Hearing Impairment, is a partial or total inability to hear. In children hearing problems can affect the ability to learn spoken language and it interferes in social, psychological and emotional life. Therefore, enabling the disabled to hear is of primary importance for overall development of a child. A Cochlear implant (CI) is surgically implanted electronic device that provides a sense of sound to a person with severe to profound sensorineural hearing loss. [1] There are four manufacturers providing cochlear implants for use (Advanced Bionics, Cochlear, MED-EL and Oticon Medical (previously Neurelec) [2]. All of the devices share a similar basic design [3]: • The external part: the microphone, sound processor and transmitter coil • The internal receiver–stimulator package • The intracochlear electrode. These components are summarized below. The external part: the microphone, sound processor and transmitter coil: This part of the cochlear implant detects the acoustic signal and converts it to an electrical signal with both temporal and spatial components. The encoded signal is transmitted to the internal device using radiofrequency via the external coil. The internal receiver– stimulator package: This contains the internal magnet, telemetry coil and hermetically sealed electronics system. There is also a ground electrode for current return, either incorporated within the package or as a separate electrode placed under the temporalis muscle. Once received, the decoded signal is sent to the electrodes within the cochlea according to the processing strategy being used. The intracochlear electrode: The electrode that is placed into the cochlea is in fact a group of individual wires, each ending at a contact point along the silicone casing. The number of individual wires varies depending on the manufacturer and type of electrode. Electrodes have become generally smaller in an attempt to reduce the trauma of insertion and allow for hearing preservation as well as the potential use of future technologies that might require preservation of cochlear function.[1]. It helps in social rehabilitation of the patient with hearing loss. The modern cochlear implant is a device designed to convert environmental sound into electrical impulses that are delivered along a multiple electrode array situated in close relation to the cochlear (auditory) nerve. Principles of Functioning of Cochlear Implants [4,5] The current cochlear implant design consists of– • External device (microphone, speech processor, headpiece) • Internal device (receiver -stimulator, multichannel electrode array). These two communicates with each other by way of radio frequency. The microphone detects sound and transmits the information to a signal processor. The processor includes a series of filter banks that use fast-Fourier transforms to partition the acoustic signal into the respective frequency bands and decodes the information into an electrical signal. The signal is processed according to a predefined strategy, amplified, and compressed to match the narrow, electric dynamic range of the ear and sent through the intact skin to the implanted receiver-stimulator. The tonotopic organization of the cochlea is emulated by orienting the electrode contacts toward the modiolus within the Scala tympani and assigning frequencies to specific electrodes along the length of the electrode array such that electrical stimulation corresponding to the highest pitches are delivered within the basal region of the cochlea while electrical stimulation corresponding to the lowest pitches are delivered within the apical region of the cochlea. The electrical impulses directly depolarize the primary afferent neurons, effectively bypassing the dysfunctional hair cells. [5] There have been enormous studies on cochlear Implants but this study is novel since it is catering to tribal population and is performed with least possible resources and in a government sector tertiary care hospital without much sophisticated instruments. OBJECTIVES: • To evaluate the outcomes of cochlear implant in terms of hearing and speech gain. • To evaluate the effect of age of implantation on the outcomes of cochlear implanted patients. • To evaluate the effect of duration of Deafness on results.

The was a prospective observational study carried out in a cohort design. By purposive sampling, a type of non-probability sampling technique; 15 patients attending the Department of ENT in RNT Medical college in two and half years from June, 2017 to November, 2019 were undertaken for the study. Initially there were more patients but due to loss to follow up, final sample size was of 15 patients. It was carried out by means of information obtained from patients who underwent CI Surgery in the department of Otorhinolaryngology of RNT Medical College, Udaipur. The various parameters that were analyzed were duration of deafness, type of implant, classification of the deafness, age, and gender. The patients were selected for cochlear implantation after thorough evaluation of their type and degree of hearing loss, lack of benefit with hearing aids, radiological analysis of the temporal bone–cochlear anatomy for feasibility for implantation, adequate parental motivation for habilitation and the possibility/accessibility of pre-and post-implantation habilitation/therapy and programming centers. The patient’s hearing loss which was classified on the basis of time of onset of hearing loss as prelingual (hearing loss prior to development of speech and language); perilingual (hearing loss occurring around the period of language acquisition) and post-lingual (hearing loss after development of speech and language). Criteria for inclusion were severe to profound hearing loss in bilateral ear, below 6 years of age. While subjects with agenesis of cochlea, absence of cochlear nerve, age above 6 years, active infection in ear were excluded from study. The patients were followed up for rehabilitation and speech therapy and their outcomes were recorded in terms of audiometry and speech perception scores. The results obtained from our study were recorded, tabulated and compared with those of peer reviewed journals who have studied and evaluated outcomes of CI.

