title: Improved perception of speech in noise and Mandarin tones with acoustic simulations of harmonic coding for cochlear implants.
abstract: Harmonic and temporal fine structure (TFS) information are important cues for speech perception in noise and music perception. However, due to the inherently coarse spectral and temporal resolution in electric hearing, the question of how to deliver harmonic and TFS information to cochlear implant (CI) users remains unresolved. A harmonic-single-sideband-encoder [(HSSE); Nie et al. (2008). Proceedings of IEEE International Conference on Acoustics, Speech, and Signal Processing; Lie et al., (2010). Proceedings of IEEE International Conference on Acoustics, Speech, and Signal Processing] strategy has been proposed that explicitly tracks the harmonics in speech and transforms them into modulators conveying both amplitude modulation and fundamental frequency information. For unvoiced speech, HSSE transforms the TFS into a slowly varying yet still noise-like signal. To investigate its potential, four- and eight-channel vocoder simulations of HSSE and the continuous-interleaved-sampling (CIS) strategy were implemented, respectively. Using these vocoders, five normal-hearing subjects' speech recognition performance was evaluated under different masking conditions; another five normal-hearing subjects' Mandarin tone identification performance was also evaluated. Additionally, the neural discharge patterns evoked by HSSE- and CIS-encoded Mandarin tone stimuli were simulated using an auditory nerve model. All subjects scored significantly higher with HSSE than with CIS vocoders. The modeling analysis demonstrated that HSSE can convey temporal pitch cues better than CIS. Overall, the results suggest that HSSE is a promising strategy to enhance speech perception with CIs.
authors.affiliation: Department of Electrical Engineering, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Xing
authors.initials: X
authors.lastname: Li
authors.forename: Kaibao
authors.initials: K
authors.lastname: Nie
authors.forename: Nikita S
authors.initials: NS
authors.lastname: Imennov
authors.forename: Jong Ho
authors.initials: JH
authors.lastname: Won
authors.forename: Ward R
authors.initials: WR
authors.lastname: Drennan
authors.forename: Jay T
authors.initials: JT
authors.lastname: Rubinstein
authors.forename: Les E
authors.initials: LE
authors.lastname: Atlas
mesh_terms: D000161:Acoustic Stimulation; D001302:Audiometry, Speech; D003054:Cochlear Implants; D003198:Computer Simulation; D003463:Cues; D006801:Humans; D016018:Least-Squares Analysis; D009622:Noise / Q000009:adverse effects*; D010470:Perceptual Masking; D010700:Phonetics; D011571:Psychoacoustics; D021641:Recognition, Psychology; D012815:Signal Processing, Computer-Assisted; D013018:Sound Spectrography; D013061:Speech Acoustics; D013067:Speech Perception; D013997:Time Factors