This study investigated the effect of masking noise on the threshold for s tape dial reflex. It has been shown that masking which shifts the hearing threshold causes a loudness function typical of recruitment. It was hypothesized that the stapedial reflex threshold remains the same in a masked situation as in the unmasked situation. It was suggested that this demonstrates recruitment in that the presence of noise reduces the range between hearing thresholds and stapedial reflex thresholds. Ten subjects, with no known hearing loss or pathology involving the ear or reflex arc were used in this study. A 1000 Hz tone was used as the pure tone stimulus and narrow band noise centered at 1000 Hz was used as the masking stimulus. Pure tone thresholds were obtained without masking. The amount of masking necessary to shift the pure tone threshold. 30 dB was then found. Stapedial reflex thresholds were found without masking and in the presence of the masking stimulus at the intensity required to shift the hearing threshold 30 dB. The differences in stapedial reflex thresholds obtained with masking and without masking were evaluated for significance, as were the differences in intensity above hearing threshold in each case needed to elicit the stapedial reflex. It was found that there was no significant difference in the stapedial reflex thresholds when those obtained without masking were compared with those obtained in the presence of masking. There was a significant reduction in intensity above hearing threshold at which stapedial reflex occurred when the results in the masked situation were compared with those obtained in the unmasked situation. It was concluded that the stapedial reflex threshold is not affected by the 30 dB effective masking used in this study, but that this masking stimulus can be applied to simulate a sensori-neural hearing loss and recruitment in the study of stapedial reflex thresholds.

LLU Discipline

Speech Pathology


Speech-Language Pathology


Graduate School

First Advisor

Rodney R. Rowley

Second Advisor

E. Evelyn Britt

Third Advisor

Grover C. Mathewson

Fourth Advisor

Robert Rowe

Degree Name

Master of Science (MS)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Reflex, Acoustic

Subject - Local

Speech-Language Pathology Program -- dissertations



Page Count

iv, 30

Digital Format


Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.


Loma Linda University Electronic Theses and Dissertations

Collection Website



Loma Linda University. Del E. Webb Memorial Library. University Archives