware digitizes four channels of input and transmits it over
    a serial, RS232 serial port (which means it can be plugged in virtually
    unchanged into any computer).  He did an FFT, written in assembly,
    on the computer (a PC), but was apparently able to keep up with 2
    channels at a time -- at least if he was going to keep up with the
    rest of his display processing.  I suspect that some more sophisticated
    processing -- perhaps using the Hartley Transform rather than the
    Fourier Transform -- might get better results.

    A kit containing most of the components ("Does not include battery
    holders, batteries, scalp electrodes, or connecting cables") could be
    had from Steve Ciarcia's personal business CCI.  I suspect it still
    may, although the Circuit Cellar is no longer a BYTE feature.  The
    cost then was $179, including the PC program and a "user's manual"
    (which is probably an expanded version of the article).  I would
    inquire rather than just sending money since the price may have
    changed, their may be different models or additional software etc.
    The address is:

		    CCI
		    PO Box 428
		    Tolland, CT 06084
		    (203)875-2751

    [NOTE, I post this information for the convenience of NOTErs.  I have
    no financial stake in CCI, nor can I recommend from personal experience
    this product or other products of CCI, although the Circuit Cellar
    always struck me as a creative and competent engineering column].

					Topher

    re.  .16
    
    	We'd love to hear your impressions. Books tend to put a spin
    on things that direct contact cuts through. Did you take Cade's
    courses? I understand that he's dead now. Is anyone carrying on the
    research? 
    
    re. .17 I called CCI and the biofeedback kit is still available
    for $179.00 I blew my "toy"  budget on an MOE biofeedback machine,
    so I will have to hold off on further investment. But I'll offer
    my impressions If I have any. I may try to scrounge some Q-bus A/D
    device and stick it in the office Micro.....
    
    john