O implante coclear tem como objetivo promover a percepção auditiva de indivíduos com deficiência auditiva de grau severo e profundo. Seu uso resulta na otimização do desenvolvimento da linguagem, da fala e da produção vocal de seus usuários. Esse dispositivo tem se mostrado uma das tecnologias mais efetivas e promissoras para remediar a perda auditiva, sendo que seus resultados são altamente dependentes da estratégia de codificação selecionada no processador de fala. O objetivo deste trabalho foi comparar as características perceptivas e acústicas da voz de crianças deficientes auditivas usuárias de implante coclear que utilizam as estratégias de codificação de fala Advanced Combination Encoder (ACE) e Fine Structure Processing (FSP), bem como investigar se as vozes dessas crianças se diferenciam das de crianças ouvintes. Crianças de 3 anos a 5 anos e 11 meses de idade foram selecionadas. Foi realizada análise acústica da vogal /a/ por meio do Multi Dimentional Voice Program (MDVP), da fala encadeada e da conversa espontânea por meio do Real Time Pitch (RTP), e análise perceptiva das mesmas emissões por meio de escalas visuais analógicas de parâmetros pré-selecionados. Em comparação com os usuários da estratégia ACE, os usuários da estratégia FSP apresentaram maior valor da frequência fundamental (F0) na vogal sustentada (p=0,004), maior desvio padrão da F0 na vogal sustentada (p=0,008), maior coeficiente de variação da amplitude também na vogal sustentada (p= 0,019), e maior desvio do pitch para o agudo na conversa espontânea (0,011). Em relação ao grupo controle os usuários da estratégia FSP apresentaram, na vogal sustentada, maior valor da F0 (p=0,012), maior desvio padrão da F0 (p=0,000), maior coeficiente de variação da frequência (p=0,039), maior coeficiente de variação da amplitude (p= 0,039), maior desvio de ressonância (p=0,027), maior instabilidade (p=0,001) e maior desvio da loudness para o forte (p=0,029). Apresentaram também na fala encadeada maior média da F0 (p=0,002), maior frequência máxima (p=0,009), maior grau geral do impacto negativo da voz (p=0,003) e maior tensão (p=0,001). Na conversa espontânea apresentaram maior grau geral do impacto negativo da voz (p=0,001), maior tensão (p=0,012), maior desvio do pitch para o agudo (0,000) e maior desvio de ressonância (p=0,010). Em comparação com os usuários da estratégia FSP, os usuários da estratégia ACE apresentaram maior valor do índice de fonação suave (SPI) na vogal sustentada (p=0,013). Em relação ao grupo controle os usuários da estratégia ACE apresentaram maior instabilidade na vogal sustentada (p=0,001), maior extensão da frequência em Hertz (p=0,004) e em semitons (p=0,048) na fala encadeada, maior frequência máxima (p=0,011) também na fala encadeada, maior grau geral do impacto negativo da voz na conversa espontânea (p=0,009) e maior desvio da ressonância na conversa espontânea (p=0,021). A partir dos dados concluiu-se que os usuários da estratégia FSP apresentaram vozes mais agudas e instáveis do que os usuários da estratégia ACE, que apresentaram produção vocal mais suave. Em relação ao grupo controle, os usuários da estratégia ACE apresentaram valor mais elevado do grau geral do impacto negativo da voz, maior grau de desvio da ressonância e maior extensão vocal para o agudo. Os usuários da estratégia FSP apresentaram vozes com maior valor do desvio global do impacto da voz, voz mais aguda, com maior desvio de ressonância, maior grau de tensão, maior desvio da loudness e maior extensão vocal. / The cochlear implant has the pupose of providing hearing perception for individuals with severe and profound hearing loss. The implants use result on optimization of development of language, speech and voice production of its users. This device is one of the most promissing and effective technologies to remedy hearing loss, and its results depend highly on the speech coding strategy selected in the speech processor. The pupose of this study was to compare perceptual and acoustic characteristics of the voices of children who use the Advanced Combination Encoder (ACE) or Fine Structure Processing (FSP) speech coding strategies, and to investigate whether these characteristics differ from children with normal hearing. Children between 3 and 5 years and 11 months of age participated. Acoustic analysis of the sustained vowel /a/ was performed using the Multi Dimentional Voice Program. Analysis of sequential speech and spontaneous speech were performed using the Real Time Pitch. Perceptual analysis of these speech samples were performed using visual-analogic