• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2
  • 1
  • Tagged with
  • 5
  • 5
  • 4
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

O uso do mascaramento no potencial evocado auditivo de tronco encefálico com estímulo tone burst por condução aérea em indivíduos com perda auditiva unilateral / The use of masking in auditory brainstem response with tone burst stimulus by air conduction in individuals with unilateral hearing loss

Silva, Bárbara Cristiane Sordi 26 February 2018 (has links)
A utilização do mascaramento contralateral durante a pesquisa do potencial evocado auditivo de tronco encefálico é uma temática bastante discutida, visto a inexistência de um consenso na literatura acerca de sua necessidade. O objetivo deste estudo foi verificar a necessidade do uso do mascaramento contralateral no potencial evocado auditivo de tronco encefálico com estímulo tone burst apresentado com fone de inserção 3A e propor a aplicabilidade do ruído mascarador white noise na perda auditiva sensorioneural unilateral de graus severo ou profundo. Foram avaliados 15 indivíduos, de ambos os sexos, com o diagnóstico audiológico prévio de perda auditiva sensorioneural unilateral de graus severo ou profundo, com idades entre 2 a 40 anos. Para tanto, foi pesquisada a resposta neural definida pela presença da onda V na orelha com perda auditiva, nas frequências de 500, 1000, 2000 e 4000 Hz. Nos casos em que houve o registro, a pesquisa foi repetida com mascaramento white noise na orelha contralateral. Os registros foram analisados por dois juízes experientes em eletrofisiologia, a fim de verificar a concordância entre as análises. O Coeficiente Kappa (1,00) apresentou força de concordância quase perfeita e o de Correlação Intraclasse (1,00) foi excelente, entre as duas avaliadoras, em todas as análises. Como resultado, foi observada a audição cruzada, ao menos uma vez, em todas as frequências analisadas. Os níveis de mascaramento contralateral mínimos necessários para eliminar a participação da orelha não testada variaram de 10 a 20 dBnNA acima do limiar eletrofisiológico da orelha sem perda auditiva. Não foi possível realizar a análise para a frequência de 500 Hz devido à presença de artefato e ruído elétricos. Conclui-se que o uso do mascaramento contralateral no potencial evocado auditivo de tronco encefálico com estímulo tone burst apresentado com fone de inserção 3A é necessário nas frequências de 1000, 2000 e 4000 Hz em indivíduos com perda auditiva sensorioneural unilateral de graus severo ou profundo, nas intensidades de 15, 20 e 10 dB acima dos limiares eletrofisiológicos, respectivamente. / The use of contralateral masking on the investigation of auditory brainstem response is a topic widely discussed, however there is no consensus in literature about its necessity. The aim of this study was to verify the need of using masking in auditory brainstem response with tone burst stimulus presented with 3A insert earphones and to propose the applicability of white noise masking in severe or profound unilateral sensorineural hearing loss. Fifteen individuals of both genders with previous audiological diagnosis of severe or profound unilateral sensorineural hearing loss, aged between 2 to 40 years, were evaluated. For this, the neural response, which is defined by the presence of the V wave in the ear with hearing loss, was investigated in frequencies of 500, 1000, 2000 and 4000 Hz. In cases where there was a record, the search was repeated using white noise masking in the contralateral ear. The records were analyzed by two judges experienced in electrophysiology, in order to verify the concordance between the analyses. The Kappa coefficient (1.00) had almost perfect agreement strength and the Intraclass Correlation (1.00) was excellent between the two evaluators in all analyses. As a result, cross-audition was observed at least once in all analyzed frequencies. The minimum contralateral masking levels required to eliminate the untested ear involvement varied from 10 to 20 dBnNA above the electrophysiological threshold of the ear without hearing loss. It was not possible to perform the analysis for the frequency of 500 Hz due to the presence of electrical artifact and noise. It is concluded that the use of contralateral masking in the auditory brainstem response with tone burst stimulus presented with 3A insert earphone is necessary in frequencies of 1000, 2000 and 4000 Hz in individuals with severe or profound unilateral sensorineural hearing loss in intensities of 15, 20 and 10 dB above the electrophysiological thresholds, respectively.
2

