Os potenciais evocados auditivos de tronco encefálico (PEATE) são um instrumento clínico muito útil na avaliação da maturação das vias auditivas em crianças nascidas pré-termo. Objetivos: Observar a maturação da via auditiva pela análise PEATE em crianças nascidas prétermo em três idades (4, 12 e 20 meses de idade). Casuística e Método: Coorte, individual, observacional, comparativo e contemporâneo. O fator em estudo foi crianças nascidas pré-termo e o desfecho à observação da maturação da via auditiva neste grupo, pela análise PEATE, em três avaliações (aos 4, 12 e 20 meses de idade), precedido de avaliação otorrinolaringológica e audiológica com objetivo de garantir que não apresentavam alteração auditiva. Resultados: Ingressaram 73 crianças pré-termo. Não foi encontrada diferença estatística (P>0,05) na comparação dos resultados entre os gêneros, bem como interaural. Houve diferença estatiticamente significante entre idade gestacional, as latências absolutas e intervalos interpicos nas três avaliações realizadas, ocorrendo uma diminuição das latências com o aumento da idade. Verificamos que a maturação da onda I foi mais rápida, e a maturação da onda V foi mais lenta. Podemos perceber que a maturação da via auditiva até o tronco encefálico segue o sentido caudorostral, sendo a da via periférica mais precoce, e a da rostral, mais tardia. Conclusão: Com base nos achados deste estudo, recomendamos que a aplicação do procedimento de avaliação audiológica através do PEATE em crianças nascidas pré-termo, pelo menos até os 20 meses de idade, seja realizado levando-se em conta a idade gestacional a fim de se obter análises fidedignas. / Brainstem Auditory Evoked Potential (BAEP) is a very useful clinical instrument in the evaluation of the auditory pathways maturation in preterm children. Objective: To observe the maturation of the auditory pathway with the use of the BAEP analysis in preterm children at three different ages (four, 12 and 20 months). Casuistry and Method: Group, individual, observational, comparative and contemporary. Preterm children and the outcome to observation of the auditory pathway maturation by the BAEP analysis in three evaluations (at 4, 12 and 20 months of age) were studied. The procedures were preceded by otolaryngological and auditory evaluation with the objective to guarantee the non presence of auditory alteration. Results: Seventy-three preterm children participated in the study. Statistically significant difference was not found (P> 0,05) in the comparison between genders and between ears. There was a statistically significant difference among gestational ages, absolute latencies and interpic intervals in the three evaluations conducted, occurring a reduction of latencies with age increase. We verified that maturation of wave I was faster and the maturation of wave V was slower. We could perceive that the maturation of the auditory pathway up to the brainstem follows the caudorostral direction, being the peripheral pathway more precocious and the rostral pathway more delayed. Conclusion: Based on the findings of this study, we recommend the application of the audiological evaluation procedure using BAEP in preterm children, at least until 20 months of age, by taking into account the gestational age in order to obtain reliable analyses.

