title: Vowel discrimination by hearing infants as a function of number of spectral channels.
abstract: Reduced spectral resolution negatively impacts speech perception, particularly perception of vowels and consonant place. This study assessed impact of number of spectral channels on vowel discrimination by 6-month-old infants with normal hearing by comparing three listening conditions: Unprocessed speech, 32 channels, and 16 channels. Auditory stimuli (/ti/ and /ta/) were spectrally reduced using a noiseband vocoder and presented to infants with normal hearing via visual habituation. Results supported a significant effect of number of channels on vowel discrimination by 6-month-old infants. No differences emerged between unprocessed and 32-channel conditions in which infants looked longer during novel stimulus trials (i.e., discrimination). The 16-channel condition yielded a significantly different pattern: Infants demonstrated no significant difference in looking time to familiar vs novel stimulus trials, suggesting infants cannot discriminate /ti/ and /ta/ with only 16 channels. Results support effects of spectral resolution on vowel discrimination. Relative to published reports, young infants need more spectral detail than older children and adults to perceive spectrally degraded speech. Results have implications for development of perception by infants with hearing loss who receive auditory prostheses.
authors.affiliation: Department of Communication Sciences and Disorders, The University of Texas at Dallas, Callier Advanced Hearing Research Center, 1966 Inwood Road, Dallas, Texas 75235.
authors.forename: Andrea D
authors.initials: AD
authors.lastname: Warner-Czyz
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Indiana University School of Medicine, 699 Riley Hospital Drive/RR044, Indianapolis, Indiana 46202.
authors.forename: Derek M
authors.initials: DM
authors.lastname: Houston
authors.affiliation: Departments of Clinical Sciences and Psychiatry, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390.
authors.forename: Linda S
authors.initials: LS
authors.lastname: Hynan
mesh_terms: D000161:Acoustic Stimulation / Q000295:instrumentation* / Q000379:methods; D000328:Adult; D003463:Cues; D004192:Discrimination, Psychological / Q000502:physiology*; D004522:Educational Status; D005260:Female; D006801:Humans; D007182:Income; D007223:Infant; D008297:Male; D009035:Mothers / Q000706:statistics & numerical data; D046709:Pattern Recognition, Physiological / Q000502:physiology*; D010469:Perceptual Distortion / Q000502:physiology*; D010700:Phonetics; D011571:Psychoacoustics; D002666:Psychology, Child; D011897:Random Allocation; D013018:Sound Spectrography; D013063:Speech Discrimination Tests; D013067:Speech Perception / Q000502:physiology*