Auditory Filters Measured at Neighboring Center Frequencies

Fagelson, Marc A., Champlin, C. A. 01 June 1997 (has links)
Auditory filters were derived in 20 normal-hearing human listeners at center frequencies (CFs) of 913, 1095, 3651, and 4382 Hz using the roex (p,r) method. Comparisons were made between slopes of the filters' skirts at the neighboring CFs with filter output levels of 45 and 70 dB. The same comparisons were made with regard to filter equivalent rectangular bandwidth (ERB). In the 1000-Hz region, the low-frequency slopes (Pl) of filters centered at 913 and 1095 Hz were significantly correlated at both stimulus levels, while the high-frequency slopes (Pu) were similar only at the high test level. In the 4000-Hz region, for sinusoids of 3651 and 4382 Hz, the level effect was clearer as both Pu and Pl values diverged at the low level but were related at high levels. The ERBs centered at the same CFs displayed a similar level dependence. At the stimulus level most likely to be affected by an active feedback mechanism, auditory filters centered at nearly the same frequency displayed quite distinct frequency selectivity, and this trend was stronger in the 4000-Hz region than the 1000-Hz region. The findings suggest that a saturating, active cochlear mechanism may not be distributed evenly, or contribute to peripheral tuning with equal effectiveness throughout the length of the partition.
3

O uso do mascaramento no potencial evocado auditivo de tronco encefálico com estímulo tone burst por condução aérea em indivíduos com perda auditiva unilateral / The use of masking in auditory brainstem response with tone burst stimulus by air conduction in individuals with unilateral hearing loss

Bárbara Cristiane Sordi Silva 26 February 2018 (has links)
A utilização do mascaramento contralateral durante a pesquisa do potencial evocado auditivo de tronco encefálico é uma temática bastante discutida, visto a inexistência de um consenso na literatura acerca de sua necessidade. O objetivo deste estudo foi verificar a necessidade do uso do mascaramento contralateral no potencial evocado auditivo de tronco encefálico com estímulo tone burst apresentado com fone de inserção 3A e propor a aplicabilidade do ruído mascarador white noise na perda auditiva sensorioneural unilateral de graus severo ou profundo. Foram avaliados 15 indivíduos, de ambos os sexos, com o diagnóstico audiológico prévio de perda auditiva sensorioneural unilateral de graus severo ou profundo, com idades entre 2 a 40 anos. Para tanto, foi pesquisada a resposta neural definida pela presença da onda V na orelha com perda auditiva, nas frequências de 500, 1000, 2000 e 4000 Hz. Nos casos em que houve o registro, a pesquisa foi repetida com mascaramento white noise na orelha contralateral. Os registros foram analisados por dois juízes experientes em eletrofisiologia, a fim de verificar a concordância entre as análises. O Coeficiente Kappa (1,00) apresentou força de concordância quase perfeita e o de Correlação Intraclasse (1,00) foi excelente, entre as duas avaliadoras, em todas as análises. Como resultado, foi observada a audição cruzada, ao menos uma vez, em todas as frequências analisadas. Os níveis de mascaramento contralateral mínimos necessários para eliminar a participação da orelha não testada variaram de 10 a 20 dBnNA acima do limiar eletrofisiológico da orelha sem perda auditiva. Não foi possível realizar a análise para a frequência de 500 Hz devido à presença de artefato e ruído elétricos. Conclui-se que o uso do mascaramento contralateral no potencial evocado auditivo de tronco encefálico com estímulo tone burst apresentado com fone de inserção 3A é necessário nas frequências de 1000, 2000 e 4000 Hz em indivíduos com perda auditiva sensorioneural unilateral de graus severo ou profundo, nas intensidades de 15, 20 e 10 dB acima dos limiares eletrofisiológicos, respectivamente. / The use of contralateral masking on the investigation of auditory brainstem response is a topic widely discussed, however there is no consensus in literature about its necessity. The aim of this study was to verify the need of using masking in auditory brainstem response with tone burst stimulus presented with 3A insert earphones and to propose the applicability of white noise masking in severe or profound unilateral sensorineural hearing loss. Fifteen individuals of both genders with previous audiological diagnosis of severe or profound unilateral sensorineural hearing loss, aged between 2 to 40 years, were evaluated. For this, the neural response, which is defined by the presence of the V wave in the ear with hearing loss, was investigated in frequencies of 500, 1000, 2000 and 4000 Hz. In cases where there was a record, the search was repeated using white noise masking in the contralateral ear. The records were analyzed by two judges experienced in electrophysiology, in order to verify the concordance between the analyses. The Kappa coefficient (1.00) had almost perfect agreement strength and the Intraclass Correlation (1.00) was excellent between the two evaluators in all analyses. As a result, cross-audition was observed at least once in all analyzed frequencies. The minimum contralateral masking levels required to eliminate the untested ear involvement varied from 10 to 20 dBnNA above the electrophysiological threshold of the ear without hearing loss. It was not possible to perform the analysis for the frequency of 500 Hz due to the presence of electrical artifact and noise. It is concluded that the use of contralateral masking in the auditory brainstem response with tone burst stimulus presented with 3A insert earphone is necessary in frequencies of 1000, 2000 and 4000 Hz in individuals with severe or profound unilateral sensorineural hearing loss in intensities of 15, 20 and 10 dB above the electrophysiological thresholds, respectively.
4

