First Advisor

Douglas Martin

Date of Publication


Document Type


Degree Name

Master of Science (M.S.) in Speech Communication


Speech Communication




Hearing aids -- Design and construction



Physical Description

1 online resource (52 p.)


Hearing aid users often complain of poor speech understanding in the presence of background noise. There have been many attempts to overcome this problem by hearing aid manufactures and dispensers. The purpose of the present study was to determine if differences existed between three different styles of hearing aids (i.e. in the ear (ITE), in the canal (ITC), and completely in the canal (CIC)) in the presence of a multi-talker babble. Five sensori-neural hearing impaired subjects were selected from the Portland State University audiology clinic. The subjects were required to listen to a recording of the California Consonant Test (CCT) against a background noise of multi-talker babble. Stimuli were presented through headphones in the sound booth. The stimuli were recorded through three different hearing aids placed on KEMAR's left ear and adjusted to a 10 dB signal-to-noise ratio. Once the speech samples were recorded and digitized, they were routed through a GSl-16 audiometer to the listener. In order to determine performance differences across the three hearing aid configurations from within a single-subject design, each subject's performance was compared in a pairwise fashion between the hearing aid configurations. An analysis of the data was completed using the Randomization test. Using this statistical model, no significant difference was found between the individual scores. Further research is warranted to determine if a better measure exists that qualitatively defines the effect of microphone placement on speech understanding ability in hearing aid users.


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