Matching Items (5)
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- All Subjects: Audiology
- Creators: Dorman, Michael
Description
A multitude of individuals across the globe suffer from hearing loss and that number continues to grow. Cochlear implants, while having limitations, provide electrical input for users enabling them to "hear" and more fully interact socially with their environment. There has been a clinical shift to the bilateral placement of implants in both ears and to bimodal placement of a hearing aid in the contralateral ear if residual hearing is present. However, there is potentially more to subsequent speech perception for bilateral and bimodal cochlear implant users than the electric and acoustic input being received via these modalities. For normal listeners vision plays a role and Rosenblum (2005) points out it is a key feature of an integrated perceptual process. Logically, cochlear implant users should also benefit from integrated visual input. The question is how exactly does vision provide benefit to bilateral and bimodal users. Eight (8) bilateral and 5 bimodal participants received randomized experimental phrases previously generated by Liss et al. (1998) in auditory and audiovisual conditions. The participants recorded their perception of the input. Data were consequently analyzed for percent words correct, consonant errors, and lexical boundary error types. Overall, vision was found to improve speech perception for bilateral and bimodal cochlear implant participants. Each group experienced a significant increase in percent words correct when visual input was added. With vision bilateral participants reduced consonant place errors and demonstrated increased use of syllabic stress cues used in lexical segmentation. Therefore, results suggest vision might provide perceptual benefits for bilateral cochlear implant users by granting access to place information and by augmenting cues for syllabic stress in the absence of acoustic input. On the other hand vision did not provide the bimodal participants significantly increased access to place and stress cues. Therefore the exact mechanism by which bimodal implant users improved speech perception with the addition of vision is unknown. These results point to the complexities of audiovisual integration during speech perception and the need for continued research regarding the benefit vision provides to bilateral and bimodal cochlear implant users.
ContributorsLudwig, Cimarron (Author) / Liss, Julie (Thesis advisor) / Dorman, Michael (Committee member) / Azuma, Tamiko (Committee member) / Arizona State University (Publisher)
Created2015
Description
Otoacoustic emissions (OAEs) are soft sounds generated by the inner ear and can be recorded within the ear canal. Since OAEs can reflect the functional status of the inner ear, OAE measurements have been widely used for hearing loss screening in the clinic. However, there are limitations in current clinical OAE measurements, such as the restricted frequency range, low efficiency and inaccurate calibration. In this dissertation project, a new method of OAE measurement which used a swept tone to evoke the stimulus frequency OAEs (SFOAEs) was developed to overcome the limitations of current methods. In addition, an in-situ calibration was applied to equalize the spectral level of the swept-tone stimulus at the tympanic membrane (TM). With this method, SFOAEs could be recorded with high resolution over a wide frequency range within one or two minutes. Two experiments were conducted to verify the accuracy of the in-situ calibration and to test the performance of the swept-tone SFOAEs. In experiment I, the calibration of the TM sound pressure was verified in both acoustic cavities and real ears by using a second probe microphone. In addition, the benefits of the in-situ calibration were investigated by measuring OAEs under different calibration conditions. Results showed that the TM pressure could be predicted correctly, and the in-situ calibration provided the most reliable results in OAE measurements. In experiment II, a three-interval paradigm with a tracking-filter technique was used to record the swept-tone SFOAEs in 20 normal-hearing subjects. The test-retest reliability of the swept-tone SFOAEs was examined using a repeated-measure design under various stimulus levels and durations. The accuracy of the swept-tone method was evaluated by comparisons with a standard method using discrete pure tones. Results showed that SFOAEs could be reliably and accurately measured with the swept-tone method. Comparing with the pure-tone approach, the swept-tone method showed significantly improved efficiency. The swept-tone SFOAEs with in-situ calibration may be an alternative of current clinical OAE measurements for more detailed evaluation of inner ear function and accurate diagnosis.
ContributorsChen, Shixiong (Author) / Bian, Lin (Thesis advisor) / Yost, William (Committee member) / Azuma, Tamiko (Committee member) / Dorman, Michael (Committee member) / Arizona State University (Publisher)
Created2012
Description
In this study, the Bark transform and Lobanov method were used to normalize vowel formants in speech produced by persons with dysarthria. The computer classification accuracy of these normalized data were then compared to the results of human perceptual classification accuracy of the actual vowels. These results were then analyzed to determine if these techniques correlated with the human data.
