Factors Influencing Cortical Auditory Evoked Potentials in Cochlear Implantees

Sathiya, K (2015) Factors Influencing Cortical Auditory Evoked Potentials in Cochlear Implantees. Doctoral thesis, The Tamilnadu Dr.M.G.R. Medical University, Chennai.


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INTRODUCTION: Cortical auditory evoked potentials (CAEPs) are a non-invasive tool that can provide objective information on the functioning of the auditory pathways. In our study, we study CAEP parameters like P1 latency, amplitude and morphology as tools of measure of auditory cortical maturation after electrical stimulation following cochlear implantation and compare the values in children implanted below 3 years (yrs) of age and between 3-6 years of age. Furthermore, in our study, we also recorded Category of Auditory Perception (CAP) and Speech Intelligibility Ratio (SIR) scores for subjectively assessing post-implantation outcomes and correlated the values with CAEP parameters. The results of our study are discussed. AIMS OF THE STUDY: The aim of the study is to investigate the impact of age at implantation and its influence on the neural plasticity provided by auditory stimulation with the implant. OBJECTIVES: 1. To assess the pattern of change in the CAEP parameters over time, in the first year of implantation. 2. To assess the impact of age on the CAEP parameters. 3. To correlate the CAEP parameters with subjective outcomes over time. 4. To predict the outcomes across different age groups using CAEP as a prognostic indicator. MATERIALS AND METHODS: 64 congenitally deaf children were enrolled for the study. They were divided into 2 groups (A-below 3 yrs of age & B-between 3 and 6 yrs). All implantees were followed up at 3, 6 and 12 months with CAEP parameters (P1 amplitude and latency and morphology), CAP and SIR scores were recorded. Students paired and un-paired t-tests, Pearson’s correlation and Hosmerand Lemeshow Goodness of fit test were the statistical tools used. OBSERVATION AND RESULTS: CAEP latency at 3 months, group 1 showed statistically significant difference when compared with group B. At 6 months post implantation there is no statistically significant mean difference between group 1 and 2 in SIR score whereas other variables were found to be significant. However at 12 months, the P1 latency alone was comparable in both groups indicating that intensive post implantation auditory-verbal habilitation plays significant role in both groups. The correlation between CAP, SIR with P1 latency, amplitude is discussed. Multiple logistic regression test was done to assess how well the model fitted the data. It resulted in a non-significant value, which is an indication of a model that predicts the population fairly well. CONCLUSION: Overall CAEP P1 latency, amplitude, CAP and SIR scores in cochlear implantees show significant improvement following implantation and values improve with increased use of the implant, thus indicating ongoing cortical maturation. The earlier the implantation, the earlier the maturation of auditory cortex and stress on intensive auditory-verbal habilitation after implantation must be appropriately explained to the care-givers / parents.

Item Type: Thesis (Doctoral)
Additional Information: Ref.No.50730/2012 (Reg No 141210006)
Uncontrolled Keywords: Cortical Auditory Evoked Potential (CAEP) ; Categories of Auditory Perception (CAP) ; Speech Intelligibility Rating (SIR ) ; early implantees ; late implantees.
Subjects: Respiratory Medicine > Otolaryngology
> Respiratory Medicine > Otolaryngology
Depositing User: Subramani R
Date Deposited: 01 Jan 2019 14:09
Last Modified: 18 Oct 2022 06:20
URI: http://repository-tnmgrmu.ac.in/id/eprint/10294

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