title: Spectral contrast enhancement improves speech intelligibility in noise for cochlear implants.
abstract: Spectral smearing causes, at least partially, that cochlear implant (CI) users require a higher signal-to-noise ratio to obtain the same speech intelligibility as normal hearing listeners. A spectral contrast enhancement (SCE) algorithm has been designed and evaluated as an additional feature for a standard CI strategy. The algorithm keeps the most prominent peaks within a speech signal constant while attenuating valleys in the spectrum. The goal is to partly compensate for the spectral smearing produced by the limited number of stimulation electrodes and the overlap of electrical fields produced in CIs. Twelve CI users were tested for their speech reception threshold (SRT) using the standard CI coding strategy with and without SCE. No significant differences in SRT were observed between conditions. However, an analysis of the electrical stimulation patterns shows a reduction in stimulation current when using SCE. In a second evaluation, 12 CI users were tested in a similar configuration of the SCE strategy with the stimulation being balanced between the SCE and the non-SCE variants such that the loudness perception delivered by the strategies was the same. Results show a significant improvement in SRT of 0.57 dB (p < 0.0005) for the SCE algorithm.
authors.affiliation: Department of Otolaryngology, Medical University Hannover, Cluster of Excellence Hearing4all, Hannover, Germany.
authors.forename: Waldo
authors.initials: W
authors.lastname: Nogueira
authors.affiliation: HörSys GmbH, Hannover, Germany.
authors.forename: Thilo
authors.initials: T
authors.lastname: Rode
authors.affiliation: Department of Otolaryngology, Medical University Hannover, Cluster of Excellence Hearing4all, Hannover, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Büchner
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001309:Auditory Threshold; D019929:Cochlear Implantation / Q000295:instrumentation; D003054:Cochlear Implants; D004558:Electric Stimulation; D006801:Humans; D008144:Loudness Perception; D008875:Middle Aged; D009622:Noise / Q000009:adverse effects*; D010470:Perceptual Masking; D019986:Persons with Hearing Disabilities / Q000523:psychology / Q000534:rehabilitation*; D011474:Prosthesis Design; D012815:Signal Processing, Computer-Assisted; D059629:Signal-To-Noise Ratio; D013065:Speech Intelligibility; D013067:Speech Perception; D013069:Speech Reception Threshold Test