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.

Mentally retarded children demonstrate an abnormally high incidence of hearing impairment, and many, particularly those with IQs below 40, are difficult for audiologists to test. Consequently, there is great need among this population for investigating response modes and conditioning of responses to auditory stimuli. A review of the literature reveals no studies of echoic vocalization as a conditioned response mode to pure tone stimuli among the retarded. In this study, a heterogenous sample of 13 moderately and severely retarded children ranging in age from 7 years 7 months to 16 years 3 months were compared on two response modes to suprathreshold pure tone signals of 500 and 4000 Hz: (1) dropping poker chips, and (2) echoic vocalization (EVR). All subjects received both treatments but were divided into Groups A and B, the former receiving Treatment One (object dropping) first, the latter receiving Treatment Two (EVR) first. Operant procedures combined social and tangible reinforcement in each treatment to achieve stimulus control without specific verbal instructions. EVR included two unusual stages: (1) conditioning of imitations to the experimenter’s vocalizations, usually /a/ and (2) conditioning of response transfer from vocal to pure tone stimuli. Acquisition and extinction to first 500, then 4000 Hz proceeded sequentially within each treatment. Acquisition criterion for vocal and pure tone stimuli was eight consecutive responses. Extinction criterion was failure to respond to six out of eight tonal stimuli following withdrawal of reinforcement. Eleven of the 13 children achieved acquisition criterion for both response modes, with only three of the older subjects encountering substantial difficulty in response transfer in Treatment Two. Differences in acquisition data between treatments were not significant. Three times as much extinction occurred with EVR in Treatment Two than with object dropping in Treatment One, but there was a tendency toward more false responses in the latter mode. Otherwise, data up to achievement of extinction criterion in the extinction phases did not differ significantly between treatments Order of presentation of treatment and frequency of the pure tone stimuli were not significant factors in the results. It was concluded that despite substantially greater occurrence of extinction following withdrawal of reinforcement as compared with object dropping, echoic vocalization response has been shown to be an effective, practical response mode to suprathreshold pure tone stimuli among the children in this sample. It was recommended that further investigation with EVR be directed toward: (1) the feasibility of eliminating response transfer by use of verbal assistance and direct conditioning of EVR to pure tones; (2) if response transfer is necessary, comparison of older and younger retardates on that procedure; (3) the possibility of increasing resistance to extinction in EVR through visual reinforcement; (4) comparison of EVR and object dropping on threshold determination among MR children; (5) the practicability of paring EVR and object dropping response modes; and (6) investigation of other forms of both breath expulsion and breath inspiration as response modes to pure tone stimuli among mentally retarded children.

Thesis (M. Sc.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Thesis (M. Sc.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Otoacoustic emissions (OAEs) have been under investigation since their discovery 30 years ago (Kemp, 1978). Otoacoustic emissions are quiet sounds generated within the cochlea that can be detected with a sensitive microphone placed within the ear canal. They are used clinically as a hearing screening tool but have the potential for diagnostic and monitoring purposes. For this dissertation, high-resolution instrumentation was developed for improving the acquisition of OAEs. It was shown that a high bit-depth device is required in order to simultaneously characterize the ear canal and the cochlear responses. This led to a reduction in the stimulus artifact that revealed early latency, high-frequency otoacoustic emissions. Next, a swept-tone technique originally developed for use in acoustical systems was formally developed for use in the human ear. The swept-tone technique allows for the simultaneous acquisition of a system's impulse response and its distortion components. The swept-tone was first used in this study to characterize the ear canal transfer properties. From that transfer function, a compensation routine was developed which equalized the magnitude and phase distortions of the ear canal. As a result, an improved acoustical click could be presented to the ear, which allowed for further reduction of the stimulus artifact, revealing early latency emissions. Spectral flatness and effective duration measurements of the compensated click showed an improvement over traditional click stimuli. Furthermore, wavelet analysis and time-frequency latency computations showed that higher frequency otoacoustic emissions were recoverable when using a compensated click stimulus. The swept-tone technique was then utilized for the direct acquisition of otoacoustic emissions. The swept-tone response was compressed to an impulse response and compared to a standard click response. It was found that several similarities exist between the two response types. The divergences, primarily in the low-frequencies, have implications in the generation mechanisms involved in a click-evoked otoacoustic emission. The swept-tone response provided some clinical benefits, namely in an improved signal-to-noise ratio, and in the removal of obstructive synchronized spontaneous OAEs when compared to a standard click response. Current methods are restricted by noise contamination, and the use of a swept-tone technique can reduce the acquisition time by up to a factor of four, compared to standard click methods. These implications and future potential studies are discussed.

Thesis (M. Communication Pathology)--University of Pretoria, 2005. / Summary in English and Afrikaans. Includes bibliographical references.

Thesis (M.S.)--Brigham Young University. Dept. of Communication Disorders, 2009. / Includes bibliographical references (p. 36-41).

published_or_final_version / abstract / toc / Speech and Hearing Sciences / Master / Master of Science in Audiology

Thesis (M. Aud.)--University of Canterbury, 2008. / Typescript (photocopy). Includes bibliographical references (p. 143-150). Also available via the World Wide Web.

Thesis (M. Communication Pathology)--University of Pretoria, 2003. / Includes bibliographical references.