title: Clinical significance of probe-tone frequency ratio on distortion product otoacoustic emissions.
abstract: Parametric variations in the ratio of primary-tone frequencies were explored to optimize the amplitude of the 2f1-f2 distortion product otoacoustic emission for clinical purposes. Ten ears from 5 normally hearing human subjects were examined with primary tones geometrically centred around the standard audiometric frequencies of 0.5, 1, 1.5, 2, 3, 4, 6 and 8 kHz. The distortion product at the frequency 2f1-f2 (f1 < f2) was measured at six probe tone frequency ratios (f2:f1) varying between 1.15 and 1.40 using equal level primaries of 75 dB SPL. The results showed that a single f2:f1 ratio between 1.20 and 1.25 provides a reasonable value for clinical use in that it optimizes the magnitude of the distortion product at 2f1-f2, provides for sufficient resolution in the test frequency range, and is applicable to the standard clinical test frequencies.
authors.affiliation: Department of Otolaryngology, Head & Neck Surgery, University Hospital, Copenhagen, Denmark.
authors.forename: L H
authors.initials: LH
authors.lastname: Nielsen
authors.forename: G R
authors.initials: GR
authors.lastname: Popelka
authors.forename: A N
authors.initials: AN
authors.lastname: Rasmussen
authors.forename: P A
authors.initials: PA
authors.lastname: Osterhammel
mesh_terms: D000161:Acoustic Stimulation; D000162:Acoustics; D000328:Adult; D001299:Audiometry; D001489:Basilar Membrane / Q000502:physiology*; D003051:Cochlea / Q000502:physiology*; D005260:Female; D006198:Hair Cells, Auditory / Q000502:physiology; D006801:Humans; D008297:Male; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D012022:Reflex, Acoustic