This study evaluated a time-restricted region-suppressed event-related synthetic aperture magnetoencephalography (TRRS-ER-SAM) beamformer algorithm against equivalent current dipole (ECD), and event-related synthetic aperture magnetoencephalography (ER-SAM) post-processing methods for magnetoencephalography data. This evaluation was done numerically and with auditory evoked field (AEF) data elicited by binaurally presented 500 Hz tones. The TRRS-ER-SAM beamformer demonstrated robustness to noise, and the ability to handle coherent sources. The TRRS-ER-SAM algorithm was then applied to a study of N1m AEFs in 8 subjects aged 12-25 years. The study examined the effects of age, stimulus frequency, and right-sided monaural versus binaural stimulation on the N1m location, amplitude, and latency. It was found that age affected the N1m latency; stimulus frequency affected the N1m location, amplitude, and latency; and monaural versus binaural stimulation affected the N1m amplitude. In the context of these effects, the auditory pathway structure and neurophysiological changes due to maturation were discussed.

This study evaluated a time-restricted region-suppressed event-related synthetic aperture magnetoencephalography (TRRS-ER-SAM) beamformer algorithm against equivalent current dipole (ECD), and event-related synthetic aperture magnetoencephalography (ER-SAM) post-processing methods for magnetoencephalography data. This evaluation was done numerically and with auditory evoked field (AEF) data elicited by binaurally presented 500 Hz tones. The TRRS-ER-SAM beamformer demonstrated robustness to noise, and the ability to handle coherent sources. The TRRS-ER-SAM algorithm was then applied to a study of N1m AEFs in 8 subjects aged 12-25 years. The study examined the effects of age, stimulus frequency, and right-sided monaural versus binaural stimulation on the N1m location, amplitude, and latency. It was found that age affected the N1m latency; stimulus frequency affected the N1m location, amplitude, and latency; and monaural versus binaural stimulation affected the N1m amplitude. In the context of these effects, the auditory pathway structure and neurophysiological changes due to maturation were discussed.

This paper provides an overview of developmental timetables relevant to hearing and of current pediatric audiological techniques and practices. The first sections summarize structural and functional development of the auditory pathway and the development of primary auditory processing. These developmental sequences appear to follow similar paths in humans and animals. Speech and music perception involve more complex processing and are strongly influenced by experience. Hearing disorders affect the perception of complex sounds in a variety of ways, depending on the site(s) of lesions. Early onset hearing impairment, including conductive loss from chronic otitis media, can seriously impede language development. Language cannot develop normally without adequate speech stimulation. Sensitive and inexpensive techniques are available for performing neonatal hearing screening, and early intervention has a positive effect on development of language skills in hearing-impaired children. Thus, the National Institute of Health has recommended nationwide universal newborns hearing screening. The rationale and methodology of universal screening programs is summarized in the chapter. Advances in the field of the genetics of hearing impairment are also reviewed Recent advances in the field of auditory physiology - coupled with longstanding concerns about delayed identification of hearing impairment - have precipitated public health initiatives (National Institute of Health, 1993) and legislation for neonatal hearing screening programs (Blake & Hall, 1990). Pediatric audiology, once more “art” than science, is now largely based on physiologic methods rather than observed behavior. With current techniques, it is not only possible to detect hearing impairment at birth but also to determine the site of the lesion and to obtain close estimates of hearing threshold at specific frequencies (Werner, Folsom, & Mancl, 1993). Habilitative measures, including amplification, can begin within weeks of birth. Protocols for the management of hearing impairment are guided not only by the site of the lesion but by the developmental sequences and interactions among all of the child’s sensory modalities. This chapter provides an overview of developmental timetables relevant to hearing and of current pediatric audiological techniques and practices.

