Research Article  |   June 2012
Hearing Aid Processing Changes Tone Burst Onset: Effect on Cortical Auditory Evoked Potentials in Individuals With Normal Audiometric Thresholds
 
Author Affiliations & Notes
  • Danielle Glista
    The University of Western Ontario, Canada
  • David W. Purcell
    The University of Western Ontario, Canada
  • Susan D. Scollie
    The University of Western Ontario, Canada
  • Correspondence to Vijayalakshmi Easwar: veaswar@uwo.ca
  • Editor: Larry Humes
    Editor: Larry Humes×
Article Information
Hearing Disorders / Hearing Aids, Cochlear Implants & Assistive Technology / Research Article
Research Article   |   June 2012
Hearing Aid Processing Changes Tone Burst Onset: Effect on Cortical Auditory Evoked Potentials in Individuals With Normal Audiometric Thresholds
American Journal of Audiology, June 2012, Vol. 21, 82-90. doi:10.1044/1059-0889(2012/11-0039)
History: Received December 22, 2011 , Accepted March 11, 2012
 
American Journal of Audiology, June 2012, Vol. 21, 82-90. doi:10.1044/1059-0889(2012/11-0039)
History: Received December 22, 2011; Accepted March 11, 2012

Purpose: The validity of using the cortical auditory evoked potential (CAEP) as an objective measure of hearing aid outcome has been questioned in the literature due to stimulus modifications caused by hearing aid processing. This study aimed to investigate the effects of hearing aid processing on the CAEP elicited with tone bursts that may have altered onsets.

Method: CAEPs to unprocessed and hearing aid–processed tone bursts were obtained from 16 individuals with normal audiometric thresholds when the onset time, level, and signal-to-noise ratio (SNR) were matched between the 2 conditions. Tone bursts processed by the hearing aid were recorded in an anechoic box and were presented through insert receivers. Unprocessed tone bursts were superimposed with hearing aid noise floor to match the SNR of the hearing aid–processed tone bursts.

Results: Shortening of rise time and overshoot at the onset of the tone burst were evident in the hearing aid–processed stimuli. Statistical analysis of data showed no significant effects of hearing aid processing on the latency or amplitude of CAEP peaks (p > .05).

Conclusion: The changes in rise time occurring in the tone bursts due to hearing aid processing may not confound CAEP measures that are used to validate hearing aid fitting.

Acknowledgments
This work was supported by Early Researcher Award ERA07-03-051 from the Ontario Ministry of Research and Innovation and a New Opportunities Award from the Canada Foundation for Innovation/Ontario Innovation Trust to Susan Scollie. The authors would like to thank David Suelzle for his assistance in stimulus generation for this project and Lorienne Jenstad for helpful comments on an earlier version of this manuscript.
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