Made available in DSpace on 2016-04-27T18:11:56Z (GMT). No. of bitstreams: 1 Taise Argolo Sena.pdf: 595972 bytes, checksum: 7693a80adc39a593cccdae56ded0102f (MD5) Previous issue date: 2012-02-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Introduction: The Automated Auditory Brainstem Response (AABR) is an important tool to make Newborn Hearing Screening. However, some aspects that make it more difficult to exam, like time and intensity of acoustic stimulus, must be taken into consideration. Aim: Analyze the results of Newborn Hearing Screening with Automated Auditory Brainstem Response with new technologies that use the detection method in the frequency domain and stimulus repetition rate at 93Hz. Methodology: The Automated Auditory Brainstem Response was made at 200 newborns (93 female and 107 male), at 30 and 35dBnHL. Subsequently all newborns were submitted to the Auditory Brainstem Response (ABR) Diagnostic Mode, as golden standard test. Results: The sensibility and specificity were calculated through Fisher Exact Test taken into consideration the ABR Diagnostic Mode. The sensibility found at AABR at 35dBnNA was 100% and the specificity was 100%, at the intensity of 30dBnNA the sensibility found was 100% and the specificity was 97.23%. The average time to make the automated exam was 28.3 seconds in the 35 dBnHL and 32.9 seconds in the 30 dBnHL. The time was analyzed considering the state of consciousness of the newborn, based on the Brazelton Scale classification. It was possible to notice that when the newborn was quieter the examination time was quicker. Conclusion: The AABR made at frequency domain with stimulus repetition rate at 93Hz shows high sensibility and specificity, with relative short time to get the results. The state of consciousness influences the execution time of the exam. / Introdução: O Potencial Evocado Auditivo de Tronco Encefálico Automático (PEATE-A) é uma ferramenta importante para realização da Triagem Auditiva Neonatal. Entretanto, alguns aspectos que dificultam a realização do exame, como o tempo e a intensidade do estímulo acústico, devem ser levados em consideração. Objetivos: Analisar os resultados da Triagem Auditiva Neonatal com Potencial Evocado Auditivo de Tronco Encefálico Automático, com novas tecnologias que utilizam método de detecção no domínio da frequência e taxa de repetição do estímulo a 93Hz. Metodologia: O Potencial Evocado Auditivo de Tronco Encefálico Automático foi realizado em 200 neonatos (93 do sexo feminino e 107 do masculino), nas intensidades de 30 e 35dBnNA. Em seguida, todos os neonatos foram submetidos ao exame de Potencial Evocado Auditivo de Tronco Encefálico (PEATE) Modo Diagnóstico, como teste padrão ouro. Resultados: A sensibilidade e especificidade foram calculadas por meio do Teste Exato de Fisher, levando em consideração o resultado do PEATE Modo Diagnóstico. A sensibilidade encontrada para o PEATE-A na intensidade de 35dBnNA foi de 100% e a especificidade de 100%; para a intensidade de 30dBnNA a sensibilidade encontrada foi de 100% e a especificidade, de 97,23%. O tempo médio de realização do exame automático foi de 28,3 segundos para a intensidade de 35 dBnNA e de 32,9 segundos para a intensidade de 30dBnNA. O tempo também foi analisado de acordo com o estado de consciência do neonato, conforme a classificação da Escala de Brazelton. Foi possível observar que quanto mais quieto o neonato, mais rápido o tempo de realização do exame. Conclusão: O PEATE-A realizado no domínio da frequência com taxa de repetição em 93Hz apresenta alta sensibilidade e especificidade, com tempo consideravelmente curto para a determinação da resposta. O estado de consciência influencia no tempo de execução do exame

