Integrated Active Noise Control and Noise Reduction Schemes in Open-Fitting Hearing Aids

Understanding speech in the presence of background noise is one of the major problems for hearing-impaired persons. Although most digital hearing aids currently make use of advanced digital signal processing and multiple microphones to achieve noise reduction [1], the majority of hearing aid users still reports a significant reduction in speech understanding in noisy environments. Whereas open fittings, i.e. using an ear mould with a large vent, substantially reduce the occlusion effect and hence improve the physical comfort, current signal processing techniques in open-fitting hearing aids largely ignore the occurrence of signal leakage, which reaches the ear canal directly through the vent of the ear mould. Recent miniaturization advances however enable to incorporate an internal microphone in the ear mould, which provides information about the signal leakage and hence enables to improve the performance of noise reduction algorithms. In this paper, two multichannel noise reduction algorithms, exploiting this internal microphone signal, are presented and their performance is compared.