‘Totally Implantable Cochlear Implant Is The Future Of Cochlear Implant’

Dr Sandra DeSa Souza

A cochlear implant surgery at grand old age of 71 made dramatic changes in the life of renowned artist Satish Gujral. Hearing sounds after 62 long years of silence, Gujral now adds more vibrant colours to his paintings, discarding the usual dreary dark and light. Such is the impact of sounds! And hence the significance of cochlear implant surgeons like Dr Sandra DeSa Souza. The pioneer in cochlear implant surgery in 1987 and the first woman cochlear implant surgeon in the world, Dr Souza is the head of ENT at Jaslok Hospital & Research Centre. Such is the respect she commands that she is always the chosen one to introduce a new technology, whether it is Nucleus Cochlear Implant from Australia, Medel Cochlear Implant, Clarion Cochlear Implant and Clarion’s latest Implant HiRes 90K. She was also the first one to use implants on children with ossified cochleas and abnormal cochleas like Mondini. For her path-breaking work, she has been awarded International Scientist of the year 2003 for outstanding contribution to Neurootologie, Cochlear Implants. In an interview with Rita Dutta, Dr Sandra speaks on the newest technology in cochlear implants and their affordibility.

As the pioneer in cochlear transplant in India, how do you assess the evolution of cochlear implant technology over the years?

Cochlear Implant Technology has made tremendous strides in the past decade in design, batteries, and in the electronics. Battery technology has introduced chargeable battery packs that fit into the body worn or BTE Processor. The headsets earlier consisted of two parts, the headset with microphone and the transmitter. Today, with the Advanced Bionics device, the microphone fits in the transmitter and there is no extra headpiece. The biggest revolution has been the speed at which the cochlear can get stimulated. While earlier it was 12 to 18000 pulses per second, today with the Clarion Implant of Advanced Bionics, we have up to 83,000 pulses per second. The number of channels and virtual channels can also be increased up to 120 channels with the patient differentiating speech and music.

How different is a cochlear implant from a hearing aid?

A hearing aid amplifies the sound. The cochlear implant changes the sound into electrical signals, which stimulate the hearing nerve. Cochlear implants is adviced when the patient does not benefit from hearing aid; this is for patients having severe deafness.

Please tell me how a cochlear implant functions.

The cochlear implant collects the sound, filters it and changes it into electrical signals. These are programmed according to the patient’s need and then sent via the transmitter to the electrodes, which then stimulate the hearing nerve, enabling the patient to hear sounds.

How long does one take to integrate the patient with the society after the surgery?

If the patient is post-lingual (deaf after birth), the integration time is one to two months. If the patient is prelingual (born deaf), then it depends on the age. The younger children after six months and the old adolescents and adult prelinguals after 1 ½ - 2 years as it takes time for their heavy speech to become normal.

What are the risks associated with the surgery? How does one overcome such risks?

The same risks as with any ear operation, weakness of the nerve of the face and infection like meningitis. By taking adequate precautions during the surgery not to damage the facial nerve or to identify any abnormal course of the nerve giving Hibtitre and Pneumo 23 vaccines can prevent meningitis.

Does India have enough centres and sufficient ENT surgeons working on cochlear implants?

Not for the entire population which requires implant, but enough for the small group of patients who can afford implants.

What is the population, which require cochlear implants? What size of the needy population actually receive the implants?

About 15 million - but this not an accurate figure as all India patients are not tested and there is no accurate survey of deafness. Only 750 to 800 patients have received cochlear implants in the last 18 years.

The implants are priced at Rs 6 to 8 lakh. Why are the implants so exorbitantly priced?

Because the implant is under warranty for 10 years (in which the replacement and surgery is free) and warranty for the speech processor is three years. Also the foreign experts visit all the centers every few months and research is an ongoing process.

What is the significance of indigenous implants encouraged by Dr A P J Abdul Kalam?

Cochin-based Amrita Institute of Medical Sciences have tried indigenous implants, but failed. Now they are being researched and produced at Vishakhapatnam by Dr S K Apparao under the guidance of President Dr APJ Abdul Kalam. The implants costs Rs 1 to 1.5 lakh and stimulate the cochlea 12,000 pulses per second. At least some patients can afford it, though the rehabilitation will be much longer than with implants stimulate at 83,000 pulses per second.

Globally, what kind of research is going on cochlear implants? What is the future of cochlear implants?

Research is going on totally implantable cochlear implant, where the battery and processor are also implanted and not worn outside. Future continues to look promising because of the new fast stimulating implant and because of the possibility of the totally implantable cochlear implant. The brain stem implant is already available for those who have no hearing nerve.

rita@expresshealthcaremgmt.com