- [Kevin Chou] So movement disorders are
neurological disorders that basically
cause abnormal movements.
The two most common movement disorders
that we see here at the University of Michigan
are Parkinson's disease and essential tremor.
Parkinson's disease is a progressive neurodegenerative
disorder, meaning that it gets worse slowly over time.
That cause tremors, bradykinesia,
which is a fancy term meaning slowed movements,
and rigidity, or stiffness in the limbs.
The essential tremor is a condition that causes
tremors in the hands, the head,
and sometimes the voice.
And the tremors in essential tremor are most
prominent when using the hands, so these patients
often have difficulty writing, drinking, eating
because the hand shakes when they do that.
Deep brain stimulation is a surgical procedure
where you place electrodes in the brain.
And then they're connected to a pacemaker-like
device in the chest. When you turn on the stimulation
it can help the symptoms of both Parkinson's disease
and essential tremor. So in the case of a Parkinson's
disease patient, they would qualify for deep brain
stimulation when their medications aren't quite
working as well as they should. They may have
fluctuations in their movement, where things are good,
and then things kind of aren't so good throughout the day.
Alternatively, some Parkinson's patients have tremor,
in which the medications don't really help the tremor,
and they would also be good deep brain
stimulation candidates. In the case of
essential tremor, these are patients in whom
the medications for essential tremor do not work
for their tremor. So then they would be candidates
for deep brain stimulation.
- [Parag G. Patil] When we have certain diseases
the signals, the electrical signals, traveling
around the brain become disordered. A little bit
like when an orchestra is first tuning
and everyone is kind of playing whatever
they want to play. What deep brain stimulation does
is it provides a regular set of electrical impulses
that kind of drown out that noise
and let the natural impulses go through.
So whether it's Parkinson's disease or tremor,
deep brain stimulation helps with the symptoms
by getting rid of the bad or disordered signals
that are traveling in the brain.
The first stage of deep brain stimulation surgery
is the placement of the electrode.
What's involved here is putting a lead
that is about the size of a piece of spaghetti
precisely into the brain, into a spot
that's about the size of a peanut.
To accomplish this we need to be able to know
we're exactly where we want to be.
We do this in a couple of different ways.
The first step, is to do imaging, using a magnetic
resonance scanner to get a very good picture
of where we want to go. Second, there's an entire
technology called frame based stereotaxy.
Which puts a coordinate system into the brain
so that we know exactly what coordinates
that target is located at.
In the operating room, we want to test and retest
to make sure we're in exactly the right spot.
The first kind of testing we do, is called
microelectrode recording. Microelectrode recording is
where an electrode smaller than the dbs electrode
listens to the sounds being made by the individual
neurons in the brain. The sounds that are made
by the neurons themselves tell us where we are.
Next, and most important, is intraoperative testing.
Everyone's brain is not wired the same,
and so even if you're exactly where you want to be
not every patient will have exactly the same
therapeutic effect from an electrode in that location.
This is where having Dr. Chou and Karen Kluin
come to the operating room for testing
is so important. What we do in the operating room is
we test each of the contacts of the dbs electrode
and see what the therapeutic effect is.
And also what the side effects are of stimulation
location. On occasion, what we discover, is that
the patient has side effects from stimulation,
and we need to move the electrode just a little bit.
Deep brain stimulation is all about precision,
moving even a millimeter can make all the difference.
The second stage of the procedure is the placement
of the battery. What we do in the first procedure,
is we place the end of the lead underneath the skin.
In the second stage, that skin is then opened,
and a battery, or implantable pulse generator,
is placed in the chest, and a wire going underneath
the skin, connects the two. That second surgery
is done with the patient asleep.
- In the case of Parkinson's disease,
when we turn the deep brain stimulation on,
it often times works in conjunction with medications.
So patients aren't always able to come off the medications,
in fact, many of them need both the stimulation
and the medications in order to help their symptoms.
And on average we're able to reduce medications
in Parkinson's disease by about 50 percent.
In essential tremor the deep brain stimulation
can help the tremor so much that they don't
really need to be on medications for their tremor.