A neuropatia/dessincronia auditiva é caracterizada pelo funcionamento coclear normal, evidenciado pela presença das emissões otoacústicas e/ou do microfonismo coclear associado à ausência dos potenciais evocados auditivos de tronco encefálico. Este estudo teve por objetivo avaliar a função coclear e neural em indivíduos com o diagnóstico de neuropatia/dessincronia auditiva através da eletrococleografia extratimpânica. Dezoito crianças foram estudadas, sendo divididas em dois grupos: grupo controle (n = 7) formado por crianças, com idade média de 7 anos, com sistema auditivo periférico normal e grupo estudo (n = 11) formado por crianças com idade média de 3 anos, com emissões otoacústicas presentes, reflexos acústicos e potencial evocado auditivo de tronco encefálico ausentes. A eletrococleografia extratimpânica foi aplicada em ambos os grupos, utilizando para registrar os potenciais elétricos um eletrodo de conduto auditivo externo, modelo TIPtrode. O estímulo utilizado para pesquisa do microfonismo coclear foi o tone burst de 2000Hz e, para a pesquisa dos potenciais de ação e de somação foi utilizado o click. Ambos os estímulos foram aplicados nas polaridades rarefação e condensação. Vinte e seis orelhas foram analisadas, sendo 10 orelhas do grupo controle e 16 orelhas do grupo estudo. Os resultados de ambos os grupos foram analisados em relação à amplitude, início, término e duração do microfonismo coclear e à ocorrência do potencial de ação e do potencial de somação. Após análise estatística dos resultados, observou-se que os dois grupos, quando comparados entre si, apresentaram resultados semelhantes em relação à amplitude do microfonismo coclear. O microfonismo coclear no grupo estudo teve início atrasado quando comparado ao grupo controle, mas sem diferença estatisticamente significante.Houve diferenças estatísticas p<0,001) em relação aos parâmetros de término e duração do microfonismo coclear. O grupo estudo apresentou tempo de término e de duração maiores que o grupo controle. O potencial de ação e o de somação foram ausentes em 100% do grupo estudo (n= 16 orelhas). Observou-se que o funcionamento do microfonismo coclear e dos potenciais de ação e de somação das crianças com neuropatia/dessincronia auditiva estava alterado quando comparado ao grupo controle. / The auditory neuropathy/auditory dys-synchrony is characterized by the normal cochlear functioning due to the presence of the otoacoustic emissions and/or of the cochlear microphonic associated to the absence of the auditory brainstem response. This study had as an objective to evaluate the cochlear and neural functions in individuals with the diagnosis of auditory neuropathy/auditory dys-synchrony through the extratympanic electrocochleography. Eighteen children were studied, having been divided into two groups: the control group (n = 7) formed by children averaging 7 years of age with normal peripheral auditory system and the study group (n = 11) formed by children averaging 3 years with present otoacoustic emissions, absent of the acoustic reflexes and the auditory brainstem response. The extratympanic electrocochleography was applied in both groups, using in order to register electrical potentials, an electrode of external ear canal, TIPtrode model. The stimulus used for research of cochlear microphonic was the tone burst of 2000Hz and the click was used for the research of action potentials and of the summation. Both stimuli were applied in the rarefaction and condensation polarities. Twenty-six ears were analyzed, being 10 from the control group and 16 from the study group. The results of both groups were analyzed in relation to the amplitude, beginning, ending and duration of the cochlear microphonic and to the occurrence of the action potentials and of the potential of summation. After statistical analysis of the results, it was observed that both groups, when compared among each other presented similar results in relation to the amplitude of the cochlear microphonic. The cochlear microphonic in the study group had a late beginning when compared to the control group, but with no significant statistical difference. There were statistical differences (p<0,001) in relation to the ending and duration parameters of the cochlear microphonic. The study group presented time of ending and duration higher than the control group. The action potentials and the summation were absent in 100% of the study group (n = 16 ears). It was observed that the cochlear microphonic functioning and the action potentials and the summation of the children with auditory neuropathy/auditory dyssynchrony were altered when compared to the control group.