Professional research project (Au.D.)--University of South Florida, 2002. / Title from PDF of title page. / Document formatted into pages; contains 48 pages. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: This paper provides an overview of developmental timetables relevant to hearing and of current pediatric audiological techniques and practices. The first sections summarize structural and functional development of the auditory pathway and the development of primary auditory processing. These developmental sequences appear to follow similar paths in humans and animals. Speech and music perception involve more complex processing and are strongly influenced by experience. Hearing disorders affect the perception of complex sounds in a variety of ways, depending on the site(s) of lesions. Early onset hearing impairment, including conductive loss from chronic otitis media, can seriously impede language development. Language cannot develop normally without adequate speech stimulation. / ABSTRACT: Sensitive and inexpensive techniques are available for performing neonatal hearing screening, and early intervention has a positive effect on development of language skills in hearing-impaired children. Thus, the National Institute of Health has recommended nationwide universal newborns hearing screening. The rationale and methodology of universal screening programs is summarized in the chapter. Advances in the field of the genetics of hearing impairment are also reviewed / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.

The purpose of this study was to determine the effects of an atypical pattern of early acoustic stimulation on auditory development. Previous human research suggests that the acoustic environment of pre-term human infants in the Neonatal Intensive Care Unit (NICU) negatively affects some aspects of auditory development. Animal research suggests that premature auditory stimulation interrupts auditory development. Because mice are born before their auditory systems are developed, they make an excellent model for research on fetal and postnatal plasticity of the auditory system. The premature auditory state of newborn mice is similar to that of the NICU pre-term infant, albeit, natural for mice C57 mouse pups were exposed to an augmented acoustic environment (AAE) of a nightly 12-hour regiment of 70 dB SPL noise burst, beginning before age 12 days (onset of hearing) and lasting for one month. The prepulse inhibition (PPI) of mice exposed to the AAE was compared to that of non-exposed mice to observe short-term and long-term effects. Results showed that the prepulse inhibition of the AAE exposed mice did not differ significantly from that of the non-exposed mice. However, it is possible that the measurement used, PPI, may not have been appropriate or that the AAE may not have been an appropriate simulation of the NICU environment.

L’environnement (E) du grand prématuré (GP) diffère de l’E. utérin et contribue aux séquelles neurosensorielles qui le menace. Les stimuli auditifs y sont prédominants et atypiques. Peu de choses sont connues sur la sensibilité auditive du GP à ces stimuli. Elle est évaluée ici par l’analyse de sa réactivité physiologique, comportementale, et cérébrale (NIRS) aux variations de cet E. Une étude observationnelle montre que i) le GP réagit à des stimuli auditifs dès un seuil de 5-10 dBA de ratio signal-bruit ambiant ; ii) certaines stimulations altèrent son bien-être (désaturations, rupture du sommeil) ; iii) ses réponses autonomiques sont les plus sensibles. Sa réactivité varie selon la source sonore, suggérant une discrimination du caractère vocal ou non des stimuli. Une étude expérimentale évalue d’autres aspects de ses performances auditives (impact de la fréquence sonore, de la valence émotionnelle des voix) et leur maturation de 30-32 à 34-36 sem. d’âge post-menstruel. Son champ de perception fréquentiel de sons purs s’élargit des moyennes (500-2500 Hz) aux basses et hautes fréquences (100 et 4500 Hz). Après 34 sem., il discrimine la voix maternelle de celle d’une autre mère et d’une autre femme (émotionnellement neutre). Cette réactivité préférentielle se traduit par un « réflexe cardiaque d’orientation » et témoigne qu’un GP soustrait précocement à la voix de sa mère développe des capacités perceptives similaires à celles du fœtus exposé en continue à la prosodie de la voix maternelle. Ces résultats ouvrent un champ de recherche complémentaire sur les conséquences à long terme de son expérience auditive précoce (attachement, développement du langage et des émotions). / The environment (E) of very preterm infant (VPI) greatly differs from the uterine E and contributes to his risk of altered neurodevelopment. Although auditory stimuli are prominent and atypical in the NICU, little is known about the auditory sensitivity of VPI to his acoustic E. It is evaluated through their physiological, behavioral, and brain (NIRS) responsiveness to auditory environmental changes. An observational study shows that i) VPIs respond to “naturalistic” auditory stimuli from a minimum signal-to-noise ratio threshold of 5-10 dBA, ii) some stimuli can affect their well-being (desaturation, sleep disruption), iii) their autonomic reactivity is the most sensitive. Their reactivity varies depending on the sound sources, suggesting an ability to discriminate vocal from non vocal sounds. An experimental approach assess other aspects of their auditory performance (impact of sound frequency, emotional valence of voices) and their maturation from 30-32 to 34-36 wks post-menstrual age. Their perceptual field of sound frequencies expands for pure tones from the middle frequencies (500-2500 Hz) to low and high frequencies (100 and 4500 Hz). After 34 wks, VPIs discriminate their mother's voice from that of another mother and of another woman (emotionally neutral). This preferential reactivity relies on a "cardiac orienting reflex" suggesting that VPI not exposed for weeks to their mother’s voice in utero, can develop perceptual abilities similar to those of the fetuses continuously exposed to the prosody of their mother’s voice. They open ways for further research on the long-term consequences of early auditory experience (attachment, language and emotions development).

