비종양 환자의 청성뇌간이식술에서의 고음역 인지의 한계

Abstract

Background and Objectives Auditory brainstem implantation (ABI) is another option forhearing rehabilitation in non-neurofibromatosis type 2 patients who cannot undergo cochlearimplantation (CI). However, the average performance of ABI is worse than that of CI. We analyzedthe psycho-electrical parameters of each electrode and psycho-acoustic response to differentfrequency sounds in nontumor patients with ABI. Subjects and Method Sixteen patients with ABI from July 2008 to May 2013 were includedin the study. They were followed up for 4 to 56 months. Among them, 12 were prelingualdeaf with a narrow internal auditory canal or cochlear ossification. The remaining four were postlingualdeaf adults with severely ossified cochleae. We analyzed the electrical parameters [impedance,threshold level (T level), and dynamic range] of each of the 12 electrodes. We alsoevaluated the sound field pure-tone threshold, Ling 6 sound detection-identification test (Ling6 test), and pitch ranking data of these patients. Results The impedance, T level, and dynamic range did not significantly differ among electrodes. However, the pure-tone threshold to sound field stimulation was elevated in the hightone area, where more variables were found than in the low frequency area. Patients could notidentify /S/ and /Sh/ sounds in the Ling 6 test. The mean T level and the dynamic range of thethree highest pitch-perceiving electrodes in each patient was higher and narrower, respectively,than those of the three lowest pitch-perceiving electrodes. Conclusion The nontumor patients with ABI have difficulty perceiving high pitch sound. More sophisticated penetrating type electrodes and, if possible, bimodal stimulation with CI,could be considered.