Hearing Preservation During Cochlear Implantation and Electroacoustic Stimulation in Patients With SLC26A4 Mutations.

Background and Objectives: Patients with SCL26A4 mutations presenting with Mondini deformity and enlarged vestibular aqueduct (EVA) tend to have comparable residual hearing. Although cochlear implantation (CI) produces good results in this group, deterioration of residual hearing can be an adverse event after surgery due to accompanying cochlear malformation and perilymph leakage during cochleostomy. The purpose of this study was to investigate if CI in patients with SCL26A4 mutations via the round window (RW) approach could achieve preservation of residual hearing, and to evaluate their speech reception with electroacoustic stimulation (EAS).
Subjects and Methods: This is a retrospective chart review of eight patients with bilateral EVA, who were bi-allelic patients with SCL26A4 mutations. CI was performed in all patients by a single surgeon using the RW approach. Audiological results were compared before and after implantation.
Results: Additional hearing loss after CI was less than 10 dBHL in five out of eight patients. Average hearing deterioration after CI was 8.75 dB (range, 0-26). Six out of eight patients used EAS mode after CI. The acoustic stimulation frequency ranged from 271 to 438 Hz. Patients showed better speech recognition in quiet and in noise using EAS mode compared with electrical stimulation alone.
Conclusions: Preservation of residual hearing could be achieved after CI in patients with the SLC26A4 mutation via the RW approach. For successful preservation of residual hearing, application of newly-developed soft electrode and meticulous surgical is necessary. Our study showed that patients with the SLC26A4 mutation can be good candidates for EAS surgery.