title: Streaming of vowel sequences based on fundamental frequency in a cochlear-implant simulation.
abstract: Cochlear-implant (CI) users often have difficulties perceiving speech in noisy environments. Although this problem likely involves auditory scene analysis, few studies have examined sequential segregation in CI listening situations. The present study aims to assess the possible role of fundamental frequency (F(0)) cues for the segregation of vowel sequences, using a noise-excited envelope vocoder that simulates certain aspects of CI stimulation. Obligatory streaming was evaluated using an order-naming task in two experiments involving normal-hearing subjects. In the first experiment, it was found that streaming did not occur based on F(0) cues when natural-duration vowels were processed to reduce spectral cues using the vocoder. In the second experiment, shorter duration vowels were used to enhance streaming. Under these conditions, F(0)-related streaming appeared even when vowels were processed to reduce spectral cues. However, the observed segregation could not be convincingly attributed to temporal periodicity cues. A subsequent analysis of the stimuli revealed that an F(0)-related spectral cue could have elicited the observed segregation. Thus, streaming under conditions of severely reduced spectral cues, such as those associated with CIs, may potentially occur as a result of this particular cue.
authors.affiliation: Neurosciences Sensorielles, Comportement, Cognition, CNRS UMR 5020, Universite Lyon 1, 50 Avenue Tony Garnier, 69366 Lyon Cedex 07, France.
authors.forename: Etienne
authors.initials: E
authors.lastname: Gaudrain
authors.forename: Nicolas
authors.initials: N
authors.lastname: Grimault
authors.forename: Eric W
authors.initials: EW
authors.lastname: Healy
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Béra
mesh_terms: D001309:Auditory Threshold; D003054:Cochlear Implants; D003463:Cues; D006309:Hearing / Q000502:physiology*; D006801:Humans; D010507:Periodicity; D010700:Phonetics; D010898:Pitch Perception; D012016:Reference Values; D013017:Sound Localization / Q000502:physiology; D013060:Speech; D013065:Speech Intelligibility; D013067:Speech Perception / Q000502:physiology*