Electrode selection for hearing preservation in cochlear implantation: A review of the evidence

OBJECTIVE: To review and assess the ideal length of electrode in cochlear implant patients for hearing preservation. METHODS: The English language literature was reviewed for studies including hearing preservation and speech understanding for electrodes of different lengths. RESULTS: One prospective trial was found, and there were no studies that randomized patients into different length electrodes with an intent to preserve hearing. Eight studies total included multiple length electrodes and contained data regarding hearing preservation. CONCLUSIONS: Although there is some evidence that indicates that shorter electrodes may improve both short and long-term hearing preservation rates in cochlear implant patients, no study has directly compared implant length on hearing preservation in a similar patient population. A randomized trial of short and standard length electrodes for hearing preservation is warranted. In the interim, utilization of current electrodes measuring 20–25 mm could seem to be a prudent approach when seeking to preserve residual hearing without unduly compromising cochlear coverage.