Through the preserved acoustic hearing, we believe the subject will experience better signal to noise ratios for speech perception in noise, better localization of sound and an improvement music perception. Histological evidence from patients implanted with standard arrays and our experience with a short electrode array for implantation of individuals with significant residual hearing both support this assumption (Nadol, Shiao, Burgess, Ketten, Eddington et al., 2001). The duration of this study will be 2 years (24 months) for adults and for 5 years (60 months) in children and adolescents.