Made available in DSpace on 2016-04-27T18:12:39Z (GMT). No. of bitstreams: 1 Paula Couto Fortes.pdf: 917717 bytes, checksum: 9a729ae5a95bdbfbc274acf2ee2f5553 (MD5) Previous issue date: 2009-02-19 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Introduction: Parental satisfaction with auditory and language development of their hearing impaired children can be an important factor in constructing quality indicators of intervention process. Goals: To describe and discuss parental satisfaction with auditory and language development of their hearing impaired children during the periodical follow up process within a high complexity service within the public health system, aiming at raising aspects related to quality indicators. Method: Twenty hearing impaired children less than three years of age, their parents and therapists participated in the study. All children were diagnosed and received their hearing aids at the Center for hearing in children CeAC, in the city of São Paulo. Data were collect using: children s files, an interview guide for parents, Questionnaire for satisfaction, and a parental involvement scale used by clinicians to assess the family. Results: Most parents were satisfied with auditory skills development, but not satisfied with language development. Hearing aids were the most recalled factor related to child s development. Length of time in intervention had a negative moderate relation with parental satisfaction with language development. Regarding the clinicians, the majority was satisfied with auditory skills of the children but was also not satisfied with language development. Hearing aids, intervention and family were the most recalled factor related to child s progress. Conclusion: Results indicate that there is a need to work with parents within the therapeutic process, regarding their hopes, needs and expectations regarding auditory and language development of their hearing impaired children / Introdução: A literatura tem apontado que a satisfação de pais de crianças deficientes auditivas em relação ao desenvolvimento auditivo e de linguagem pode ser fundamental para a construção dos indicadores de qualidade quanto aos objetivos da intervenção terapêutica. Objetivo: Descrever e discutir a satisfação de pais e/ ou responsáveis por crianças com deficiência auditiva quanto ao desenvolvimento auditivo e de linguagem no processo de acompanhamento de um serviço de saúde auditiva de alta complexidade e de buscar instrumentos para avaliar a satisfação com serviços de saúde voltados para crianças com deficiência auditiva. Método: Participaram do estudo 20 crianças deficientes auditivas abaixo de três anos, seus pais e/ou responsáveis e suas terapeutas, diagnosticadas e que receberam a concessão do AASI no Centro Audição da Criança (CeAC), na cidade de São Paulo/SP. Os instrumentos utilizados foram: Prontuários dos sujeitos; Roteiro de entrevista para pais; Critério de Classificação Econômica Brasil ; Questionário de satisfação e avaliação da família pelas terapeutas das crianças deficientes auditivas e Escala de Envolvimento Familiar. Resultados: A maioria dos pais está satisfeita com o desenvolvimento de habilidades auditivas das crianças, porém, também a maioria está insatisfeita com o desenvolvimento de linguagem. O AASI foi o fator mais mencionado como contribuinte ou não para o desenvolvimento de audição e de linguagem das crianças. O tempo de terapia teve relação significativa com a insatisfação dos pais. Em relação às terapeutas a maioria apresentou satisfação em relação à audição das crianças; porém, também a maioria referiu insatisfação quanto ao desenvolvimento de linguagem. Os fatores AASI, terapia e família foram considerados principais por elas para o desenvolvimento auditivo e de linguagem. Conclusão: Os resultados indicam que existe a necessidade de envolver os familiares no processo terapêutico, trabalhando seus desejos, suas necessidades e expectativas quanto ao desenvolvimento auditivo e de linguagem das crianças deficientes auditivas

