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alpha waves

Dag Stenberg stenberg at cc.Helsinki.FI
Fri May 16 04:35:48 EST 1997

In bionet.neuroscience Stephen Black <sblack at UBISHOPS.CA> wrote:
> Well, I'm probably wasting my time speaking to the converted on this
> one, but the alpha wave stuff is a crock. Barry Beyerstein (references
> below) says "Alpha brain-waves are marketed as a way to produce
> relaxation, healing and meditative or occult states. In fact, they are
> related to activity in the visual system and have no proven curative or
> paranormal powers" (Beyerstein, 1985). 

I just chose this entry to get into the discussion. We have been out of
news for a while, and now postings are dropping in in scrambled order.

While alpha-waves and their relationship to relaxation was described in
1929, and while their possible use in feedback setups to give a person
an indication of his/her state of arousal has been in use for decades,
including all this about "inducing relaxed states", I have never been
too impressed with generalizing claims that do not take into account
individual variability.

An anecdotal account from own experience: we used to take the EEG of
medical students as a part of their studies in neurophysiology. Some
could easily relax and produce long runs of alpha on demand, some 
found it difficult. A couple of times, I was the sucject myself, and
found that I can produce alpha only in short runs of 1-2 seconds without
feeling uncomfortably drowsy. In fact, only when I have a nearly
insufferable, disgusting feeling of slackness and exhaustion, do I have
any consistent alpha lasting tens of seconds or more. A different person
might feel pleasantly relaxed during the same EEG state, and the
uncomfortable, drowsy feeling is more characterized by low-voltage theta
than by alpha.
  When we observed this, I found references in the literature indicating
that people with a tendency to vivid visual imagery in general have low
or short-bursted alpha. Since this is a long time ago, I cannot recall
the references without some work. We checked out a few individuals, and
this seemed to apply.
  Without going into this too much, I have remained in the impression
that the mental content and the composition of the EEG are not
necessarily stricly coupled so as to make comparisons between
individuals valid.
  This impression has greatly reduced my own interest in correlating EEG
to mental states.

Dag Stenberg

Dag Stenberg     MD PhD                    stenberg at cc.helsinki.fi
Institute of Biomedicine		   tel: int.+358-9-1918532
Department of Physiology                   fax: int.+358-9-1918681
P.O.Box 9        (Siltavuorenpenger 20 J)   
FIN-00014 University of Helsinki,Finland   


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