Date of Award


Degree Type


Degree Name

Master of Science


Communication Sciences and Disorders


Dr. Susan Scollie

Second Advisor

Dr. Vijay Parsa

Third Advisor

Dr. Richard Seewald


Hearing loss is common in today’s society, it is estimated that 1 in 10 Canadians has hearing loss with estimates rising to 8 in 10 for geriatric populations. Hearing loss is known to have dramatic effects on the individuals that extend well beyond communicative issues. Psychological consequences range from depression exhaustion. Children suffer additional problems such as failure to acquire language and poor academic performance. While hearing aids remain the primary avenue by which hearing loss is treated, numerous individuals with hearing loss in the high frequencies get very little benefit from conventional amplification due to biological and technological limitations. One proposed solution to problems of this nature has been to present high frequency speech information to low frequency hearing regions where residual hearing is often fairly good. Past attempts at doing this have enjoyed only mixed success largely due to aberrations in sound quality introduced as a result of the frequency lowering process. Since degraded sound quality is known to predict discontinuation of hearing aid use, new developments need to undergo sound quality testing. For this reason this study measured subjective sound quality ratings in normal hearing and hearing impaired individuals on a prototype frequency lowering device allowing predictions of acceptance and user settings. Results indicate that sound quality decreases as a function of increased processing for normal hearing individuals. For hearing impaired subjects there exists a range of acceptable setting that appears to be determined by cutoff frequency where subjects do not appear to suffer from diminished sound quality.



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