After the findings were reported for the Women’s Health Initiative (WHI) study in the past decade, there has been a significant decline in the overall use of hormone replacement therapy (HRT) among women. However, there are still millions of middle-aged, menopausal women in the U.S. who are currently undergoing hormone therapy. Their reasons for continuing treatment include relief of severe menopausal symptoms, aid in the management of osteoporosis and reduction in the risk of colon cancer (Ness et al., 2005). The purpose of the following investigation was to evaluate the impact of HRT on the central and peripheral auditory systems both during and after treatment. Over the course of the study, hormone treatments were administered to female aging CBA/CaJ mice to observe what effects estrogen (E) and progestin (P) have on the peripheral and central auditory systems. Female CBA/CaJ middle age mice were ovariectomized and placed into 4 HRT groups (E, P, E+P and Placebo [Pb]). Hormone treatment lasted 6 months followed by a recovery/washout period of 1 month. During this time, electrophysiology tests such as auditory brainstem responses (ABR) and ABR gap in noise (GIN) were used to measure neural activity for the auditory nerve and brainstem. Distortion product otoacoustic emission (DPOAE) testing was also implemented to assess the functional status of the outer hair cells (OHC) and their ability to amplify sound in the cochlea. After 6 months of treatment, animals treated with E exhibited the least amount of changes in ABR thresholds and ABR GIN amplitudes than any other subject groups. Interestingly, P animals exhibited an abrupt increase in ABR thresholds only 3 months after treatment; however, for ABR GIN amplitude levels a progressive reduction observed throughout the study. E+P and Pb animals showed signs of accelerated age-related hearing loss (ARHL) with significantly elevated ABR thresholds and dwindling ABR GIN amplitude levels. No significant signs of recovery were observed for any of the hormone groups. Therefore, in the present murine investigation, the effects of HRT were long lasting. To further expand on the results obtained for the electrophysiology tests, molecular biology experiments were performed to evaluate the expression of IGF-1R and FoxO3 in the cochlea during hormone therapy, from both in vitro and in vivo perspectives. Both genes play significant roles in the PI3K/AKT pathway and were specifically chosen because of their role in anti-apoptotic responses and cell survival. It was hypothesized that E attenuates the effects of ARHL via the PI3K/AKT pathway by up-regulating IGF-1R and FoxO3 to counteract the effects of oxidative stress in the aging mammalian cochlea. qPCR experiments were performed with stria vascularis (SV) lateral wall cells extracted from the cochlea of each animal in the hormone groups post-treatment (in vivo) and in SVK-1 cells treated with HRT over various lengths of time (in vitro) to evaluate the expression levels of IGF-1R and FoxO3. In-vivo experiments showed that the E-treated animals had significantly higher IG-1R levels compared to the other subject groups after treatment was discontinued. Similarly, IGF-1R levels steadily increased for E-treated SVK-1 cells over the course of hormone therapy, compared to P and E+P cells. FoxO3 expression, on the other hand, declined for all of the hormone-treated cells groups, relative to control SVK-1 cells (in vitro), and no statistical differences were detected for FoxO3 levels among the post-treatment animals (in vivo). These findings indicate that there is cross talk between E and IGF-1R involving the PI3K/AKT pathway, which contributes to the delayed onset of ARHL observed during HRT with E. Meanwhile, FoxO3 may not play a role in neuro-protective properties in the cochlea during HRT, as initially hypothesized.

Background: Iron deficiency, anemia, and iron excess have been associated with altered hearing functions in children and adults. Animal studies suggest that iron deficiency during pregnancy negatively affect fetal auditory development. The relationship between maternal iron status and auditory functions in healthy term newborns has not been clearly elucidated among humans. The goal of this pilot study was to determine the relationship between markers of iron status during pregnancy and brainstem auditory function in healthy neonates. Methods: Pregnant women who gave birth at the Montfort Hospital were recruited to take part in this study (n=6). Within two weeks after birth, their newborn’s hearing function was assessed by wave amplitude, latency and inter-latency from the Auditory Brainstem Response (ABR) test. Markers of iron status, namely hemoglobin (Hb) and mean corpuscular volume (MCV), were collected retrospectively for the first and second trimester from the women’s medical chart. Results: Overall, no significant relationship was observed between maternal Hb and MCV concentrations and newborns auditory function. Although two significant Spearman correlations were observed (MCV and inter-latency I-V; r=0.87; p=0.005 and Hb and amplitude V; r=0.89; p=0.04), these findings may be due to chance because of multiple testing and the small sample size. Conclusion: Although iron is a key nutrient involved in the brain and auditory system development, we were not able to demonstrate a relationship between iron status during pregnancy and newborn hearing function. Prospective or intervention studies with a larger sample size and with more specific iron markers (ex. ferritin) are required to confirm these findings.

