>Eric E. Sabelman, PhD
>
>October 9
>
>Brain Control: Surgical Technology for Fixing the Malfunctioning
Brain
>
>
> It is now possible to treat Parkinson’s Disease and similar
movement
> disorders by implanting a multi-contact electrode into the region
of
> the brain that causes tremor and stiffness. Such Deep Brain
> Stimulation (DBS) electrodes do not cure the disease, but relieve
> symptoms when medication is no longer effective – the definition
of a
> “neuroprosthesis.” Unlike older surgical treatments that
simply
> burned out the malfunctioning region, the stimulation parameters
of
> the DBS pulse generator can be tuned (varying contact selection
and
> polarity, pulse rate, width and amplitude) for best effect as the
> patient’s disease progresses. Since DBS recipients may be
given
> partial control over stimulation parameters, the patient’s
> participation in determining long-term outcome differs from other
> neurosurgery.
>
> DBS surgery can be beneficial whenever a precise causative
location in
> the brain can be reached by a straight path without passing
through
> life-dependent structures. Thus, DBS is unsuitable for
problems that
> afflict the whole brain, like Alzheimer’s Disease.
Surprisingly,
> besides movement disorders, DBS targets have been identified for
> neuropsychiatric syndromes: Tourette’s Disease,
obsessive-compulsive
> disorder, and some forms of depression and behavioral
addiction. Does
> this mean that everyone with a treatable “illness” will be given a
DBS
> implant? Or that DBS surgery will be used to enforce
“normal”
> behavior? Not very likely, given the extreme difficulty of
deep
> electrode implantation surgery, which requires accuracy an order
of
> magnitude better than “routine” brain surgery.
>
> Dr. Sabelman is the founder of Pro-Zooics Research, which has been
> engaged in biomedical design & consulting since 1979. Eric has
been on
> the core staff of the VA Palo Alto Rehabilitation R&D Center,
where he
> investigated wearable computers for human body motion analysis,
acute
> spinal cord injury patient care, and tissue engineering for nerve
> repair and reconstructive surgery. He is an Adjunct Lecturer in
> Mechanical Engineering at Santa Clara University, and affiliated
with
> the Biodesign Program at Stanford. He will discuss his current
work at
> Kaiser Permanente on Deep Brain Stimulation for treatment of
> Parkinson's Disease.
>
Eric began by explaining that a Deep
Brain Stimulation system looks a
lot like a heart pacemaker, and is installed in about the same place in
the patient's body. The main difference is that there is a cable that
extends up the patient's neck to the electrodes in the brain from
there.
Then he showed us a list of diseases that DBS is proven to be effective
in treating, including Parkinson's which Kaiser employs him to install
DBS equipment to treat.
Eric showed us a beautifully stained
slide of a stem cell and explained
that stem cell research could come up with competing treatments for
Parkinson's and other diseases. However, at this point in time there is
not the technology to precisely place the stem cells, and nobody has
figured out how to encourage them to grow in exactly the directions
desired. Placing the wires and probes from a surgical standpoint is
easy by comparison.
Eric showed us a CAT scan of the human
head, with these small almond
shaped areas highlighted. He explained that for the surgery to have the
desired effect, the probes must be placed within half a millimeter of
the right location. Enormous care goes into this. After a patient has
qualified for the surgery their head is extensively studied, to
identify
the exact path to insert the probe through and the exact location where
it needs to end up. In planing the operation, care must be taken to
keep
from severing arteries, which could have the effect of a stroke.
Installing DBS equipment is an ordeal.
The patient's head is held still
for the procedure by a viselike apparatus on a steel post bolted to the
floor. Because one way to get feedback on where the probe is to turn it
on and ask the patient "how does that feel", patients are awake during
surgery, which could take a full day. The other way to get feedback
during surgery is to take X-rays to see where things are, and this is
also done. Once that is done, they wait for the wounds to heal before
powering it up.
Kaiser now installs DBS equipment in
about a person a month here in
Northern California. Parkinson's patients do show that the technique is
a good therapy in many cases.
During Q&A the following points
came up:
Brain stimulation signals range from 3
to 7 Volts, are pulses of only a
few milliAmps for a few milliseconds, and are generally between 2-300
Hertz.
If surgery accidentally causes a
patient to have a seizure, they have
emergency procedures for cutting them out of the equipment that keeps
them still during surgery. The same procedures are invoked when there
is
an earthquake during surgery.
It's hard to tell, but probably Kaiser
spends $50,000 to $100,000 per
DBS installation.
Most Parkinson's patients ready for DBS
are in their '70s or later,
although the number of patients as young as 40 is rising.
The URL list is below. Thanks to
Dave Jaffe for looking up
reviews of
the Wired article and Stanford MDs' profiles.
A Shock to the System
From: Wired Magazine - March 2007
By: Steven Gulie
“To slow the progress of Parkinson’s
disease, doctors planted
electrodes deep in my brain. …”
[First-hand report on DBS surgery at
Stanford]
Deep brain electrodes - from the inside
[review of Wired article]
A first-hand account of deep brain
stimulation [review of Wired
article]
photogallery of DBS surgery at Emory
University
animation of the placement of DBS
electrodes and pacemakers
Jaimie Henderson
Helen Bronte-Stewart
Gary Heit
Re-Wired for Life Foundation
WE MOVE - resource for movement
disorder information
American Society of Stereotactic and
Functional Neurosurgery
Parkinson's Disease Research Web (NINDS
Neurodegeneration Group)
American Parkinson Disease Association
Parkinson's Disease Resource Center
(MedScape)
the Parkinson's Institute in Sunnyvale
Tian Harter