Professional research project (Au.D.)--University of South Florida, 2003. / Title from PDF of title page. / Document formatted into pages; contains 20 pages. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: The purpose of this study was to determine the effects of an atypical pattern of early acoustic stimulation on auditory development. Previous human research suggests that the acoustic environment of pre-term human infants in the Neonatal Intensive Care Unit (NICU) negatively affects some aspects of auditory development. Animal research suggests that premature auditory stimulation interrupts auditory development. Because mice are born before their auditory systems are developed, they make an excellent model for research on fetal and postnatal plasticity of the auditory system. The premature auditory state of newborn mice is similar to that of the NICU pre-term infant, albeit, natural for mice C57 mouse pups were exposed to an augmented acoustic environment (AAE) of a nightly 12-hour regiment of 70 dB SPL noise burst, beginning before age 12 days (onset of hearing) and lasting for one month. / ABSTRACT: The prepulse inhibition (PPI) of mice exposed to the AAE was compared to that of non-exposed mice to observe short-term and long-term effects. Results showed that the prepulse inhibition of the AAE exposed mice did not differ significantly from that of the non-exposed mice. However, it is possible that the measurement used, PPI, may not have been appropriate or that the AAE may not have been an appropriate simulation of the NICU environment. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.

L'objectif de cette thèse est de s'intéresser à l'impact de la dégradation du signal de parole sur le traitement et les représentations du langage. Le signal peut être dégradé de façon transitoire (i.e., parole dans le bruit, Axe 1) ou permanente (Axe 2). L'Axe 1 étudie l'impact de la présence de bruit sur le traitement sémantique au niveau du mot isolé et dans un contexte phrastique. Deux études ont permis de mettre en évidence que lorsque le signal de parole est masqué, le traitement sémantique est moins efficace, voire disparait. A la lumière de l'Effortfulness Hypothesis nous suggérons que le traitement sémantique n'est pas automatique mais dépendant de ressources cognitives. Lorsque le signal de parole est dégradé ces ressources cognitives sont allouées aux traitements linguistiques de bas niveau, les traitements de haut niveau comme le traitement sémantique sont donc moins efficaces. L'Axe 2 évalue les liens entre la dégradation permanente du signal de parole du fait d'un manque de maturité des traitements auditifs centraux ou à un Trouble du Traitement Auditif (TTA) et les représentations langagières. Deux études se sont intéressées au développement des traitements auditifs et à la présence de TTA au sein d'une population d'adultes dyslexiques. Les résultats ont mis en évidence que les traitements auditifs centraux continuent leur maturation durant l'adolescence. La dernière étude a permis de mettre en évidence chez la population dyslexique des difficultés dans les tests impliquant des traitements spectral et temporel. Ces compétences sont apparues liées au sein de cette population aux représentations phonologiques. L'ensemble des résultats suggèrent que la dégradation du signal de parole a différents effets sur le langage selon sa nature. Ainsi, lorsqu'elle est transitoire elle impacte sa compréhension en dépit d'une intelligibilité préservée. Une dégradation transitoire impacte la compréhension malgré l'intelligibilité, la dégradation permanente impacte les représentations différemment selon la population / This thesis aims at investigating the effect of speech degradation on language processing and representation. Speech signal can be degraded temporary (i.e., speech in noise) or continually, when central auditory processes are deficient. Experimental work was therefore based on two main axes. The first one got interested in the effect of noise on semantic processing, despite preserved intelligibility. Two studies showed that semantic processing is less efficient when speech is presented in noisy condition. In light of the Effortfulness Hypothesis, we suggest that semantic processing relies on cognitive resources. When signal is degraded these resources are reallocated to low level processes and therefore few are left available to perform higher level processes. Axe 2 aims at evaluating links between continuous speech degradation because of immaturity of central auditory processes or Auditory Processing Disorder (APD) and language representation. Two studies investigated the effect of auditory processing development on language on a children population (6-11 years old) and the effect of APD on language representation in an adult dyslexic population. Both populations were evaluated using the BECAC (Donnadieu et al. 2014). This battery aims at evaluating central auditory processes using non-verbal material so that auditory performances can be related to language competences. Results evidenced that central auditory processes mature until adulthood, and at some point in development (8-9 years old) are linked to language representation. Results of the last study showed that dyslexic adults are impaired in tests involving spectral and temporal processes; in addition these abilities are related with phonological awareness. Altogether, these results indicate that speech degradation has distinct effects on language depending on its nature. Therefore when temporary, speech degradation impacts its comprehension despite intelligibility. When continuous, speech degradation’s impact evolves during development and disappears in normal adults. However, it stays for dyslexics

