Cochlear Implants | Barrie Tan ENT

What Is a Cochlear Implant?

Cochlear implants are an advanced and highly promising hearing technology that allows individuals with profound sensorineural hearing loss to hear again. This device benefits a wide range of patients—from infants born deaf to elderly individuals even into their nineties. It is a safe procedure that provides reliable, high-quality hearing for the rest of the patient’s life, if one is an eligible candidate for it.

Sensorineural hearing loss arises when the cochlea, the organ responsible for hearing, malfunctions. This impairs its ability to activate the auditory nerve, preventing sound signals from reaching the brain. Cochlear implants offer a remarkable solution by bypassing these damaged hair cells in the cochlea, typically the site of the malfunction.

The implant directly stimulates the healthy nerve endings within the cochlea. This enables the auditory nerve to carry new electrical signals, effectively replacing lost sound information. These signals are then transmitted to the brain, allowing recipients to perceive sound again.

How Does a Cochlear Implant Work?

A cochlear implant is a medical device designed to restore hearing for individuals with severe sensorineural hearing loss by bypassing damaged parts of the ear and directly stimulating the auditory nerve. Here is a breakdown of how this remarkable technology works:

The external components of a cochlear implant play a crucial role in capturing and processing sound from the environment. These components include:

Microphone

The process begins with a small microphone on the implant's external part, usually worn behind the ear. This microphone picks up sounds from the environment.

Sound Processor

The captured sounds are sent to a sound processor, also part of the external component. This processor converts the sounds into digital signals.

Transmitter Coil

The digital signals are then sent to a transmitter coil, which sends them via radio frequency through the skin to the internal components of the implant.

The intricate internal components of a cochlear implant then work seamlessly with the external components to facilitate the perception of sound.

Receiver/Stimulator

The transmitter coil communicates with an implanted receiver/stimulator placed just under the skin behind the ear. This receiver converts the digital signals into electrical impulses.

Electrode Array

These electrical impulses are sent down a thin, flexible electrode array surgically inserted into the cochlea. The array contains multiple electrodes positioned at different points along the cochlea to stimulate various regions, mimicking the natural place-frequency arrangement of the cochlea.

The electrode array directly stimulates the nerve endings of the cochlear nerve. By bypassing the damaged hair cells in the cochlea, the implant ensures that the electrical signals can still activate the auditory nerve.

The stimulated cochlear nerve then transmits the electrical signals to the brain, which interprets them as sound. Because the brain can adapt and decode these signals over time, cochlear implant users can significantly improve their ability to perceive and understand speech and other sounds.

How Are Cochlear Implants Implanted?

The procedure is performed under general anaesthesia, keeping the patient asleep and pain-free. The surgeon makes a small incision behind the ear to access the mastoid bone and removes a portion to create a pathway to the middle ear and cochlea. A small opening, known as a cochleostomy, is created in the cochlea, or the round window membrane is used as an entry point. The electrode array is then carefully inserted into the cochlea.

After the electrode array is inserted, the internal receiver/stimulator component is placed under the skin behind the ear and secured in a specially drilled depression in the skull bone. Once the internal components are in place, the incisions are sutured closed, and a protective bandage is applied around the head to minimise swelling and aid healing.

Potential Risks & Complications of Cochlear Implants

While cochlear implants offer significant benefits to eligible patients; as with all surgical procedures, there are nonetheless some potential risks and complications to be aware of. However, in the hands of an experienced cochlear implant surgeon and a well-trained medical team, the likelihood of complications is low.

Infection

As with any surgical procedure, there is a risk of infection at the incision site. Proper post-surgical care and antibiotics can help minimise this risk.

Device Failure

Over time, the internal or external components of the implant may malfunction.

Facial Nerve Injury

As the facial nerve runs close to where the implant is placed, there is a small risk of damage during surgery.

Tinnitus

Some patients may experience an increase in tinnitus (ringing in the ears) after the surgery.

Skin Irritation

If not properly fitted, the external components of the implant can cause skin irritation where they contact the skin.

Meningitis

Following cochlear implant surgery, there is a rare risk of developing meningitis, an infection of the membranes covering the brain and spinal cord.

Electrode Displacement

Over time, the electrode array inside the cochlea may shift or become dislodged.

Residual Hearing Loss

Patients may sometimes lose residual natural hearing in the implanted ear.

Dizziness or Balance Issues

The inner ear plays an important role in balance, and surgery can sometimes affect this.

Are Cochlear Implants Safe for Children?

Yes, cochlear implants are recognised as a safe and effective solution for children with severe to profound hearing loss. In recent years, it has become common to simultaneously perform cochlear implant surgery on both ears, even in children as young as one year old.

Children born deaf who receive cochlear implants often experience remarkable benefits. Many children can attend mainstream schools and develop speech and language skills comparable to those of their hearing peers.

For optimal development of speech and language, early cochlear implantation offers children the critical advantage of starting their hearing journey without missing crucial learning windows. This allows their young brains to effectively utilise sound for language acquisition, which can significantly impact their overall development and quality of life.

Young children aside, it is also important to dispel the myth that hearing loss is an inevitable part of ageing that must simply be accepted. With advancements in hearing technologies, even the very old can benefit significantly from cochlear implants.

Dr Barrie Tan, for example, has successfully implanted patients as old as 86 years. This demonstrates that cochlear implants can offer improved hearing and quality of life across all stages in life.

Why Choose Our Cochlear Implant Clinic

Our clinic is led by Dr Barrie Tan, an experienced ENT specialist who was formerly the Director of the Centre for Hearing and Ear Implants at Singapore General Hospital, the largest cochlear implant unit in Singapore. Dr Tan has personally performed hundreds of cochlear implant surgeries and is well-recognised as a skilled cochlear implant surgeon both in Singapore and Southeast Asia, where he continues to share his expertise and supervise cochlear implant surgeries.

Barrie Tan Hearing and Cochlear Implant Centre offers a comprehensive and compassionate approach to every patient’s hearing journey. Together with Dr Barrie Tan, our well-trained team of implant audiologists, auditory verbal therapists, and nurses collaborate closely to ensure each patient receives the best possible care. We keep you informed throughout the post-implantation process, carefully monitoring your progress until your treatment journey is satisfactorily complete.