When To Have Vagus Nerve Stimulation For Epilepsy

Vagus nerve stimulation (VNS) is a therapy that uses electrical impulses to stimulate the vagus nerve. The vagus nerve is one of the 12 cranial nerves in our bodies and extends from the base of the brain to the neck, heart, lungs, and gut. Each of us has a pair of vagus nerves on both the left and right sides of the body.

The nerve plays an important role in several body functions, including heart rate regulation, digestion, and immune system response. In the late 1980s, doctors discovered that stimulating the vagus nerve can treat epilepsy (a neurological disorder that causes seizures).¹

How does vagus nerve stimulation work?

While there is no definitive answer to how VNS works, recent research has suggested a few different hypotheses in an attempt to answer this question.²

One such hypothesis is the ‘synchronization theory,’ which proposes that seizures may occur when various brain areas are overly synchronized. VNS may work by contributing to their desynchronization, decreasing the frequency of seizures. 

Another hypothesis is exemplified in the ‘neurotransmitter theory,’ which suggests that seizures may be caused by a lack of the neurotransmitter gamma-aminobutyric acid (GABA) and norepinephrine in certain parts of the brain. Increases in GABA and norepinephrine, with concurrent decreases in neurotransmitters like glutamate, have been associated with decreased frequency of seizures.

The cerebral blood flow theory hypothesizes that seizures occur due to a lack of blood flow to key brain areas. Some researchers have demonstrated that VNS increases blood flow to all areas of the brain and posit that increasing blood flow may reduce seizures. 

What happens during vagus nerve stimulation surgery?

VNS surgery is a minimally invasive procedure that uses electrical current to help reduce the seizure frequency.

If you are undergoing vagus nerve stimulation surgery for epilepsy, your doctor will implant a programmable vagus nerve stimulator in your upper chest through a small incision. Afterward, the doctor will attach the lead wire of the stimulator to the left vagus nerve through a second incision on the left side of your neck. The system will then be tested to ensure it works before the incisions are stitched up. 

Although many people choose general anesthesia, you can have the surgery while staying conscious. If you choose this option, your doctor will give you local anesthesia that will numb your neck and chest during the surgery, but you'll be awake.

Doctors usually perform vagus nerve stimulation surgery on outpatients since it's a short surgery that takes an hour or an hour and a half, meaning you can go home on the same day as your procedure. 

How VNS device works and what to expect

The VNS device sends regular electrical impulses to your brain through the vagus nerve. This implantable device is similar to a pacemaker. In fact, some people call it a “pacemaker for the brain.”

Doctors usually recommend starting the vagus nerve stimulation two weeks after implantation. By delaying the operation, the incision site will have time to heal and discomfort will be avoided.

When you visit your doctor two weeks after the implantation, they program the device by setting the strength and duration of the impulses. The device will go on and off based on the set time intervals.

The healthcare provider will also teach you how to control the VNS device in magnet mode. You will learn how to swipe a special magnet across the left part of your chest to get an additional electrical burst in order to stop or reduce the strength of the seizure.

The latest VMS models can also monitor heart rate increases related to seizures. A sudden increase in the heart rate (according to your parameters) triggers automatic stimulation for seizure control.

After the implantation, you would need to visit the doctor every two weeks so they can see how well the device is working and make adjustments if necessary. Later, the time between visits can increase to two to six months.

Battery life

Batteries in new VNS devices can last between 6 and 12 years.³ When the battery gives out, your healthcare provider will replace the device.

Benefits of vagus nerve stimulation therapy

There are several benefits to vagus nerve stimulation treatments for epilepsy. The stimulation can help to:

• Improve seizure control in people with epilepsy. It is important to note that VNS is not a cure for epilepsy, and patients will still need to take anti-epileptic medications. VNS does, however, reduce the number, duration, and severity of your seizures.

• Reduce inflammation and pain in people with epilepsy

• Improve cognitive function in people with epilepsy

• Reduce hospitalization rates and cost of healthcare for people with epilepsy

In general, vagus nerve stimulation treatment improves the quality of the patients who undergo the procedure. About 50% of epileptic patients experience a 50% reduction in seizures two years after the treatment.⁴

What does the vagus nerve stimulation device feel like?

The stimulator is usually quite comfortable, and you won't feel the electrical pulses it sends to your brain. However, you may experience a tingly but painless sensation in your neck.  It's uncommon for patients to feel pain with the stimulator on, but if you experience discomfort, speak to your doctor about reprogramming the stimulator to a lower frequency.

Eligibility for the vagus nerve stimulation treatment (VNS)

According to the US Food and Drug Administration (FDA), the following people are eligible for vagus nerve stimulation surgery:⁵

People with epilepsy who are four years and older and have:

• Partial seizures that haven't responded to other treatments

• Generalized seizures that frequently occur and are unresponsive to medicine

Individuals who are 18 years and older and have:

• Severe depression that hasn't responded to at least four antidepressant medications

• Migraines that don't respond to other forms of treatments

• Moderate to severe upper extremity motor deficits associated with chronic ischemic stroke

Who should not receive vagus nerve stimulation (VNS)?

