title: Auditory temporal-order processing of vowel sequences by young and elderly listeners.
abstract: This project focused on the individual differences underlying observed variability in temporal processing among older listeners. Four measures of vowel temporal-order identification were completed by young (N=35; 18-31 years) and older (N=151; 60-88 years) listeners. Experiments used forced-choice, constant-stimuli methods to determine the smallest stimulus onset asynchrony (SOA) between brief (40 or 70 ms) vowels that enabled identification of a stimulus sequence. Four words (pit, pet, pot, and put) spoken by a male talker were processed to serve as vowel stimuli. All listeners identified the vowels in isolation with better than 90% accuracy. Vowel temporal-order tasks included the following: (1) monaural two-item identification, (2) monaural four-item identification, (3) dichotic two-item vowel identification, and (4) dichotic two-item ear identification. Results indicated that older listeners had more variability and performed poorer than young listeners on vowel-identification tasks, although a large overlap in distributions was observed. Both age groups performed similarly on the dichotic ear-identification task. For both groups, the monaural four-item and dichotic two-item tasks were significantly harder than the monaural two-item task. Older listeners' SOA thresholds improved with additional stimulus exposure and shorter dichotic stimulus durations. Individual differences of temporal-order performance among the older listeners demonstrated the influence of cognitive measures, but not audibility or age.
authors.affiliation: Department of Speech and Hearing Sciences, Indiana University, Bloomington, Indiana 47405, USA. dfogerty@indiana.edu
authors.forename: Daniel
authors.initials: D
authors.lastname: Fogerty
authors.forename: Larry E
authors.initials: LE
authors.lastname: Humes
authors.forename: Diane
authors.initials: D
authors.lastname: Kewley-Port
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology / Q000523:psychology; D001306:Auditory Pathways / Q000502:physiology*; D001309:Auditory Threshold; D003071:Cognition; D032882:Comprehension; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011571:Psychoacoustics; D015203:Reproducibility of Results; D017603:Signal Detection, Psychological; D013017:Sound Localization; D013061:Speech Acoustics; D013067:Speech Perception; D013647:Task Performance and Analysis; D013997:Time Factors; D013998:Time Perception; D055815:Young Adult