Severe motor disabilities can render a person almost completely incapable of communication. Nevertheless, in many cases, the sensory systems are intact and the eye movements are still under good control. In these cases, one can use a device such as the Brain Response Interface (BRI) to command a remote control (e.g. room temperature, bed position), a word-processor, a speech synthesizer, and so on.

Τα τελευταία χρόνια, το πρόβλημα της απόκτησης και χρήσης ενός συστήματος ηλεκτροεγκεφαλογραφίας λόγω του υψηλού κόστους του έχει υπερπηδηθεί με την κυκλοφορία πολλών εναλλακτικών συστημάτων λιγότερων δαπανηρών. Το πιο εξελιγμένο από αυτά του μικρού κόστους συστήματα είναι το Emotiv Epoc. Ένα επιπλέον πλεονέκτημα του Emotiv Epoc έναντι των συμβατικών συστημάτων ηλεκτροεγκεφαλογραφίας αποτελεί το γεγονός ότι είναι ασύρματο. Το γεγονός αυτό ανοίγει καινοτόμες οδούς στο πεδίο το νευροεπιστημών αφού δύναται η εκτέλεση πειραμάτων ευρέων εφαρμογών όπως π.χ. λήψη ηλεκτροεγκεφαλικών μετρήσεων εν κινήσει. Μια τέτοια εφαρμογή μπορεί επίσης να αποτελεί και η εκτέλεση πειραμάτων σε μικρά παιδιά στα οποία η καλωδίωση μπορεί να καταστεί πολύ δύσκολη. Με βάση λοιπόν τα παραπάνω, ένα τέτοιο σύστημα θα μπορούσε να χρησιμοποιηθεί με επιτυχία σε παιδία για έγκαιρη διάγνωση της δυσλεξίας η οποία κρίνεται επιβεβλημένη σε πολύ μικρές ηλικίες .Μειονέκτημα όμως ενός τέτοιου ασύρματου συστήματος θα μπορούσε να υποθέσει κανείς ότι είναι η αυξημένη παρουσία θορύβου. Ο θόρυβος αυτός θα μπορούσε να πηγάζει τόσο κατασκευαστικά ( αφού η πληροφορία καταγράφεται ασύρματα ) όσο και λόγω του γεγονότος ότι τέτοιου είδους πειράματα δεν λαμβάνουν χώρα σε μονωμένο ηλεκτρομαγνητικά περιβάλλον. Επιπρόσθετα, οι ηλεκτρονικοί υπολογιστές είναι απαραίτητοι προκειμένου να σχεδιαστεί και να εκτελεστεί ένα οποιοδήποτε πείραμα προκλητών δυναμικών και η αξιοπιστία τους ως ένα μεγάλο βαθμό εξαρτάται από αυτούς. Παρόλα αυτά, η πλειοψηφία των ηλεκτρονικών υπολογιστών λόγω του ότι η χρήση τους βρίσκει εφαρμογή σε μια πληθώρα εφαρμογών δεν καθίσταται δυνατό να παρέχει την χρονική ακρίβεια η οποία είναι απαραίτητη σε τέτοιου είδους πειράματα. Σκοπός της παρούσας διπλωματικής εργασίας είναι η διερεύνηση του κατά πόσο ένα τέτοιο σύστημα ασύρματης ηλεκτροεγκεφαλογραφίας όπως το Emotiv Epoc σε συνδυασμό με τους ηλεκτρονικούς υπολογιστές τους οποίους έχουμε στην διάθεση μας, μπορεί να χρησιμοποιηθεί σε πειράματα προκλητών δυναμικών σε άτομα με δυσλεξία για την ανάκτηση μετρήσεων μεγάλης ακρίβειας. / In recent years, the low-cost wireless EEG systems have become available, spurred by applications in the game industry. These systems offer a wider and more innovative range of options, for example EEG recordings while in motion and are easier to use so they are suitable for children and special populations. For example such systems can in principle be used for mass screening for early diagnosis of dyslexia, an application of tremendous importance for the individual and society. One of the most advanced such systems is the Emotiv Epoc. The wider and more innovative range of options that EEG systems like the Emotiv Epoc provide cannot however be applied to neuroscience experiments, before some technical limitations are overcome. One such drawback is the higher noise levels compared to clinical devices. The source of the noise could be a manufacturing issue (since the data are recorded wirelessly) or the fact that such experiments do not take place in an environment properly insulated from electromagnetic