scales of pre-selected parameters. In comparison with the users of the ACE strategy, the users of the FSP strategy presented greater value of fundamental frequency (F0) for the sustained vowel (p=0,004), greater standard deviation of the F0 for the sustained vowel (p=0,008), greater amplitude variation coheficient, also for the sustaned vowel (p= 0,019), and greater pitch deviation for the spontaneous speech (p=0,011). In relation to the control group, the users of the FSP strategy presented, for the sustained vowel, greater F0 value (p=0,012), greater standard deviation of the F0 (p=0,000), greater frequency variation coheficient (p=0,039), grater amplitude variation coheficient (p= 0,039), greater ressonance deviation (p=0,027), greater instability (p=0,001) and greater loudness deviation (p=0,029). They also presented, for the sequential speech, greater F0 average (p=0,002), greater maximum frequency (p=0,009), greater overall severity of the voice (p=0,003) and greater strain (p=0,001). For the spontaneous speech, they presented greater overall severity (p=0,001), greater strain (p=0,012), greater pitch deviation (0,000) and greater ressonance deviation (p=0,010). In comparison the users of the FSP strategy, the users of the ACE strategy presented greater value of the Soft Phonation Index (SPI) for the sustained vowel (p=0,013). In relation to the control group, the users of the ACE strategy presented greater instability for the sustained vowel (p=0,001), greater frequency range in Hertz (p=0,004) and in semitones (p=0,048) for the sequential speech, greater maximum frequency (p=0,011) also for the sequential speech, greater overall severity for the spontaneous speech (p=0,009) and greater ressonance deviation for the spontaneous speech. (p=0,021). The study concluded that the users of the FSP strategy presented more high pitched and unstable voices than the users of the ACE strategy, who presented softer phonation. In relation to the control group, the users of the ACE strategy presented greater value of overall severity, greater ressonance deviation and greater frequency range. The users of the FSP strategy presented greater value of overall severity, more high pitched voices, greater ressonance deviation, greater vocal strain e and greater frequency range.

O implante coclear tem como objetivo promover a percepção auditiva de indivíduos com deficiência auditiva de grau severo e profundo. Seu uso resulta na otimização do desenvolvimento da linguagem, da fala e da produção vocal de seus usuários. Esse dispositivo tem se mostrado uma das tecnologias mais efetivas e promissoras para remediar a perda auditiva, sendo que seus resultados são altamente dependentes da estratégia de codificação selecionada no processador de fala. O objetivo deste trabalho foi comparar as características perceptivas e acústicas da voz de crianças deficientes auditivas usuárias de implante coclear que utilizam as estratégias de codificação de fala Advanced Combination Encoder (ACE) e Fine Structure Processing (FSP), bem como investigar se as vozes dessas crianças se diferenciam das de crianças ouvintes. Crianças de 3 anos a 5 anos e 11 meses de idade foram selecionadas. Foi realizada análise acústica da vogal /a/ por meio do Multi Dimentional Voice Program (MDVP), da fala encadeada e da conversa espontânea por meio do Real Time Pitch (RTP), e análise perceptiva das mesmas emissões por meio de escalas visuais analógicas de parâmetros pré-selecionados. Em comparação com os usuários da estratégia ACE, os usuários da estratégia FSP apresentaram maior valor da frequência fundamental (F0) na vogal sustentada (p=0,004), maior desvio padrão da F0 na vogal sustentada (p=0,008), maior coeficiente de variação da amplitude também na vogal sustentada (p= 0,019), e maior desvio do pitch para o agudo na conversa espontânea (0,011). Em relação ao grupo controle os usuários da estratégia FSP apresentaram, na vogal sustentada, maior valor da F0 (p=0,012), maior desvio padrão da F0 (p=0,000), maior coeficiente de variação da frequência (p=0,039), maior coeficiente de variação da amplitude (p= 0,039), maior desvio de ressonância (p=0,027), maior instabilidade (p=0,001) e maior desvio da loudness para o forte (p=0,029). Apresentaram também na fala encadeada maior média da F0 (p=0,002), maior frequência máxima (p=0,009), maior grau geral do impacto negativo da voz (p=0,003) e maior tensão (p=0,001). Na conversa espontânea apresentaram maior grau geral do impacto negativo da voz (p=0,001), maior tensão (p=0,012), maior desvio do pitch para o agudo (0,000) e maior