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Balance & Hearing Center
Department of Otolaryngology

925 Chestnut Street
Sixth Floor
Philadelphia, PA 19107

Contact

Balance & Hearing Center
Department of Otolaryngology

925 Chestnut Street
Sixth Floor
Philadelphia, PA 19107

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Cochlear Implants

A cochlear implant is a surgically implanted device that aims to improve hearing sensitivity to those with hearing loss who no longer benefit from hearing aids. 

It consists of an internal device placed within the inner ear (cochlea) and an external device or speech processor which includes the microphone, battery and a transmitting coil or headpiece.

How do we hear?

Sound waves travel from the environment through the ear canal and reach the middle ear to vibrate the eardrum.

The eardrum then vibrates the ossicles, which are three small bones in the middle ear. The sound vibrations travel through the ossicles to the inner ear.

When the sound vibrations reach the inner ear, the cochlea, they push against specialized cells known as hair cells. The hair cells turn the vibrations into electrical nerve impulses.

The auditory nerve connects the cochlea to the auditory centers of the brain. When these electrical nerve impulses reach the brain, they are experienced as sounds. 

How do cochlear implants work?

Sound is picked up from the environment by a microphone on the outside part of the implant (worn behind the ear). A small processor then transmits the sound into a digital signal. The digital signal is sent to the internal part of the implant, which is placed under the skin behind the ear.

The implant sends electrical signals directly to the cochlea (the inner ear), bypassing damaged parts of the ear. The cochlear implant then stimulates the auditory nerve, which sends the signal to the brain — and the person hears the sound. So, instead of amplifying sound like a hearing aid, a cochlear implant replaces the damaged parts of the inner ear and sends signals directly to the auditory nerve. Over time, your brain is able to translate these electrical signals into sounds/words.

A cochlear implant bypasses the inner ear and converts acoustical sound into electrical signals that stimulate the auditory nerve directly and are then interpreted by the brain as sound.

A hearing aid amplifies acoustical sound and, via an earpiece in the ear canal, sends the louder sound to the eardrum.

In December 1984, the cochlear implant was approved by the United States Food and Drug Administration to be implanted into adults in the United States. In 1990 the FDA lowered the approved age for implantation to 2 years, then 18 months in 1998, and finally 12 months in 2002.

In 2019, the FDA approved cochlear implants to treat single sided deafness. 

Jefferson Balance and Hearing Center only implants adults (18 years or older).  The following are guidelines according to the FDA for cochlear implant candidacy:

  • Moderate to profound bilateral sensorineural hearing loss 
  • Single-sided deafness/unilateral profound hearing loss
  • Limited benefit from well-fit/programmed hearing aids
  • No medical contraindications
  • Realistic expectations on what a cochlear implant can and cannot do
  • Motivation to participate in hearing rehabilitation programs
  • Appropriate family or friend support

The benefit of a cochlear implant can be a dramatic improvement in hearing.  The ability to hear environmental sounds, the improved ability to read lips and in many cases to be able to understand speech and conversations without reading lips and recovering the ability to talk on the telephone are all potential benefits of a cochlear implant.  A large number of patients can get back into a normal life, return to work and improve their chances for success. 

The limitation of a cochlear implant is that not everyone will have dramatic results.  For most people who obtain an implant their results may be limited.  Not everyone will be able to use the telephone or underhand speech without reading lips, but in most cases the results will be beneficial to the individual receiving the implant.  A very small percentage of patients with a cochlear implant may receive no benefit.  The factors that impact success with the cochlear implant include history of hearing loss, timeline of hearing loss, motivation and aural rehabilitation.

A cochlear implant evaluation appointment is completed by a board certified audiologist. The patient will complete testing while wearing properly programmed hearing aids. Testing involves listening for beeps, and repeating back words and sentences both in quiet and in noise with hearing aids on. If the patient is not currently wearing hearing aids, a hearing aid trial may be required.

Cochlear implant surgery is an outpatient procedure. The surgery is performed under general anesthesia and usually lasts about 2 hours.

Some side effects from surgery might include: pain at the incision site, tinnitus, dizziness, and headache. These symptoms should resolve in the weeks following surgery.

The patient will be seen approximately two weeks following surgery to have the implant site inspected and to have the cochlear implant turned on and programmed.

The sound processor must be specially programmed for the individual user. Programming sound processors involves measurement of the individual's sensitivity to the electronic impulses. Other sound quality such as pitch also may be assessed. These responses are used to customize each person's implant system so that sound is as comfortable as possible for them. Modern multichannel implants can provide very high levels of sound recognition to many recipients.

Recently implanted internal cochlear implant devices are now MRI compatible up to 3.0 tesla when the external processor is removed.

If you are interested in learning more about cochlear implants, follow the link to schedule a telehealth appointment.

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