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  • 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.
71

Sound Encoding in the Mouse Cochlea: Molecular Physiology and Optogenetic Stimulation

Jing, Zhizi 23 October 2013 (has links)
No description available.
72

Avaliação da audição residual em candidatos  a implantes coclear atráves da resposta  auditiva de estado estável / Evaluation of residual hearing in cochlear implants candidates using auditory steady-state response

Henrique Faria Ramos 02 April 2013 (has links)
INTRODUÇÃO: A identificação e preservação da audição residual em candidatos a implante coclear vêm assumindo maior importância clínica. A resposta auditiva de estado estável (RAEE) pode fornecer informação frequência-específica sobre o limiar auditivo em níveis de intensidade máximos de 120 dB NA, possibilitando a investigação da audição residual. Os objetivos deste estudo são avaliar a audição residual em candidatos a implante coclear, comparando os limiares eletrofisiológicos da RAEE com os limiares psicoacústicos da audiometria nas frequências de 500, 1 000, 2 000 e 4 000 Hz. MÉTODO: Foram avaliados 40 candidatos a implante coclear (80 orelhas) com perda auditiva neurossensorial severa a profunda bilateral. A audiometria foi realizada com o tom \"warble\" nas frequências de 500, 1 000, 2 000 e 4 000 Hz com intensidade máxima de estimulação de 120 dB NA. A RAEE foi obtida através da estimulação dicótica de uma frequência de tons contínuos sinusoidais modulados 100% em amplitude exponencial e 20% em frequência, nas frequências portadoras de 500, 1 000, 2 000 e 4 000 Hz, com estimulação máxima de 117, 120, 119 e 118 dB NA, respectivamente. RESULTADOS: Foram obtidos limiares mensuráveis em 62,5% de todas as frequências estudadas na audiometria tonal e em 63,1% na RAEE. A RAEE apresentou sensibilidade de 96% e especificidade de 91,6% na detecção da audição residual. As diferenças médias entre os limiares da audiometria tonal e da RAEE não apresentaram significância estatística em nenhuma das frequências. As correlações entre os limiares comportamentais e da RAEE foram significantes em todas as frequências avaliadas, sendo fortes em 500, 1 000 e 2 000 Hz e moderada em 4 000 Hz, com coeficiente de correlação de Pearson entre 0,65 e 0,81. Em 90% dos casos, os limiares da RAEE foram adquiridos nos limites de 10 dB dos limiares comportamentais. CONCLUSÕES: As correlações entre os limiares tonais e da RAEE foram significantes nas frequências de 500, 1 000, 2 000 e 4 000 Hz. A RAEE apresentou alta sensibilidade e especificidade na detecção da audição residual em candidatos a implante coclear, em comparação com a audiometria tonal / INTRODUCTION: Identification and preservation of residual hearing in cochlear implantation are becoming more important lately. Auditory steadystate response (ASSR) can provide frequency-specific information regarding the auditory thresholds at maximum intensity levels of 120 dB HL, allowing investigation of residual hearing. The study objectives are to assess residual hearing in cochlear implant candidates by comparing the electrophysiological thresholds obtained in ASSR with psychoacoustic thresholds of audiometry at 500, 1 000, 2 000 and 4 000 Hz. METHOD: Forty cochlear implant candidates (80 ears) with bilateral severe-to-profound sensorineural hearing loss were studied. Warble-tone audiometry was performed at the frequencies 500, 1 000, 2 000 e 4 000 Hz, with stimuli up to 120 dB HL. ASSR was obtained with dichotic single-frequency stimulation of sinusoidal continuous tones modulated in exponential amplitude of 100% and in frequency of 20%, at the carrier frequencies of 500, 1 000, 2 000 and 4 000 Hz at maximum stimulation levels of 117, 120, 119 and 118 dB HL, respectively. RESULTS: Thresholds were obtained in 62,5% of all frequencies evaluated in warbletone audiometry and in 63,1% in the ASSR. ASSR showed sensitivity of 96% and specificity of 91,6% in the detection of residual hearing. The mean difference between the thresholds of behavioral audiometry and ASSR were not statistically significant in any of the frequencies. Strong correlations between behavioral and ASSR thresholds were observed in 500, 1 000 and 2 000 Hz and moderate in 4 000 Hz, with Pearson correlation coefficient between 0,65 and 0,81. In 90% of the occasions, ASSR thresholds were within 10 dB of behavioral thresholds. CONCLUSIONS: The correlations between behavioral and ASSR thresholds were significant at 500, 1 000, 2 000 and 4 000 Hz. ASSR showed high sensitivity and specificity in the detection of residual hearing in cochlear implant candidates, compared to warble-tone audiometry
73

Avaliação do recesso do nervo facial e cóclea no osso temporal de cadáveres de recém nascidos natimortos com vistas ao implante coclear percutâneo / Evaluation of the facial nerve recess and cochlea on the temporal bones of cadaveric newborns and its applicability in the percutaneous cochlear implant technique