noise. Moreover, computers are necessary in order to design and execute a protocol for evoked response potentials (ERPs) experiments and the precision of the measurements and specifically issues of timing control depend critically on the computer hardware and software. In clinical and research systems specialized software and hardware for this purpose are available and they are the product of decades of highly specialized work. Very few such software exist today for research and clinical applications with wireless EEG systems in general although some simple tools are beginning to appear. The purpose of this thesis is to investigate whether a wireless EEG system like the Emotiv Epoc can be used with general-purpose computers to retrieve and record precise measurements in order to successfully conduct ERP experiments in general, focusing for the sake of an explicit example to an application for dyslexia, that is of interest to the host laboratory today.

[Truncated abstract] The cochlea presumably possesses a number of regulatory mechanisms to maintain cochlear sensitivity in the face of disturbances to its function. Evidence for such mechanisms can be found in the time-course of the recovery of CAP thresholds during experimental manipulations, and in observations of slow oscillations in cochlear micromechanics following exposure to low-frequency tones (the “bounce phenomenon”) and other perturbations. To increase our understanding of these oscillatory processes within the cochlea, and OHCs in particular, investigations into cochlear regulation were carried out using a combination of mathematical modelling of the ionic and mechanical interactions likely to exist within the OHCs, and electrophysiological experiments conducted in guinea pigs. The electrophysiological experiments consisted of electrocochleographic recordings and, in some cases, measurement of otoacoustic emissions, during a variety of experimental perturbations, including the application of force to the cochlear wall, exposure to very-low-frequency tones, injection of direct current into scala tympani, and intracochlear perfusions of artificial perilymph containing altered concentrations of potassium, sodium, and sucrose. To obtain a panoramic view of cochlear regulation under these conditions, software was written to enable the interleaved and near-simultaneous measurement of multiple indicators of cochlear function, including the compound action potential (CAP) threshold, amplitude and waveshape at multiple frequencies, the OHC transfer curves derived from low-frequency cochlear microphonic (CM) waveforms, distortion-product otoacoustic emissions (DPOAEs), the spectrum of the round-window neural noise (SNN), and the endocochlear potential (EP). ... The mathematical model we have developed provided a physiologically-plausible and internally-consistent explanation for the time-courses of the cochlear changes observed during a number of different perturbations. We show that much of the oscillatory behaviour within the cochlea is consistent with underlying oscillations in cytosolic calcium concentration. We conclude that a number of the discrepancies between the simulation results and the experimental data can be resolved if the cytosolic calcium functions as two distinct pools: one which controls basolateral permeability and one which controls slow motility. This two-calcium-pool model is discussed.

Thesis (Ph.D.)--James Madison University, 2010. / Includes bibliographical references.