As ours was a State Government sponsored programme for ‘Hearing Disabled Children’. Upper age limit was fixed as 6 years. There were 5/15 (33.33 %) female patients while 10/15 (66.67%) were males. 100% patients (15/15) were operated was on right side. Table 1. Cochlear Implant Brand: Brand of cochlear Implant Number of patients Percentage% Advanced Bionics Hi Res 90K Advantage 9 60% Med El Sonatati 100 +Standard 4 26.67% Nucleus Cochlear Implant CL24RE 2 13.33% Total 15 100% 9/15 i.e., (60%) patients were implanted with Advance Bionic HiRes 90K Advantage CI Hi Focus 1j Electrode and 4 (26.67%) patients were implanted with Med-El Cochlear Implant and 2 (13.3%) patients were implanted with Nucleus Cochlear Implant CL24RE. All 15 patients to be admitted for Cochlear implant underwent screening for TORCH Complex. Table 2. TORCH Screening: Name of the Test Patient Positive Percentage CMV IgG 5 33.33% Rubella IgG 1 6.67% HSV 1 IgG 0 0% HSV 2 IgG 3 20% Unknown Etiology 6 40% Total 15 100% In the Present Study testing for the etiology of the deafness was done, results indicate that 5 (33.33%) patients were infected with CMV Prenatally, 3(20%) were infected with HSV type 2 Prenatally, and 6 (40%) were of unknown etiology. Pre-Op Hearing Assessment was done via TEOAE and BERA. All the patients who underwent BERA Screening showed hearing loss above 90 db and TEOAE Screening showed outer hair cell Dysfunction. A total of 3/15 (20%) patients that were operated at our institute had complications. Amongst them two patients had rupture of tympano-meatal flap which is a minor perioperative complication and one patient had CSF leak during the drilling of bed which was plugged with temporalis muscle. Post Cochlear Implantation Auditory receptive skills and speech development were measured using- 1. Revised Category of Auditory Performance (CAP) Scores. (The Shepherd Centre's revised version, based on Nottingham CI Program, 1995) [6] 2. Speech Intelligibility Rating (SIR) Scale. (As per O'Donoghue et al 1999) [7,8] 3. Meaningful Auditory Integration Scale (MAIS) Questionnaire.[9] Before Cochlear Implant Revised CAP Score was 0 in 8 (53.33%) patients, and was 1 in 7 (46.67%) patients. Table 3. Revised CAP Score at 6 Months post- operatively CAP Score Number of patients in respective score Category Percentage 3 4 26.67% 4 9 60% 5 2 13.33% Total 15 100% 6 Months post-surgery, revised CAP score observed was 3 in 4 patients (26.67%), 4 in 9 Patients (60%) and was 5 in 2 patients (13.33%). Table 4. Revised CAP Score at 12 Months post- operatively CAP Score Number of patients in respective score Category Percentage 7 4 26.67% 8 7 46.67% 9 2 13.33% Not available 2 13.33% Total 15 100% 12 months after surgery, revised CAP Score was 7 in 4 patients (26.67%), 8 in 7 patients (46.67%) and was 9 in 2 patients (13.33%). Data was not available for 2 patients at the end of 12 months. Table 5. CAP score v/s age of implantation at 1 year post - operatively Age (years) CAP score 0 1 2 3 4 5 6 7 8 9 NA 4-5 1 (6.67%) 5 (33.3%) 0 (0%) 1 (6.67%) >5-6 3 (20.0%) 2 (13.33%) 2 (13.33%) 1 (6.67%) Total 4 (26.67%) 7 (46.67%) 2 (13.33%) 2 (13.23%) In the age group of 4-5 years, out of 7 patients 1 (6.67%) had CAP score 7, 5(33.33%) had CAP Score 8 and 1 patient did not show up for follow up. In age group 5-6 year, out of 8 patients, 3 (20%) had CAP Score 7 while 2 (13.33%) had CAP Score 8, 2 (13.33%) had CAP Score 9 and 1 did not show up for follow up. Table 6. CAP score v/s parent education at 1 year post - operatively Education CAP score 0 1 2 3 4 5 6 7 8 9 NA Educated 4 (26.67%) 6 (40.0%) 1 (6.67%) 0 (0%) Un- educated 0 (0%) 1 (6.67%) 1 (6.67%) 2 (13.33%) Total 4 (26.67%) 7 (46.67%) 2 (13.33%) 2 (13.33%) At the end of 1 year, 4 patients had CAP Score 7 out of these all the 4 (100%) had educated parents. 7 had CAP Score 8, out of which 6 had educated parents and 1 had uneducated parents. 2 patients had CAP Score 9, 1 had educated and 1 had uneducated parents. Table 5. Mean Revised CAP Score Preop. 