Table 1: Clinical history of the twins.

ICC088 (III : 7) ICC089 (III : 6) Gender Female Male Deafness etiology Congenital Congenital Suspicion of deafness 18 months 18 months Diagnosis 24 months 24 months Clinical history Normal pregnancy No associated pathologies No previous surgical procedures 2 episodes of ear infections (otitis) prior implantation (without suppuration) No allergies Vaccination plan up to date Normal pregnancy No associated pathologies No previous surgical procedures No allergies Vaccination plan up to date Audiogram Neurosensorial bilateral profound deafness, stage 3 Neurosensorial bilateral profound deafness, stage 3 Placement of hearing aids 24 months 24 months Gain with hearing aids Very poor adaptation No language development Good adaptation Functional gain up to 1000 Hz No language development Auditory evoked potentials (AEP) Wave V present above 90 dB nHL on the right and above 100 dB nHL on the left Absence of AEPs until 110 dB nHL bilaterally Computerized axial tomography scan (CAT scan) Morphologically normal and permeable cochlea Normal inner ear canals Morphologically normal and permeable cochlea Normal inner ear canals Magnetic resonance imaging (MRI) No morphological alterations No congenital malformations No cochlear nerve atrophy Normal cochleas No morphological alterations No congenital malformations No cochlear nerve atrophy Normal cochleas Age at implantation 42 months 42 months Duration of CI use 56 months 56 months Age at audiological tests and present study 8 years 8 years CI model CI24R CA Advance CI24R CA Advance Speech processor SPRINT SPRINT Stimulation mode MP1+2 MP1+2 Stimulation strategy ACE ACE Implanted ear Right Right