title: A physiologically-inspired model reproducing the speech intelligibility benefit in cochlear implant listeners with residual acoustic hearing.
abstract: This study introduces a speech intelligibility model for cochlear implant users with ipsilateral preserved acoustic hearing that aims at simulating the observed speech-in-noise intelligibility benefit when receiving simultaneous electric and acoustic stimulation (EA-benefit). The model simulates the auditory nerve spiking in response to electric and/or acoustic stimulation. The temporally and spatially integrated spiking patterns were used as the final internal representation of noisy speech. Speech reception thresholds (SRTs) in stationary noise were predicted for a sentence test using an automatic speech recognition framework. The model was employed to systematically investigate the effect of three physiologically relevant model factors on simulated SRTs: (1) the spatial spread of the electric field which co-varies with the number of electrically stimulated auditory nerves, (2) the "internal" noise simulating the deprivation of auditory system, and (3) the upper bound frequency limit of acoustic hearing. The model results show that the simulated SRTs increase monotonically with increasing spatial spread for fixed internal noise, and also increase with increasing the internal noise strength for a fixed spatial spread. The predicted EA-benefit does not follow such a systematic trend and depends on the specific combination of the model parameters. Beyond 300 Hz, the upper bound limit for preserved acoustic hearing is less influential on speech intelligibility of EA-listeners in stationary noise. The proposed model-predicted EA-benefits are within the range of EA-benefits shown by 18 out of 21 actual cochlear implant listeners with preserved acoustic hearing.
authors.affiliation: Medizinische Physik, Cluster of Excellence "Hearing4all", and Forschungszentrum Neurosensorik, Carl-von-Ossietzky Universität Oldenburg, Germany. Electronic address: ladan.zamaninezhad@uni-oldenburg.de.
authors.forename: Ladan
authors.initials: L
authors.lastname: Zamaninezhad
authors.affiliation: Medizinische Physik, Cluster of Excellence "Hearing4all", and Forschungszentrum Neurosensorik, Carl-von-Ossietzky Universität Oldenburg, Germany. Electronic address: volker.hohmann@uni-oldenburg.de.
authors.forename: Volker
authors.initials: V
authors.lastname: Hohmann
authors.affiliation: Deutsches Hörzentrum der Medizinischen Hochschule Hannover and Cluster of Excellence "Hearing4all", D-30625, Germany. Electronic address: Buechner@hoerzentrum-hannover.de.
authors.forename: Andreas
authors.initials: A
authors.lastname: Büchner
authors.affiliation: Medizinische Physik, Cluster of Excellence "Hearing4all", and Forschungszentrum Neurosensorik, Carl-von-Ossietzky Universität Oldenburg, Germany. Electronic address: marc.r.schaedler@uni-oldenburg.de.
authors.forename: Marc René
authors.initials: MR
authors.lastname: Schädler
authors.affiliation: Medizinische Physik, Cluster of Excellence "Hearing4all", and Forschungszentrum Neurosensorik, Carl-von-Ossietzky Universität Oldenburg, Germany. Electronic address: tim.juergens@uni-oldenburg.de.
authors.forename: Tim
authors.initials: T
authors.lastname: Jürgens
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000368:Aged; D001309:Auditory Threshold; D019929:Cochlear Implantation / Q000295:instrumentation*; D003054:Cochlear Implants; D003056:Cochlear Nerve / Q000503:physiopathology*; D032882:Comprehension; D004558:Electric Stimulation; D006309:Hearing; D006311:Hearing Disorders / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology / Q000628:therapy*; D006801:Humans; D008875:Middle Aged; D008959:Models, Neurological; D009622:Noise / Q000009:adverse effects; D010363:Pattern Recognition, Automated; D046709:Pattern Recognition, Physiological; D010470:Perceptual Masking; D019986:Persons with Hearing Disabilities / Q000523:psychology / Q000534:rehabilitation*; D012815:Signal Processing, Computer-Assisted; D013065:Speech Intelligibility; D013067:Speech Perception; D013069:Speech Reception Threshold Test; D055815:Young Adult
keywords: Auditory models; Cochlear implants; Electro-acoustic stimulation; Hybrid cochlear implant; Low frequency acoustic hearing; Speech intelligibility