Thesis (Ph. D.)--Ohio State University, 2009. / Title from first page of PDF file. Includes bibliographical references (p. 93-101).

Spontaneous otoacoustic emissions (SOAEs) are narrowband continuous signals that can be recorded from the ear canals of humans in the absence of external stimulation. SOAEs have been detected in 30 to 50% of individuals whose hearing is within normal limits. They are believed to originate in the cochlea but the mechanism by which they are produced remains unknown. It has not been determined if SOAEs are an indication of subtle abnormality in the cochlea or if they are the result of an auditory system that is functioning normally. Most investigators agree, however, that an active source of energy within the cochlea is required for the generation of SOAEs. The objective of this study was to describe the effects of SOAEs on behavioral sensitivity and frequency selectivity. Eight subjects with SOAEs were evaluated. Sensitivity was measured using a Bekesy tracking method to obtain thresholds at 30-Hz intervals. Microstructure audiograms were obtained in this manner from the frequency region surrounding the SOAE and from the same frequency region in the other ear where no SOAE was detected. Frequency selectivity was assessed using a Bekesy tracking method to obtain psychophysical tuning curves (PTCs) from frequency regions with and without SOAEs. SOAEs were found to be associated consistently with threshold minima (regions of increased sensitivity) on the microstructure audiograms, although not all threshold minima corresponded to SOAE frequencies. PTCs centered at SOAE frequencies were characterized by higher Q10 values than PTCs from the same frequency region in the other ear or from a higher frequency region in the same ear. The high and low frequency slopes were not found to differ significantly when PTCs from frequency regions with and without SOAEs were compared. These results suggest that the differences between PTCs obtained from frequency regions with and without SOAES are restricted to the tips of the PTCs. Complex interactions among the SOAE, the probe tone, and the masker were thought to be responsible for the enhanced frequency selectivity observed near SOAE frequencies and manifested by higher Q10 values.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 156-162). Also available via the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 174-184). Also available via the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 189-199). Also available via the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 205-209). Also available via the Internet.

The purpose of this study was to indicate norms for most comfortable loudness levels (MCLs) and to investigate the relationships among MCL and related measures. In addition MCL values for males and MCL values for females were separated to see if any differences existed between sexes.A pure tone average (PTA) and a spondee threshold (ST) were obtained for each of 54 subjects (23 males, 31 females) to assure normal hearing. The following measures were then obtained on all subjects: 1.) The MCL was obtained using a bracketing method. 2.) A Bekesy audiometer was used to determine MCL using both a 2.5 dB/second and a 5 dB/second attenuation rate. 3.) The lower limit of the most comfortable loudness range (LLMCR) was determined using a nonBekesy procedure. 4.) The upper limit of the most comfortable loudness range (MCR). Again, both 2.5 dB/second and 5 dB/second attenuation rates were used. The Bekesy MCR tracings also provided the ULMCR and the LLMCR values for Bekesy obtained MCRs. Four analyses of variance (ANOVA) were computed for various MCL and MCR measures to investigate the relationships among these measures. It was concluded that no significant differences occurred between males and females in all MCL and related measures.Averages were presented for each individual MCL procedure which ranged from 51.29 dB to 56.77 dB HL. Average MCRs (actual ranges) were 30.54 to 42.78 dB. Some significant differences were found among specific procedures which are discussed in the text, however, these differences may not be significant from a clinical standpoint. In general, non-Bekesy procedures were recommended for use clinically because they produced the least variability in subjects and they require the least amount of time in administration.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 183-192). Also available via the Internet.

To date there are no acceptable speechreading tests with normative or psychometric data indicating the test is a valid and reliable measure of speechreading assessment. Middlewerd and Plomp (1987) completed a study of speechreading assessment using sentences (auditory-only and auditory-visual) in the presence of background noise. Results revealed speech reception thresholds to be lower in the auditory-visual condition. Montgomery and Demorest ( 1988) concurred that these results were appealing, but unfortunately not efficient enough to be used clinically. The purpose of this study was to develop a clinically valid and reliable assessment of speech reading ability, following Middlewerd and Plomp's ( 1987) framework to achiev~ this goal. The method of obtaining a valid assessment tool was to define a group of stimuli that can be administered and scored to produce reliable data efficiently. Because spondaic words are accepted as a reliable method of clinically achieving speech reception thresholds, they were chosen to be used as the stimuli in this study to develop an efficient clinical speechreading assessment tool. Ten subjects were presented with spondaic words in each of two conditions, auditory-only and auditory-visual, in the presence of background noise. The spondee words were randomized for each presentation, to validate the data. A computerized presentation was used so that each subject received the identical input. The computer also produced a performance-intensity function for each spondaic word. Results revealed an acceptable speech recognition threshold for 18 of the 36 spondee words in the auditory-only condition; 6 words were outside of one standard deviation; and the remaining 12 words did not produce obtainable thresholds. In the auditory-visual condition, all words except one had no obtainable threshold. Although these results invalidated the spondee words as an acceptable stimuli, the study does validate the foundation for further research to study different types of stimuli using this same framework.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2008. / Title from title screen (site viewed Mar. 10, 2009). PDF text: xvi, 233 p. : ill. ; 4 Mb. UMI publication number: AAT 3330703. Includes bibliographical references. Also available in microfilm and microfiche formats.