Gabriela Pereira Bom Braga 23 January 2017 (has links)
INTRODUÇÃO: A literatura evidencia as diferenças anatômicas do osso temporal em crianças quando comparadas à adultos. Mais e mais a literatura enfatiza a importância de que as crianças com surdez congênita devem ser implantadas cada vez mais precocemente. Estudos anátomo-radiológicos são importantes para o desenvolvimento de técnicas cirúrgicas que possibilitem implantar crianças recém natas. Técnicas de implante coclear percutâneo (através de robótica) tem sido desenvolvidas na Universidade de Vanderbilt. Criamos então nossa principal pergunta \"Seria possível implantar crianças recém natas através de implante percutâneo?\" e procuraremos respondê-la no curso desse trabalho. OBJETIVO: Aferir as medidas do recesso do nervo facial e sua relação com a cóclea visando simular o trajeto da broca através desse recesso, para realização da cocleostomia, objetivando o implante coclear percutâneo. CASUÍSTICA E METODOLOGIA: Estudo experimental realizado com 9 espécimes de natimortos com idade gestacional entre 32 e 40 semanas, submetidos à tomografia computadorizada com individualização e reconstrução do nervo facial, cadeia ossicular, membrana timpânica, cóclea e labirinto, seguido da definição da trajetória da broca até a escala timpânica, utilizando o software Improvise. RESULTADOS: As medidas da trajetória da broca até o nervo facial, variaram de 0.58 a mais próxima e, 1.71 a mais distante; quando analisamos os resultados obtidos para cadeia ossicular, temos uma variação que vai de 0.38 até 1.49. A membrana timpânica se encontra entre 0.85 e 1.96 de distância da trajetória simulada da broca. A trajetória da cortical do osso temporal até a escala timpânica, variou de 5.92 a 12.65. CONCLUSÃO: As medidas da relação, entre a broca e as estruturas anatômicas da orelha média e, a simulação da trajetória, mostraram que é possível executar com segurança a técnica de implante coclear percutâneo em crianças a partir de 32 semanas de gestação / INTRODUCTION: Literature shows changes in the temporal bone anatomy in children when compared with adults. More and more literature emphasizes the importance of children with congenital deafness should be implanted increasingly early. Anatomical radiologic studies are important for the development of surgical techniques that allow implanting new born. Percutaneous cochlear implant technique (through robotics) was developed in Vanderbilt University. So we created our main question \" Is it possible to implant new born children using the percutaneous technique? \" and we\'ll try to answer it in the course of this work. PATIENTS AND METHODS: Experimental study done in 9 stillbirth specimens with 32 and 40 weeks of age, submitted to CT study followed by reconstruction of the facial nerve, ossicular chain, tympanic membrane, labyrinth and cochlea. The CT evaluation and reconstruction was done with Improvise software, also used for measurements of the distances and in the simulation of the drill\'s trajectory (mm). RESULTS: The drill trajectory measurements to the facial nerve, ranged from 0.58 the nearest and the farthest 1.71, when we analyzed the results for ossicular chain, we have a range that goes from 0.38 to 1.49. The tympanic membrane is between 0.85 and 1.96 away from the simulated drill path. Cortical trajectory of the temporal bone to the scala tympani, ranged from 5.92 to 12.65. CONCLUSION: The measures of the relationship between the drill and the anatomical structures of the middle ear and the simulated trajectory, showed that it is possible to use safely the percutaneous cochlear implant technique in children of 32 weeks/old
74

COMPRESSÃO DE FREQUÊNCIAS: RECONHECIMENTO DE FALA EM IDOSOS COM PERDA AUDITIVA DE CONFIGURAÇÃO DESCENDENTE / FREQUENCY COMPRESSION: SPEECH RECOGNITION IN ELDERLY PEOPLE WITH DESCENDING CONFIGURATION HEARING LOSS