A neuropatia/dessincronia auditiva é caracterizada pelo funcionamento coclear normal, evidenciado pela presença das emissões otoacústicas e/ou do microfonismo coclear associado à ausência dos potenciais evocados auditivos de tronco encefálico. Este estudo teve por objetivo avaliar a função coclear e neural em indivíduos com o diagnóstico de neuropatia/dessincronia auditiva através da eletrococleografia extratimpânica. Dezoito crianças foram estudadas, sendo divididas em dois grupos: grupo controle (n = 7) formado por crianças, com idade média de 7 anos, com sistema auditivo periférico normal e grupo estudo (n = 11) formado por crianças com idade média de 3 anos, com emissões otoacústicas presentes, reflexos acústicos e potencial evocado auditivo de tronco encefálico ausentes. A eletrococleografia extratimpânica foi aplicada em ambos os grupos, utilizando para registrar os potenciais elétricos um eletrodo de conduto auditivo externo, modelo TIPtrode. O estímulo utilizado para pesquisa do microfonismo coclear foi o tone burst de 2000Hz e, para a pesquisa dos potenciais de ação e de somação foi utilizado o click. Ambos os estímulos foram aplicados nas polaridades rarefação e condensação. Vinte e seis orelhas foram analisadas, sendo 10 orelhas do grupo controle e 16 orelhas do grupo estudo. Os resultados de ambos os grupos foram analisados em relação à amplitude, início, término e duração do microfonismo coclear e à ocorrência do potencial de ação e do potencial de somação. Após análise estatística dos resultados, observou-se que os dois grupos, quando comparados entre si, apresentaram resultados semelhantes em relação à amplitude do microfonismo coclear. O microfonismo coclear no grupo estudo teve início atrasado quando comparado ao grupo controle, mas sem diferença estatisticamente significante.Houve diferenças estatísticas p<0,001) em relação aos parâmetros de término e duração do microfonismo coclear. O grupo estudo apresentou tempo de término e de duração maiores que o grupo controle. O potencial de ação e o de somação foram ausentes em 100% do grupo estudo (n= 16 orelhas). Observou-se que o funcionamento do microfonismo coclear e dos potenciais de ação e de somação das crianças com neuropatia/dessincronia auditiva estava alterado quando comparado ao grupo controle. / The auditory neuropathy/auditory dys-synchrony is characterized by the normal cochlear functioning due to the presence of the otoacoustic emissions and/or of the cochlear microphonic associated to the absence of the auditory brainstem response. This study had as an objective to evaluate the cochlear and neural functions in individuals with the diagnosis of auditory neuropathy/auditory dys-synchrony through the extratympanic electrocochleography. Eighteen children were studied, having been divided into two groups: the control group (n = 7) formed by children averaging 7 years of age with normal peripheral auditory system and the study group (n = 11) formed by children averaging 3 years with present otoacoustic emissions, absent of the acoustic reflexes and the auditory brainstem response. The extratympanic electrocochleography was applied in both groups, using in order to register electrical potentials, an electrode of external ear canal, TIPtrode model. The stimulus used for research of cochlear microphonic was the tone burst of 2000Hz and the click was used for the research of action potentials and of the summation. Both stimuli were applied in the rarefaction and condensation polarities. Twenty-six ears were analyzed, being 10 from the control group and 16 from the study group. The results of both groups were analyzed in relation to the amplitude, beginning, ending and duration of the cochlear microphonic and to the occurrence of the action potentials and of the potential of summation. After statistical analysis of the results, it was observed that both groups, when compared among each other presented similar results in relation to the amplitude of the cochlear microphonic. The cochlear microphonic in the study group had a late beginning when compared to the control group, but with no significant statistical difference. There were statistical differences (p<0,001) in relation to the ending and duration parameters of the cochlear microphonic. The study group presented time of ending and duration higher than the control group. The action potentials and the summation were absent in 100% of the study group (n = 16 ears). It was observed that the cochlear microphonic functioning and the action potentials and the summation of the children with auditory neuropathy/auditory dyssynchrony were altered when compared to the control group.

