Clinic: How does deep brain stimulation for epilepsy work?
Whoís a good candidate for this treatment? Is it effective?
A: Deep brain
stimulation is a technique that uses a wire placed permanently
in the brain to send electrical pulses to the brain. It has
been approved by the Food and Drug Administration to treat
epilepsy that hasnít responded to other forms of therapy. In
most people, deep brain stimulation doesnít completely
eliminate seizures caused by epilepsy, but it can
significantly reduce seizures.
Epilepsy is a
central nervous system disorder. In a person with epilepsy,
nerve cell activity in the brain becomes abnormal, causing
seizures and sometimes loss of consciousness. The symptoms of
a seizure can vary widely from one person to another. For
example, some people with epilepsy stare blankly for a few
seconds during a seizure or appear confused. Others may lose
consciousness and have repetitive jerking of their arms and
epilepsy requires treatment because seizures can be dangerous
during activities such as driving. Medication to reduce or
eliminate seizures usually is the first step in treatment. For
about two-thirds of people with epilepsy, seizures are
effectively controlled with the first or second anti-seizure
drug they try.
doesnít provide adequate seizure control, surgery may be an
option. Epilepsy surgery typically involves removing the area
of the brain thatís causing seizures. That approach only
works, however, when the place within the brain thatís
triggering the seizures can be identified clearly. In some
people, thatís not possible. Itís those individuals who
are most likely to benefit from deep brain stimulation.
stimulation for epilepsy involves one surgery where you are
asleep. During surgery, the surgeon implants a thin wire lead
with several contacts, or electrodes, at the tip into an area
deep within the brain called the "thalamus." The
thalamus is basically a relay station that distributes signals
that come from the bodyís senses to other regions of the
imaging exam confirms that the electrodes are placed properly,
a battery-operated device called a pulse generator is
implanted under the skin near the collarbone. Wires running
from the electrodes in the brain are placed under the skin and
connected to the generator. The generator is programmed to
send continuous electrical pulses to the brain.
clinical research trial found that in people with epilepsy
whose seizures didnít respond to other therapies, around 15
percent became seizure-free for more than six months after
deep brain stimulation. Although that number is fairly low, it
represents significant ó often life-changing ó improvement
for those individuals.
But the goal of
deep brain stimulation typically is not complete relief of all
seizures. Instead, itís used as a method to reduce the
number of seizures a person has. The same clinical trial
showed that between 50 and 60 percent of patients in the study
had a decrease in their seizures in response to deep brain
stimulation. The research also showed that within the group
who did respond, the number of seizures they had continued to
decrease over time.
brain stimulation is a major surgical procedure, the risks
involved are fairly low, compared to other types of brain
surgery. And if deep brain stimulation is found to be
ineffective for a patient, itís reversible. The electrodes
and generator can be removed without injuring the brain. That
makes it an attractive option to consider for people with
epilepsy who havenít had success with other treatment and in
whom the location within the brain where the seizures arise
cannot be pinpointed.