Dillon Dsouza1, Sandra DeSaSouza2, Natasha Dsouza3

1DeSa’S Hospital, Jaslok Hospital, Breach Candy Hospital, Mumbai, India/2DeSa’S Hospital, Jaslok Hospital, Breach Candy hospital, Saifee Hospital, Mumbai, India/3DeSa’S Hospital, Jaslok Hospital, Breach Candy hospital, Saifee Hospital, Mumbai, India

■ OBJECTIVES: Electrode arrays in Cochlear implants, depending on the state of the cochlear can be inserted partially (22 to 30 mm) into the cochlea, which results in a frequency mismatch between electrodes and nerve fibers. In 15 patients implanted with a CII Bionic Ear and 38 patients implanted with a Hires90K with a normal cochlea, electrode insertion depths were measured and compared with speech discrimination scores after rehabilitation.

■ METHODS: A Modified Stenvers View of the temporal bone of each patient was taken post operatively on a DSA machine. The number of intracochlear electrodes of the HiFocus I were counted and the length of insertion of the electrodes was determined by adding up the distance between electrodes. All patients were mapped with Hires strategy, and consonant/vowel and sentence recognition tests were carried out after I week and 4 weeks of rehabilitation.

■ RESULTS: The speech perception and speech production average scores attained were higher in patients with insertions of 25mm or more and lower in patients who had insertion depths of 20 to 24 mm.