Thesis (M. Aud.)--University of Canterbury, 2009. / Typescript (photocopy). Includes bibliographical references (p. 87-98). Also available via the World Wide Web.

Auditory impairment in patients with craniofacial clefts has been well studied for decades. However, most previous research has only focused on middle ear disorders and related auditory consequences in this group. Studies of higher level auditory status and central auditory processing abilities of this group—particularly in children—have been unsystematic and have significant limitations, while the potentially negative impact of central auditory impairment on children should not be ignored. One important area which needs further research is the status of the central auditory nervous system (CANS) in children with non-syndromic cleft lip and/or palate (NSCLP). In order to objectively investigate possible central auditory impairment in children with NSCLP, the present research programme was initiated. Firstly, two major studies aimed to provide anatomical structural analysis and functional evaluation of the auditory structures of CANS in a group of infants with NSCLP, and compare the results to those of normal controls (Studies 1 and 2). Secondly, a pilot study (Study 3) was conducted to provide preliminary data and suggest methodology to support a major, future research programme to comprehensively investigate central auditory processing abilities in children with NSCLP. A multi-disciplinary approach that included brain magnetic resonance image (MRI) scanning, auditory evoked potentials (AEP) recording, and a central behavioural auditory test battery assessment protocol, was applied in the present research programme. Based on the results of the studies and data analysis, it was concluded that: (1) Structural abnormalities of CANS in infants with NSCLP may be primarily located in the left cerebral hemisphere and cortical abnormalities were more marked compared with those in other subcortical locations. The development and maturation of the auditory cortex in infants with NSCLP may be abnormal, compared with that in normal children; (2) Infants with NSCLP might have normal auditory sensory function at brain stem and subcortical levels, yet this group may have significant impaired auditory discriminatory function at cortical level; (3) Children with NSCLP may show normal auditory processing abilities in a quiet listening environment. However, they may be more vulnerable to background noise and have impaired auditory processing abilities in areas such as monaural low redundancy and temporal resolution ability. In summary, combining the results of MRI, AEP and behavioural measurements in the present research programme, it is suggested that children with NSCLP are at potential risk of both structural abnormalities and functional disorders of the CANS, particularly at auditory cortical level. In addition, this group might also be at risk of auditory processing impairments to some degree, particularly in noisy environments. The present research programme has made a contribution to our understanding of the central auditory status of children with NSCLP, which was not systematically investigated in previous studies, and provided information on which to base further research. The research findings should draw the attention of researchers and clinicians to improving auditory assessment and intervention for patients with craniofacial cleft disorders. Further efforts in this field in the long-term may help to develop a more sophisticated audiological evaluation and intervention approach for this population. / published_or_final_version / Speech and Hearing Sciences / Doctoral / Doctor of Philosophy

Not available / text

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

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

The aim of the study – to justify theoretically and to investigate empirically the improvement of the education of parents (as adults) in the educational institution for the children with hearing impairment through the case-analysis. Base of study and participants. The subjects were the parents of pupils from one Lithuanian educational institution for the Deaf and hard-of-hearing. The answers were received from 134 parents (mothers, fathers, foster-parents) whose children attend preliminary- the 10th grades. Results and conclusions. The study showed that parents are interested and know quite well about the activity of their child in school, about the activities of school in general, and about persons with hearing disorders. Parents are the most concern about the information, which is directly associated with their child. It was found out that the parents prefer informal learning to formal one. The one fifth of the parents have expressed their wish to be educated during the seminars, and only 2 percents of respondents have named their willingness to study in the formal educational institution. The evaluations of parents’ opinions about the dissemination of their experience let us conclude that majority of respondents has positive attitude toward educational activity: they tend to participate in the mobile groups of self-assistance, to share their knowledge and experience during mass events (meetings, seminars). Almost all departments of the educational institution for the... [to full text]