Gresele, Amanda Dal Piva 17 December 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Purpose: to evaluate and compare the performance of elderly people with descending hearing loss, still considering the presence or absence of dead regions in cochlea (DRs), in speech recognition tests, in silence and in noise, using auditory prostheses with and without the activation of the nonlinear frequency compression (NLFC). Materials and Methods: the study presents quantitative, observational, descriptive, and transversal traits. 48 subjects were evaluated: 33 men and 15 women, aged between 61 and 84 years, with mild to moderate hearing loss and descending configuration. In order to collect the data the Lists of Sentences in Portuguese test was used (LSP), seeking the Sentence Recognition Thresholds in Silence (LRSS), the Sentences Recognition Threshold in Noise (LRSR) expressed by the signal/noise relationship (S/R) and Percentage Index Sentence Recognition of Threshold in Silence (IPRSS) and in noise (IPRSR). The subjects were evaluated using binaural auditory prostheses, which had their adjustments verified through measurements with a probe microphone. All measurements were obtained using auditory prostheses both without the activation of the NLFC (SC) and with the activation of the NLFC (CC). For the analysis of collected data, the subjects were distributed in two formats; in one study the 48 subjects comprised a sample, in the other, considering the results obtained in the DRs identification test, the subjects distributed themselves in Group A (24 elderly people without evidence of DRs) and Group B (14 elderly people with evidence of DRs). Results: in the first study, a statistically significant difference between LRSS and IPRSS obtained using auditory prostheses SC and CC was observed, the latter being those that provided the better results. In the S/R relationship and in the IPRSR there was no statistically significant difference observed between the use of auditory prostheses SC and CC. In the second study analyzing the results of group A and B separately, in both a statistically significant difference in performance between the IPRSS obtained using auditory prostheses SC and CC, the latter being those that provided the better results. There was no difference observed in IPRSR. Comparing the groups, one verifies that there was no statistically significant difference in performance in IPRSS SC, IPRSS CC, and in IPRSR CC. Yet, the IPRSR SC presented statistically significant difference between the groups, the best being the performance of Group B. Conclusion: in the first study, the general sample presented statistically significant improvement in the measurements obtained in silence using auditory prostheses with CNLF if compared to the auditory prostheses without NLFC. In noise, no difference in performance was verified with or without NLFC. In the second study, both the group of subjects without and the group with DRs obtained statistically significant improvement in performance, in silence, using auditory prostheses with NLFC, in noise, however, there was no difference. Comparing the groups with and without DRs, the only measure that presented a significant difference was that obtained in noise with auditory prostheses without NLFC, in which the group with DRs obtained better performance than the group without DRs. / Objetivo: avaliar e comparar o desempenho de idosos com perda auditiva de configuração descendente, considerando ainda a presença ou não de zonas mortas na cóclea (ZMC) em testes de reconhecimento de fala, no silêncio e no ruído, usando próteses auditivas sem e com a ativação do algoritmo de compressão não linear de frequências (CNLF). Material e método: o estudo apresenta caráter quantitativo, observacional, descritivo e transversal. Foram avaliados 48 sujeitos, sendo 33 homens e 15 mulheres, com idade entre 61 e 84 anos, perda auditiva de grau leve a moderado e configuração descendente, sem experiência com o uso de próteses auditivas. Para coleta dos dados, foi utilizado o teste Listas de Sentenças em Português (LSP), sendo pesquisados os Limiares de Reconhecimento de Sentenças no Silêncio (LRSS), relações sinal/ruído (S/R) e Índices Percentuais de Reconhecimento de Sentenças no Silêncio (IPRSS) e no ruído (IPRSR). Os sujeitos foram avaliados usando próteses auditivas de forma binaural, as quais tiveram seus ajustes verificados por meio de mensurações com microfone sonda. Todas as medidas foram obtidas com o uso de próteses auditivas sem a ativação da CNLF (SC) e com próteses auditivas com a CNLF ativada (CC). Para análise dos dados, os sujeitos foram distribuídos de duas formas: em um estudo os 48 sujeitos compuseram a amostra; em outro, considerando os resultados obtidos no teste para identificação de ZMC, distribuíram-se os sujeitos em Grupo A (24 idosos sem indícios de ZMC) e Grupo B (14 idosos com indícios de ZMC). Resultados: considerando a amostra geral, foi observada diferença estatisticamente significante entre os LRSS e IPRSS obtidos usando próteses auditivas SC e CC, sendo as últimas as que proporcionaram melhores resultados. Na relação S/R e IPRSR, não foi observada diferença estatisticamente significante entre o uso de próteses auditivas SC e CC. Analisando-se separadamente os resultados do grupo A e B, em ambos observou-se diferença estatisticamente significante de desempenho entre os IPRSS obtidos usando próteses auditivas SC e CC, sendo as últimas as que proporcionaram melhores resultados. Não foi observada diferença no IPRSR. Comparando-se os grupos A e B, verificou-se que não houve diferença estatisticamente significante de desempenho no IPRSS SC, no IPRSS CC e no IPRSR CC. Já o IPRSR SC apresentou diferença estatisticamente significante entre os grupos, sendo o melhor o desempenho do grupo B. Conclusão: Considerando-se a amostra geral, no silêncio, as próteses auditivas CC proporcionaram maiores benefícios do que as SC. No ruído, o reconhecimento de fala foi semelhante com o uso de próteses auditivas SC e CC. Considerando-se a presença de ZMC, no silêncio, tanto no grupo de idosos sem quanto no com ZMC, o uso de próteses auditivas CC apresentou tendência a proporcionar maiores benefícios do que as SC. No ruído, os resultados foram semelhantes nas condições SC e CC em ambos os grupos. Comparando-se os grupos sem e com ZMC, a única medida que apresentou diferença significante foi a obtida no ruído com próteses auditivas CC, na qual o grupo com ZMC obteve desempenho melhor do que o sem ZMC.
75

INTERFERÊNCIA BINAURAL E ADAPTAÇÃO DE PRÓTESES AUDITIVAS EM PERDAS AUDITIVAS SIMÉTRICAS / BINAURAL INTERFERENCE AND ADAPTATION TO HEARING AIDS INSYMMETRICAL HEARING LOSS

