An epilepsy diagnosis was made on an 11-year-old girl. Various antiepileptic medications were prescribed but breakthrough tonic-clonic and absence seizures continued. Brain surgery was explored but she was found to have bilateral epileptic foci. Surgery, therefore, was ruled out.1
A year later Vagus Nerve Stimulation (VNS) was
considered a possible treatment. In VNS a battery device is implanted under the
skin in the chest and its electrodes are threaded under the skin and then the
side of the neck is opened by the surgeon and placed on the left vagus nerve
inside the neck. The left and the right vagus nerves course from both sides of
the brainstem in the lower part of the skull down to the chest and the stomach.
The right vagus nerve, however, is not used as it primarily affects the heart.
The Federal Drug Administration (FDA) has
approved vagus nerve stimulation for people who:
- Are 4 years old and older.
- Have focal epilepsy where the brain activity that causes
seizures happens in one area of the brain only.
- Have seizures that aren't well-controlled with medicines.
Vagus nerve stimulation also is considered for people with
generalized epilepsy.2
Research has
shown that VNS theoretically may help control seizures by: Increasing blood
flow in key brain areas; raising levels of some brain substances (called
neurotransmitters) that are important to control seizures; changing EEG
(electroencephalogram) patterns during a seizure.
Stroke recovery: For people who are
recovering from a stroke, vagus nerve stimulation has been FDA-approved
when combined with rehabilitation. Vagus nerve stimulation paired with
rehabilitation may help people recover function in their hands and arms after a
stroke.2
Risks:
Having a vagus nerve stimulator implanted is safe for most
people. But it does have some risks, both from the surgery to implant the device
and from the brain stimulation.
Surgery risks
Surgical complications with implanted vagus nerve
stimulation are rare and are similar to the dangers of having other types of
surgery. They include:
- Pain where the cut is made to implant the device.
- Infection.
- Difficulty swallowing.
- Vocal cord paralysis. This is usually temporary but can be permanent.
Side effects after surgery:
Some of the side effects and health problems associated with implanted vagus nerve stimulation include: Voice changes. A hoarse voice. Throat pain. Cough. Headaches. Shortness of breath. Trouble swallowing. Tingling or prickling of the skin. Trouble sleeping. Worsening of sleep apnea.
For most people, side effects are tolerable and typically
lessen over time. However, some side effects may remain for as long as you use
implanted vagus nerve stimulation.
Adjusting the electrical impulses from the battery device
under the skin on the chest can help minimize these effects. If you can't
tolerate the side effects, the device can be shut off.
Then it can be programmed to
deliver electrical impulses to the vagus nerve at various durations,
frequencies, and currents. Vagus nerve stimulation usually starts at a low
level. It gradually is increased depending on your symptoms and side effects.
Stimulation is programmed to
turn on and off in cycles — such as 30 seconds on, five minutes off. You may
have some tingling sensations or slight pain in your neck. You also may have a
hoarse voice when the device is on.
Results
If you had the device implanted for epilepsy, it's
important to understand that vagus nerve stimulation isn't a cure. Most people
with epilepsy won't stop having seizures. They'll also likely continue taking
epilepsy medicine after the procedure. But many might have fewer seizures — up
to 50% fewer. The seizures also may be less intense. It can take months or even
a year or longer of stimulation before you notice any significant reduction in
seizures. Vagus nerve stimulation also may shorten the recovery time after a
seizure. People who have had vagus nerve stimulation to treat epilepsy may
experience improvements in mood and quality of life.
1) Touching
a Nerve. Brain and Life April/May 2023 p32-35.
2) The
Mayo Clinic has reviewed VNS at https://www.mayoclinic.org/tests-procedures/vagus-nerve-stimulation/about/pac-20384565
Lance Fogan, M.D. is Clinical Professor of Neurology at the David Geffen School of Medicine at UCLA. His hard-hitting emotional family medical drama, “DINGS, is told from a mother’s point of view. “DINGS” is his first novel. Aside from acclamation on internet bookstore sites, U.S. Report of Books, and the Hollywood Book Review, DINGS has been advertised in recent New York Times Book Reviews, the Los Angeles Times Calendar section and Publishers Weekly. DINGS teaches epilepsy and is now available in eBook, audiobook, soft and hard cover editions.