desvio de ressonância (p=0,010). Em comparação com os usuários da estratégia FSP, os usuários da estratégia ACE apresentaram maior valor do índice de fonação suave (SPI) na vogal sustentada (p=0,013). Em relação ao grupo controle os usuários da estratégia ACE apresentaram maior instabilidade na vogal sustentada (p=0,001), maior extensão da frequência em Hertz (p=0,004) e em semitons (p=0,048) na fala encadeada, maior frequência máxima (p=0,011) também na fala encadeada, maior grau geral do impacto negativo da voz na conversa espontânea (p=0,009) e maior desvio da ressonância na conversa espontânea (p=0,021). A partir dos dados concluiu-se que os usuários da estratégia FSP apresentaram vozes mais agudas e instáveis do que os usuários da estratégia ACE, que apresentaram produção vocal mais suave. Em relação ao grupo controle, os usuários da estratégia ACE apresentaram valor mais elevado do grau geral do impacto negativo da voz, maior grau de desvio da ressonância e maior extensão vocal para o agudo. Os usuários da estratégia FSP apresentaram vozes com maior valor do desvio global do impacto da voz, voz mais aguda, com maior desvio de ressonância, maior grau de tensão, maior desvio da loudness e maior extensão vocal. / The cochlear implant has the pupose of providing hearing perception for individuals with severe and profound hearing loss. The implants use result on optimization of development of language, speech and voice production of its users. This device is one of the most promissing and effective technologies to remedy hearing loss, and its results depend highly on the speech coding strategy selected in the speech processor. The pupose of this study was to compare perceptual and acoustic characteristics of the voices of children who use the Advanced Combination Encoder (ACE) or Fine Structure Processing (FSP) speech coding strategies, and to investigate whether these characteristics differ from children with normal hearing. Children between 3 and 5 years and 11 months of age participated. Acoustic analysis of the sustained vowel /a/ was performed using the Multi Dimentional Voice Program. Analysis of sequential speech and spontaneous speech were performed using the Real Time Pitch. Perceptual analysis of these speech samples were performed using visual-analogic scales of pre-selected parameters. In comparison with the users of the ACE strategy, the users of the FSP strategy presented greater value of fundamental frequency (F0) for the sustained vowel (p=0,004), greater standard deviation of the F0 for the sustained vowel (p=0,008), greater amplitude variation coheficient, also for the sustaned vowel (p= 0,019), and greater pitch deviation for the spontaneous speech (p=0,011). In relation to the control group, the users of the FSP strategy presented, for the sustained vowel, greater F0 value (p=0,012), greater standard deviation of the F0 (p=0,000), greater frequency variation coheficient (p=0,039), grater amplitude variation coheficient (p= 0,039), greater ressonance deviation (p=0,027), greater instability (p=0,001) and greater loudness deviation (p=0,029). They also presented, for the sequential speech, greater F0 average (p=0,002), greater maximum frequency (p=0,009), greater overall severity of the voice (p=0,003) and greater strain (p=0,001). For the spontaneous speech, they presented greater overall severity (p=0,001), greater strain (p=0,012), greater pitch deviation (0,000) and greater ressonance deviation (p=0,010). In comparison the users of the FSP strategy, the users of the ACE strategy presented greater value of the Soft Phonation Index (SPI) for the sustained vowel (p=0,013). In relation to the control group, the users of the ACE strategy presented greater instability for the sustained vowel (p=0,001), greater frequency range in Hertz (p=0,004) and in semitones (p=0,048) for the sequential speech, greater maximum frequency (p=0,011) also for the sequential speech, greater overall severity for the spontaneous speech (p=0,009) and greater ressonance deviation for the spontaneous speech. (p=0,021). The study concluded that the users of the FSP strategy presented more high pitched and unstable voices than the users of the ACE strategy, who presented softer phonation. In relation to the control group, the users of the ACE strategy presented greater value of overall severity, greater ressonance deviation and greater frequency range. The users of the FSP strategy presented greater value of overall severity, more high pitched voices, greater ressonance deviation, greater vocal strain e and greater frequency range.

