Comparison of sound perception using CIS and ACE sound coding strategies in cochlear implants

Objectives to study the effect of ACE and CIS sound coding strategies on sound perception in patients with the cochlear implants system produced by Cochlear Limited. Material and methods. The study included 50 patients taking the rehabilitation course in the Astrakhan branch of the National Medical Research Center for Otorhinolaryngology of the Federal Medico-Biological Agency over the past 5 years (from 2014 to 2019). The group of subjects included children over 7 years old and adults, whose success in rehabilitation made it possible to perform a full range of tests. The patients underwent tonal threshold audiometry and speech audiometry in a free sound field; the results obtained were registered in special MS Excel tables and further analysed using statistical methods. Results. There were no statistically significant differences in hearing thresholds on tonal audiometry when using the coding strategies ACE and CIS, however, differences in speech perception were observed on average by 4.2%. The patients experienced in using hearing aids reported improved speech recognition, with scores varying within 5%. Conclusion. Using a higher-resolution coding strategy can significantly improve speech recognition, while lower-resolution coding is beneficial for patients with digital hearing aid experience.

DIGITAL HEARING AID SIGNAL PROCESSING SYSTEM USING ANDROID PHONE

Objective: The objective of this research is to propose an Android-based digital hearing aid signal processing algorithm with following key features:(1) Regenerated audio match the patient-specific pattern of hearing loss, (2) noise reduction, and (3) provide flexibility to the users.Methods: The proposed signal processing algorithm is designed based on the specific hearing loss of the hearing disorder patient using inverse Fouriertransform; besides, noise reduction feature is included in the digital algorithm design as well. Proposed digital algorithm has been implemented intoan Android-based smartphone and its performance has been tested under real-time condition.Results: Simulation results show that the frequency response of the proposed digital hearing aid signal processing algorithm is in agreement withthe initial theoretical design that was carried out based on the hearing impaired patient’s audiogram. The proposed algorithm has been implementedin the Android-based smartphone and tested in real time. Results show that most of the patients are satisfied with the regenerated audio quality.According to patient’s comments, the regenerated audio is clear and the users are allowed to control the volume level. Besides, no obvious hearinglatency can be detected.Conclusion: Audio signals generated by the proposed digital signal processing algorithm show similar audio signal frequency response in boththeoretical design and MATLAB simulation results. The only difference between the design and simulation results is the amplification levels. Theproposed algorithm provides flexibility to the users by allowing them to choose the desired amplification level. In real-time testing, the proposedAndroid-based digital hearing aid is able to reduce noise level from the surrounding and the output processed speech match the patient-specifichearing loss.