Azevedo, Milena Manoel de 18 September 2013 (has links)
Purpose: To investigate the occurrence of binaural interference. To investigate the mono or binaural use of hearing aids and the complaints of speech comprehension in silence and noise.To evaluate the speech recognition with and without the use of mono and binaural hearing aids and the auditory processing skills.To correlate the obtained results in different tests. To evaluate the recognition of sentences in silence and noise by elderly individuals with symmetrical hearing loss, users of hearing aids with mono and binaural adaptation, and to investigate in which of both situations it may be verified the best performance in conditions that simulate daily communication situations. Material and Method: The evaluated subjects were 25 men and 13 women, with ages between 60 and 89 years old, with sensorineural hearing loss from mild to moderate severe level, symmetrical configuration, users of hearing aids with binaural indication. It was researched the Percentage Index of Speech Recognition (PISR) in both ears (BE) and it was performed the Dichotic Digits Test (DDT) of divided and directed attention, and the Portuguese Sentence List test (PSL). It was also studied the sentence recognition threshold in quiet (SRTQ) and in noise (SRTN) and the percentual indexes of sentence recognition in quiet environment and under noise (PISRQ and PISRN), with binaural adaptation (BA) and monaural in the right ear (RE) and in the left ear (LE). Results: Among the evaluated individuals, 31 (81.58%) referred that they use binaural hearing aids, 19 subjects (50%) reported they have never had difficulties to understand speech in silent places and 17 (44.75%) answered sometimes. 22 (57.89%) referred difficulties to recognize speech in noisy places, sometimes and 15 (39.47%) said it always happened. The obtained average values for the PISR were 72.95% in BE, 59.26% in the RE and 60.53% in the LE, respectively. The obtained averages in the DDT were 54.58% in BE, 65.16% in the RE and 71.95% in the LE. Regarding the PISRQ data, they were 79.63% in BE, 74.79% in the RE and 72.40% in the LE. The correlation of the PISR, DDT and PISRQ, the PISR and the PSL tend to present similar values. About analyzes into silence and into noise with binaural and monaural adaptation, the average values for PISRQ were 80.89% in BE, 76.33% in the RE and 71.16% in the LE, respectively. The obtained averages for PISRN were 62.05% in BE, 60.52% in the RE and 60.33% in the LE. Conclusion: It was found in an individual, the presence of binaural interference. Most elderly people used binaural hearing aids; only one individual did not present complaints of speech comprehension into noise. The PISR showed better performance in binaural condition; the DDT may not be the most proper option to be used in elderly patients with hearing loss; the PISR and the PSL tend to present similar values. The sentence recognition by the evaluated subjects presented better performance with the binaural adaptation, as into silence as into noise. However, that difference was not statistically significant. / Objetivo:Investigar a ocorrência da interferência binaural. Investigar o uso mono ou binaural das próteses auditivas e as queixas de compreensão de fala no silêncio e no ruído. Avaliar o reconhecimento de fala com e sem uso de próteses auditivas mono e binaural e habilidades do processamento auditivo. Correlacionar os resultados obtidos nos diferentes testes. Avaliar o reconhecimento de sentenças no silêncio e no ruído, de indivíduos idosos com perdas auditivas simétricas, usuários de próteses auditivas com adaptação mono e binaural, investigando em qual das duas situações pode ser verificado o melhor desempenho em condições que simulam situações de comunicação do diaadia. Material e método: Foram avaliados 38 sujeitos, sendo 25 homens e 13 mulheres, com idade entre 60 e 89 anos, perda auditiva neurossensorial de grau leve a moderadamente severo, de configuração simétrica, usuários de próteses auditivascom indicação binaural. Foi pesquisado o Índice Percentual de Reconhecimento de Fala (IPRF) em ambas as orelhas (AO) e realizados dois testes: oTeste Dicótico de Dígitos (TDD) atenção dividida e direcionada e o teste Listas de Sentenças em Português (LSP). Pesquisou-se aindaos Limiares de Reconhecimento de Sentenças no Silêncio e no Ruído (LRSS e LRSR) e Índice Percentual de Reconhecimento de Sentenças no Silêncio e no ruído (IPRSS e IPRSR), com adaptação binaural (AO) e monoaural orelha direita (OD) e orelha esquerda (OE). Resultados:Entre os indivíduos avaliados, 31(81,58%) relataram fazer uso binaural das próteses auditivas, 19 (50%) relataram nunca ter dificuldade de compreender a fala no silêncio e 17(44,75%) às vezes. 22 (57,89%) referiram dificuldade para reconhecer a fala no ruído, às vezes e 15 (39,47%) sempre. Os valores médios obtidos para os IPRF foram de 72,95% em AO, 59,26% na OD e 60,53% na OE, respectivamente. As médias obtidas do TDD foram 54,58% em AO, 65,16% na OD e 71,95% OE. Quanto aos dados do IPRSS, foram de 79,63% em AO, 74,79% na OD e 72,40% na OE. A correlação das variáveis IPRF, TDD e IPRSS, o IPRF e o LSP tendem a apresentar resultados semelhantes. Em relação às análises no silêncio e no ruído com adaptação binaural e monoaural, os valores médios obtidos para os IPRSS foram de 80,89% em AO, 76,33% na OD e 71,16% na OE, respectivamente. Já as médias obtidas do IPRSR foram 62,05 % em AO, 60,52% na OD e 60,33%OE. Conclusão:Foi encontrado em um indivíduo indícios da presença de interferência binaural. A grande maioria dos idosos fazia uso binaural das próteses auditivas.Somente um indivíduo não apresentou queixa de compreensão de fala no ruído. O IPRF demonstrou melhor desempenho na condição binaural. O TDD evidenciou pior desempenho na tarefa de integração binaural. Já no LSP não foi encontrada diferença estatisticamente significante entre o desempenho mono e binaural. O teste TDD pode não ser a opção mais adequada para ser utilizado em pacientes idosos com perda auditiva; já o IPRF e o LSP tendem a apresentar resultados semelhantes. O reconhecimento de sentenças dos sujeitos avaliados mostrou melhor desempenho com a adaptação binaural, tanto no silêncio como no ruído. Entretanto, essa diferença não foi estatisticamente significante.
76

