Effects of Frequency Modulation (FM) Transmitter Microphone Directivity on Speech Perception in Noise Frequency modulation (FM) technology can significantly improve the speech perception ability of individuals with sensorineural hearing loss (SNHL) in background noise. Previous investigations have demonstrated that the microphone design of the FM transmitter can have a significant impact on this improved speech perception. The purpose of this investigation was to ... Research Article
Research Article  |   June 01, 2004
Effects of Frequency Modulation (FM) Transmitter Microphone Directivity on Speech Perception in Noise
 
Author Affiliations & Notes
  • M. Samantha Lewis, PhD
    University of Florida, Gainesville
  • Carl C. Crandell
    University of Florida, Gainesville
  • Nicole V. Kreisman
    University of Florida, Gainesville
  • Corresponding author: e-mail: Michele.Lewis3@med.va.gov
  • * Currently at the Veterans Affairs Rehabilitation Research and Development, National Center for Rehabilitative Auditory Research, Portland VA Medical Center, Portland, OR
    Currently at the Veterans Affairs Rehabilitation Research and Development, National Center for Rehabilitative Auditory Research, Portland VA Medical Center, Portland, OR×
Article Information
Hearing Disorders / Research and Technology / Research Articles
Research Article   |   June 01, 2004
Effects of Frequency Modulation (FM) Transmitter Microphone Directivity on Speech Perception in Noise
American Journal of Audiology, June 2004, Vol. 13, 16-22. doi:10.1044/1059-0889(2004/004)
History: Received November 17, 2003 , Accepted December 3, 2003
 
American Journal of Audiology, June 2004, Vol. 13, 16-22. doi:10.1044/1059-0889(2004/004)
History: Received November 17, 2003; Accepted December 3, 2003

Frequency modulation (FM) technology can significantly improve the speech perception ability of individuals with sensorineural hearing loss (SNHL) in background noise. Previous investigations have demonstrated that the microphone design of the FM transmitter can have a significant impact on this improved speech perception. The purpose of this investigation was to compare 3 types of FM transmitter microphone designs: (a) wide angle (omnidirectional microphone), which amplifies sounds coming from all directions around the microphone equally; (b) zoom (1 directional microphone), which provides less amplification to signals coming from the rear, and (c) superzoom (2 directional microphones), which provides less amplification to signals originating from the rear and the sides. Fifteen adults with bilateral slight to moderately severe SNHL participated. Speech perception was assessed using the Hearing in Noise Test (M. Nilsson, S. Soli, & J. Sullivan, 1994). Speech spectrum shaped noise served as the noise competition. Results revealed that the best speech perception in noise was obtained when the FM transmitter was used in the zoom setting. The poorest performance was obtained when the FM transmitter was in the wide-angle mode. The clinical implications of these results are discussed.

Acknowledgments
This article is based on work sponsored by Phonak Corporation. We are grateful to Randi Gerson and Lisa Bancroft for their assistance with participant scheduling and data collection. We would also like to acknowledge Michael Valente for his invaluable suggestions. Additionally, the first author would like to acknowledge the Department of Veterans Affairs, Veterans Health Administration, Rehabilitation Research and Development Service and the National Center for Rehabilitative Auditory Research for their support during preparation of this manuscript.
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