What is a Cochlear Implant (Bionic Ear)? Surgery and Treatment Process

A cochlear implant, commonly known as a bionic ear, is an advanced electronic medical device developed for patients experiencing severe to profound hearing loss who do not benefit sufficiently from standard hearing aids. This system directly takes over the function of a damaged inner ear by converting mechanical sound energy into electrical signals, which then stimulate the auditory nerve to transmit information to the brain. It is considered one of the most effective hearing loss treatments, particularly for ensuring healthy language development in children with congenital hearing loss and preventing adults from becoming socially isolated.

At a Glance

• Offers a permanent solution for severe to profound sensorineural (nerve-related) hearing loss.
• While standard hearing aids merely amplify sound, a bionic ear directly stimulates the auditory nerve.
• Early diagnosis in babies and intervention by the age of 1 is highly critical for normal language development.
• The surgery is performed under general anaesthesia and takes an average of 2 to 4 hours to complete.
• Long-term speech and language therapy is essential to achieve a successful outcome after the surgical procedure.

What is a Cochlear Implant and How Does It Work?

The clearest answer to what a cochlear implant is: it is a highly advanced prosthesis that bypasses the damaged hair cells in the inner ear to send signals directly to the auditory nerve. The system fundamentally consists of two main parts. The internal part, surgically placed under the skin and into the inner ear (cochlea), works in harmony with the external part (sound processor) worn behind the ear or on the head. The external microphone picks up sounds from the environment, and the sound processor converts these into digital signals, transmitting them to the internal part beneath the skin.

The internal part converts these received signals into electrical impulses and sends them to an electrode array inserted into the cochlea. The electrodes stimulate the auditory nerve, which then transmits this information to the brain. The brain perceives these signals as sound. According to statistics, hearing loss occurs in 1 to 3 out of every 1,000 live births. Detecting and fitting these babies with devices at an early stage is of vital importance to prevent the brain's hearing centre from atrophying. This technology is also successfully applied to adults who have lost their hearing later in life, helping their brains make sense of the sounds stored in their auditory memory.

What is the Difference Between a Hearing Aid and a Bionic Ear?

Many patients and their relatives may think that standard hearing aids and cochlear implants serve the exact same function. However, the working principles of the two systems are completely different. Traditional hearing aids deliver sound to the ear by increasing the volume of incoming external sounds (acoustic amplification). If there is only mild or moderate damage to the hair cells in the inner ear, amplifying the sound may be enough for the patient to hear and understand. This is similar to turning up the volume on a quiet speaker.

However, in individuals with severe to profound hearing loss, the hair cells in the inner ear are too damaged to perceive sound. In this case, no matter how much you amplify the volume, the sound is heard as distorted, meaningless noise, or not heard at all. This is where the bionic ear comes into play. By completely bypassing the damaged cells, it transmits sound directly to the auditory nerve in the form of electrical energy. As a result, the patient becomes able to distinguish not only the presence of sound but also the content of conversations and the emphasis of words.

Who is a Candidate for a Bionic Ear and What Are the Causes?

Cochlear implantation is applied to individuals with severe or profound sensorineural hearing loss in both ears who have shown no improvement in speech comprehension despite using powerful hearing aids for at least 3 to 6 months. In children, bionic ear application is generally preferred for deafness caused by congenital genetic factors, infections the mother contracted during pregnancy (such as rubella or cytomegalovirus), or severe newborn jaundice. Meningitis contracted in early childhood is also one of the primary conditions requiring urgent implantation, as it can lead to ossification (bone formation) in the inner ear.

For adults, the situation is slightly different. Adults who previously had normal hearing but lost it later due to sudden hearing loss, severe head trauma, the use of ototoxic drugs that damage the inner ear, Meniere's disease, or severe presbycusis (age-related hearing loss) are suitable candidates for this treatment. When deciding whether a patient is suitable for this surgery, it is required that the auditory nerve is intact and the anatomy of the inner ear allows for the placement of electrodes.

Symptoms of Hearing Loss and the Diagnostic Process at the Hospital

The most obvious signs of hearing loss in babies are a lack of response (not startling) to loud noises, not turning to look when their name is called, and failing to produce meaningful syllables (like ba-ba, ma-ma) by the age of 1. In adults, symptoms such as an inability to distinguish conversations in crowded environments, a constant need to turn up the TV volume, a tendency to lip-read, and difficulty talking on the phone are prominent. When you apply to the hospital with these complaints, a comprehensive audiological and radiological evaluation process begins.

During the diagnostic phase, hearing thresholds in newborns and children are objectively measured using OAE (Otoacoustic Emissions) and ABR/BERA (Auditory Brainstem Response) tests. For adults, pure-tone audiometry and speech discrimination tests are performed. For patients deemed audiologically suitable for an implant, high-resolution Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) scans are conducted to check whether the inner ear structure (cochlea) is suitable for electrode placement and to confirm the presence of the auditory nerve. Following all these tests, a multidisciplinary council consisting of Ear, Nose, and Throat (ENT) physicians, audiologists, and radiologists approves the patient's eligibility for surgery.

What is the Bionic Ear Surgery Process Like?

Bionic ear surgery is performed in a hospital environment within a fully equipped operating theatre under general anaesthesia. The duration of the operation varies between 2 and 4 hours on average, depending on the patient's ear anatomy and the surgical technique used. During the surgery, the surgeon makes a small incision behind the ear and drills a small bed in the bone behind the ear, called the mastoid, using special surgical drills. Through this opening, the middle ear and subsequently the inner ear (cochlea) are accessed.

