Channel Interaction in Cochlear Implant and Speech Understanding in Noise

Subjects will be asked to repeat lists of words played by speakers in a noisy environment generated by the same speakers. A percentage of correct recognition is calculated for each list.

Sounds of variable center frequency are used as maskers, and a tone with a fixed frequency at a fixed level is the target. What is tested here is the level of masker that just masks the target.

Channel interaction assessment using eABRs (auditory nerve responses). The method consists of two measurements: 1) eABR measurements with stimulation by a single electrode of the cochlear implant at 70% of the dynamic range (four different electrodes are tested); 2) Measurement of a single eABR with stimulation from all four electrodes at 70% of the dynamic range. A comparison of the eABRs obtained by these two measurements, indicates the electrical and neural interactions between the electrodes.

Tonal audiometry will be performed with headphones

Otoscopic examination of external auditory canal and eardrum