O diagnóstico precoce da perda auditiva tem sido cada vez mais freqüente em virtude dos programas de saúde auditiva que estão sendo implantados em todo o país. Existe, contudo, a necessidade de técnicas e procedimentos que ajudem a identificar, com maior precisão, a presença e o grau da mesma. A Resposta Auditiva de Estado Estável (RAEE) é um procedimento eletrofisiológico que, ao contrário do Potencial Evocado Auditivo de Tronco Encefálico (PEATE) realizado com estímulo tone burst, possibilita avaliar, ao mesmo tempo limiares auditivos com especificidade por freqüência e por orelha, reduzindo assim o tempo do exame. Além disso, ele permite a estimulação até níveis próximos a 130 dBHL, podendo assim medir a audição residual. O objetivo deste estudo foi verificar a aplicabilidade da RAEE para determinar os limiares auditivos nos diferentes graus de perda auditiva neurossensorial. Foram avaliados 65 indivíduos com perda auditiva neurossensorial, sendo que 48 apresentaram alteração neurossensorial (coclear) de grau leve até profundo, e idades entre sete e 30 anos; e 17 apresentaram alteração neurossensorial (Neuropatia Auditiva/Dessincronia Auditiva) e idades entre 0,6 e cinco anos. A avaliação foi composta por Audiometria Tonal Liminar (ATL) e pesquisa da RAEE para o grupo com alteração neurossensorial (coclear) e somente a pesquisa da RAEE para o grupo com alteração neurossensorial (NA/DA). Os resultados demonstraram que, nos indivíduos com perda auditiva neurossensorial (coclear), houve associação significante (p<0,01) entre os limiares obtidos na ATL e RAEE para as freqüências de 0,5 a 4 kHz, ocorrendo uma maior concordância para graus de deficiências auditivas mais acentuadas. Já na perda auditiva neurossensorial (NA/DA), a RAEE mostrou ausência de resposta na maioria dos indivíduos avaliados. Concluímos que a RAEE pode predizer os limiares da ATL com maior precisão para os graus de perda auditiva mais acentuados, e que a utilização deste procedimento não mostrou informações adicionais que podem contribuir para o diagnóstico da perda auditiva neurossensorial (NA/DA). / The diagnosis of hearing loss in the first months of life has been increasingly frequent due to hearing health programs established throughout the country. Thus, techniques and procedures should be developed for accurate identification of the presence and severity of hearing loss, in a population whose motor and cognitive development does not allow response to behavioral methods. The auditory steady state response (ASSR) is an electrophysiological procedure which, different from the brainstem evoked response audiometry (BERA) conducted with tone burst stimuli, allows the establishment of hearing thresholds at multiple frequencies and for both ears, thus reducing the examination time. Moreover, it allows measurement of residual hearing due to the possibility of stimulation at levels close to 130 dBHL. Therefore, the present study aimed to investigate the applicability of ASSR for establishment of hearing thresholds in different severities of sensorineural hearing loss. A total of 65 individuals with sensorineural hearing loss were evaluated, among whom 48 presented mild to deep sensorineural disorder (cochlear), at the age range 7 to 30 years; and 17 presented sensorineural disorder (neuropathy/hearing dyssynchrony) aged 0.6 to 5 years. The evaluation comprised pure-tone threshold audiometry (PTTA) and ASSR analysis for the group with deep sensorineural disorder (cochlear) and only ASSR analysis for the group with sensorineural disorder (neuropathy/hearing dyssynchrony). The results demonstrated that, for individuals with deep sensorineural hearing loss (cochlear), there was significant association (p<0.01) between the thresholds obtained by PTTA and ASSR at frequencies from 0.5 to 4 kHz, with higher agreement in cases with more severe hearing loss. On the other hand, for the sensorineural hearing loss (neuropathy/hearing dyssynchrony), the ASSR was absent in most individuals analyzed. It was concluded that there is significant association between the thresholds obtained by PTTA and ASSR, and that the utilization of this procedure did not provide additional information that might contribute to the diagnosis of sensorineural hearing loss (neuropathy/hearing dyssynchrony), when compared to BERA

Previous studies have found that behavioral and P300 responses to speech are influenced by linguistic cues in the stimuli. Research has found conflicting data regarding the influence of phonemic characteristics of stimuli in the mismatch negativity (MMN) response. The current investigation is a replication of the study designed by Tampas et al. (2005), which studied the effects of linguistic cues on the MMN response. This current study was designed to determine whether the MMN response is influenced by phonetic or purely acoustic stimuli, and to expand our knowledge of the scalp distribution of processing responses to within- and across-category speech and nonspeech stimuli. The stimuli used in this study consisted of within-category synthetic speech stimuli and corresponding nonspeech frequency glides. Participants consisted of 21 (11 male and 10 female) adults between the ages of 18 and 30 years. A same/different discrimination task was administered to all participants. Data from behavioral responses and event-related potentials (MMN and P300) were recorded. Results provided additional evidence that the MMN response is influenced by linguistic information. MMN responses elicited by the nonspeech contrasts had more negative peak amplitudes and longer latencies than MMN responses elicited by speech contrasts. Brain maps of t scores for speech vs. nonspeech contrasts showed significant differences in areas of cognitive processing for all contrast pairs over the left hemisphere near the temporal and parietal areas. The present investigation confirms that there are significant differences in the cortical processing of speech sounds vs. nonspeech sounds.

