Blog #154: VAGUS NERVE STIMULATION BENEFITS EPILEPSY

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.