You are not a good candidate for VNS if you:

• Have a bleeding disorder, or you are on blood-thinning medication

• Have a pacemaker or any other implanted electronic device in your body

• Are pregnant

• Have significant breathing or lung conditions, e.g., asthma, sleep apnea, and emphysema

• Have peptic ulcer disease

• Have poorly controlled diabetes

• Have problems with your autonomic nervous system or dysautonomias 

• Have heart arrhythmias

• Only have one vagus nerve

• Previously had schizophrenia or any other similar disorders

How to prepare for vagus nerve stimulation surgery

If you are considering VNS surgery, here are some things you can do to prepare:

Evaluate all your options

Before the surgery, discuss it with your doctor. Ask your doctor if other medications, diets, and lifestyle changes can reduce seizures. If both of you agree that surgery is the best option, proceed.

Learn about the procedure

Read various documents about the process and choose between local or general anesthesia during the surgery. If you are a parent or a guardian of a child scheduled for surgery, it's best to book them for general anesthesia. The doctor will give them a sedative, and your little one will wake up after the surgery.

Go for any required blood tests

The test will reveal if you have any underlying conditions that may cause complications or rule you out as a candidate for the surgery.

Have your support system in place

Although vagus nerve stimulation surgery is short, it doesn't hurt to have family and friends waiting outside the operating room. Knowing they are there for you can help you relax, especially if you choose to go with local anesthesia.

Are there any side effects of vagus nerve stimulation surgery?

As with any type of surgery, vagus nerve stimulation surgery is not without potential complications and side effects. However, these complications and side effects (depending on which symptoms arise) may be easier to manage than frequent seizures. Be sure to consult with your doctor about the following complications and side effects of VNS surgery.

Complications

Like most surgeries, there is always the risk of complications. 

Common complications include the following:

• Infection

• Pain at the incision site

• Scarring

• Damage to the vagus nerve, structures surrounding the vagus nerve

Side effects

VNS surgery has a few troubling side effects. However, the benefits outweigh the risks and side effects. The most common side effect of vagus nerve stimulation is a tingling sensation in the neck. 

Other possible side effects of the surgery include:

• Sore throat

• Hoarseness of voice

• Shortness of breath

• Coughing

•  Difficulty swallowing

• Chest pain

• Nausea and vomiting

• Lightheadedness

Most of these side effects fade within a few days and won't cause long-term problems. Some of the more serious and long-term side effects include:

• Vocal cord paralysis

• Infection

• Horner’s syndrome (where a nerve is affected, causing changes in the eye, eyelid, and sweating)

• Muscle weakness in your lower face (facial muscle paresis)

• Your heart may stop beating (cardiac arrest)

• Sudden unexplained death (occurs more rarely than naturally seen in a population of people who have epilepsy)

• Mechanical complications like a break in the lead wire or device malfunction

Care and precautions with the vagus nerve stimulation device

Once the stimulator is in place, there are certain things you can do to avoid damage to it.

• Inform your doctor of the device before taking any MRI scans

• Keep your distance from devices such as loudspeakers and magnets, as they can interfere with the working of your stimulator

• Avoid playing rough sports to prevent physical damage and trauma to the device

• Avoid areas that have pacemaker warning posters

The lowdown

We are privileged to be in an era of technology where medicine keeps evolving and solving the problems we face in our daily lives. Through vagus nerve stimulation treatment, people with epilepsy can lead a better lifestyle with fewer seizures. It also helps find a way of stopping and ending a seizure promptly.

Remember to consult your doctor if you experience pain or discomfort after the surgery that interferes with your daily activities.

Frequently asked questions

Can I still have a seizure with the vagus stimulator device?

Vagal nerve stimulation is not a cure for epilepsy but has been shown to reduce the frequency, duration, and severity of seizures for most people. Sometimes, seizures still happen even when the device is working correctly.

If you detect a seizure by noticing the change in your heartbeat, you can stop it from happening by using a handheld magnet. Swipe the magnet next to your chest, where the stimulator will send a strong signal to your brain to stop the seizure from happening. If you live with friends or family, inform them of this hack so they can stop the seizure for you in case you cannot do it for yourself.

Newer VNS models can detect a rise in heart rate, automatically triggering an extra burst of stimulation to help stop the seizures.

Can I turn off my vagus nerve stimulator device?

It's possible to turn off the stimulator, although doctors advise against it. Many patients turn it off during public speaking since the stimulator may cause their voices to become hoarse.

You can turn off the device by swiping the handheld magnet that your doctor gave you after your surgery. Remember to turn the stimulator back on as soon as possible.