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Objectives: Hearing preservation is an important touchstone in cochlear implantation influencing speech understanding, music perception and quality of life. Patients with functional residual hearing benefit in complex hearing situations, such as noise, as well as speech recognition and understanding. Here, we investigated to which extend the CI532 electrode (Cochlear®) can preserve hearing assuming a reduced insertion trauma due to the thin, flexible and modiolus-close electrode characteristics. Methods: In this study patients were divided in two groups with (experimental group, RH) and without residual hearing (control group, no RH) prior to implantation. RH was defined as a hearing threshold above 85 dB for pure tone audiogram (PTA) frequencies 125-500-1000-2000 Hz, and/ or hearing loss for Freiburger numbers of less than 60 dB and maximum Freiburger monosyllables better than 50%. Data of PTA, Freiburger speech test and neural response telemetry (NRT) were compared prior to, one day and three months after surgery. Intraoperative position check performed by 3D C-arm imaging was evaluated. Results and Conclusions: A total of 27 patients received a CI532 electrode, 13 with and 14 patients without RH. Within the first three months PTA showed a decline especially in lower frequencies (125-250Hz) from 45dB to 65dB, whereas higher frequencies (500-100Hz) remained consistent at a mean of 60dB. NRTs showed comparable results: during surgery 187 (RH) vs. 185 (noRH), 3 months post 172 (RH) vs. 169 (noRH) und 6 months following surgery 162 (RH) vs. 168 (noRH). The intraoperative position control demonstrated regular electrode positions in 25 patients and tip fold over in two patients.Hearing results of CI532 implanted patients with and without RH seem to align postoperative. These first results suggest that preservation of residual hearing is not only influenced by the electrode shape. Thus alternative pathways have to be evaluated for long term hearing preservation. [ABSTRACT FROM AUTHOR]