Made available in DSpace on 2016-04-27T18:12:05Z (GMT). No. of bitstreams: 1 Raquel Alves Nobre.pdf: 1069573 bytes, checksum: b8d1295a1b5de37c7e8a3aac4652d769 (MD5) Previous issue date: 2014-09-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Universal Newborn Hearing Screening (UNSH) aims to provide early diagnosis in newborns. The procedure uses objective measures such as the Transient Evoked Otoacustic Emissions (TEOAEs) and the Auditory Brainstem Response (ABR). Different stages and protocols are broadly used in TANU, and that may change the values of passes and fails of each program. Purpose: To study the rate of passes and fails in the protocols and stages that are used at TANU, which were performed using electroacoustic (TEOAEs) and electrophysiological (ABR) procedures through an integrative review. Methods: Type of study: An integrative review. Search strategy: The following databases were examined: PubMed, SciELO and SCOPUS.Criteria for selecting the readings: Articles that have evaluated at least a minimum of 1,000 newborns; specifying the time (hours of life of the newborn) in which the test was accomplished; articles specifying how many days later the retest was performed after the hospital discharge, if the infant failed the test; in the article´s methodology the tests that were used and its stages must be included. The method of choice should be: TEOAEs test and retest in newborns with no risk; TEOAEs in conjunction with ABR and ABR in the retest in newborns with no risk and ABR on the test and retest in newborns with a risk factor; the results should present the pass and fail results of each step, such as the diagnosis result. Results: A total of 3950 references were found in English, Portuguese and Spanish. After removing duplicated studies (300), 3650 references were obtained, that were analyzed through titles and summaries. Of this total, 3500 were excluded for being researches with different topics. Hereby, 15 filled all the inclusion criteria. The final rates of pass and fail found in the studied protocols were the following: for the TEOAEs test/retest protocol the pass rate varied from 99,53% to 97,39% and the fail rate from 2,41% to 0,44%. In the TEOAEs and ABR test protocol and in the ABR retest the pass results ranged from 99,84% to 98% and fail from 0,35% to 0,16%. And in the ABR test/retest protocol in newborns with risk factors the pass rate was reached from 98,62% to 92,74% and the fail rate from 1,7% to 1,38%. All the pass and fail rates are within of what is recommended by literature. Conclusion: The protocol that presented the smaller number of false positives was the TEOAEs combined with the ABR in the test and ABR in retest. The findings indicate that the probability of fail for the TEOAEs in the test and retest is larger than the TEOAEs and ABR in the test and ABR in retest, both for the newborns screened until 24 hours of life and for the newborns screened between 25 and 72 hours of life / A Triagem Auditiva Neonatal Universal (TANU) tem como objetivo realizar o diagnóstico precoce em neonatos. A sua realização utiliza medidas, como as emissões otoacústicas evocadas por estímulo transiente (EOAET) e o potencial evocado auditivo de tronco encefálico (PEATE). Diferentes etapas e protocolos são utilizados na TANU, o que pode alterar os índices de passa e falha de cada programa. Objetivo: Estudar os resultados de índice de passa-falha dos protocolos e etapas utilizados na TANU, realizada com procedimentos eletroacústicos (EOAET) e eletrofisiolóficos (PEATE) por meio de uma revisão integrativa. Método: Tipo de estudo: Revisão integrativa Estratégia de busca: Foram pesquisadas as seguintes bases de dados: PUBMED, SCieLO e SCOPUS. Critério para a seleção dos estudos: artigos que avaliaram um número mínimo de 1000 neonatos; artigos que especificaram as horas de vida do neonato em que foi realizado o teste; artigos que especificaram quantos dias depois da alta hospitalar foi realizado o reteste, caso o neonato falhasse no teste; no método, deveriam constar quais os testes utilizados e suas etapas. Neste caso, os testes utilizados deveriam ser: EOAET no teste e no reteste em neonatos sem risco; EOAET combinado com PEATE no teste e PEATE no reteste em neonatos sem risco e PEATE no teste e no reteste em neonatos com risco; os estudos deveriam apresentar o resultado de passa e falha de cada etapa, assim como o resultado do diagnóstico. Resultados: Foi identificado um total de 3950 referências no idioma inglês, português e espanhol. Após a remoção dos estudos duplicados (300), foram obtidas 3650 referências, que foram analisadas por meio dos títulos e dos resumos. Deste total, 3500 foram excluídos por se tratarem de pesquisas com outro tema. Desta forma, 150 estudos foram selecionados, na íntegra. Deste total, 15 preencheram todos os critérios de inclusão. Os índices de passa e falha final encontrados nos protocolos estudados foi de: para o protocolo EOAET no teste e reteste, o índice de passa variou de 99,53 a 97,39% e falha de 2,41% a 0,44%. No protocolo de EOAET combinado com PEATE no teste, e PEATE no reteste foi de passa em 99,84% a 98%, e falha de 0,35% a 0,16%. No protocolo PEATE no teste e reteste em neonatos com risco o índice de passa foi de 98,62% e 92,74% e falha de 1,7% e 1,38%. Todos os índices de passa e falha estão dentro do que é recomendado pela literatura. Conclusão: O protocolo que apresentou menor número de falso-positivo foi o EOAET combinado com PEATE no teste, e PEATE no reteste. Os resultados mostram que a probabilidade de falha para protocolo- EOAET no teste e reteste é maior do que para o protocolo- EOAET combinado com PEATE no teste, e PEATE no reteste, tanto para o neonatos triados até 24 horas de vida, quanto para o grupo de neonatos triados entre 25 e 72 horas

