A Longitudinal Study of Frequency Specific Electrical Stimulation Levels in Cochlear Implant Users

초록

Background and Objectives The purpose of the study was to evaluate the changes in electrical stimulation levels, i.e. threshold (T) levels, comfortable (C) levels, dynamic range (DR), and electrode impedance values (EIVs) during the first year in cochlear implant users. Subjects and Method The maps of 49 cochlear implant users (at least 1 year mapping), using the Nucleus device, were examined at the time of initial connection, and at 6 and 12 months post-initial stimulation. T levels, C levels, DR and EIVs were analyzed according to three frequency levels. Results During the first 6 months of implant use, C levels and DR increased significantly whereas T levels were stable. EIVs of current carrying electrodes decreased significantly from the connection to the 12-month visit. The changes of electrical stimulation levels did not differ among three frequency levels during the entire follow-up. Conclusion During the first 6 months of implant use, C levels and DR increased significantly. Thus, an appropriate mapping in the first 6 month is critical to setup hearing capacity in implant users. The mapping should be performed under the best communication environment between the audiologist and the patient, and it makes correct setting of T levels from the initial connection period.

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