title: Peripheral auditory tuning for vowels.
abstract: In this study, 35 young, healthy adults were tested on whether speech-like stimuli evoke a unique response in the auditory efferent system. To this end, descending cortical influences on medial olivocochlear (MOC) activity were indirectly evaluated by studying the effects of contralateral suppression on distortion product otoacoustic emissions (DPOAEs) under four conditions: (a) in the absence of any contralateral noise (Baseline), (b) presence of contralateral broadband noise (Noise Baseline), (c) vowel discrimination-in-noise task (VDN) and (d) tone discrimination-in-noise (TDN) task. A statistically significant release from suppression was evident across all tested DPOAE frequencies (1, 1.5 and 2 kHz) only for the VDN task (p < 0.05), which yielded greater release from suppression than the TDN task. These findings indicate that during active listening in the presence of noise, the MOC activity may be differentially modulated depending on the type of stimulus (vowel vs. tone). Specifically, in the presence of background noise, vowels may show a greater release from suppression in the cochlea than frequency, intensity and duration matched tones.
authors.affiliation: Department of Speech-Language Pathology, University of Toronto, Toronto, ON, Canada M5G 1V7, Canada , Toronto Rehabilitation Institute (TRI), Toronto, ON, Canada M5G 2A2, Canada.
authors.forename: Aravind Kumar
authors.initials: AK
authors.lastname: Namasivayam
authors.forename: Duc James
authors.initials: DJ
authors.lastname: Le
authors.forename: Jennifer
authors.initials: J
authors.lastname: Hard
authors.forename: Samantha Evelyn
authors.initials: SE
authors.lastname: Lewis
authors.forename: Chris
authors.initials: C
authors.lastname: Neufeld
authors.forename: Pascal
authors.initials: P
authors.lastname: van Lieshout
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000704:Analysis of Variance; D001306:Auditory Pathways / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D004192:Discrimination, Psychological / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D011571:Psychoacoustics; D055815:Young Adult