No description available.

<p>Topical treatment of several inner ear diseases through the round window membrane (RWM) might be feasible in the near future. Bacteria toxins, ototoxic drugs and noise trauma seem to harm the inner ear by a common pathway which involves, excessive outflow of the afferent neurotransmitter glutamate and formation of nitric oxide (NO), which can severely damage cells/nerve endings and lead to cell death.</p><p>In this study we used 98 Sprague-Dawley rats and seven human temporal bones. Various substances were instilled into the middle ear of the rat, such as Pseudomonas Aeruginosa Exotoxin (PaExoA), gentamicin, NO-inhibitor N-Omega-Nitro-L-Arginine Methyl Ester (L-NAME), and glucocorticoids. The effects of the substances were studied by morphological analysis of RWM and the endolymphatic sac (ES) by light and electron microscopic. Hearing level was measured in the rats by ABR technique. The human temporal bones were studied immunomorphologically to search for glutamate.</p><p>In the human inner ear, glutamate receptors and glutamine synthetase, were identified. In the rat, we found, following PaExoA exposure, reversible and permanent hearing loss and morphological changes in the RWM. The ES showed increased numbers of macrophages and thickening of the epithelia. When L-NAME was used as an otoprotector from gentamicin ototoxicity a therapeutic effect in the high frequency area was found. Hydrocortisone (but not dexamethasone) exposure of the RWM resulted in membrane thickening, and adjacent to the membrane, inflammatory cells.</p><p>The importance of the RWM as a portal for toxic substances and topical treatment of inner ear diseases was highlighted in this study. The difficulties of applying drugs in the round window niche were exposed. The results of this study add important knowledge concerning certain mechanisms of inner ear injury and help us to understand possibilities and problems of local treatment of inner ear diseases in patients.</p>

Topical treatment of several inner ear diseases through the round window membrane (RWM) might be feasible in the near future. Bacteria toxins, ototoxic drugs and noise trauma seem to harm the inner ear by a common pathway which involves, excessive outflow of the afferent neurotransmitter glutamate and formation of nitric oxide (NO), which can severely damage cells/nerve endings and lead to cell death. In this study we used 98 Sprague-Dawley rats and seven human temporal bones. Various substances were instilled into the middle ear of the rat, such as Pseudomonas Aeruginosa Exotoxin (PaExoA), gentamicin, NO-inhibitor N-Omega-Nitro-L-Arginine Methyl Ester (L-NAME), and glucocorticoids. The effects of the substances were studied by morphological analysis of RWM and the endolymphatic sac (ES) by light and electron microscopic. Hearing level was measured in the rats by ABR technique. The human temporal bones were studied immunomorphologically to search for glutamate. In the human inner ear, glutamate receptors and glutamine synthetase, were identified. In the rat, we found, following PaExoA exposure, reversible and permanent hearing loss and morphological changes in the RWM. The ES showed increased numbers of macrophages and thickening of the epithelia. When L-NAME was used as an otoprotector from gentamicin ototoxicity a therapeutic effect in the high frequency area was found. Hydrocortisone (but not dexamethasone) exposure of the RWM resulted in membrane thickening, and adjacent to the membrane, inflammatory cells. The importance of the RWM as a portal for toxic substances and topical treatment of inner ear diseases was highlighted in this study. The difficulties of applying drugs in the round window niche were exposed. The results of this study add important knowledge concerning certain mechanisms of inner ear injury and help us to understand possibilities and problems of local treatment of inner ear diseases in patients.

