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Brain Mapping the Chemically Sensitive
 by Donald L. Dudley, M.D., Seattle.


Donald L. Dudley, M.D. was one of the speakers at the
Well Mind Association 1992 Symposium in October.

He presented new research that he is doing on identifying
actual injury in the brains of sensitive individuals on
exposure to substances using electroencephalogram and
evoked response measuring techniques and exposing them
to common chemicals.


"My interest in chemical sensitivity began about 18 months
ago when patient after patient challenged me. The final
challenge came from someone who persisted for about six
months in telling me that there must be some way of
quantifying chemical sensitivity, since the symptoms were
so overwhelming.

I first thought if it were possible to be quantified, somebody
should have done it before. Then I thought that maybe people
aren't doing the before and after testing that we did in the
1950s.  So I agreed with this patient to set up a protocol to
test her before and after she was exposed chemically to
common ordinary, technical things that we use in neurological

In other words, all the testing that I am going to show are things
that are available in virtually any neurological laboratory.  
Anybody can do exactly what I am showing you.

"I had a lot of difficulty in terms of how a smell changes something
in the brain. I studied the embryology of the nose and the olfactory
apparatus and learned that indeed the cells that produce hormones
travelled up the olfactory nerve to the brain and the reason you
have hormones that affect the thyroid gland and other parts of
the body is because these cells migrated up the olfactory nerve
while you were being developed in your mother's womb.

In other words, the cells weren't developed in the brain, they
travelled up the olfactory nerve.

"The same thing happens today. When you smell something,
the signal actually travels up the olfactory nerve and he odour
actually affects the brain itself.

Odours that have within them five or less carbon atoms are the
odours that affect the brain, usually. The reason they affect the
brain is that they release molecules in the centre of the cortex
of the brain that have 4 to 5 carbon atoms -glutamate and aspartate.

They are neurotransmitters. These neurotransmitters, when
released, irritate the cell and finally open calcium channels that
kill the cell.

So you can smell something and actually become intellectually
reduced, have a reduction in thinking, concentration, and memory.
You can actually have problems with depression and fatigue and
you can have muscle problems with weakness and inability to

These are things that can happen just by smelling something
that releases the aspartate and glutamate, the neurotransmitters
in the brain. This, to me, was a startling new fact. I had no
idea that smelling something had such a powerful reaction on
what happened inside the brain."

Dr. Dudley then showed a series of slides as follows:

     *An electroencephalogram and evoked potential apparatus on
       a patient.

     *A normal electroencephalogram of a patient before being
       exposed to a chemical.

     *An abnormal electroencephalogram of the same patient after
       exposure to a chemical, at which time the patient developed
       an occipital seizure at about 6 cycles per second. The patient
       was unable to respond, was in a dreamlike state and tended to
       have movement in the limbs.

     *A brain map of a patient before exposure showing a normal

     *A brain map of the seizure in the occipital lobe. Remember,
       this is because the patient had smelled something. The seizure
       shows up in great clarity in various colours.

     *A brain map showing the seizure going into the left temporal
       lobe, affecting speech and, to some degree, movement.

"The electroencephalogram and the brain mapping is an interesting
way of looking at these problems. But a more interesting way is
called evoked potentials. In this methodology we put a signal,
an electrical impulse, into a nerve in the leg or the hand or
into the retina of the eye or the ear and we follow the electrical
signal through that nerve to the cortex of the brain and find out
what happens to it. We are looking at intellectual problems,
emotional problems, and physical problems after smelling

     *A measurement of transmission of nerve impulse from ankle to
       brain in milliseconds before exposure to smelling a chemical;
       also measure of energy in microvolts.

      *After smelling the substance, the signals coming in from the
       leg are very weak and arrive slowly.

      *A normal signal from an arm nerve.

      *After exposure the signal from the arm is much slower and
       weaker (by more than half). The nerve is actually injured at
       the level of the brain.

      *A normal signal from the retina of the eye called a pattern
       reversal evoked potential.

      *The signal from the retina after the patient has smelled
       something that she is sensitive to. The signal is weaker and

      *A normal cognitive/auditory evoked potential. This measure
       the time it takes for a thought to be formed in the brain after
       you hear a signal in the ear.

     *When the patient is exposed, the signal is again slower and
       weaker.  The person is having trouble with memory.

"Over the last eight or nine months we have had this system in
place trying to show people what happens when they are exposed
to these toxic chemicals.

"We've had a lot of difficulty because it's become a political
issue. The data I have just showed you I haven't been able to get
to anybody who has authority. When you try to put this kind of
information in a scientific format, it's rejected because "it
doesn't happen." People know it doesn't happen and they think
that you are faking. It's very difficult to get this information
into the public forum."

In response to questions:

"As a treatment, blockers of glutamate and aspartate are used
to stop the reaction before it gets started. Prior to treatment
a patient would walk by someone with perfume on and their whole
day would be ruined, they're practically unable to think. With
treatment they have no reaction at all. "Peptides are also used
and work in a different way to fine-tune the brain and treat the
reaction after it occurs."Smell is one of our more refined senses
and very much associated with memory.

I think as we continue this research, we'll find that memory is
virtually wiped out with certain smells. Glutamate and aspartate
have 4-5 carbon units. Compounds that have fewer than that tend
to set off a reaction; whereas compounds with more tend to block
the reaction, according to a recent book on receptors in the brain.

"Some common substances that cause reactions are formaldehyde,
methyl ketone, ethyl ketone, acetone, etc. There are blocking
agents to offset these, but they must be used very carefully as
they can make you psychotic.

"A typical patient comes in and says 'everyone says I'm crazy
because I smell certain things and have trouble thinking and
concentrating and get weepy' and so on. They bring in 3-4
chemicals to test and I show them the changes in their brain
after exposure to them and they say "Wow, it really does
happen, I really have to stay away from these things."

"The minimum time of exposure to a substance to get a change
in the brain seems to be about 30 minutes. But the time to get
over the exposure was sometimes weeks.

These people are really taking a risk. They say, 'you caution me
about this (testing substance), but I'm exposed every day on the
job and people are telling me that exposure does nothing.'

"As houses become tighter and we get more and more exposure
to chemicals, I don't know how to advise people to deal with
them. When I was a kid, houses had to exchange the air every
20 minutes or hour. Now they are made airtight. Old builders
would say that people get sick if they build a house so it
changes air every few minutes. And I think they were right."


Dr. Dudley is the Medical Director of the Washington Institute
of Neurosciences. Seattle, Washington. He has published 100
articles, some on brain injury, some disorders, and psychiatric


From Well Mind 1992.  
His written material on brainmapping and chemical sensitivity,
including photocopies of slides is available for perusal at the
Mind Office.    Tel: 206-322-0030.


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