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Cochlear & Auditory Brain Stem Implant Clinic

Cochlear & Auditory Brain Stem Implant Clinic 

The MERF Cochlear Implant & ABI Clinic is one of the most advanced and experienced centres for implantable hearing solutions in South Asia. We are a national and international referral centre for complex, syndromic, revision, and anatomically challenging implant cases.

The clinic is headed by Prof. Mohan Kameswaran, with Dr. Shanmugapriya overseeing clinical operations, and supported by two Implantation Otology Fellows. The Audiology and Auditory Verbal Habilitation services are led by Prof. Ranjith Rajeswaran (Chief Audiologist).

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Pioneering Leadership

  • The first surgeon in South & South-East Asia to perform the Auditory Brainstem Implant (ABI).

  • The first surgeon in Asia to perform the Pediatric ABI (January 2009).

  • The first in the Asia-Pacific region to perform surgery for a Totally Implantable Hearing Device.

  • He has played a pivotal role in establishing Cochlear Implant programs in over 50 centres across India, and in 7 centres overseas, including Sri Lanka, Bangladesh (Armed Forces Hospital), Nigeria, and Nepal.

MERF remains one of the few centres in the world, and the only centre in India and South-East Asia, performing routine Auditory Brainstem Implantation for children and adults with cochlear nerve deficiency or complex inner ear anomalies.

He initiated ABI programs at Apollo Hospitals (Bengaluru), PGIMER (Chandigarh), Army R&R Hospital (Delhi), and SMS Medical College (Jaipur).

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What We Do

The clinic provides implant solutions for the following conditions :

  1. Severe to Profound Sensorineural Hearing Loss - Cochlear Implantation (CI)

  1. Residual Low-Frequency Hearing with High-Frequency Loss - Electro-Acoustic Stimulation (EAS)

  1. Cochlear Nerve Deficiency / Cochlear Aplasia / Mondini Variants - Auditory Brainstem Implant (ABI)

  1. Single-Sided Deafness & Complex / Revision Cases - Customised CI, BoneBridge / ABI planning & surgery

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MERF is among the very few centres in India and South Asia to routinely perform Transtympanic Electrically Evoked Auditory Brainstem Response (TTEABR/eEABR) under general anaesthesia. This technique allows direct assessment of cochlear nerve responsiveness, which is especially valuable in cochlear nerve deficiency, inner ear malformations (e.g., IP-II, EVA), post-meningitic cochlear ossification, and Auditory Neuropathy Spectrum Disorder (ANSD). It enables accurate CI vs. ABI candidacy decisions and guides electrode selection in complex anatomical conditions.

MERF was the first centre in India to incorporate intraoperative Electrocochleography (ECochG) in Auditory Neuropathy Spectrum Disorder (ANSD) and hearing-preservation / EAS cochlear implantation, allowing real-time monitoring of cochlear function and supporting residual hearing preservation during surgery.

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What Happens When a Patient/Parent Visits the CI/ABI Clinic

Patient presents to CI OPD, followed by ENT consultation & clinical examination and are subjected to audiological test battery (BOA/PTA, OAE, BERA, aided audiogram), speech & language assessment, HRCT temporal bone + MRI inner ear, clearances from pediatrician, ophthalmologist, cardiologist, occupational therapist, psychologist, anaesthetist. Followed by implant selection, surgery scheduling and switch-on at ~ 1 week with AVT (Audio Verbal Rehabilitation)

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Device & Electrode Planning

MERF uses a brand-neutral, anatomy-guided implant selection strategy supported by OTOPLAN, which provides 3D cochlear measurements to tailor electrode choice and insertion depth. Electrode Families Used:

  • Lateral Wall Flexible Arrays (optimised for atraumatic, hearing-preservation insertions)

  • Perimodiolar Arrays ( provide closer neural proximity in malformed / ossified cochleae)

  • Short / Slim Arrays (used in EAS to preserve apical low-frequency hearing)

  • FLEX Series (FLEX 20/24/28)  ultra-flexible, ideal for hearing preservation

  • FORM Series  (designed for inner ear malformations & CSF gusher control)

  • Synchrony Platform ( MRI-safe magnet system, supporting long-term follow-up)

 

Auditory Brainstem Implant Clinic

MERF performs both Paediatric and Adult ABI surgeries, especially in:

  • Cochlear aplasia / hypoplasia

  • Cochlear nerve deficiency

  • Ossified cochlea (post-meningitic)

  • Failed/revision CI candidates

  • NF II cases

Post-operative mapping and habilitation are conducted through specialist ABI-trained audiologists and therapists, making MERF a global training hub for ABI rehabilitation.

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Family-Centered Care & Rehabilitation

  • Early parent counselling & therapy orientation

  • Individualized Mapping & Auditory-Verbal Hablitation (AVH) in MERF’s dedicated in-house habilitation unit

  • Ongoing objective device checks and outcome monitoring

The AVR unit remains the hallmark of MERF’s program, enabling children to develop age-appropriate listening, spoken language, and mainstream school readiness.

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You May Be Eligible for Government Support

Children under 5 years from Tamil Nadu may receive CI/ABI under the Chief Minister’s Comprehensive Health Insurance Scheme.

 

Centre of Excellence

With over 6000 Cochlear Implant surgeries and more than 105 Auditory Brainstem Implants, MERF is one of the largest and longest-standing implant centres in South Asia, known especially for:

  • Complex and syndromic cases

  • Inner ear malformations

  • Failed / revision implant surgeries

  • Paediatric ABI expertise

  • Consistent habilitation outcomes

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