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In a collaborative research project, several monaural and binaural noise reduction algorithms have been comprehensively evaluated. In this article, eight selected noise reduction algorithms were assessed using instrumental measures, with a focus on the instrumental evaluation of speech intelligibility. Four distinct, reverberant scenarios were created to reflect everyday listening situations: a stationary speech-shaped noise, a multitalker babble noise, a single interfering talker, and a realistic cafeteria noise. Three instrumental measures were employed to assess predicted speech intelligibility and predicted sound quality: the intelligibility-weighted signal-to-noise ratio, the short-time objective intelligibility measure, and the perceptual evaluation of speech quality. The results show substantial improvements in predicted speech intelligibility as well as sound quality for the proposed algorithms. The evaluated coherence-based noise reduction algorithm was able to provide improvements in predicted audio signal quality. For the tested single-channel noise reduction algorithm, improvements in intelligibility-weighted signal-to-noise ratio were observed in all but the nonstationary cafeteria ambient noise scenario. Binaural minimum variance distortionless response beamforming algorithms performed particularly well in all noise scenarios., (© The Author(s) 2015.)

Using current speech processors, Cochlear Implant (CI) users already reach up to 100% speech intelligibility in quiet. Listening in noisy environments however, still remains a challenge. The increasing supply of profoundly deaf patients with two independent implants (bilateral supply) already provides improved speech intelligibility in noise compared to unilateral supply. In this study, the potential of binaural speech enhancement strategies to further improve speech intelligibility of bilaterally implanted CI users in noise was assessed. Instrumental measures as well as perceptual (listening) tests were used to evaluate 2 monaural and 6 binaural noise reduction schemes. All algorithms were implemented in the Master Hearing Aid framework and run online in real-time. 4 spatially distinct noise scenarios were created in a reverberant environment (T60 ≅ 1250 ms) using virtual acoustics. The Oldenburg matrix sentence test (Oldenburger Satztest OLSA) was used as speech material. Several instrumental measures were applied to evaluate the algorithms' potential in improving speech intelligibility independent of inter-subject variability. Results from this instrumental evaluation demonstrate the ability of the tested algorithms to provide improvements in speech intelligibility as well as sound quality. For the perceptual evaluation, speech reception thresholds (SRT50) were determined using a maximum likelihood adaptive measurement procedure. 8 bilaterally implanted CI subjects, using processors from 3 different manufacturers have participated in the evaluation. The results show substantial and significant improvements in perceptual speech reception threshold (SRT50) in reverberant, spatial testing conditions using the algorithms presented here. [ABSTRACT FROM AUTHOR]