Today’s blog is all about cochlear implants, something many people have heard about on the news or social media. These devices have the power to transform lives, and although HearingLife does not provide them, we want to share how they work and more in case you or someone you know is a candidate. Your HearingLife provider can always give you a referral to a specialist in cochlear implants.
Next month, we’ll discuss another of the 3 types of implantable hearing devices (cochlear implants, bone-anchored implants and brainstem implants).
What are Cochlear Implants?
Cochlear implants are surgically implanted devices that are best for people who don’t benefit from traditional hearing aids. A cochlear implant is widely considered one of the most advanced sensory prosthetic devices in medicine (Wolfe, 2020).
Currently, there are 3 cochlear implant manufacturers that are approved in the United States: Advanced Bionics, Cochlear Americas and MED-EL. Cochlear and Advanced Bionics have partnerships with major hearing aid brands, to provide solutions for those who have one implant and one hearing-aided ear.
How do Cochlear Implants Work?
Cochlear implants work by bypassing the function of the middle ear and cochlea and directly stimulating the Cranial Nerve VIII (vestibulocochlear nerve); specifically, the auditory branch. Instead of hearing acoustically as we do with hearing aids, CI users hear electrically.
Cochlear implants are attached to the skull using 2 magnets, an internal and an external magnet that allow the processor to stay in place on the skin.
What are the Parts of a CI?
There are 2 main parts of an implantable device, the external sound processor and the internal. The external processor contains microphones, a power source, signal processor, a receiver coil and a magnet. The magnets come in different strengths and connect the internal and external parts.
The internal processor is made up of a magnet, electrode array, electrode lead, and receiver/transmitting coil that are housed in a bio-compatible casing (Wolfe, 2020).
Who is a Good Candidate for a Cochlear Implant?
Audiologists are encouraged to refer their patients who fit the “60/60” rule for a full implant evaluation. The 60/60 rule is defined as anyone who has a Pure Tone Average (PTA) of greater than or equal to 60 dB in the better ear and speech understanding less than or equal to 60% in the better ear.
These criteria are always being re-evaluated and updated to encompass more individuals who can benefit from implantable technology. Currently, candidates should also have moderate to profound sensorineural hearing loss, be 18+ years old and demonstrate a lack of benefit from traditional amplification.
Other Uses for Cochlear Implants
There are also other uses for cochlear implants, such as the recent FDA approval for single-sided deafness. Children with severe to profound hearing loss may also be considered implant candidates, but that is often more situational due to medical history and there should be a discussion between the parents, child and multi-specialty medical team (Cochlear, 2024) (Advanced Bionics, 2024).
CI Evaluation Process
During the cochlear implant evaluation process, an audiologist who specializes in implants will complete a series of tests that include traditional audiometry and additional speech testing with appropriately fit hearing aids to determine candidacy.
The evaluation will include imaging (such as an MRI) and may also involve balance testing and consultations with other medical specialists based on the individual's medical history. It should be noted that age is NOT a contraindication to implantation, if the individual is approved for anesthesia.
The audiologist and surgeon will discuss results with the patient and family to help determine which type of implant (traditional or hybrid) and which manufacturer is best for them. Once candidacy is determined, and if the answer is yes, the surgery will be scheduled.
Cochlear Implant Surgery
Cochlear implantation surgery is usually completed as an outpatient procedure under general anesthesia. It takes approximately 1-2 hours and is considered low risk for most people. The surgical techniques used will be determined by the surgeon; typically, the surgery involves a series of openings being made through the mastoid, into the middle ear, and finally into the cochlea, where the electrode array is placed to stimulate the vestibulocochlear nerve (Wolfe, 2020).
Cochlear Implant Activation
Activation of cochlear implants generally occurs 4-6 weeks following surgery. This allows the proper time for the surgical site to heal. Once the site is healed, the proper magnet size and strength can be selected, and the audiologist can turn the implant on.
Activation includes many beeps, buzzes and other sounds. At first, speech may sound robotic, or not like speech at all. This is normal while the brain learns to sort out the electrical signals and interpret them. Over time, the brain will learn to recognize these new sounds as speech and the patient will have improved clarity of speech and enhanced communication.
It should be noted that a cochlear implant is not a magic fix, and that work must be done by patients and families to ensure the best outcome. Auditory-Verbal Therapy with a Speech-Language Pathologist is needed, along with many trips to the audiologist in the first few months. For those who have strong support systems and a true desire to communicate better, a cochlear implant is a fantastic option!
Citations
1.Wolfe, J. (2020). Cochlear Implants - Audiologic Management and Considerations for Implantable Hearing Devices. Plural Publishing.
2. Cochlear (2024). Cochlear Implant Candidacy Information. cochlear.com/professionals. Retrieved January 16, 2025, from https://www.cochlear.com/us/en/professionals/products-and-candidacy/candidacy/cochlear-implant.
3. Advanced Bionics. (2024). How a Cochlear Implant Works. advancedbionics.com. Retrieved January 6, 2025 https://www.advancedbionics.com/us/en/home/learn/adults/getting-a-cochlear-implant.