Myringotomy plays an important role in otological therapy. The procedure requires an efficient anesthesia, which can be obtained without general anesthesia. However, the use of local anesthetics on the tympanic membrane (TM) has been abandoned in many places, as general anesthesia has been readily available. In the present study the effects of some commonly used topical anesthetics on the TM structure and inner ear were tested in an animal model (rat and guinea pig).Four different anesthetic compounds—Xylocaine®, Bonain's liquid, phenol and Emla®—were applied to the TMs of the animals, which were sacrificed 10 minutes to 5 months after application. Morphological effects regarding time after treatment and number of applications were elucidated. At sacrifice the tissue was fixed and the TMs analysed by light microscopy (LM) and transmission electron microscopy (TEM). In nine animals phenol, Xylocaine® Spray or Emla® was applied to the round window niche and ABR recordings were made at 24 h to 6 months after exposure. After the final ABR evaluation the animals were sacrificed and the cochleae prepared for LM and scanning electron microscopy (SEM).On the TM phenol and Bonain's liquid caused instant destruction of the keratinizing stratified squamous epithelium followed by long-lasting hyperplasia of this epithelium and the underlying connective tissue. A pronounced hyperplasia of these two layers was also noted for the Xylocaine® Spray group, but without immediate destruction of the keratinizing epithelium. The extent of structural changes differed in relation to the extent of spreading of the agent. Emla® showed little, if any, sign of epithelial reaction and had no effect on the connective tissue. Regarding the inner ear Emla®, Xylocaine® Spray and phenol induced significantly impaired ABR thresholds mainly affecting the higher frequencies. However, the impaired ABR thresholds were reversible and at the end of the experiment there was no significant impairment compared to the control data. All agents, except Xylocaine®, damaged the hair cells in the basal part of the cochlea as shown by cytocochleogram and SEM analysis.Instant destruction of the epidermis seems to be necessary for an instant anesthetic effect. All agents caused profound connective tissue reactions. The manner of application, depending on the physical properties of the agent, determined the extent of the structural changes. The changes of the connective tissue were concentrated to the submucosal layer, which seems to be the area for reconstruction of the damaged TM. All agents caused functional inner ear changes. With the exception of Xylocaine® they also caused morphological alterations of the cochlea. The functional changes were partly reversible. Topical anesthetics applied to the TM should be used with caution and when used in an appropriate manner they can be considered safe, especially in an inflamed middle ear, with a thickened round window membrane, which should prevent the agents from reaching the inner ear structures. / digitalisering@umu

Intratympanic injection of various otoprotectants through the round window membrane (RWM) might become available in the near future as an alternative to the currently available medical and surgical methods used to treat several inner ear diseases. The most common outcome of such diseases is sensorineural hearing loss (SNHL). Two examples of  these otoprotectants are Edaravone and Brain-Derived Neurotrophic Factor (BDNF), both of which have already proved effective against  noise-induced hair cell loss, barotrauma  and ototoxicity caused by cisplatin. In four different studies we used two electrophysiological methods, auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE), to study the effects of tobramycin and Pseudomonas aeruginosa exotoxin A (PaExoA) on the inner ears of 129 male Sprague-Dawley rats. In two investigations, not only the otoprotective effects of Edaravone on tobramycin-induced ABR threshold shifts and PaExoA-induced DPOAE  threshold changes, were studied but even different application times, in order to establish in which interval it was still possible to achieve effective otoprotection.We found that Edaravone gave otoprotection from tobramycin when injected simultaneously or within 7 days, but it had only a limited effect on the changes in DPOAE thresholds caused by PaExoA when injected 1, 2, or 4 hours after the exotoxin. The effect of BDNF on PaExoA-induced ABR threshold shifts was investigated in two studies, where different doses of intratympanically injected PaExoA were used and where BDNF was applied simultaneously, 12 or 72 hours efter exotoxin instillation. We found that BDNF had an otoprotective effect on SNHL induced by different doses PaExoA when injected simultaneously or with no more than 12 hours delay.