ContributorsJones, Hanna Vanessa (Author) / Liss, Julie (Thesis director) / Dorman, Michael (Committee member) / Borrie, Stephanie (Committee member) / Barrett, The Honors College (Contributor) / Department of Speech and Hearing Science (Contributor) / Department of English (Contributor) / Speech and Hearing Science (Contributor)
Created2013-05
Description
Pitch and timbre perception are two important dimensions of auditory perception. These aspects of sound aid the understanding of our environment, and contribute to normal everyday functioning. It is therefore important to determine the nature of perceptual interaction between these two dimensions of sound. This study tested the interactions between pitch perception associated with the fundamental frequency (F0) and sharpness perception associated with the spectral slope of harmonic complex tones in normal hearing (NH) listeners and cochlear implant (CI) users. Pitch and sharpness ranking was measured without changes in the non-target dimension (Experiment 1), with different amounts of unrelated changes in the non-target dimension (Experiment 2), and with congruent/incongruent changes of similar perceptual salience in the non-target dimension (Experiment 3). The results showed that CI users had significantly worse pitch and sharpness ranking thresholds than NH listeners. Pitch and sharpness perception had symmetric interactions in NH listeners. However, for CI users, spectral slope changes significantly affected pitch ranking, while F0 changes had no significant effect on sharpness ranking. CI users' pitch ranking sensitivity was significantly better with congruent than with incongruent spectral slope changes. These results have important implications for CI processing strategies to better transmit pitch and timbre cues to CI users.
ContributorsSoslowsky, Samara Miranda (Author) / Luo, Xin (Thesis director) / Yost, William (Committee member) / Dorman, Michael (Committee member) / Department of Speech and Hearing Science (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Children with hearing impairment are at risk for poor attainment in reading decoding and reading comprehension, which suggests they may have difficulty with early literacy skills prior to learning to read. The first purpose of this study was to determine if young children with hearing impairment differ from their peers with normal hearing on early literacy skills and also on three known predictors of early literacy skills – non-verbal cognition, executive functioning, and home literacy environment. A second purpose was to determine if strengths and weaknesses in early literacy skills of individual children with hearing impairment are associated with degree of hearing loss, non-verbal cognitive ability, or executive functioning.
I assessed seven children with normal hearing and 10 children with hearing impairment on assessments of expressive vocabulary, expressive morphosyntax, listening comprehension, phonological awareness, alphabet knowledge, non-verbal cognition, and executive functioning. Two children had unilateral hearing loss, two had mild hearing loss and used hearing aids, two had moderate hearing loss and used hearing aids, one child had mild hearing loss and did not use hearing aids, and three children used bilateral cochlear implants. Parents completed a questionnaire about their home literacy environment.
Findings showed large between-group effect sizes for phonological awareness, morphosyntax, and executive functioning, and medium between-group effect sizes for expressive vocabulary, listening comprehension, and non-verbal cognition. Visual analyses provided no clear pattern to suggest that non-verbal cognition or degree of hearing loss were associated with individual patterns of performance for children with hearing impairment; however, three children who seemed at risk for reading difficulties had executive functioning scores that were at the floor.
Most prekindergarten and kindergarten children with hearing impairment in this study appeared to be at risk for future reading decoding and reading comprehension difficulties. Further, based on individual patterns of performance, risk was not restricted to one type of early literacy skill and a strength in one skill did not necessarily indicate a child would have strengths in all early literacy skills. Therefore, it is essential to evaluate all early literacy skills to pinpoint skill deficits and to prioritize intervention goals.
I assessed seven children with normal hearing and 10 children with hearing impairment on assessments of expressive vocabulary, expressive morphosyntax, listening comprehension, phonological awareness, alphabet knowledge, non-verbal cognition, and executive functioning. Two children had unilateral hearing loss, two had mild hearing loss and used hearing aids, two had moderate hearing loss and used hearing aids, one child had mild hearing loss and did not use hearing aids, and three children used bilateral cochlear implants. Parents completed a questionnaire about their home literacy environment.
Findings showed large between-group effect sizes for phonological awareness, morphosyntax, and executive functioning, and medium between-group effect sizes for expressive vocabulary, listening comprehension, and non-verbal cognition. Visual analyses provided no clear pattern to suggest that non-verbal cognition or degree of hearing loss were associated with individual patterns of performance for children with hearing impairment; however, three children who seemed at risk for reading difficulties had executive functioning scores that were at the floor.
Most prekindergarten and kindergarten children with hearing impairment in this study appeared to be at risk for future reading decoding and reading comprehension difficulties. Further, based on individual patterns of performance, risk was not restricted to one type of early literacy skill and a strength in one skill did not necessarily indicate a child would have strengths in all early literacy skills. Therefore, it is essential to evaluate all early literacy skills to pinpoint skill deficits and to prioritize intervention goals.
ContributorsRunnion, Elizabeth (Author) / Gray, Shelley (Thesis advisor) / Dorman, Michael (Committee member) / Thompson, Marilyn (Committee member) / Arizona State University (Publisher)
Created2017