Most of the millions of implanted medical devices in existence today have a wireless component that allows doctors to monitor patients’ vital signs and revise treatment programs by tapping into the device’s signal.

But those wireless capabilities could also make devices susceptible to hackers, say researchers at the Massachusetts Institute of Technology.

Worst case scenario – hackers could program a device to deliver a medication overdose or electric shock that kills the victim.

MIT researchers have devised a defensive measure against hackers in their wearable "shield" device. The investigators imagine an external device that creates a jamming signal to hide the implanted device’s signal, resulting in radio noise that hackers won’t be able to decipher.

The jamming device will be an external complement to an implanted device so that emergency medics can easily remove the shield in case of emergency, rather than needing to find a key to decode the signals.

The shield will eventually be fit into a necklace or watch that patients can wear, so the jammer will work with existing devices.

The designers plan to unveil the shield system at an upcoming Sigcomm conference.