title: Steep and shallow phase gradient distortion product otoacoustic emissions arising basal to the primary tones.
abstract: Distortion product otoacoustic emission (DPOAE) level/phase maps were collected in humans with and without an interference tone (IT) near the DPOAE frequency place (f(dp)) at primary-tone levels of 75 dB SPL. A DPOAE component with the expected steep phase gradient could be extracted at f(dp), however, considerable vertical-phase banding, presumably indicative of reflection emissions, remained. An IT placed 0.33 oct above f(2) removed most of this banding, revealing DPOAE components originating basal to the IT frequency place. These findings suggest that the commonly accepted two-source model of DPOAE generation may need to be qualified when higher primary-tone levels are utilized.
authors.affiliation: Research Service 151, VA Loma Linda Healthcare System, Loma Linda, California 92357, USA. glen.martin2@va.gov
authors.forename: Glen K
authors.initials: GK
authors.lastname: Martin
authors.forename: Barden B
authors.initials: BB
authors.lastname: Stagner
authors.forename: Paul F
authors.initials: PF
authors.lastname: Fahey
authors.forename: Brenda L
authors.initials: BL
authors.lastname: Lonsbury-Martin
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D003051:Cochlea / Q000502:physiology*; D006801:Humans; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D055815:Young Adult