Date of Award

Spring 2015

Document Type

Dissertation

Degree Name

Doctor of Audiology (AuD)

Department

Department of Communication Sciences and Disorders

Advisor(s)

Ayasakanta Rout

Abstract

Hearing impaired individuals often report feeling fatigue at the end of the day. These individuals are forced to exert more cognitive effort throughout the day as they strain to understand speech in an ever-changing auditory environment through an impaired/degraded auditory system (Rabbitt, 1991). Today’s digital hearing aids attempt to increase audibility and relieve cognitive strain through advanced signal processing techniques such as digital noise reduction (DNR). Recent research regarding noise and its effects on auditory fatigue in hearing impaired listeners suggests that DNR may reduce the effects of auditory fatigue (Sarampalis et al, 2009). The overarching goal of a future project is to understand the effectiveness of DNR in reducing listening effort and ways to quantify it. The present study sought to determine if reaction time alone is an accurate measure of auditory fatigue while isolating listening fatigue as a sole factor. Twenty young adults with normal hearing participated. Testing consisted of three parts: pre-test, fatigue inducing condition, and post-test. Pre- and post- tests consisted of a reaction time task using nonsense syllables and a subjective listening questionnaire. The overall reaction time in the post-fatiguing condition was higher than the pre-fatiguing condition. A one sample t test revealed no significant difference between the pre and post fatiguing condition reaction time for overall nonsense syllables and consonant final nonsense syllables. Pre- and post-fatiguing reaction time was significantly different for consonant initial nonsense syllables only. Results indicated that the 30 minute fatigue inducing condition did not affect reaction time in the post-tests for overall nonsense syllables and for consonant final nonsense syllables. This could be due to several factors. The reaction time task used in this study may not be an accurate measure of listening effort or the 30 minutes of effortful listening may not have been enough. The subjective listening effort questionnaire showed that subjects did feel more fatigued after the post-test than after the pre-test. Future studies are planned to expand upon the current study by assessing individuals with hearing loss as well as those exposed to longer duration of noise throughout the day.

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