The knowledge and attitude of pediatricians regarding the diagnosis and intervention of infants and children with a sensorineural hearing loss

Slabbert, Erna 08 December 2005 (has links)
The pediatric audiology landscape changed dramatically with the advances in screening and diagnostic procedures, amplification possibilities and early identification outcomes. Pediatricians play a key role in this rapidly developing field. The aim of this study was to investigate Pediatricians’ knowledge and attitudes regarding the diagnosis and intervention of infants and children with a sensorineural hearing loss. A questionnaire was compiled to obtain the relevant empirical data. This was distributed to 257 pediatricians in the Gauteng Province. Of the 257 questionnaires only 47 could be utilised. According to the results obtained from the pediatricians it appears that the respondents possess adequate knowledge regarding the diagnosis and intervention of infants and children with sensorineural hearing loss. This is despite having received limited or no information and training on this subject. As is discussed in Chapter 4 it became evident that knowledge gaps were found to exist. The pediatrician is an important team member of the hearing intervention team. Their involvement is crucial and their referral can be the important stepping-stone for early identification and intervention. A lack of skills and proficient knowledge is a major constraint during the implementation of efficient primary health care services in developing countries. Throughout the results of this study, it is found that pediatricians have a need for additional information and training in the intervention process of infants and children with sensorineural hearing loss, therefore showing a positive attitude towards continuous education. This is based on the results found throughout the study, in terms of a void in certain areas surrounding effective intervention of hearing loss. The aim of the study was to highlight areas of uncertainty that the respondents might experience and to provide educational programmes in order to equip them with the relevant knowledge with regards to sensorineural hearing loss. The findings of this study would hopefully encourage future research and a more in-depth study regarding this topic. / Dissertation (M (Communication Pathology))--University of Pretoria, 2006. / Speech-Language Pathology and Audiology / Unrestricted
77

Avaliação do trauma intracoclear causado pela inserção do feixe de eletrodos do implante coclear via fossa média em ossos temporais / Evaluation of intra cochlear trauma after cochlear implant electrode insertion through a middle fossa approach in temporal bones

Cisneros Lesser, Juan Carlos 01 February 2017 (has links)
Introdução: O acesso pela via da fossa craniana média para colocação do implante coclear provou ser uma alternativa valiosa em pacientes com otite média crônica e cavidades de mastoidectomia instáveis, cócleas parcialmente ossificadas e em alguns casos de displasia do ouvido interno. Até hoje não existem pesquisas que descrevam se a inserção do feixe de eletrodos pela via da fossa média pode ser feita com um mínimo de traumatismo intracoclear, comparável ao observado nas inserções pela janela redonda. Objetivo: Avaliar o trauma intracoclear com dois modelos distintos de implante quando o feixe de eletrodos é inserido por cocleostomia na fossa craniana média em ossos temporais. Método: 20 ossos temporais retirados antes de 24 horas pós-óbito, foram implantados através do local da cocleostomia no giro basal da cóclea identificado no assoalho da fossa cerebral média. Dez peças receberam um implante reto e dez um pré-curvado, e foram fixadas em resina epóxi. Foi realizada tomografia computadorizada para determinar a colocação adequada do feixe eletrodos, profundidade de inserção e a distância entre a janela redonda e a cocleostomia. Por último, as peças foram polidas em série, tingidas e visualizadas por estereomicroscópio para avaliar a posição do feixe e trauma intracoclear. Resultados: A tomografia mostrou um posicionamento intracoclear do feixe de eletrodos nas 20 peças. No grupo dos implantes retos a média de eletrodos inserido foi 12,3 (10 a 14) e dos pré-curvados 15,1 (14 a 16) com uma diferença significativa (U=78, p=0,0001). A mediana de profundidade de inserção foi maior para o eletrodo pré-curvado (14,5mm) que para o reto (12,5mm) com diferenças estatisticamente significativas (U = 66, p = 0,021). Só uma das 20 inserções foi atraumática e 70% tiveram graus de trauma altos (grau 3 ou 4). Não foram observadas diferenças significativas do grau de trauma entre os dois tipos de feixes nem quando as inserções foram no sentido da janela redonda, comparado com o sentido do giro médio. Conclusões: A técnica cirúrgica utilizada permitiu a inserção do feixe de eletrodos na cóclea em todas as peças, porém sem garantir uma inserção na escala timpânica e com alto risco de trauma nas microestruturas da cóclea / Introduction: In recent years, a middle fossa approach has been described for the insertion of cochlear implants, and it proved to be a reliable alternative for implantation in patients with chronic supurative otitis media, unstable mastoid cavities with recurrent otorrhea, partially ossified cochlea and in some cases of inner ear dysplasia. Until now, no research has been done to describe if this approach allows for anatomic preservation and non-traumatic insertions comparable to those through the round window. Objective: To evaluate cochlear trauma when the cochlear implant electrode is inserted through a middle fossa approach by means of histologic and imaging studies in temporal bones. Methods: 20 temporal bones retrieved before 24 hours after death were implanted through a middle cranial fossa cochleostomy in the basal turn of the cochlea. Ten received a straight electrode and 10 a perimodiolar electrode. After reducing the bone size with preservation of the inner ear structures, the temporal bones were fixed, dehydrated and embedded in an epoxy resin. CT scans were performed to determine if an adequate direction of insertion was attained, the depth of insertion and the distance between the cochleostomy and the round window. At last, the samples were polished by micro-grinding technique and microscopically visualized to evaluate intracochlear trauma. Results: The CT-scan showed an adequate intracoclear position of the electrode in all the samples. In the straight electrode group the average number of inserted electrodes was 12.3 (10 to 14) against 15.1 (14- 16) for the perimodiolar (U=78, p=0.0001). The median depth of insertion was significantly larger for the perimodiolar electrode group (14.4mm vs. 12.5mm U=66, p = 0.021). Only one atraumatic insertion was achieved and 70% of the samples had important trauma (grades 3 and 4). No differences were identified for the trauma grades between the two groups of electrodes. Also, there were no differences in trauma if the cochlear implants were inserted in the direction of the basal turn of the cochlea or in the direction of the middle and apical turns. Conclusions: The surgical technique that was used allowed for a proper intracochlear insertion of the electrodes in all 20 temporal bones but it does not guarantee a correct scala tympani position and carries high trauma risk for the intracochlear microstructures
78