Os objetivos deste trabalho foram: avaliar os efeitos das diferentes relações sinal/ruído, no reconhecimento da fala com o implante coclear; comparar o reconhecimento da fala no ruído, com diferentes tipos de implantes cocleares multicanais; avaliar a influência do tempo de surdez, tempo de uso do implante coclear e progressão da surdez, no reconhecimento da fala com o implante coclear e avaliar o grau de dificuldade dos usuários de implante coclear, em situações com ruído competitivo no dia-a-dia. Foram selecionados 40 adultos com deficiência auditiva pós-lingual, com os implantes cocleares Nucleus 22 (N=13, estratégia SPEAK), Nucleus 24 (N=7, estratégia ACE), Combi 40 (N=6), Combi 40+ (N=7) e Clarion (N=7) com a estratégia CIS, com experiência de mais 6 meses de uso do implante coclear e reconhecimento de fala em conjunto aberto. Foi avaliado o reconhecimento das sentenças CPA (Valente 1998), no silêncio e nas relações S/R de +15 dB, +10 dB, +5 dB e aplicado o questionário Social Hearing Handicap Index - SHHI (Wedel e Tegtmeier 1979, Wedel 1983), para a auto-avaliação do desempenho com o implante coclear, em situações de silêncio (componente da deficiência auditiva) e ruído (componente da seletividade), no dia-a-dia. Os usuários de todos os tipos de implante coclear apresentaram redução significativa dos índices de reconhecimento de sentenças CPA, em função da diminuição da relação S/R, com a curva das medianas de reconhecimento das sentenças CPA alcançando 50% na relação S/R de +10 dB. Não houve diferença estatisticamente significante nos índices de reconhecimento das sentenças CPA e escores de dificuldade do Social Hearing Handicap Index (SHHI), obtidos com os diferentes tipos de implantes cocleares e estratégias de codificação da fala. As dificuldades dos usuários de implante coclear foram raras nas situações de silêncio (componente da deficiência auditiva) e ocasionais nas situações com ruído competitivo (componente da seletividade), no questionário SHHI. Observou-se, também, a influência das características dos sujeitos (tempo de surdez, tempo de uso do implante coclear e progressão da surdez) nos índices de reconhecimento das sentenças CPA. O presente estudo permitiu concluir que os usuários de todos o tipos de implante coclear multicanais apresentaram redução dos índices de reconhecimento da fala, em função da diminuição da relação S/R e maior dificuldade, no dia-a-dia, em ambientes com ruído competitivo, do que no silêncio. / The aims of this study were: to evaluate the effects of different signal to noise ratios on speech recognition obtained by the use of the cochlear implant; to compare the speech recognition in noise with different types of multichannel cochlear implants; to evaluate the influence of duration of deafness, time of implant use and hearing loss progression in the speech recognition with cochlear implant and to evaluate the degree of difficulty for speech understanding in noise in daily life situations as well. Forty adults with post lingual hearing loss implanted with Nucleus 22 (n=13, SPEAK strategy), Nucleus 24 (n=7, ACE strategy), Combi 40 (n=6, CIS strategy), Combi 40+ (n=7, CIS strategy) and Clarion (n=7, CIS strategy). The minimum time of implant use was 6 months. All subjects enjoyed some degree of open set recognition. It was evaluated the recognition for CPA sentences (Valente 1998), in silence and in S/N +15, +10 and +5 dB. It was also applied the Social Hearing Handicap Index - SHHI questionnaire (Wedel e Tegtmeier 1979, Wedel 1983) for self assessment in daily life in silence (hearing loss component) and noise (selectivity component). All the implanted adults presented a significant reduction in the scores for sentences recognition as the S/N decreased. The medians´ curve for sentence recognition reached 50% in the signal to noise ratio of +10 dB. There was no difference statistically significant in sentences recognition scores and difficulty scores obtained with the Social Hearing Handicap Index (SHHI), for all types of implants and different speech strategy. The difficulties of implanted adults were rare in silence (hearing loss component) and occasional in noisy situations (selectivity component) in the SHHI questionnaire. It was also observed the influence of duration of deafness, time of implant use and hearing loss progression in the sentences recognition scores. In this study it was concluded that all subjects presented a significant reduction in sentences recognition scores as the S/N decreased and all subjects showed more difficulty for speech understanding in noisy environments independently of the type of multichannel cochlear implants used.

