Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.


Date of Graduation


Document Type


Degree Name

Doctor of Audiology (AuD)


Department of Communication Sciences and Disorders


Christopher Clinard

Lincoln Gray

Yingjiu Nie


It is a known phenomenon that speech understanding in background noise declines with advancing age. Although there is ample evidence of behavioral measures declining with age, there is less physiologic evidence. This study hypothesizes that the FFR will be degraded with advancing age, consistent with poorer phase locking. This is hypothesized to be present even in people with audiograms within normal limits. A second hypothesis is that middle-aged adults will have degraded neural representation as frequency increases, compared to a younger normal hearing group which will have better high frequency neural representation than the middle-aged group. Subjects were divided into two age groups: young (21-30 years old, n = 17, average age 23) and middle-aged (41-50 years old, n = 5, average age 44) adults. Each subject underwent twelve conditions of the FFR. Four frequencies were recorded (500, 750, 1,000, and 1,125 Hz). Each frequency was recorded in a left ear, right ear, and binaural condition. When comparing the data of young normal participants with that of middle-aged participants, it was seen that amplitudes were largest in younger participants. Additionally, amplitudes were biggest in low frequencies, and amplitudes were smallest in higher frequencies across both age groups. The largest amplitudes were seen in the binaural conditions. In general, larger stimulus-to-response correlations were observed in the younger group. Smaller correlations were observed in the middle-aged group. Results of this study could be used in patient counseling, and in the formulation of more tailored and informed treatment plans (particularly in aged individuals).



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