Mapping of Paediatric Cochlear Implant Using Neural Response Threshold (NRT) and Behavioural Observation Audiometry (BOA).

Abstract

To measure the correlation between neural response threshold (NRT) and most comfortable level for behaviouralresponse (MCLB) whichever is better for rehabilitation purpose and to calculate the impedance of the electrode in cochlear implant recipient. Mapping may be done by various methods here we did by NRT and behavioral observation audiometry (BOA). NRT is technique by which we measure the response from the auditory nerve using the hi-resolution bionic ear system. Neural response measurement depends on the-neural tissue, stimulus used and recording technique. BOA is used for observing motor response on presenting sound to the implanted child. Most comfortable level for behaviouralresponse (MCLB) is calculated for behavioural response. It measures the useful information about low frequency hearing, it provides more information about the hearing of neurologically immature babies giving indication of uncomfortable loudness levels. The NRT and MCLB is calculated for 2nd, 6th, and 11th electrode for all patients in our study. Auditory response threshold is better for rehabilitations then behavioural observation audiometry for Cochlear implant patients. Mean value and standard deviation of neural response threshold (NRT) (qu) are 10.23, 3.67; 11.27, 4.39; 10.71, 3.88 at 2nd, 6th, and 11th electrode respectively. Mean value and standard deviation of Most comfortable level for behavioral response (qu) are 20.49, 7.08; 21.26, 7.31; 21.01, 6.03 at 2nd, 6th and 11th electrode respectively. NRT is better for post-operative rehabilitations and MCL and threshold vary with different electrode and in different patients.