<p> Hearing provides a vital means for infants to discover their environment and communicate with their caregivers. Identifying and discriminating the pitch of sounds is critical for infants in order to acquire information from speech and music. Therefore, how infants process pitch is a fundamental question in research on auditory development. The focus of this dissertation is the use of auditory event related potentials (ERPs) derived from electroencephalogram (EEG) recordings to examine the maturation of pitch perception in early infancy. </p> <p> Pitch perception in adults has been extensively studied, but little is known about the development of pitch perception during early infancy. Infant mismatch responses (MMRs) are ERP components that are elicited by infrequent changes in auditory stimuli. MMR is a promising tool to study infant pitch perception because it can be elicited without attention or a behavioural response. However, previous studies on MMRs in infants have reported inconsistent results, some reporting frontally positive responses while others report frontally negative mismatch responses. In Chapter 2, we examined MMRs to simple pitch changes in infants between 2 and 4 months of age and found both types of infant MMRs are present, but the morphological distributions and developmental trajectories are different. In Chapter 3, we reported that both types of infant MMRs are affected similarly by the amplitude of pitch change but only the positive MMR becomes stronger when stimulus presentation rate increases, which suggests different neural mechanisms for the two types of infant MMRs. The studies reported in Chapter 4 found that only the negative MMR can be elicited readily by changes in pitch patterns, suggesting that it may be functionally similar to mismatch negativity (MMN) in adults. </p> <p> The experiments in Chapter 5 used MMR as the indication of whether infants automatically integrate the frequency components of a complex tone into a single pitch percept, even when the fundamental frequency component (corresponding to the pitch) is removed. Previous studies show that adult MMN is elicited by a pitch change in such tones missing the fundamental. Previous behavioural studies using a conditioned head tum method show that 7-month-olds also perceive pitch with tones missing the fundamental. The results of the present study indicate that infants as young as 4 months of age integrate components into a single pitch percept, but evidence for this in younger infants could not be found. </p> <p> In conclusion, the current dissertation established a promising procedure utilizing infant MMR to study infant pitch perception and contributed to the knowledge of early development of pitch perception by demonstrating dramatic changes in brain response to pitch in harmonic tones in infants between 2 and 4 months old, and to pitch in tones in infants missing the fundamental between 3 and 4 months old . </p> / Thesis / Doctor of Philosophy (PhD)