Avaliação do trauma intracoclear causado pela inserção do feixe de eletrodos do implante coclear via fossa média em ossos temporais / Evaluation of intra cochlear trauma after cochlear implant electrode insertion through a middle fossa approach in temporal bones

Juan Carlos Cisneros Lesser 01 February 2017 (has links)
Introdução: O acesso pela via da fossa craniana média para colocação do implante coclear provou ser uma alternativa valiosa em pacientes com otite média crônica e cavidades de mastoidectomia instáveis, cócleas parcialmente ossificadas e em alguns casos de displasia do ouvido interno. Até hoje não existem pesquisas que descrevam se a inserção do feixe de eletrodos pela via da fossa média pode ser feita com um mínimo de traumatismo intracoclear, comparável ao observado nas inserções pela janela redonda. Objetivo: Avaliar o trauma intracoclear com dois modelos distintos de implante quando o feixe de eletrodos é inserido por cocleostomia na fossa craniana média em ossos temporais. Método: 20 ossos temporais retirados antes de 24 horas pós-óbito, foram implantados através do local da cocleostomia no giro basal da cóclea identificado no assoalho da fossa cerebral média. Dez peças receberam um implante reto e dez um pré-curvado, e foram fixadas em resina epóxi. Foi realizada tomografia computadorizada para determinar a colocação adequada do feixe eletrodos, profundidade de inserção e a distância entre a janela redonda e a cocleostomia. Por último, as peças foram polidas em série, tingidas e visualizadas por estereomicroscópio para avaliar a posição do feixe e trauma intracoclear. Resultados: A tomografia mostrou um posicionamento intracoclear do feixe de eletrodos nas 20 peças. No grupo dos implantes retos a média de eletrodos inserido foi 12,3 (10 a 14) e dos pré-curvados 15,1 (14 a 16) com uma diferença significativa (U=78, p=0,0001). A mediana de profundidade de inserção foi maior para o eletrodo pré-curvado (14,5mm) que para o reto (12,5mm) com diferenças estatisticamente significativas (U = 66, p = 0,021). Só uma das 20 inserções foi atraumática e 70% tiveram graus de trauma altos (grau 3 ou 4). Não foram observadas diferenças significativas do grau de trauma entre os dois tipos de feixes nem quando as inserções foram no sentido da janela redonda, comparado com o sentido do giro médio. Conclusões: A técnica cirúrgica utilizada permitiu a inserção do feixe de eletrodos na cóclea em todas as peças, porém sem garantir uma inserção na escala timpânica e com alto risco de trauma nas microestruturas da cóclea / Introduction: In recent years, a middle fossa approach has been described for the insertion of cochlear implants, and it proved to be a reliable alternative for implantation in patients with chronic supurative otitis media, unstable mastoid cavities with recurrent otorrhea, partially ossified cochlea and in some cases of inner ear dysplasia. Until now, no research has been done to describe if this approach allows for anatomic preservation and non-traumatic insertions comparable to those through the round window. Objective: To evaluate cochlear trauma when the cochlear implant electrode is inserted through a middle fossa approach by means of histologic and imaging studies in temporal bones. Methods: 20 temporal bones retrieved before 24 hours after death were implanted through a middle cranial fossa cochleostomy in the basal turn of the cochlea. Ten received a straight electrode and 10 a perimodiolar electrode. After reducing the bone size with preservation of the inner ear structures, the temporal bones were fixed, dehydrated and embedded in an epoxy resin. CT scans were performed to determine if an adequate direction of insertion was attained, the depth of insertion and the distance between the cochleostomy and the round window. At last, the samples were polished by micro-grinding technique and microscopically visualized to evaluate intracochlear trauma. Results: The CT-scan showed an adequate intracoclear position of the electrode in all the samples. In the straight electrode group the average number of inserted electrodes was 12.3 (10 to 14) against 15.1 (14- 16) for the perimodiolar (U=78, p=0.0001). The median depth of insertion was significantly larger for the perimodiolar electrode group (14.4mm vs. 12.5mm U=66, p = 0.021). Only one atraumatic insertion was achieved and 70% of the samples had important trauma (grades 3 and 4). No differences were identified for the trauma grades between the two groups of electrodes. Also, there were no differences in trauma if the cochlear implants were inserted in the direction of the basal turn of the cochlea or in the direction of the middle and apical turns. Conclusions: The surgical technique that was used allowed for a proper intracochlear insertion of the electrodes in all 20 temporal bones but it does not guarantee a correct scala tympani position and carries high trauma risk for the intracochlear microstructures
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Vestibular Evoked Myogenic Potentials: Preliminary Report

