Modulation Detection Interference for Asynchronous Presentation of Masker and Target in Listeners With Normal and Impaired Hearing Purpose The sensitivity to sinusoidal amplitude modulations (SAMs) is reduced when other modulated maskers are presented simultaneously at a distant frequency (also referred to as modulation detection interference [MDI]). This article describes the results of onset differences between masker and target as a parameter. Method Carrier frequencies were ... Research Article
Research Article  |   December 01, 2008
Modulation Detection Interference for Asynchronous Presentation of Masker and Target in Listeners With Normal and Impaired Hearing
 
Author Affiliations & Notes
  • Jan Koopman
    Academic Medical Center, Amsterdam, the Netherlands, and Erasmus Medical Center, Rotterdam, the Netherlands
  • Tammo Houtgast
    VU University Medical Center, Amsterdam
  • Wouter A. Dreschler
    Academic Medical Center, Amsterdam
  • Contact author: Jan Koopman, Department of ENT, Erasmus Medical Center, Audiological Center – D1.26, Antwoordnummer 55, 3070 WB Rotterdam, The Netherlands. E-mail: j.koopman@erasmusmc.nl.
Article Information
Hearing Disorders / Hearing / Research Articles
Research Article   |   December 01, 2008
Modulation Detection Interference for Asynchronous Presentation of Masker and Target in Listeners With Normal and Impaired Hearing
Journal of Speech, Language, and Hearing Research, December 2008, Vol. 51, 1588-1598. doi:10.1044/1092-4388(2008/07-0075)
History: Received April 3, 2007 , Revised September 28, 2007 , Accepted March 4, 2008
 
Journal of Speech, Language, and Hearing Research, December 2008, Vol. 51, 1588-1598. doi:10.1044/1092-4388(2008/07-0075)
History: Received April 3, 2007; Revised September 28, 2007; Accepted March 4, 2008

Purpose The sensitivity to sinusoidal amplitude modulations (SAMs) is reduced when other modulated maskers are presented simultaneously at a distant frequency (also referred to as modulation detection interference [MDI]). This article describes the results of onset differences between masker and target as a parameter.

Method Carrier frequencies were 1 kHz (target: 625 ms, 8 Hz SAM) and 2 kHz (masker: 625 ms, 8 Hz SAM; modulation depth = 1) presented at 25 dB SL for listeners with impaired hearing (n = 8) and at 25 dB SL and 50 dB SL for listeners with normal hearing (n = 6). Masker was delayed by 0, 125, 250, 500, 625, or 750 ms relative to the target.

Results Sensitivity to SAMs was reduced in both groups by a modulated masker simultaneous presentation. Reducing the temporal overlap (i.e., increasing the onset delay between masker and target) increased the sensitivity to SAMs in the presence of modulated maskers.

Conclusion The gradual reduction in MDI with increasing asynchrony between masker and target suggests that MDI is not solely related to perceptual grouping. Reduced sensitivity to SAMs due to prior stimulation with SAM stimuli (forward masking), and deficits in across-channel integration, are other factors that may play a role.

Acknowledgments
We thank Johannes Lyzenga for helpful comments on an earlier version of this paper.
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