Yu, Shing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 87-93). / Abstracts in English and Chinese; includes Chinese. / Abstract --- p.i / Acknowledgement --- p.vi / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Hearing impairment --- p.1 / Chapter 1.2 --- Limitations of existing CI --- p.2 / Chapter 1.3 --- Objectives --- p.3 / Chapter 1.4 --- Thesis Outline --- p.4 / Chapter 2 --- Background --- p.6 / Chapter 2.1 --- Signal Processing in CI --- p.6 / Chapter 2.1.1 --- Continuous Interleaved Sampler (CIS) --- p.7 / Chapter 2.1.2 --- Advanced Combination Encoder (ACE) --- p.12 / Chapter 2.2 --- Tone perception by cochlear implantees --- p.15 / Chapter 2.2.1 --- Pitch and Tone --- p.15 / Chapter 2.2.2 --- Mechanisms of pitch perception by cochlear im- plantees --- p.20 / Chapter 3 --- Tone-enhanced ACE Strategy for CI --- p.23 / Chapter 3.1 --- Basic principles --- p.23 / Chapter 3.2 --- Acoustical simulation with noise excited vocoder --- p.26 / Chapter 3.3 --- Implementation in a real CI system --- p.29 / Chapter 3.3.1 --- Technical details --- p.30 / Chapter 3.3.2 --- Visual comparison --- p.31 / Chapter 4 --- Robust Generation of F0 Trajectory --- p.33 / Chapter 4.1 --- Requirement on the F0 contour --- p.33 / Chapter 4.2 --- Extraction of F0 contour --- p.34 / Chapter 4.3 --- Post-processing of F0 contour --- p.36 / Chapter 4.3.1 --- Removal of octave-jump --- p.36 / Chapter 4.3.2 --- Interpolation --- p.36 / Chapter 4.3.3 --- Prediction --- p.36 / Chapter 4.3.4 --- Smoothing --- p.38 / Chapter 4.4 --- Performance evaluation --- p.38 / Chapter 5 --- Design of Listening Tests --- p.41 / Chapter 5.1 --- Speech Materials --- p.41 / Chapter 5.2 --- Testing modes --- p.43 / Chapter 5.2.1 --- Sound field mode --- p.45 / Chapter 5.2.2 --- Direct stimulation mode --- p.46 / Chapter 5.3 --- Test Interface --- p.47 / Chapter 6 --- Sound-field Tests --- p.49 / Chapter 6.1 --- Materials and Methods --- p.50 / Chapter 6.1.1 --- Subjects --- p.50 / Chapter 6.1.2 --- Signal processing and test stimuli --- p.52 / Chapter 6.1.3 --- Procedures --- p.52 / Chapter 6.2 --- Results --- p.54 / Chapter 6.3 --- Discussion --- p.57 / Chapter 7 --- Evaluation of Tone-enhanced Strategy --- p.59 / Chapter 7.1 --- Materials and Methods --- p.60 / Chapter 7.1.1 --- Subjects --- p.60 / Chapter 7.1.2 --- Signal processing and test stimuli --- p.60 / Chapter 7.1.3 --- Procedures --- p.62 / Chapter 7.2 --- Results --- p.63 / Chapter 7.3 --- Discussion --- p.66 / Chapter 8 --- Use of Automatically Generated F0 Contour --- p.72 / Chapter 8.1 --- Materials and Methods --- p.73 / Chapter 8.2 --- Results --- p.74 / Chapter 8.3 --- Discussion --- p.76 / Chapter 9 --- Conclusions --- p.80 / Chapter A --- LSHK Cantonese Romanization Scheme --- p.85 / Bibliography --- p.87

No description available.