Made available in DSpace on 2016-04-27T18:12:40Z (GMT). No. of bitstreams: 1 Jenny Andrea Agurto Cea.pdf: 1275724 bytes, checksum: 78ad5db17a86b6b6ad07d074ae7768e4 (MD5) Previous issue date: 2009-02-19 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Introduction Conventional (ABR) or automatic (AABR) auditory brain responses is an electrophysiological method used in auditory screening, mainly in newborns with hearing loss risk indicators. Studies indicate that click stimulus used in auditory steady state response (ASSR) can quickly detect the presence of response at low intensities as well as can simultaneously stimulate both ears. The procedure could then be useful in newborn auditory screening (NAS). Objective To describe and to compare the results of pass and refer as well as the duration of the hearing screening in infants by the use of ABR, AABR and ASSR with click stimulus techniques at 30 and 35dBHL intensities. Methods Once referred from public hospitals for hearing screening, 30 infants with hearing loss risk indicators aging from 10 to 97 days were evaluated. ASSR and ABR techniques were performed at 30 and 35dBHL intensities. The AABR one was held at 35dBHL. In ASSR 11 infants underwent binaural stimulation and 19 infants, the mononaural one. Those who failed could be reevaluated. The duration of each of the techniques was also analysed. Results The AABR technique showed that 28 (93.3%) infants passed in both ears and 2 (6.7%) had bilaterally failed. The meantime of test duration was nearly 1.8 minutes for right ear(RE) and 2.1 minutes for left Ear (LE). For ABR at 30dBHL , 27 (90%) subjects passed in both ears, 2 (6.7%) failed bilaterally and only 1 (3.3%) failed unilaterally. At 35dBHL, 26 (86.7%) passed in both ears, 2 (6.7%) failed unilaterally and 2 (6.7%) failed bilaterally. The meantime of test duration was nearly 2.4 minutes for each ear, at both intensities. For ASSR at 30dBHL, 26 (86.6%) infants passed in both ears and 4 (13.3%) failed unilaterally. The average test duration in monoaural evaluation was nearly 2.3 minutes in RE and 2.5 minutes in LE. In binaural evaluation the average duration was 3.1 minutes. At 35dBHL, 25 (83.3%) infants passed in both ears and 5 (16.7%) failed unilaterally. For RE evaluation the average duration was 2.2 minutes and for LE it was 2.1 minutes. When performed the binaural test, the average duration was 3.7 minutes. At 30 dBHL, results suggest agreement for both tests. As to the duration, no significant difference was detected between ABR and ASSR values. At 35dBHL most individuals showed concordant results when compared in twos. In duration assessment the lowest mean and median values were observed in AABR test and the highest in ASSR binaural. Most subjects who passed in ASSR were evaluated only once. There was no association between the results and gestational age at both intensities. Conclusion There was a clear agreement between ABR and ASSR results at 30dBHL; AABR and ABR techniques showed strong concordant results at 35dBHL and no significant differences were detected among the three techniques as to the test duration. Additional investigations on ASSR in NAS are needed so that the technique can be improvingly adjusted / Introdução O potencial evocado auditivo de tronco encefálico (PEATE) convencional ou automático é um método eletrofisiológico