The microscopic electrode array is delicately inserted into the cochlea. The receiver and stimulator body of the device are secured into the prepared bed on the skull bone. Just before the surgery is completed, an audiologist present in the operating theatre checks whether the device is working properly and if the nerve is being stimulated using electrophysiological tests (NRT). The incision is closed with aesthetic stitches, and the head is bandaged. Patients are usually kept under observation in the hospital for 1 or 2 days post-surgery and are then discharged. It takes an average of 3 to 4 weeks for the surgical wound to heal before the external part can be attached and the device activated.

Post-Surgery Speech and Language Therapy (Rehabilitation)

In bionic ear treatment, a successful surgery is only half the battle. On the day the external part of the device is attached and turned on for the first time, patients typically hear sounds as mechanical, robotic, or like radio static. It takes time for the brain to convert these new and different electrical signals coming from the auditory nerve into meaningful sounds, words, and sentences. For this reason, it is of vital importance that the post-surgery speech and language therapy (rehabilitation) process is carried out without interruption.

In paediatric patients, although learning new sounds is faster thanks to brain plasticity (flexibility), years of regular training with special educators and audiologists are required to close the language development gap with their peers. For adults, the process is built on matching the newly heard electrical sounds with their past auditory memory. Additionally, the device's settings are periodically readjusted on a computer by audiologists according to the patient's progress. This process is called mapping. The patience of the family, the motivation of the patient, and regular training are the most fundamental factors determining the success of the treatment.

Possible Complications and Risk Groups

As with any surgical intervention, cochlear implant surgery carries its own unique risks and potential complications. In addition to the standard risks associated with general anaesthesia, there is a risk of damaging the facial nerve during surgery, as it passes through the middle ear. This can lead to temporary or, very rarely, permanent facial paralysis. Furthermore, temporary taste changes on the tongue (due to the taste nerve being affected), post-surgery dizziness (vertigo), and ringing in the ears (tinnitus) may occur.

One of the most serious risks is a meningitis infection. Because the electrode placed in the inner ear is close to areas connected with cerebrospinal fluid, there is a risk of infection. To minimise this risk, it is mandatory for all patients scheduled for surgery to receive the pneumococcal (pneumonia/meningitis) vaccine at least two weeks before the operation. Skin infections at the device site or wound healing problems are also among the rarely seen complications.

When to See a Doctor?

Any situation where hearing loss is suspected requires consulting a specialist without delay. In particular, you should urgently visit an Ear, Nose, and Throat specialist in cases of unresponsiveness to loud noises in newborn babies, or sudden hearing loss, a feeling of fullness in the ear, and severe tinnitus in adults. Medical treatments started within the first 48 hours for sudden hearing loss can prevent permanent damage.

For patients who have undergone bionic ear surgery, there are red flags (emergency symptoms) to watch out for post-operatively or in the following years. If the patient develops symptoms suspicious of meningitis—such as a sudden high fever, severe headache, stiff neck, extreme sensitivity to light, confusion, or nausea/vomiting—the 112 emergency service must be called immediately, or you should go to the nearest hospital emergency department without losing any time. Additionally, if there is facial drooping on one side, severe and persistent dizziness, the device suddenly stops working, or if redness, swelling, and discharge are seen at the wound site, the surgeon who performed the operation must be contacted immediately.

Hearing Loss Treatment and Surgical Processes at BHT CLINIC

At BHT CLINIC İstanbul Tema Hastanesi, we manage the diagnosis, surgical treatment, and post-operative rehabilitation processes of severe hearing loss with a multidisciplinary approach. Our Ear, Nose, and Throat specialists, experienced audiologists, and radiology team work in coordination to ensure our patients receive the most appropriate device and treatment. In addition to ENT operations, many surgeries in fields such as the digestive system and thyroid are professionally performed in our General Surgery clinic at our hospital.

Your pre-operative general health screenings are conducted with great care; for example, during the anaesthesia preparation process, all relevant departments are involved to ensure we are protecting gallbladder health, evaluating liver functions, or managing chronic diseases. With our 24/7 emergency service and fully equipped operating theatres, your safety is kept at the highest level both during and after the surgical process. You can book an appointment with our specialist physicians for a detailed evaluation and treatment planning regarding your hearing health.

Frequently Asked Questions

How many hours does bionic ear surgery take?

The surgery generally takes between 2 and 4 hours, depending on the patient's ear anatomy and the condition of the inner ear. Since the procedure is performed under general anaesthesia, the patient does not feel any pain during this time.

Does Turkish Social Security (SGK) cover the cochlear implant?

Yes, the Turkish Social Security Institution (SGK) covers the cost of the cochlear implant device and surgical expenses for patients who meet specific audiological criteria and are documented with a medical board report. For both children and adults, the hearing loss threshold values and the condition of not benefiting from hearing aids, as determined by SGK, must be met.

Is a bionic ear noticeable from the outside?

Because the internal part of the device is under the skin, it is invisible. However, the external part that collects and processes sound is located behind the ear or on the head, so it can be seen from the outside. Since new generation devices have very small, lightweight designs that can match hair colours, they attract much less attention aesthetically.

Can I have an MRI scan after surgery?

This varies depending on the brand and model of the implant used. Many new generation cochlear implants are compatible with 1.5 or 3 Tesla MRI machines. However, before having an MRI scan, the compatibility of the device must absolutely be checked, and your doctor must be informed.

Can implants be placed in both ears at the same time?

Yes, especially in children with congenital hearing loss, bionic ear surgery can be performed on both ears in the same session (simultaneous bilateral) to stimulate both hearing centres of the brain and to develop the ability to determine the direction of sound.

This article is for informational purposes only; please ensure you consult your doctor for diagnosis and treatment.