How safe are cochlear implants?

Fact check on materials, technology and myths about CIs

For people with profound hearing loss or deafness, a cochlear implant (CI) is often the only way to hear sounds and speech again. But many people rightly ask themselves: How safe is a cochlear implant? And what happens if you have an electronic device permanently implanted in your head?

The right material

Cochlear implants are inserted under the skin on the head and remain there for many years. Safety and compatibility must therefore be the top priority. This is why high-quality, biocompatible materials are used in the manufacture of the implant.

The implant housing is made of high-purity titanium, which is corrosion-resistant and fully biocompatible. Titanium forms a natural oxide layer that isolates the material from the body tissue. This is a key factor for long-term compatibility. It is also lightweight and robust.

The wires and the electrode contacts that stimulate the auditory nerve are made of a platinum-iridium alloy. These precious metals are known for their high stability and electrical conductivity and are therefore perfect for years of safe operation.

The coil and the electrode holder are encased in medical silicone, which is soft, flexible and well tolerated. This flexibility protects the sensitive cochlea when the electrode is inserted.

Durability and reliability

Safety also means that the implant must function reliably for many years. Currently[1], the Austrian manufacturer MED-EL offers the most durable implants[2][3][4]: Its latest generation titanium implants since 2006 achieve a cumulative survival rate of over 99%.

This means that almost all the systems used will function without any problems for many years.

Every single implant is put through its paces before dispatch, from leak tests to electrical function checks. A technician is also on site during the implantation itself to check that everything is working as it should before closing.

MRI safety with a cochlear implant

Medical examinations are also an issue when it comes to the question of how safe a cochlear implant is. Not all cochlear implants are suitable for MRI examinations. The magnet in the implant can interact with the strong magnetic field of the MRI machine, which can lead to pain, complications or even damage to the implant. It can also be difficult to interpret an MRI image of the head. This is because the implant casts a shadow that leads to distortions in the surrounding area.

However, modern cochlear implants now enable problem-free MRI examinations without pain, surgery or hearing breaks. MED-EL is the first and only CI manufacturer to offer a lifetime MRI guarantee - depending on the implant type, MRIs with 1.5 or even 3.0 Tesla are possible. For more detailed information on this, please contact your CI technician or your CI manufacturer directly.

Residual hearing may remain

It used to be believed that cochlear implantation would result in the patient losing any remaining hearing. This risk often deters patients with progressive hearing loss from undergoing implantation for a long time, even if they are no longer able to achieve satisfactory speech understanding even with hearing aids.

In the 50 years of development of CI implantation, CI technology and surgical techniques have improved significantly. Thanks to the particularly thin and atraumatic electrodes that MED-EL introduced in 2006 under the name FLEX, existing hearing can be preserved even with medium-length and long electrodes. The FLEX 34 is even the world's longest CI electrode available using this hearing-preserving technology.

How safe is a cochlear implant - myths uncovered

Cochlear implantation is an operation on the brain.

The procedure involves inserting an electrode into the cochlea (inner ear), not the brain. The operation takes about 1 hour, is minimally invasive and the scar is covered by the hair. Clinicians describe the operation in comparison: "There are fewer complications with cochlear implantation than with tonsillectomy."

You get a tumor from the metal in your head.

The materials in cochlear implants are biocompatible and do not harm the body. There are no proven cases of head tumors associated with cochlear implants.

The implant causes headaches.

Headaches caused by the magnetic voltage are not typical, but can be alleviated by using softer pads or weaker magnetic strengths. If you have pain or other complaints, please contact the clinic treating you directly.

Children must not slide down plastic slides because they become electrically charged.

Modern processors now have protection technologies against ESD (electrostatic discharge), so the use of plastic slides is generally not a problem.

The implant has to be replaced regularly, which means many operations.

MED-EL cochlear implants are designed for lifelong hearing and usually only need to be replaced after decades, if at all. The external audio processor can be regularly upgraded to a newer model so that you can benefit from the latest technology.

You must not have WLAN, a cell phone or a high-voltage power line nearby.

Modern cochlear implant systems are shielded against electromagnetic interference. WLAN, mobile phones and power lines pose no danger or interference.

Cochlear implants attract lightning.

The idea that you will be struck by lightning more quickly is completely unfounded. The implant does not conduct electricity to the outside and does not pose any additional sources of risk.

[1] As of June 2025

[2] Advanced Bionics AG and affiliates. (2024). Reliability Report July 2024 IMPLANTABLE COCHLEAR STIMULATORS AND SOUND PROCESSORS. 028-Q048-02 Rev F.

[3] Cochlear Ltd (2023). Cochlear Nucleus System Reliability Report - Volume 22, December 2023. D2182827 V3 2024-04.

[4] MED-EL. (2025). MED-EL Cochlear Implant Systems Reliability Report April 2025 https://www.medel.com/de-at/hearing-solutions/cochlear-implants/reliability#Implant_Reliability