title: Comparing Binaural Pre-processing Strategies II: Speech Intelligibility of Bilateral Cochlear Implant Users.
abstract: Several binaural audio signal enhancement algorithms were evaluated with respect to their potential to improve speech intelligibility in noise for users of bilateral cochlear implants (CIs). 50% speech reception thresholds (SRT50) were assessed using an adaptive procedure in three distinct, realistic noise scenarios. All scenarios were highly nonstationary, complex, and included a significant amount of reverberation. Other aspects, such as the perfectly frontal target position, were idealized laboratory settings, allowing the algorithms to perform better than in corresponding real-world conditions. Eight bilaterally implanted CI users, wearing devices from three manufacturers, participated in the study. In all noise conditions, a substantial improvement in SRT50 compared to the unprocessed signal was observed for most of the algorithms tested, with the largest improvements generally provided by binaural minimum variance distortionless response (MVDR) beamforming algorithms. The largest overall improvement in speech intelligibility was achieved by an adaptive binaural MVDR in a spatially separated, single competing talker noise scenario. A no-pre-processing condition and adaptive differential microphones without a binaural link served as the two baseline conditions. SRT50 improvements provided by the binaural MVDR beamformers surpassed the performance of the adaptive differential microphones in most cases. Speech intelligibility improvements predicted by instrumental measures were shown to account for some but not all aspects of the perceptually obtained SRT50 improvements measured in bilaterally implanted CI users.
authors.affiliation: Medizinische Physik, Carl von Ossietzky Universität, Oldenburg, Germany Cluster of Excellence 'Hearing4all', Oldenburg, Germany regina.baumgaertel@uni-oldenburg.de.
authors.forename: Regina M
authors.initials: RM
authors.lastname: Baumgärtel
authors.affiliation: Medizinische Physik, Carl von Ossietzky Universität, Oldenburg, Germany Cluster of Excellence 'Hearing4all', Oldenburg, Germany.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Hu
authors.affiliation: Cluster of Excellence 'Hearing4all', Oldenburg, Germany Speech Signal Processing Group, Carl von Ossietzky Universität Oldenburg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Krawczyk-Becker
authors.affiliation: Cluster of Excellence 'Hearing4all', Oldenburg, Germany Signal Processing Group, Carl von Ossietzky Universität Oldenburg, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Marquardt
authors.affiliation: Cluster of Excellence 'Hearing4all', Oldenburg, Germany HörTech gGmbH, Oldenburg, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Herzke
authors.affiliation: Cluster of Excellence 'Hearing4all', Oldenburg, Germany HörTech gGmbH, Oldenburg, Germany.
authors.forename: Graham
authors.initials: G
authors.lastname: Coleman
authors.affiliation: Cluster of Excellence 'Hearing4all', Oldenburg, Germany HörTech gGmbH, Oldenburg, Germany.
authors.forename: Kamil
authors.initials: K
authors.lastname: Adiloğlu
authors.affiliation: Cochlear-Implant Centrum CIC, Klinik für Phoniatrie und Pädaudiologie, Ev. Krankenhaus Oldenburg, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Bomke
authors.affiliation: Cochlear-Implant Centrum CIC, Klinik für Phoniatrie und Pädaudiologie, Ev. Krankenhaus Oldenburg, Germany.
authors.forename: Karsten
authors.initials: K
authors.lastname: Plotz
authors.affiliation: Cluster of Excellence 'Hearing4all', Oldenburg, Germany Speech Signal Processing Group, Carl von Ossietzky Universität Oldenburg, Germany.
authors.forename: Timo
authors.initials: T
authors.lastname: Gerkmann
authors.affiliation: Cluster of Excellence 'Hearing4all', Oldenburg, Germany Signal Processing Group, Carl von Ossietzky Universität Oldenburg, Germany.
authors.forename: Simon
authors.initials: S
authors.lastname: Doclo
authors.affiliation: Medizinische Physik, Carl von Ossietzky Universität, Oldenburg, Germany Cluster of Excellence 'Hearing4all', Oldenburg, Germany.
authors.forename: Birger
authors.initials: B
authors.lastname: Kollmeier
authors.affiliation: Medizinische Physik, Carl von Ossietzky Universität, Oldenburg, Germany Cluster of Excellence 'Hearing4all', Oldenburg, Germany HörTech gGmbH, Oldenburg, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Hohmann
authors.affiliation: Medizinische Physik, Carl von Ossietzky Universität, Oldenburg, Germany Cluster of Excellence 'Hearing4all', Oldenburg, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Dietz
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D001302:Audiometry, Speech / Q000379:methods; D001309:Auditory Threshold / Q000502:physiology*; D019929:Cochlear Implantation / Q000295:instrumentation*; D003054:Cochlear Implants; D006801:Humans; D008875:Middle Aged; D009622:Noise / Q000517:prevention & control*; D010470:Perceptual Masking / Q000502:physiology*; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012494:Sampling Studies; D059629:Signal-To-Noise Ratio; D013065:Speech Intelligibility; D013069:Speech Reception Threshold Test; D055815:Young Adult
keywords: bilateral; cochlear implant; noise reduction algorithm; speech intelligibility; speech reception threshold