RESTORING HEARINGJuly 5, 2019
Congenital hearing loss is a very common problem affecting about 6 out of every 1,000 children. Unless parents are extremely observant and astute, diagnosis is often missed until the child is much older and hearing and speech issues become practically irreversible. Thus, early diagnosis and intervention are key to successfully treating hearing impairment.
Current guidelines recommend that all newborns undergo a screening test to determine hearing potential within 48 hours of birth. The Otoacoustic Emissions Test is a quick, easy to administer test that does not require highly trained personnel. With a sensitivity of 99% and a specificity of 80%, the test often gives false positive results. Therefore, should the child not pass the test, a second screening test at the age of 1 month is necessary. Should the child not pass this test too, a comprehensive, complete hearing test is performed by a paediatric audiologist, ideally between the age of 3 to 6 months. A complete assessment involves different tests, including diagnostic otoacoustic emissiontest, tymapnometry, auditory brainstem response or brainstem evoked response audiometry, auditory
steady-state response and behavioral observation audiometry tests. These different tests assess different parts of the hearing pathway with the aim of determining three main features: the presence or absence of hearing loss, the type of hearing loss and the severity of the hearing loss.
The course of the treatment is decided based on the type and severity of the hearing loss. Some children may have minor hearing impairment due to fluid in the ear which can be treated medically. However, moderately severe to profound hearing loss is often due to sensorineural hearing loss, which is irreversible by medication or surgery and requires hearing devices. For many, noninvasive technology such as hearing aids are enough, and hearing can be restored merely by wearing the devices. For others with more severe hearing impairment, cochlear implants may be required.
Deepak (name changed) is one such child who was diagnosed with severe hearing loss and recommended cochlear implants in both ears. He did not pass the newborn screening twice and was therefore referred to the Cochlear Implant Team. Neevita Narayan, Paediatric Audiologist, Audiology Director & Cochlear Implant Specialist at SpHear Speech and Hearing Clinic, Delhi conducted a complete hearing assessment at the SpHear Clinic when Deepak was 3 months old. The results indicated that Deepak had severe hearing loss in both ears which could not be treated with medication. Deepak’s parents then met with Narayan and Dr (Prof) Ameet Kishore, Sr Consultant Surgeon, ENT & Hearing Implant; Director of Adventis (Advanced ENT Service) and ENT – Cochlear Implant Surgeon at Indraprastha Apollo Hospital, Delhi, for a counselling session to decide on next options. As a team, they agreed to first try hearing aids. Along with hearing aids, Deepak underwent the speech and language therapy programme twice a week under the guidance of the paediatric audiologist. Deepak’s parents were taught how to provide hearing stimulation, and Deepak was taught how to listen to sound. Parents were also taught how to continue these exercises at home. These exercises are developed such that the hearing-impaired child is exposed to all types of sound. The therapist monitored hearing milestones for assessing progress. After about 4 months, at the age of 7 months, Deepak underwent some of the hearing tests again to re-assess hearing and determine the benefits of the hearing aids.
While Deepak was responding to louder levels of sound and was babbling, he was not achieving the requisite hearing milestones and would not develop normal speech with hearing aids alone. After another counselling session with the entire cochlear implant team, the parents
agreed to outfit Deepak with cochlear implants simultaneously in both ears. Two other decisions needed to be made – when to implant and which cochlear implant device to be used.
Early diagnosis and intervention are key to restoring hearing impairment. At a younger age, the brain of a child is more plastic and can easily learn from new auditory input. Research has shown that children acquire faster speech perception when implanted prior to age two rather than after age two. The earlier the implants, the better the outcomes. Having already performed over a 1,000 cochlear implants, and being experienced in paediatric ENT surgery, Dr Kishore was completely confident that his surgical team at Apollo Hospitals will be able to undertake the surgery safely in very young children. He recalls, “The
parents opted for implanting one of the latest cochlear implant devices. With its better chip and connectivity with digital devices, the child has the best chances of completely integrating into normal school and society without any hearing or speech disabilities.”
Deepak was 8 months of age when he underwent the procedure safely, which took about three hours for both ears. Deepak was discharged within a day of the surgery. Two weeks later, the device was switched on in the audiology clinic and Deepak continues to go through the same habilitation programme as before in speech and language therapy sessions. Regular monitoring and programing of the device continues, wherein the audiologist gradually increases sound levels over a period of 2-3 months. Dr Kishore is very happy to see Deepak’s progress, “Deepak is now one year old and currently doing extremely well. In another 6 months to a 1 year, he will hear and speak like a normal child.”
“Deepak is probably one of the youngest children to have a bilateral simultaneous cochlear implant in the country. With early diagnosis and better team management, we hope to see many other babies who receive appropriate interventions to address hearing impairment in a timely manner.”