Enriched in-band video : from theoretical modeling to new services for the society of knowledge / In-band enriched video : de la modélisation théorique aux nouveaux services pour la société des connaissances

Belhaj Abdallah, Maher 05 December 2011 (has links)
Cette thèse a pour ambition d’explorer d’un point de vue théorique et applicatif le paradigme de l’in-band enrichment. Emergence de la société des connaissances, le concept de média enrichi renvoie à toute association de métadonnée (textuelle, audiovisuelle, code exécutable) avec un média d’origine. Un tel principe peut être déployé dans une large variété d’applications comme la TVNi - Télévision Numérique interactive, les jeux ou la fouille des données. Le concept de l’inband enrichement conçu et développé par M. Mitrea et son équipe au Département ARTEMIS de Télécom SudParis, suppose que les données d’enrichissement sont insérées dans le contenu même à enrichir. Ainsi, un tel concept peut-il tirer parti de techniques de tatouage, dès lors que celles-ci démontrent qu’elles ont la capacité d’insérer la quantité d’information requise par ce nouveau type d’application : i.e. 10 à 1000 fois plus grande que celle nécessaire pour les enjeux d’authentification ou de protection de droit d’auteur. Si par tradition la marque est insérée dans le domaine non compressé, les contraintes relatives aux nombreuses applications émergentes (comme la VoD – Vidéo à la Demande ou la TVNi) font du tatouage en temps réel dans le domaine compressé un important défi théorique et applicatif. Cependant, le tatouage dans le domaine compressé est une alliance de mots contradictoires puisque la compression (élimination de la redondance) rend l’hôte plus sensible aux modifications et l’association hôte/marque, plus fragile / The present thesis, developed at Institut Télécom Télécom SudParis under the “Futur et Rupture” framework, takes the challenge of exploring from both theoretical and applicative points of views the in band enrichment paradigm. Emerged with the knowledge society, the enriched media refers to any type of association which may be established between some metadata (textual, audio, video, exe codes...) and a given original media. Such a concept is currently deployed in a large variety of applications like the iDTV (interactive Digital TV), games, data mining... The incremental notion of in band enrichment advanced at the ARTEMIS Department assumes that the enrichment data are directly inserted into the very original media to be enriched. In real life, in band enrichment can be supported by the watermarking technologies, assuming they afford a very large data payload, i.e. 10 to 1000 larger than the traditional copyright applications. The nowadays advent of the ubiquous media computing and storage applications imposes an additional constraint on the watermarking techniques: the enrichment data should be inserted into some compressed original media. A priori, such a requirement is a contradiction in terms, as compression eliminates the visual redundancy while the watermarking exploits the visual redundancy in order to imperceptibly insert the mark
5

Recognition Performance on Words Interrupted (10 Ips, 50% Duty Cycle) With Two Interruption Patterns Referenced to Word Onset: Young Listeners With Normal Hearing for Pure Tones and Older Listeners With Sensorineural Hearing Loss

Wilson, Richard H., Irish, Staci E. 01 January 2015 (has links)
OBJECTIVE: To determine in an interrupted word paradigm (Maryland CNCs; 10 ips, 50% duty cycle) if different locations of the interruption pattern produce different recognition performances. DESIGN: Repeated measures using two interruption patterns that were complementary halves referenced to word onset; one started with word onset (0-ms), the other started 50 ms later. The hypothesis was that recognition performance would be better on the 0-ms condition than on the 50-ms condition, but there would be some words with the reverse relation. STUDY SAMPLE: Twenty-four young adults with normal hearing for pure tones and 32 older adults (mean = 67 years) with sensorineural hearing loss participated. RESULTS: With the young listeners mean recognition performance on the 0-ms condition (63.1%) was significantly better than the mean performance on the 50-ms condition (47.8%). About twice as many words had better performance on the 0-ms condition. With the older listeners, who were given only stimuli on which performances were > 58% by the young normals, performances on the two conditions were the same. CONCLUSIONS: The hypothesis was supported with the young listeners. The equal performance by the older listeners on the two conditions was attributed to the manner in which the words were selected.

Page generated in 0.0552 seconds