Introduction: The cochlear implantation in patients with inner ear malformation has always been a challenge
even to the most experienced clinicians. We present the case of a child of 8 years old with profound bilateral
sensorineural hearing loss and the absence of language development with indication of cochlear implantation as
single solution for hearing and speech rehabilitation. Methods: The audiological assessment indicates the
cochlear implantation. Preoperative CT scan revealed a bilateral inner ear malformation (cochlear common
cavity deformity on the right side, cochlear aplasia on the left ear and bilateral vestibular malformation). Brain
magnetic resonance showed the presence of auditory nerve only to the right side. The girl was implanted on the
right ear in the common cavity with an Advanced Bionics device, HiRes90K with HiFocus1j electrode. Results:
The insertion of the portelectrode inside the malformed inner ear was confirmed by X-ray. Audiological
evaluation had shown an average of hearing thresholds at 36,25 dB HL in free field pure tone audiometry at 22
months post-implantation. The speech perception was evaluated according to CAP (categories of auditory
performance) index at 5 and to the speech intelligibility rating scale (SIR) to 3. Conclusions: The children with
inner ear malformations can safely benefit of cochlear implantation. The results for tonal hearing were close to
that of cochlear implanted children with normal ear anatomy, but were limited for speech understanding and
speech production