Neural prosthetics are used to replace or substantially augment remaining motor and sensory functions of neural pathways that were lost or damaged due to physical trauma, disease, or genetics. However, due to poor spatial signal resolution, neural prostheses fail to recapitulate the intimate, precise interactions inherent to neural networks. Designing materials and interfaces that direct de novo nerve growth to spatially specific stimulating elements is, therefore, a promising method to enhance signal specificity and performance of prostheses such as the successful cochlear implant (CI) and the developing retinal implant. In this work, the spatial and temporal reaction control inherent to photopolymerization was used to develop methods to generate micro and nanopatterned materials that direct neurite growth from prosthesis relevant neurons. In particular, neurite growth and directionality has been investigated in response to physical, mechanical, and chemical cues on photopolymerized surfaces. Spiral ganglion neurons (SGNs) serve as the primary neuronal model as they are the principal target for CI stimulation. The objective of the research is to rationally design materials that spatially direct neurite growth and to translate fundamental understanding of nerve cell-material interactions into methods of nerve regeneration that improve neural prosthetic performance. A rapid, single-step photopolymerization method was developed to fabricate micro and nanopatterned physical cues on methacrylate surfaces by selectively blocking light with photomasks. Feature height is readily tuned by modulating parameters of the photopolymerizaiton including initiator concentration and species, light intensity, separation distance from the photomask, and radiation exposure time. Alignment of neural elements increases significantly with increasing feature amplitude and constant periodicity, as well as with decreasing periodicity and constant amplitude. SGN neurite alignment strongly correlates with the maximum feature slope. Neurite alignment is compared on unpatterned, unidirectional, and multidirectional photopolymerized micropatterns. The effect of substrate rigidity on neurite alignment to physical cues was determined by maintaining equivalent pattern microfeatures, afforded by the reaction control of photopolymerization, while concomitantly altering the composition of several copolymer platforms to tune matrix stiffness. For each platform, neurite alignment to unidirectional patterns increases with increasing substrate rigidity. Interestingly, SGN neurites respond to material stiffness cues that are orders of magnitude higher (GPa) than what is typically ascribed to neural environments (kPa). Finally, neurite behavior at bioactive borders of various adhesion modulating molecules was evaluated on micropatterned materials to determine which cues took precedence in establishing neurite directionality. At low microfeatures aspect ratios, neurites align to the pattern direction but are then caused to turn and repel from or turn and align to bioactive borders. Conversely, physical cues dominate neurite path-finding as pattern feature slope increases, i.e. aspect ratio of sloping photopolymerized features increases, causing neurites to readily cross bioactive borders. The photopolymerization method developed in this work to generate micro and nanopatterned materials serves as an additional surface engineering tool that enables investigation of cell-material interactions including directed de novo neurite growth. The results of this interdisciplinary effort contribute substantially to polymer neural regeneration technology and will lead to development of advanced biomaterials that improve neural prosthetic tissue integration and performance by spatially directing nerve growth.

Objective. As a result of newborn hearing screenings, an increasing number of infants are being identified with a hearing loss at birth or within a few months of life. The literature supports that early identification in conjunction with early intervention services have led to drastic improvements in speech and language outcomes for children who have a received a cochlear implant (CI). The purpose of this study was to investigate the amount, type, and quality of services that young children with CI(s) are receiving. Methods. Participants in this study included 22 teachers of the deaf/hard of hearing (TD/HH), 7 speech-language pathologists (SLP), and 4 early childhood interventionists (ECI). All of the service providers were serving at least one child with a CI(s) at the time of the study. Three on-line service provider surveys were modified from the National Early Intervention Longitudinal Study (NEILS) in order to specifically address the concerns and interests of service provision for children with CIs. The three surveys addressed the birth-3, preschool, and school-age populations. Results. Results from the birth-3 and preschool populations with CIs were analyzed. The school-age population was not analyzed due to the low response rate from that age group. Findings from this study revealed that the TD/HH is the primary service provider for the birth-5 population with CIs. In addition, other service providers (i.e. SLP, ECI) reported that they do not feel completely comfortable working with the CI device (i.e. troubleshooting, utilizing the Ling Six Sound test). Another area of concern was the child's compliance in wearing the CI on a full-time, daily basis. Collaboration and education among professionals and the families of children with CIs must be stressed in order for early intervention services to effectively facilitate the child's speech, language, and educational development. Conclusion. The results revealed characteristics specific to both the child (i.e. services the child has received in the past 6 months as part of his/her intervention program) and the service provider (i.e. amount of professional education concerning children with CIs). More research is needed to assess the relationship between the amount and quality of service provision and the child's speech and language performance to ensure that this population is receiving appropriate early intervention services.

