title: Frequency-specific auditory brainstem responses. Effective masking levels and relationship to behavioural thresholds in normal hearing adults.
abstract: Ipsilateral masking levels and normal thresholds for tone pip auditory brainstem responses (ABRs) were investigated in normal subjects for the purpose of establishing recording parameters and norms for frequency-specific tone pip ABR testing. White noise was found to effectively mask ABRs to tone pips at mean signal-to-noise ratios of between -1 and -5.5 dB [dB peak-equivalent (pe) SPL/dB SPL] depending on the tone pip frequency. ABR thresholds were established for tone pips in the presence of ipsilateral masking with high-pass filtered noise for 50-Hz tone pips and notched noise for tone pips from 1,000 to 4,000 Hz, at a nominal signal-to-noise ratio of -5 dB (i.e. with the noise SPL measured prior to filtering). Thresholds occurred between 28.6 and 36.6 dB pe SPL, equivalent to 4.4-8.8 dB nHL. ABR thresholds for masked and unmasked tone pips did not differ significantly.
authors.affiliation: National Audiology Centre, Auckland, New Zealand.
authors.forename: S C
authors.initials: SC
authors.lastname: Purdy
authors.forename: J M
authors.initials: JM
authors.lastname: Houghton
authors.forename: W J
authors.initials: WJ
authors.lastname: Keith
authors.forename: K A
authors.initials: KA
authors.lastname: Greville
mesh_terms: D000293:Adolescent; D000328:Adult; D001300:Audiometry, Evoked Response; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold / Q000502:physiology*; D001933:Brain Stem / Q000502:physiology*; D005072:Evoked Potentials, Auditory; D005260:Female; D006801:Humans; D008297:Male; D010470:Perceptual Masking / Q000502:physiology*; D010897:Pitch Discrimination / Q000502:physiology*; D012016:Reference Values