6 months 12 months 0.47±0.49 3.90±0.61 7.84±0.66 P value = 0.00 (S) The mean pre op Revised CAP Score was 0.47±0.49 which means that the cohort under study was “unaware of the environmental Sounds”. At the end of 6 months the revised CAP Score was raised to 3.90±0.61 which means that the cohort started to identify some environmental sounds and understand some words with addition performatives. At the end of 12 months the revised CAP Score was raised to 7.84±0.66 which means that the cohort started to respond appropriately to simple Questions. It clearly indicated that the auditory perception skills are gradually increasing over time duration with the aid of Cochlear Implantation. Pre operatively all the patients had SIR score of 1. Table 6. SIR Scoring at 6 Months post - operatively SIR Score Number of patients in respective score category Percentage 1 0 0% 2 10 66.67% 3 5 33.33% Total 15 100% 6 months after surgery, SIR score was 2 in 10 patients (66.67%) and was 3 in 5 patients (33.33%). Table 7. SIR Scoring at 12 Months post- operatively SIR Score Number of patients in respective score category Percentage 2 7 46.67% 3 6 40% Not available 2 13.33% Total 15 100% 12 months after surgery, SIR score was 2 in 7 patients (46.67%), 3 in 6 patients (40%) and was not available in 2 patients (13.33%). Non availability was due to absence of child at that screening time Table 8. SIR score v/s age of implantation at 1 year post- operatively Age (years) SIR score 1 2 3 NA 4 to 5 0 3 (20.0%) 3 (20.0%) 1 (6.67%) >5 to 6 0 4 (26.67%) 3 (20.0%) 1 (6.67%) Total 0 7 (46.67%) 6 (40.0%) 2 (13.33%) In the age group of 4-5 years, out of 7 patients 3 (20%) had SIR score 2, 3 (20%) had SIR Score 3 and 1 patient did not show up for follow up. In age group 5-6 year, out of 8 patients, 4 (26.67%) had SIR Score 2 while 3 (20%) had SIR Score = 3 and 1 did not show up for follow up. 9. SIR score v/s parent education at 1 year post- operatively Parent education 1 2 3 NA Educated 0 7 (46.67%) 4 (26.67%) 0 (0%) Un-educated 0 2 (13.33%) 0 (0%) 2 (13.33%) Total 0 9 (60.0%) 4 (26.67%) 2 (13.33%) P value = 0.017 (S) At the end of 1 year, 9 patients had SIR Score 2 out of these all the 7 had educated parents, 2 had un educated parents. 4 had SIR Score 3, and all the 4 had educated parents. 2 patients did not show up for follow up and both had uneducated parents Table 10. Mean SIR Score Preop. 6 months 12 months 1.0±0.0 2.33±0.47 2.46±0.49 P value = 0.00(S) The Mean SIR Score preoperatively was 1.0±0.0 which means that the normal speech of the patient was unintelligible to guardians. At the end of 6 months the Mean SIR Score raised to 2.33±0.47 which further increased to 2.46±0.49 at the end of 12 months. It means that intelligible speech is developing in single words when context and lip-reading cues are available. OUTCOME MAIS Good - 25 and above Satisfactory - 24 and below MAIS Score Preoperatively - Pre-operatively all the patients had MAIS Score of 0 Table .11. MAIS scoring at 6 months post- operatively MAIS Score Number of patients in respective score category Percentage 24 4 26.7% 25 5 33.3% 26 2 13.3% 27 2 13.3% 28 2 13.3% Total 15 100% Out of 15 patients 4 (26.7%) patients had MAIS Score 24, 5 (33.33%) had MAIS Score 25, 2 n(13.33%) had MAIS score 26, 2 (13.33%) had MAIS Score 27 and 2 (13.33%) had MAIS Score 28. Table .12 MAIS scoring at 12 months post-operatively MAIS Score Number of patients in respective score category Percentage 31 3 20.0% 32 6 40.0% 33 6 40.0% Total 15 100% Out of 15 patients 3 (20%) patients had MAIS Score 31, 6 (40%) had MAIS Score 32 and 6 (40%) had MAIS score 33. Table 13: MAIS score v/s age of implantation at 1 year post-operatively Age (year) Satisfactory (0-24) Good (≥ 25) 1 to 5 0 (0%) 7 (46.67%) >5 to 6 0 (0%) 8 (53.33%) Total 0 15 (100%) In the age group of 4-5 years, 7/15 patients (46.67%) had Good MAIS Score (≥25). In ag group 5-6 year, 8/15 (53.33%) had Good MAIS Score. Table 14: MAIS score v/s parent education at 1 year post-operatively Parent education Satisfactory (0-24) Good (≥ 25) Educated 0 (0%) 11 (73.33%) Un-educated 0 (0%) 4 (26.67%) Total 0 15 (100%) P value = 0.141 (S) Improvement in MAIS score at 1 year was good (≥25) in 15 (100%) patients. Out of 15 patients 11(73.33%) patients had educated parents while 4 (26.67 %) patients had uneducated parents. Table 23. Mean MAIS Score Preop. 6 months 12 months 2.06±2.01 25.53±1.40 32.20±0.77 P value = 0.00(S)

