The VNS magnet gives you manual control over your vagus nerve stimulator. It has two main functions: swiping it over the generator delivers an extra burst of stimulation on demand, and holding it in place temporarily pauses stimulation. The technique matters, because doing it wrong can produce the opposite of what you intended.
Swiping to Trigger Extra Stimulation
This is the function most people use during a seizure or when they feel one coming on. The motion is simple: swipe the magnet slowly across your left chest, starting near the collarbone at mid-chest and moving toward the left armpit so it passes directly over the implanted generator. The entire swipe should take less than 3 seconds.
Speed and timing are critical here. If you hold the magnet over the generator for longer than 3 seconds, it does the opposite of what you want. Instead of triggering a stimulation burst, it turns the device off. So the goal is a smooth, deliberate pass, not a hover. Think of it like swiping a card, not pressing a button.
When the swipe works correctly, the generator delivers a single extra dose of stimulation at the settings your neurologist has programmed for magnet-activated use. These settings are often slightly stronger than the automatic cycle. The device then returns to its normal programmed schedule.
A caregiver, teacher, or friend can perform the swipe if you’re unable to do it yourself during a seizure. This is one of the main advantages of the magnet system. Many patients keep the magnet on a wristband or belt clip so it’s always accessible, and give a second magnet to someone they’re frequently around.
Holding to Pause Stimulation
If you need the stimulator to stop temporarily, place the magnet directly over the generator and keep it there. As long as the magnet stays in contact with that spot on your chest, stimulation is suspended. When you remove the magnet, the device resumes its normal programmed cycle automatically.
This is useful in a few situations. Some people experience hoarseness, throat tightness, or a cough during the “on” phase of stimulation. If that happens during a conversation, a meal, or a presentation, holding the magnet in place gives you a break. For children who experience discomfort during stimulation, the magnet can be taped to the chest to keep the device off until their neurology team can adjust the settings.
How the Generator Records Magnet Use
The pulse generator logs every magnet activation. It stores a history of magnet use alongside its operating data, including stimulation settings and the electrical condition of the lead wire. When your neurologist reads the device at a follow-up appointment using the programming wand, they can see how often you’ve used the magnet and when. This helps them understand your seizure patterns and decide whether to adjust your settings. If you’re using the magnet frequently, it may signal that the automatic stimulation cycle needs to be stronger or more frequent.
Keeping the Magnet Safe and Accessible
The VNS magnet is a strong permanent magnet, which means it can damage things around it. Keep it at least 10 inches (25 cm) away from credit cards, computer screens, televisions, microwave ovens, and other magnets. The magnetic strip on a credit card can be wiped in seconds if the magnet sits on your wallet.
Most people wear the magnet on a wristband or clip it to a belt loop so it’s easy to grab quickly. Having a second magnet at school, work, or with a caregiver is common practice. If your magnet is lost or damaged, contact your neurology team or the device manufacturer for a replacement. A weakened or cracked magnet may not generate enough force to trigger the reed switch inside the generator.
Common Mistakes to Avoid
- Swiping too slowly or hovering. If the magnet stays over the generator longer than 3 seconds, you’ll shut the device off instead of triggering extra stimulation.
- Swiping too far from the generator. The magnet needs to pass directly over the implant site on the left upper chest. If your swipe path misses it, nothing happens.
- Storing the magnet on top of electronics. Phones, laptops, and cards with magnetic strips are all vulnerable. Build a habit of keeping the magnet in a consistent, isolated spot when you’re not wearing it.
- Forgetting to bring it. The magnet is only useful if it’s within reach. Wearing it or attaching it to something you always carry prevents the situation where you need it and don’t have it.
MRI Scans and Medical Procedures
If you need an MRI, tell the imaging team that you have a VNS implant before scheduling. Some newer VNS models are conditionally approved for MRI at 1.5 and 3 Tesla, but specific safety protocols must be followed. The magnet itself should not be brought into the MRI room. Your neurology team and the MRI facility will coordinate the details, including whether the device needs to be turned off or reprogrammed before and after the scan.