The Occlusion Effect and Ear Canal Sound Pressure Level Comparisons were made between changes in the audibility of bone-conduction stimuli to differences in the sound pressure present in the external auditory canal when ears were occluded. Fifteen listeners with normal middle ear function were tested using pure tones of 250, 500, and 1000 Hz, delivered via a bone-conduction oscillator ... Research Article
Research Article  |   October 01, 1998
The Occlusion Effect and Ear Canal Sound Pressure Level
 
Author Affiliations & Notes
  • Marc A. Fagelson
    ETSU, Department of CDIS, Box 70643, Johnson City, TN 37614
  • Frederick N. Martin
    The University of Texas at Austin
Article Information
Hearing & Speech Perception / Acoustics / Research Articles
Research Article   |   October 01, 1998
The Occlusion Effect and Ear Canal Sound Pressure Level
American Journal of Audiology, October 1998, Vol. 7, 50-54. doi:10.1044/1059-0889(1998/010)
History: Received May 15, 1996 , Accepted February 23, 1998
 
American Journal of Audiology, October 1998, Vol. 7, 50-54. doi:10.1044/1059-0889(1998/010)
History: Received May 15, 1996; Accepted February 23, 1998

Comparisons were made between changes in the audibility of bone-conduction stimuli to differences in the sound pressure present in the external auditory canal when ears were occluded. Fifteen listeners with normal middle ear function were tested using pure tones of 250, 500, and 1000 Hz, delivered via a bone-conduction oscillator placed on the mastoid process and the frontal bone. At all three frequencies, and both sites of stimulation, ear canal sound pressures were greater in the occluded than in the unoccluded conditions. Concurrently, the test signals were detected at lower intensities, although the changes in audibility and external canal sound pressure levels were not unity. The occlusion effect was attenuated slightly when the skull was vibrated from the frontal bone.

Acknowledgments
This research was conducted while the first author was a doctoral candidate at the University of Texas at Austin. Special thanks go to Linda M. Thibodeau and Craig A. Champlin, in whose labs the data were collected and analyzed, respectively. The manuscript benefited from the thorough and thoughtful comments provided by Ted Glattke and two anonymous reviewers.
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