Infants with hearing loss (HL) are being diagnosed and fitted with amplification earlier than ever before. In order to acquire speech and language abilities that are on par with their normal-hearing (NH) peers, hearing-impaired (HI) infants require amplification that provides appropriate exposure to the sounds of their native language. To date, no research has addressed this issue and thus, there is a need to examine the type of amplification that is most suitable for infants during the early stages of language acquisition. In this thesis, three different amplification types were compared: one that preserves the natural spectral shape of speech (unmodified speech); a second that emphasises high-frequency speech information (positive spectral tilt); and a third that emphasises low-frequency information (negative spectral tilt). NH infants were tested to examine how each of these amplification types affects speech perception and to explore whether infants at different stages of language acquisition find modified spectral tilt a help or hindrance in perceiving native-language speech contrasts. A visual habituation (VH) procedure was used to test 288 6- and 9-month-old NH infants on their ability to discriminate the high-frequency fricative contrast /f/- /s/; the mid-frequency approximant contrast /l/-/r/; and the low-frequency vowel contrast /5/-/N/ under modified spectral tilt conditions. For each speech contrast, 96 infants were tested in one of three conditions: (a) unmodified spectral tilt (n = 32); (b) with a positive 6 dB/octave spectral tilt (n = 32); or (c) with a negative 6 dB/octave spectral tilt (n = 32). The results showed that both 6- and 9-month-olds discriminated the three speech contrasts in the unmodified condition. However, when the contrasts were spectrally modified, a consistent developmental trend emerged. Six-month-olds’ discrimination performance improved when the spectral tilt modification amplified the relevant frequency information. That is, for the consonant contrasts (fricatives /f/-/s/ and approximants /l/-/r/) 6-month-olds performed best when high-frequency information was emphasised, whereas for the vowel contrast (/5/-/N/) the best discrimination performance was found when low-frequency information was enhanced. Nine-month-olds, on the other hand, showed no evidence of discriminating any of the contrasts when spectral tilt was modified. For all three contrasts, the older infants’ best discrimination performance was in the unmodified spectral tilt condition. The findings reflect the early stages of linguistic development. Six-month olds, whose acoustically driven speech perception operates in a language-general mode, demonstrated a broad-based ability to discriminate speech sounds. They not only accommodated speech with positive or negative spectral tilt, but a facilitation effect was observed when relevant frequency information was amplified. In contrast, 9-month-olds, whose perception is linguistically driven, found that spectral tilt modifications hinder speech perception. It seems that because older infants are attuning to native phonemic categories, their attention is constrained to native language spectral profiles only. Thus, even those spectral tilt modifications that should have been beneficial for perception were eschewed by 9-month-olds because they were incompatible with the older infants���� narrow focus on spectrally intact native speech sounds. Only NH infants were tested in this study, so it is not possible draw firm conclusions about amplification schemes until HI infants are tested too. Nevertheless, the results have a number of implications for infants with HL. The demonstration that spectral tilt modifications interfere with older NH infants’ speech perception suggests that future research should investigate whether HI infants also show this developmental pattern. That is, do HI infants progressively attune to the native language, and if so, does this affect their perception of spectrally modified speech sounds? Moreover, if HI infants are to attune to the native language and acquire speech and language in the same way as their NH peers, then the research reported here suggests that, throughout infancy, HI infants will need access to amplified speech that maintains the spectral shape of natural speech. Thus, the current research demonstrates, for the first time, a developmental difference in the way that infants perceive spectrally modified speech, one that is closely linked to the infant’s stage of native-language attunement. This research provides a solid foundation on which to conduct further research with HI infants and offers preliminary suggestions with regard to amplification and intervention to ensure that HI infants have the opportunity to emulate the native-language attunement process and subsequently achieve language development outcomes comparable with their NH peers. / Doctor of Philosophy (PhD)

Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 179-220) Also available in print.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Thesis (M.A. (Communication Disorders))--Mahidol University, 1984.