title: Pitch and spectral resolution: A systematic comparison of bottom-up cues for top-down repair of degraded speech.
abstract: The brain is capable of restoring missing parts of speech, a top-down repair mechanism that enhances speech understanding in noisy environments. This enhancement can be quantified using the phonemic restoration paradigm, i.e., the improvement in intelligibility when silent interruptions of interrupted speech are filled with noise. Benefit from top-down repair of speech differs between cochlear implant (CI) users and normal-hearing (NH) listeners. This difference could be due to poorer spectral resolution and/or weaker pitch cues inherent to CI transmitted speech. In CIs, those two degradations cannot be teased apart because spectral degradation leads to weaker pitch representation. A vocoding method was developed to evaluate independently the roles of pitch and spectral resolution for restoration in NH individuals. Sentences were resynthesized with different spectral resolutions and with either retaining the original pitch cues or discarding them all. The addition of pitch significantly improved restoration only at six-bands spectral resolution. However, overall intelligibility of interrupted speech was improved both with the addition of pitch and with the increase in spectral resolution. This improvement may be due to better discrimination of speech segments from the filler noise, better grouping of speech segments together, and/or better bottom-up cues available in the speech segments.
authors.affiliation: Department of Otorhinolaryngology/Head and Neck Surgery, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, BB21, 9700 RB Groningen, The Netherlands.
authors.forename: Jeanne
authors.initials: J
authors.lastname: Clarke
authors.affiliation: Department of Otorhinolaryngology/Head and Neck Surgery, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, BB21, 9700 RB Groningen, The Netherlands.
authors.forename: Deniz
authors.initials: D
authors.lastname: Başkent
authors.affiliation: Department of Otorhinolaryngology/Head and Neck Surgery, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, BB21, 9700 RB Groningen, The Netherlands.
authors.forename: Etienne
authors.initials: E
authors.lastname: Gaudrain
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000704:Analysis of Variance; D003054:Cochlear Implants; D003463:Cues; D005260:Female; D006801:Humans; D008297:Male; D009622:Noise; D010470:Perceptual Masking / Q000502:physiology; D010897:Pitch Discrimination / Q000502:physiology*; D013018:Sound Spectrography; D013061:Speech Acoustics; D013065:Speech Intelligibility / Q000502:physiology; D013067:Speech Perception / Q000502:physiology*; D055815:Young Adult