The Nucleus Hybrid-L and the Nucleus CI422 Cochlear Implant (CI) can be used for treatment of partial deafness due to the dimensions and features of both electrodes. The audiometric thresholds before and after surgery have been measured and indicate a hearing preservation with both electrodes, since the hearing preservation with Hybrid-L could be reached in 100% and with CI422 in 91% of the measurable cases. The Hybrid-L subjects can benefit from their acoustical hearing and gain a larger benefit with the combination of electrical and acoustical stimulation versus normal CI user with electrical only stimulation, because the CI users cannot benefit from their former hearing experiences with their residual hearing.