title: Auditory discrimination: the relationship between psychophysical and electrophysiological measures.
abstract: OBJECTIVE
  This study aimed to (1) investigate the relationship between the acoustic change complex (ACC) and perceptual measures of frequency and intensity discrimination, and gap detection; and (2) examine the effects of acoustic change on the amplitudes and latencies of the ACC.
  
  
  METHODS
  Psychophysical thresholds for frequency and intensity discrimination and gap detection, as well as ACCs elicited by stimuli containing increments in frequency, or intensity or gaps, were recorded from the same group of subjects. The magnitude of the acoustic change was systematically varied for the ACC recording.
  
  
  METHODS
  Twenty-six adults with normal hearing, ranging in age between 19 and 39 years.
  
  
  RESULTS
  Electrophysiological and psychophysical measures for frequency and intensity discrimination were significantly correlated. Electrophysiological thresholds were comparable to psychophysical thresholds for intensity discrimination but were higher than psychophysical thresholds for gap detection and frequency discrimination. Increasing the magnitude of acoustic change increased the ACC amplitude but did not show consistent effects across acoustic dimensions for ACC latency.
  
  
  CONCLUSIONS
  The ACC can be used as an objective index of auditory discrimination in frequency and intensity. The ACC amplitude is a better indicator for auditory processing than the ACC latency.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7070, USA. shuman_he@med.unc.edu
authors.forename: Shuman
authors.initials: S
authors.lastname: He
authors.forename: John H
authors.initials: JH
authors.lastname: Grose
authors.forename: Craig A
authors.initials: CA
authors.lastname: Buchman
mesh_terms: D000328:Adult; D005072:Evoked Potentials, Auditory; D005260:Female; D006801:Humans; D008144:Loudness Perception; D008297:Male; D010897:Pitch Discrimination; D055815:Young Adult