Objective: This study assessed the electrode impedance change in MED–EL SONATA

Ti100 FLEX SOFT between implantation and switch on. Design: It is a retrospective

study.                    

Study sample: It includes 60 pediatrics all of whom were implanted between 2012 and

2014.

Results: It is found that the electrode impedance increased abruptly during switch on than

intraoperative impedance value. It is suggested that increase in the impedance is due to

fibrous tissue formation around electrodes..