Cochlear Implant (Bionic Ear)

The ear carries hearing and balance, and it is a delicate organ. Some hearing problems are present at birth. Others appear later, with age or with disease. Hearing devices let a person keep communicating with the people around them.

People with severe and very severe hearing loss hear almost nothing, or hear only very loud sounds. A hearing aid makes sound louder, and for these people that does not help. They need a cochlear implant, which is also called a bionic ear.

How hearing works

The ear has three parts: the outer, the middle and the inner ear.

The outer ear collects sound waves and sends them down the ear canal. There they strike the eardrum, and the middle ear begins. The middle ear holds three small bones: the hammer, the anvil and the stirrup. These bones turn the sound waves into mechanical pressure waves and pass them to the inner ear.

The inner ear holds the cochlea. Inside it, hair cells turn the mechanical waves into electrical signals. The hearing nerve carries those signals to the brain, where they become meaning.

Loud noise, age or a condition present at birth can damage the hair cells. A hearing aid, which only makes sound louder, then has nothing to work with. A cochlear implant skips the damaged part of the ear and creates the electrical signals that the nerve cells understand.

Why age matters in children

For a young child with hearing loss, an implant fitted early matters greatly for speech and language.

Research shows that children who have the operation before 18 months and then have intensive therapy do better than children implanted later. They hear, use their voice and speak better. They learn to connect sounds without needing to lip-read or to use sign language.

For an adult with severe hearing loss who gains little from a hearing aid, the implant improves communication and daily life.

The operation

The operation is done under general anaesthesia and takes about two to four hours.

The surgeon makes a cut behind the ear and opens the mastoid bone in the skull. The surgeon then makes a small opening in the cochlea and passes the electrode array of the internal device through it. The cuts are then closed.

Patients usually stay in hospital for one day, and return to work after three to five days.

After the operation

You may feel mild pressure or discomfort in the implanted ear, and dizziness or nausea from the general anaesthetic. See the doctor after a week to have the stitches removed.

The implant is not switched on straight after surgery, so that the area can heal. The doctor activates it two to six weeks later.

Rehabilitation

Rehabilitation trains the brain to understand the sounds the implant delivers. Speech and everyday sounds can feel strange at first. The brain needs time and support to learn what they mean. Wear the speech processor all day, from waking until going to bed.