aplicado na triagem auditiva, principalmente em neonatos com indicadores de risco para perda auditiva (IRPA). Estudos apontam que o estímulo clique utilizado no potencial evocado auditivo de estado estável (PEAEE) detecta de forma rápida a presença de resposta nas intensidades fracas, podendo estimular ambas as orelhas simultaneamente. Trata-se de um procedimento que pode ser útil na triagem auditiva neonatal (TAN). Objetivo Descrever e comparar os resultados de passa e falha, assim como a duração da triagem auditiva em lactentes com a utilização do PEATE, PEATE-A e PEAEE - clique nas intensidades de 30 e 35 dBNA. Método Foram avaliados 30 lactentes com IRPA encaminhados de hospitais públicos para realizar a triagem auditiva. As técnicas realizadas foram PEATE e PEAEE- clique nas intensidades de 30 e 35 dB NA. O PEATE-A foi realizado em 35dBNA. No PEAEE - clique onze lactentes realizaram a estimulação binaural e dezenove, monoaural. Aqueles que falhavam poderiam ser avaliados mais de uma vez. Foi realizada a análise da duração de cada técnica. Resultados Foram avaliados 30 lactentes com idade entre 10 e 97 dias. Os resultados encontrados no PEATE-A foram: 28(93,3%) lactentes passaram em ambas as orelhas e dois (6,7%) falharam bilateralmente. O tempo médio de duração do teste foi de, aproximadamente, 1.8 min. para a OD e 2.1 min. para a OE. No PEATE na intensidade de 30dBNA 27 lactentes (90%) passaram em ambas as orelhas; dois lactentes (6,7%) falharam bilateralmente e apenas um (3,3%) falhou unilateralmente. Na intensidade de 35dBNA 26 (86,7%) passaram em ambas as orelhas; dois (6,7%) falharam unilateralmente e dois (6,7%) falharam bilateralmente. O tempo médio de duração foi de, aproximadamente, 2.4 min. para cada orelha nas duas intensidades. No PEAEE - clique em 30dBNA 26 (86,6%) passaram em ambas as orelhas e quatro (13,3%) falharam unilateralmente. O tempo médio de duração do teste na avaliação monoaural foi de, aproximadamente, 2.3 min. na OD e 2.5 min. na OE. Na avaliação binaural o tempo médio foi de 3.1 min. Em 35dBNA os resultados encontrados foram: 25 (83,3%) lactentes passaram em ambas as orelhas; cinco (16,7%) falharam unilateralmente. Para a avaliação na OD o tempo médio foi de 2.2 min., e para a OE, de 2.1 min. Quando realizado o teste de forma binaural, o tempo foi de 3.7 min. Em 30dBNA os resultados sugerem concordância nos dois testes. Em relação ao tempo médio não foi detectada diferença significativa entre o PEATE e PEAEE - clique. Na intensidade de 35dBNA, na maioria dos indivíduos, ocorreu concordância de resultado nos testes quando comparados dois a dois. Na análise da duração os menores valores médios e medianos foram observados no PEATE-A, e os maiores no PEAEE - clique binaural. A maioria dos sujeitos que passaram no PEAEE - clique realizou a avaliação apenas uma vez. Não houve associação entre os resultados e a idade gestacional nas duas intensidades. Conclusão Houve concordância nos resultados em 30 dBNA para PEATE e PEAEE - clique; o PEATE-A e o PEATE apresentaram forte concordância em seus resultados na intensidade de 35 dBNA; não houve diferença significativa em relação à análise de duração de tempo das três técnicas estudadas. São necessários mais estudos com PEAEE - clique na TAN para que possam ser realizados ajustes nessa técnica

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.