Senior Honors Projects, 2010-2019

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

Spring 2016

Document Type


Degree Name

Bachelor of Science (BS)


Department of Communication Sciences and Disorders


Lincoln C. Gray


Presbycusis, or age-related hearing loss is a condition that affects approximately 40% of the population over 65 years of age (Gates & Mills, 2005). Studying the effects of EphA4 mutations (wild type, heterozygous, and homozygous) mice is fundamental in understanding the relationship between onset of age-related hearing loss, in both the mammalian population and the human population. In order to further understanding of age-related hearing loss, the researchers evaluated thirty-six mice in a preliminary study from two months to nine months of age. Following data analysis, the researchers confirmed the results by continuing a second round of testing. The hearing potential of nine mice in a longitudinal study evaluated thresholds, peak latencies and amplitudes of mice from six months of age to nine months of age. The researchers found a correlation between the delayed onset of hearing loss in the lower frequencies and broadband clicks of the heterozygous (EphA4lacZ/+) mice subject group. There is a positive relationship (r2 = 0.067, p < 0.001) between the dB Threshold analysis of the independent observers. Additionally, there is a positive relationship (r2 = 0.334, p < 0.001) between the independent observers’ data analyses of peak one latency. Based on a preliminary discussion with the director of the National Institute of Aging, there is reason to speculate a heterozygous advantage to delay the onset of age-related hearing loss.



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