This study aimed to answer whether current research addressing executive function abilities in cochlear implant users was accurately depicting their impairments. Secondly, this study aimed to identify differences in identification of executive function impairments when measured using parent report versus behavioral measures of executive function. Results suggest that children do have executive function impairments in areas of measure nonverbal planning, problem-solving, monitoring, and self-regulation abilities as well as attention to a visually presented array of pictures which has been documented in previous research. However, it is likely that these abilities are modulated by children with cochlear implants' poorer language ability as demonstrated on the PPVT, which seems not to be related to their age of implantation. The behavioral measures and parent report measures identified impairments in the subsets which required a greater language demand and subsequently subsets that were significantly more difficult for CI children.

Doctor of Philosophy (PhD) / An in-depth, longitudinal study of the speech and oral language development of eight infants with a profound hearing loss who receive early interventions focused on developing their auditory, speech and oral language capacity is presented in this thesis. Infants were tracked for two years, during the period when they are changed from a hearing aid to a cochlear implant. All infants in this study had their hearing loss identified early and were fitted with hearing aids between 1 and 7 months of age and received their cochlear implant between 8 and 16 months of age. They attended a number of different auditory-verbal early intervention programs (depending on where they lived) all of which focused on developing speech and language skills through listening. Attendance at their particular early intervention program at least once a week was in addition to weekly attendance the Sydney Cochlear Implant Centre for therapy and audiological services. A broad range of measures has been used to track the infants’ acquisition of oral language skills, including measures of communicative intention, pre-speech and speech development, and oral language development. Despite a wide range of individual differences across the group of infants, the results suggest some general trends. In the area of communicative intent most infants followed typical development patterns in terms of both the types (e.g. requesting, answering etc) and forms (gestural, vocal, verbal) used, but they showed delays in their frequency of usage of these types and forms. For speech development the infants demonstrated typical speech skills by 18-months post-cochlear implantation in the areas of consonant inventories, severity of phonological involvement (speech intelligibility) and phonological process development, but they showed delays in vowel and consonant acquisition. Finally, for language development the infants were delayed relative to typical development at 18 months post-implantation. The findings support and extend previous studies which have demonstrated the benefits of early intervention for communication development in infants with hearing loss (Calderon & Naidu, 2000; Mayne, Yoshinaga-Itano & Sedey, 2000; Moeller, 2000; Yoshinaga-Itano & Apuzzo, 1998). However, the delays in the oral communication skills of the infants in the current study suggest that more intensive long-term intervention is required if the infants are to attain typical oral speech and language development. The findings capture the complexity of early oral language development, which has been lacking in previous studies of infants with significant hearing loss, receiving a cochlear implant (Dettman, Briggs, & Dowell, 2005; Houston, Ying, Pisoni, & Iler Kirk, 2003; Schauwers, Gillis, Daemers, De Beukelaer, & Govaerts, 2004). The present data also provide some limited support for earlier implantation, that is, before 12 months of age, as the infants made little progress in oral language development while using hearing aids. The reduced amount of auditory signal available to them prior to implantation may be the determining factor in their inability to follow typical rates and patterns of development. However, rates of development with the implant were not straightforward and further research on this population is needed. Universal neonatal screening programs for hearing loss will potentially provide a larger population of early identified infant for future research. This will create the opportunity for large scale, prospective, longitudinal, studies examining the acquisition of speech and oral language development. Limitations of this study, tracking the early stages of speech and language development over a two year period are identified. Future studies are needed to follow the infants for a longer time to determine if their rate of development is sufficient for them to catch up in areas of delay and maintain their performance in areas where they match their typically developing peers.

This study used the largest and youngest cohort of hearing impaired (HI) children to investigate the effect age at implantation had on the trajectories of expressive and receptive language, and externalizing behavior problems. In addition, the temporal relationship between language and externalizing behavior problems was examined in children implanted before and after the age of 2. Univariate latent difference score analyses were conducted to test the effect of age at implantation on each trajectory and bivariate difference score analyses were conducted to test the temporal effect between language and externalizing behavior problems. Results showed that age at implantation had an effect on the initial level and growth of expressive and receptive language trajectory and an effect on the initial level of externalizing behavior problems. Expressive language was found to have an influence on the changes in externalizing behavior problems for both groups, children implanted before and after the age of 2. However, the relationship between receptive language and externalizing behavior problems differed between the two age groups. The effect was bidirectional for the younger group but unidirectional for the older group, with externalizing behavior problems influenced the change in receptive language. Future research and potential interventions to improve behavior difficulties in deaf children are discussed.