Akin, Faith W., Murnane, Owen 01 January 2001 (has links) (PDF)
Vestibular evoked myogenic potentials (VEMPs) are short-latency electromyograms evoked by high-level acoustic stimuli recorded from surface electrodes over the tonically contracted sternocleidomastoid (SCM) muscle. These responses are presumed to originate in the saccule. The purpose of this preliminary report is to provide an overview of our initial experience with the VEMP by describing the responses obtained in five subjects. Click-evoked VEMPs were present at short latencies in two normal-hearing subjects, one patient with profound congenital sensorineural hearing loss, and one patient with a severe sensorineural hearing loss due to Meniere's disease. Additionally, VEMPs were absent in a patient with profound sensorineural hearing loss following removal of a cerebellopontine angle tumor. The amplitude of the VEMP was influenced by the amount of background activity of the SCM muscle, stimulus level, and stimulus frequency. Tone-burst evoked responses showed an inverse relationship between stimulus frequency and response latency. VEMPs may prove to be a reliable technique in the clinical assessment of vestibular function.
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Σύνδρομο αποφολίδωσης και νευροαισθητήρια απώλεια ακοής

Παπαδόπουλος, Θεόδωρος-Αθανάσιος 10 August 2011 (has links)
Η παρούσα προοπτική ελεγχόμενη κλινική μελέτη διεξήχθη για να ερευνήσει τη συσχέτιση του συνδρόμου αποφολίδωσης με τη νευροαισθητήρια απώλεια ακοής. Τα άτομα της ομάδας μελέτης εμφάνιζαν το σύνδρομο στον ένα ή αμφοτέρους τους οφθαλμούς, ενώ τα άτομα της ομάδας ελέγχου δεν εμφάνιζαν το σύνδρομο σε κανένα οφθαλμό. Κριτήρια αποκλεισμού από τη μελέτη ήταν: προηγηθείσα ωτολογική επέμβαση, οξείες ή χρόνιες ωτολογικές παθήσεις, τραύμα κεφαλής ή ωτός, έκθεση σε θόρυβο, λήψη ωτοτοξικών φαρμάκων, λοίμωξη ανωτέρου αναπνευστικού συστήματος, γλαύκωμα, οφθαλμική υπερτονία και διάφορες συστηματικές παθήσεις. Οι συμμετέχοντες υπεβλήθησαν σε μέτρηση οπτικής οξύτητας, βιομικροσκόπηση, τονομέτρηση, γωνιοσκοπία, βυθοσκόπηση μετά από μυδρίαση, εξέταση οπτικών πεδίων, επισκόπηση και ψηλάφηση ώτων, ωτοσκόπηση, εξέταση ρινοφάρυγγα, εξέταση με τονοδότες και ακοομετρία καθαρών τόνων. Κατά την ακοομετρία υπολογίστηκε για κάθε ους ο ουδός ακοής, για την αέρινη και την οστέινη αγωγή, στις συχνότητες των 0.25, 0.5, 1, 2, 4 και 8kHz. Συνολικά έλαβαν μέρος στη μελέτη 69 άτομα (47 στην ομάδα μελέτης και 22 στην ομάδα ελέγχου). Η μέση ηλικία των συμμετεχόντων ήταν 74,7 ετών και στις δύο ομάδες. Δεν υπήρξαν στατιστικά σημαντικές διαφορές στην κατανομή ηλικιών και φύλων ανάμεσα στις δύο ομάδες. Σε όλους τους εξετασθέντες οι ουδοί ακοής αέρινης και οστέινης αγωγής ήταν ταυτόσημοι για κάθε συχνότητα, γεγονός που υποδήλωνε αμιγή νευροαισθητήρια απώλεια ακοής ή φυσιολογική ακοή. Δεν προέκυψαν κλινικά σημαντικές διαφορές, μεταξύ ουδών ακοής δεξιού και αριστερού ωτός, σε κανένα άτομο. Τα άτομα της ομάδας μελέτης, σε σύγκριση με εκείνα της ομάδας ελέγχου, παρουσίασαν: Α) Σημαντικά υψηλότερα ποσοστά επιπολασμού απώλειας ακοής στις συχνότητες των 1, 2, 4 και 8kHz. Β) Σημαντικά υψηλότερους μέσους ουδούς ακοής και σοβαρότερη απώλεια ακοής στις συχνότητες των 4 και 8kHz. Η μεγαλύτερη διαφορά στη σύγκριση των μέσων ουδών ακοής παρατηρήθηκε στα 8kHz. Τα ανωτέρω αποτελέσματα συνηγορούν υπέρ πολλαπλής συσχέτισης του συνδρόμου αποφολίδωσης με τη νευροαισθητήρια απώλεια ακοής και αφενός επιβεβαιώνουν μαρτυρίες από προηγούμενες έρευνες, αφετέρου παρέχουν ένα εντελώς νέο εύρημα που είναι η στατιστικά σημαντική επίδραση του συνδρόμου στη σοβαρότητα απώλειας ακοής στις υψηλές συχνότητες. Σε σύγκριση με προηγούμενες μελέτες, η παρούσα μελέτη πλεονεκτεί διότι η διερεύνηση της επίδρασης του συνδρόμου στον