Agewise Outcome of Speech and Hearing in Prelingually Deaf Children after Cochlear Implantation

BACKGROUND: Early onset profound hearing loss has shown to have devastating consequences for the development of language. Prelingual sensorineural deafness in children is a major cause for disability in our country which affects the development of the child in all fields. The cochlear implant surgery has created a paradigm shift in the treatment of sensorineural hearing loss. This provides the necessary auditory stimulus necessary for speech development. Knowing the ideal age for implantation is beneficial for the patient as well as for cost benefit analysis of doing the surgery in older children. AIM OF THE STUDY: 1. To assess the hearing and speech outcome of prelingually deaf children who underwent cochlear implantation over a period of 1 year. 2. To evaluate the outcome of cochlear implantation in prelingually deaf children. 3. To identify the ideal age for cochlear implantation in terms of best outcome. 4. To assess the benefit of cochlear implantation in older children. MATERIALS AND METHODOLOGY: The study was carried out on 50 children who underwent cochlear implantation surgery at Coimbatore medical college hospital. The list of the patients enrolled in the study is appended along with the dissertation. Speech and hearing was first assessed prior to the surgery. Informed signed consent from the guardians of the patients were obtained. The duration of the study was one year from July 2014 to June 2015. The children divided into two groups, < 3 years of age of implantation and 3 – 6 years at the time of implantation. The parameters recorded include Category of auditory perception, speech intelligibility rating scale, meaningful auditory integration scale and meaningful use of speech scale. First a pre op evaluation was done and then the parameters were recorded at 3 months, 6 months, and 12 month. The improvement was then compared based on the age of the child at implantation. RESULTS: Among the 50 patients 24 children were below 3 years and 26 children between 3 – 6 years. And of the 50, 29 male and 21 female children were present. The average CAP score in the < 3 year group was 5.17 ±0.702 and in the 3-6 year group it was 3.62 ± 0.983. The average SIR score of the < 3 year group was 4.04 ± 0.624 and in the 3 – 6 year group was 2.23± 0.863. These observations were found to be statistically significant. The MAIS and MUSS grading and scoring of the children also showed highly significant difference between children implanted at age <3 years and between 3 – 6years with the earlier implanted children showing better response. CONCLUSION: All children studied showed improvement in their hearing and speech abilities at the end of 1 year. The maximum benefit was seen in the younger age group (< 3 years at the time of implant) indicating a positive correlation between age and outcome in terms of clinical benefit. So it can be concluded that severe to profound hearing loss should be identified at the earliest in prelingually deaf children and considered for cochlear implantation in order to provide maximum benefit to the child