Our study was performed in a small-scale setting of a tertiary care hospital associated with government medical college with scarcity of resources and limitations in counselling and also combating the taboos of the tribal region. Several Indian authors and also global scholars like m. Bakhshaee et.al [10], Sarvanam V. et al [11] etc. have presented their researches which infer that cochlear implantation in early childhood and congenitally deaf children had better outcome from the point of auditory performance and speech intelligibility as compared to those operated in adulthood. intelligibility. In most of the existing literature, parent’s education is an ignored factor which isn’t given due attention and is therefore, covered in this study. The bundle of research literature has treasures which have findings consistent and contrary to this study. To best of author’s knowledge this study is one of its kind in tribal population where in community prevalent issues of age-old traditions sabotage the beneficiaries to avail medical facilities. Parent’s education is one of a very crucial factors predicting the outcome apart from the age of implantation. This affects overall Quality of Life of people. This study might act a template piolet project for future researchers to further carry forward the findings in rural, urban and tribal populations of various regions.

The results derived from this study lead to the conclusion that there is a definite improvement in the parameters used to assess hearing and speech at the end of 1 year when compared with preoperative levels. Cochlear implantation provides satisfactory hearing and speech ability to congenitally deaf children who do not benefit from traditional hearing amplification and speech therapy. From the point of view of complications, it can be deduced that this surgery carries very low risk and benefit to risk ratio is high. Cochlear implant surgery provides a hearing disabled child to lead a near normal life at par with peers of his age with normal hearing.

1. Jhon Hopkins Medicine. Health. Cochlear Implant Surgery. Available from: https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/cochlear- implant-surgery . 2. Medikeri’s Super specialty ENT Centre. Bangalore. Available from: https://www.enthospital.org/cochlear-implantation/ . 3. Zeng FG, Rebscher S, Harrison W, Sun X, Feng H. Cochlear implants: system design, integration, and evaluation. IEEE Rev Biomed Eng. 2008;1(115-42). 4. Balkany JT, Hodges VA, Eshraghi AA, Butts S, Bricker K, Lingvai J. et al.Acta Octo- Larynologica.2009;122(356-62). 5. Waltzmann S, Roland JT.Cochlear Implants. 2ndEd.; 2006; Thieme Publishers, New York, Stuttgart. 6. Archbold S, Lutman ME, Marshall DH. Categories of Auditory Performance. Ann OtolRhinolLaryngolSuppl 1995; 166:312-4. 7. O'Donoghue. Variation in gains in auditory performance from pediatric Cochlear Implantation. OtolNeurol 2002. 8. O'Donoghue. Reliability of a rating scale for measuring speech intelligibility after pediatric cochlear implantation. OtolNeurotol 2001. 9. Lala N, Vishwakarma R, Vishwakarma C, Kumar P. Study of MAIS score post unilateral cochlear implantation in prelingual deaf patients. B.J. Medical College, Civil Hospital, Ahmedabad.2015;5,3(1-9). 10. Bakhshaee M. Sharifian RM, Ghasemi MM, Naimi M, Moghiman T. Speech development and auditory performance in children after cochlear implantation. Medical Journal of the Islamic Republic of Iran. 2007;20(4):184-191. 11. Saravanan V, Nallasivam M, Sivakumar M. Agewise Outcome of Speech and Hearing in Prelingually Deaf Children After Cochlear Implantation. IOSR- JDMS.2017;16(4);69