επιπολασμό και στη σοβαρότητα απώλειας ακοής έγινε με πιο αναλυτική διαδικασία, ετέθησαν λεπτομερέστερα κριτήρια αποκλεισμού υποψηφίων, o ακοομετρικός έλεγχος αφορούσε σε μεγαλύτερο αριθμό συχνοτήτων και αποκλείστηκαν γλαυκωματικοί ασθενείς, ώστε η σχέση μεταξύ συνδρόμου αποφολίδωσης και απώλειας ακοής να εξεταστεί με πιο αντικειμενικό τρόπο. Τα ευρήματα της παρούσας μελέτης επαληθεύουν τη θεωρία ότι το σύνδρομο αποφολίδωσης δεν αποτελεί μόνο οφθαλμολογική πάθηση, αλλά συστηματική διαταραχή με πολυάριθμες επιπλοκές, μία εκ των οποίων αφορά το έσω ους. Συνεπώς, στους ασθενείς με σύνδρομο αποφολίδωσης, εκτός από την οφθαλμολογική εξέταση, συνιστάται η εκτίμηση της ακουστικής ικανότητας με ακοομετρική δοκιμασία. / The present prospective case control clinical study was conducted to investigate the relationship between exfoliation syndrome and sensorineural hearing loss. Study group subjects manifested the syndrome in one or both eyes, whereas control group subjects didn’t manifest the syndrome in either eye. Exclusion criteria from the study were: previous ear surgery, acute or chronic ear diseases, ear or head trauma, noise exposure, oto-toxic drug intake, upper respiratory system infection, glaucoma, ocular hypertension and various systemic diseases. All participants underwent visual acuity measurement, biomicroscopy, tonometry, gonioscopy, dilated fundoscopy, visual field testing, ear inspection and palpation, otoscopy, nasopharyngeal examination, tuning fork testing and pure-tone audiometry. During audiometry the hearing threshold was calculated for every ear, using air and bone conduction, at frequencies of 0.25, 0.5, 1, 2, 4 and 8kHz. A total of 69 subjects participated in the study (47 in study group and 22 in control group). Mean age of participants was 74.7 years in both groups. Differences in age and gender distribution between the two groups were not statistically significant. Hearing thresholds were identical for both air and bone conduction, in all examined subjects at each frequency, signifying pure sensorineural hearing loss or normal hearing. No clinically significant differences were found, between hearing thresholds of left and right ear, in any subject. Compared to control group, study group subjects displayed: A) Significantly higher prevalence rates of hearing loss at frequencies of 1, 2, 4 and 8kHz. B) Significantly higher mean hearing thresholds and more severe hearing loss at frequencies of 4 and 8kHz. The greatest difference in the comparison of mean hearing thresholds was observed at 8kHz. The above results advocate for a multiple association between exfoliation syndrome and sensorineural hearing loss and on the one hand support evidence from previous research, on the other hand provide a totally new finding, that is the statistically significant effect of the syndrome on severity of hearing loss at high frequencies. Compared to previous studies, the present study has advantages because the syndrome effect on prevalence and severity of hearing loss was investigated in a more thorough manner, the candidate exclusion criteria were more detailed, audiometric testing involved a greater number of frequencies and glaucomatous patients were excluded, in order the relationship between exfoliation syndrome and hearing loss to be examined in a more objective way. The findings of the present study verify the theory that exfoliation syndrome is not only an ocular disease, but also a systemic disorder with numerous complications, one of which concerns the inner ear. Consequently, in patients with exfoliation syndrome, besides the ophthalmologic examination, an assessment of hearing ability with audiometric testing is recommended.

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