Auditory discrimination: The relationship between psychophysical and electrophysiological measures

Abstract

Objectives: 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. Design: 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. Study sample: 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.

Key Words::

• Auditory evoked potential
• auditory event-related response
• auditory discrimination

Acknowledgements

Portions of this paper were presented at the 33rd Mid-Winter meeting of the Association for Research in Otolaryngology in February, 2010, San Diego, USA. The authors thank all of the subjects who participated in this study. The authors also wish to acknowledge Sara Mamo who assisted in pilot data collection and Emily Buss for help with programming. We also gratefully acknowledge Eun Kyung Jeon and Likuei Chiou from the University of Iowa for assistance with data analysis. This work was supported by grants from the Deafness Research Foundation and the NIH/NIDCD (1R21DC011383).

Declaration of interests: The authors have no conflict of interests to claim for this work.