Can Pitch Mismatch Be Diagnosed in Children Who Use Electric-Acoustic Stimulation?

Introduction Pitch mismatch is one of the most important problems of users of bimodal cochlear implants, which affects their life satisfaction. Children with acquired hearing loss cannot explain their pitch mismatch problems, as they have had no auditory experience. This study tries to diagnose pitch mismatch in these children through the sound-induced flash illusion test. Materials and methods In this study, 20 children with a bimodal cochlear implant and 20 children with normal hearing, within the age range of 8 to 13 years old, were examined using the sound-induced flash illusion test. In this test, participants received one flash with one to four beep sounds, and they were asked to indicate the number of perceived flashes. Results The results revealed that in the bimodal implantation group, when the flash was provided with one beep, at certain frequencies, children expressed that they saw two flashes. However, the results were not the same in children with normal hearing. Conclusion The results indicated that at frequencies where the auditory information of the hearing aids and those of the cochlear implants overlap, pitch mismatch develops, which can significantly affect the auditory performance of bimodal users.

An evaluation of the preservation of residual hearing with the Nucleus Contour Advance electrode.

CONCLUSION: Our study results confirm that it is possible to preserve preoperative hearing levels in the majority of subjects when using the Nucleus 24 Contour Advance provided that there is adherence to the major principles of 'soft surgery'. Our study group demonstrated that 71-86% of subjects showed preservation of preoperative hearing thresholds at 6 months to varying degree. OBJECTIVES: The aim of the study was to assess the degree of residual hearing preserved postoperatively in a group of standard cochlear implant (CI) candidates following implantation via soft surgery with a Nucleus 24 Contour Advance CI. Surgical technique variations from the soft surgery guidelines provided were assessed and their potential impact upon the conservation of residual hearing was examined. SUBJECTS AND METHODS: A prospective multicentre study involving a within-subject repeated measures design with each subject acting as their own control was performed. Pure-tone audiometric thresholds were assessed and compared in both implanted and contralateral ears for each subject preoperatively as baseline measures and at 6 months postoperatively. Surgeons were asked to complete a questionnaire to capture various aspects of the surgical technique used for each subject. Variations in the surgical technique performed were examined for potential correlation with conservation of residual hearing. Twenty-eight adult subjects, with a severe to profound hearing impairment, were enrolled in the study across eight implant clinics in four countries. RESULTS: In all, 36% of subjects demonstrated preservation of thresholds to within 10 dB of preoperative thresholds across the frequency range (0.25, 0.5, 1.0, 2.0 and 4.0 KHz) and for the low frequency range (0.25-1.0 KHz). Approximately two-thirds of subjects demonstrated preservation of preoperative thresholds to within 20 dB. Preservation of low frequency thresholds post-implant was shown to correlate moderately with cochleostomy site, being more likely for subjects with a site anterior-inferior to the round window but also possible with inferior locations; weakly with cochleostomy size, being more likely when smaller than 1.2 mm; and also with the use of Healon as a sealant and lubricant. Preservation of hearing thresholds across up to 4000 Hz was shown to correlate weakly with the use of suction following opening of the endostium and with bone dust contamination, both having a negative effect upon preservation, while no correlation was observed with the preservation of thresholds for low frequencies alone.

The effects of age on auditory speech perception development in cochlear-implanted prelingually deaf children.

One of the most important factors in auditory speech perception of cochlear-implanted children is age. The goal of this study was to compare auditory speech perception among children implanted from 6 different age groups: 0 to 3, 4 to 5, 6 to 7, 8 to 9, 10 to 11, and >12 years. The subjects of this study were matched based on socioeconomic status, residual hearing before cochlear implantation, the kinds of cochlear implant device, speech processing strategy, communication mode after implantation, and primary language in family. All of them have used the device minimally for 2 years. The subjects were tested with a range of closed and open-set auditory speech perception tests, and the levels of auditory speech perception in different age groups were compared. Results showed that the children who received an implant at 0 to 3 years of age had maximum auditory speech perception.