title: Simultaneous and forward masking of vowels and stop consonants: Effects of age, hearing loss, and spectral shaping.
abstract: Fluctuating noise, common in everyday environments, has the potential to mask acoustic cues important for speech recognition. This study examined the extent to which acoustic cues for perception of vowels and stop consonants differ in their susceptibility to simultaneous and forward masking. Younger normal-hearing, older normal-hearing, and older hearing-impaired adults identified initial and final consonants or vowels in noise-masked syllables that had been spectrally shaped. The amount of shaping was determined by subjects' audiometric thresholds. A second group of younger adults with normal hearing was tested with spectral shaping determined by the mean audiogram of the hearing-impaired group. Stimulus timing ensured that the final 10, 40, or 100 ms of the syllable occurred after the masker offset. Results demonstrated that participants benefited from short temporal delays between the noise and speech for vowel identification, but required longer delays for stop consonant identification. Older adults with normal and impaired hearing, with sufficient audibility, required longer delays to obtain performance equivalent to that of the younger adults. Overall, these results demonstrate that in forward masking conditions, younger listeners can successfully identify vowels during short temporal intervals (i.e., one unmasked pitch period), with longer durations required for consonants and for older adults.
authors.affiliation: Department of Communication Sciences and Disorders, University of South Carolina, 1224 Sumter Street, Suite 300, Columbia, South Carolina 29208, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Fogerty
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, South Carolina 29425-5500, USA.
authors.forename: William J
authors.initials: WJ
authors.lastname: Bologna
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, South Carolina 29425-5500, USA.
authors.forename: Jayne B
authors.initials: JB
authors.lastname: Ahlstrom
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, South Carolina 29425-5500, USA.
authors.forename: Judy R
authors.initials: JR
authors.lastname: Dubno
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000523:psychology*; D001301:Audiometry, Pure-Tone; D001302:Audiometry, Speech; D001309:Auditory Threshold; D003463:Cues; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009622:Noise / Q000009:adverse effects*; D010470:Perceptual Masking; D019986:Persons with Hearing Disabilities / Q000523:psychology*; D013061:Speech Acoustics; D013067:Speech Perception; D013997:Time Factors; D055815:Young Adult