Article  |   June 2006
Comparison of Performance on the Hearing in Noise Test Using Directional Microphones and Digital Noise Reduction Algorithms
 
Author Affiliations & Notes
  • Stacie Nordrum
    Northwestern University, Evanston, IL
  • Susan Erler
    Northwestern University, Evanston, IL
  • Dean Garstecki
    Northwestern University, Evanston, IL
  • Sumitrajit Dhar
    Northwestern University, Evanston, IL
  • Contact author: Sumit Dhar, Northwestern University, 2240 Campus Drive, Evanston, IL 60208-2952. Email: s-dhar@northwestern.edu
  • © 2006 American Speech-Language-Hearing AssociationAmerican Speech-Language-Hearing Association
Article Information
Hearing Disorders / Hearing Aids, Cochlear Implants & Assistive Technology
Article   |   June 2006
Comparison of Performance on the Hearing in Noise Test Using Directional Microphones and Digital Noise Reduction Algorithms
American Journal of Audiology, June 2006, Vol. 15, 81-91. doi:10.1044/1059-0889(2006/010)
History: Received October 15, 2005 , Revised December 25, 2005 , Accepted February 13, 2006
 
American Journal of Audiology, June 2006, Vol. 15, 81-91. doi:10.1044/1059-0889(2006/010)
History: Received October 15, 2005; Revised December 25, 2005; Accepted February 13, 2006

Purpose: Difficulty understanding speech in background noise is one of the most common complaints of hearing aid users. In modern hearing aids, directional microphones (d-mics) are considered the method of choice in improving signal-to-noise ratio, with demonstrated improvement in speech-perception-in-noise tasks. On the other hand, digital noise reduction (DNR) algorithms, in commercially available products, are considered to provide comfort but not significant assistance in improving speech perception in noise. In practice, these 2 technologies are often used in conjunction, but few studies have evaluated their interaction and the resultant effect on speech perception in noise. The purpose of this study was to evaluate the effect on speech performance of using d-mics and DNR in isolation as well as in conjunction in the presence of background noise.

Method: This study evaluates the performance of 16 experienced adult hearing aid users on the Hearing in Noise Test when each technology was activated independently and then simultaneously in 4 commercially available hearing aids.

Result: Approximately 50% of our participants performed better with both d-mics and DNR activated in conjunction, while the other 50% performed best in the d-mic-only condition. When considering statistically significant differences in performance only, a reduction or improvement in performance was observed in 17% and 14% of the conditions, respectively.

Conclusion: A direction for further research would be to identify predictive variables that could help the audiologist determine an individual’s preference a priori.

Acknowledgments
The study reported here is the capstone project for the first author’s doctor of audiology program at Northwestern University. We greatly appreciate the feedback received from Dr. Wayne Staab and Ms. Jennifer Robinson during the planning stage of this project. Their comments, as well as those of Ms. Laurel Olson and Dr. Shilpi Banerjee, on an earlier version of this article are appreciated as well. Thanks to Dr. Lowery Mayo, Dr. Kris Erickson, Ms. Rebecca Field, Ms. Diane Novak, and Ms. Marla Ross for their help in participant recruitment and general support. We are grateful to the hearing aid manufacturers for providing hearing instruments used in this project and for detailed technical information regarding each instrument.
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