Professional research project (Au.D.)--University of SouthFlorida, 2002. / Title from PDF of title page. / Document formatted into pages; contains 22 pages. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: The purpose of this study was to determine the prevalence of the binaural interaction component (BIC) in a large sample of normal hearing adults, and to measure the absolute latency and amplitude of the BIC as a function of the click rate of the stimulus and the electrode montage. The BIC is obtained by subtracting the auditory evoked potential waveform obtained with binaural stimulation from the waveform obtained by adding the responses from the left and right monaural stimulation. The tested hypothesis was that the recordings of the BIC vary among normal hearing individuals, and BIC latency and amplitude values change as a function of stimulus rate. Studies of the BIC help to explain the neural correlates of some binaural processes, and to develop an electrophysiological index of binaural processes for objective clinical evaluations.Data was completed and analyzed on 47 adults between the ages of 20 and 41 (mean = 25) with hearing in the normal range (thresholds [ 20 dB HL at 500, 1000, 2000, and 4000 Hz in each ear) and no known neurological disorders. The results revealed a great variability in BIC morphology between subjects. The BIC waveforms were categorized into five distinct groups according to the number of positive and negative peaks present. Chi-square analyses revealed a significant relationship between click rate and BIC category; however, the relationship between recording montage and BIC category was insignificant. An Analysis of Variance (ANOVAs) revealed a significant increase in absolute latency and decrease in absolute amplitude of both negative and positive peaks as click rate increased from 7.7/s to 57.7/s. The results did not reveal a significant change in the type of BIC as an effect of electrode montage.In conclusion, the BIC within the binaural difference waveform may be obtained in the majority of young individuals with normal hearing. Specifically, a slower stimulus rate revealed more components of the waveform, as well as an improvement in the morphology of the BIC compared to a faster stimulus rate. As these findings may aid in the development of an electrophysiological index of binaural neural processes in young individuals with normal hearing, more research should be attempted in the study of BIC in other age groups and patients with different audiograms. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.

Methods for collecting behavioral audiograms are often time consuming and require trained, captive subjects. It is more practical to measure hearing sensitivity using electrophysiological methods, such as auditory evoked potential (AEP) testing, in which electrodes measure action potentials in response to acoustic stimuli. These data can be collected in a matter of hours. However, results should be verified through behavioral testing. Current knowledge of marine turtle auditory abilities is based on a few electrophysiological tests. The purpose of this study was to collect and compare behavioral and auditory evoked potential audiograms in a captive adult loggerhead turtle (Caretta caretta). The behavioral audiogram was collected using a go/no-go modified staircase method utilizing 2-second pure-tone stimuli. AEP thresholds were measured underwater using subdermal electrodes placed beneath the frontoparietal scale, dorsal to the midbrain. Action potentials were measured in response to 50 ms tonal stimuli and averaged over a maximum of 1,000 responses. Evoked potential testing yielded thresholds from 100 - 1131 Hz with peak sensitivity at 200 and 400 Hz (110 dB re 1 µPa). Behavioral testing yielded thresholds from 50 - 800 Hz with peak sensitivity at 100 Hz (98 dB re 1 µPa). Behavioral thresholds averaged 8 dB lower than AEP thresholds from 100 to 400 Hz and 5 dB higher at 800 Hz. Results indicate that behavioral and evoked potential techniques are suitable for determining marine turtle hearing sensitivity. AEP testing is a good alternative when dealing with wild or untrained animals and when time is a critical factor.

Many phenomena in the BAEP are difficult to explain on the basis of the accepted hypothesis of its origin (after Jewett, 1970). The alternative mechanism of origin to which these phenomena point is summation of oscillations. Therefore, simulation of the BAEP by a mathematical model consisting of the addition of four sine waves was tested. The model did simulate a normal BAEP as well variations in the waveform produced by reversing click polarity. This simulation gives further clues to the origin of the BAEP. The four sine waves begin simultaneously; corresponding BAEP oscillations must, therefore, originate from a single structure. These oscillations begin in less than half a millisecond after the click. This suggests that the structure from which they arise is outside the brainstem. This alternative mechanism indicates that wave latencies do not reflect nervous conduction between discrete nuclei, and interpretation of BAEP abnormality need to be reconsidered. It also implies that mathematical frequency analysis is more appropriate, but this could be applied only when these methods have been perfected. Meanwhile, through visual analysis and recognition of oscillations, abnormality can be detected and described in terms that may have physiological significance.