Cette thèse porte sur la perception visuelle, auditive et audiovisuelle des voyelles nasales [ɑ̃] (« lent »),[ɔ̃] (« long ») et [ɛ̃] (« lin ») par des adultes devenus sourds, implantés cochléaires et implantés dutronc cérébral. L’étude sur la perception visuelle des voyelles, auprès de 22 adultes devenus sourds,redéfinit les sosies labiaux des voyelles nasales et propose une mise à jour de la classification desvisèmes. Trois études sur l’identification auditive des voyelles nasales auprès de 82, 15 et 10 adultesimplantés cochléaires mettent en évidence leur difficulté à reconnaitre les trois voyelles nasales, qu’ilsperçoivent comme des voyelles orales. Les analyses acoustiques et perceptives suggèrent que lesadultes implantés cochléaires s’appuient sur les informations fréquentielles des deux premiers picsspectraux mais négligent les informations d’intensité relative de ces pics. D’après l’étude menéeauprès de 13 adultes implantés du tronc cérébral, des informations acoustiques linguistiques sonttransmises par l’implant du tronc cérébral mais la fusion entre les informations auditives et visuellespourrait être optimisée pour l’identification des voyelles. Enfin, une enquête auprès de 179orthophonistes pointe le besoin d’une information sur la définition phonétique articulatoire actualiséedes voyelles [ɑ̃] et [ɛ̃]. / This thesis focuses on the visual, auditory and auditory-visual perception of french nasal vowels [ɑ̃](« lent »), [ɔ̃] (« long ») and [ɛ̃] (« lin ») by Cochlear Implant (CI) and Auditory Brainstem Implant(ABI) adults users. The study on visual perception of vowels, with 22 deafened adults, redefines thelip configuration of french nasal vowels and provides an update of the classification of vocalic visualphonemes. Three studies on auditory identification of nasal vowels with 82, 15 and 10 CI usershighlight their difficulty in recognizing the three nasal vowels, which they perceive as oral vowels.Acoustic and perceptual analyzes suggest that adults with CI rely on frequency informations of thefirst two spectral peaks but miss the informations of relative intensity of these peaks. The study with13 ABI users show that some linguistic acoustic cues are transmitted by the ABI but the fusion ofauditory and visual features could be optimized for the identification of vowels. Finally, a survey of179 Speech Language and Hearing Therapists show the need of an update on the phonetic articulationof french nasal vowels [ɑ̃] and [ɛ̃].

L’hyperacousie est définie comme une hypersensibilité aux sons d’intensité modérée. Il s’agit d’un trouble de la perception auditive qui a des répercussions néfastes sur la qualité de vie des patients. Un mécanisme impliquerait la modification du gain central des neurones auditifs centraux sous l'influence des régions cérébrales non auditives. Toutefois, la question de l'endroit où ces anomalies surviennent dans le système auditif reste ouverte, plus particulièrement lorsque l'hyperacousie survient sans perte auditive neurosensorielle. Nous avons utilisé un modèle animal d’hyperacousie réversible et sans perte audiométrique, induit par injection aigue de salicylate. Nous avons observé un raccourcissement significatif de la latence des ondes III et IV des PEA aux fréquences inférieures à 10 kHz corrélé à une diminution de 15 dB du seuil de réflexe de sursaut acoustique à basses fréquences. La diminution de l’efficacité du réflexe musculaire de l’oreille moyenne suite à l’injection de salicylate semble trop modérée pour expliquer l'hyperacousie, qui semble plutôt être causée par une altération du codage temporo-spatial de la sonie dans le tronc cérébral. L’hyperacousie fait partie des troubles de perception retrouvés dans la migraine, nous avons étudié les changements physiologiques auditifs dans un modèle animal de migraine induit par administration extradurale de soupe inflammatoire. Dans un contexte migraineux, aucun des paramètres modifiés par le salicylate n'est affecté de sorte que l'hypersensibilité au son est plutôt une phonophobie, réponse émotionnelle au son résultant d’une activation anormale du système limbique et du système nerveux autonome. / Hyperacusis is a disorder of loudness perception defined as decreased tolerance to ordinary environmental sounds that are felt as disagreeable, or even, unbearably painful. The idea that hyperacusis is underpinned by an increase in central auditory gain is now widely invoked. Besides, the neural bases of this gain abnormality remain unclear, as well as more generally the mechanisms of loudness perception. We used an animal model of reversible and hearing-loss-free hyperacusis induced by acute salicylate injection. We observed a significant shortening of the latency of ABR waves III and IV at frequencies below 10 kHz correlated to a 15 dB decrease of the threshold of acoustic startle reflex at low frequencies and without sensorineural hearing loss. The decreased effectiveness of middle ear muscle reflex following salicylate injection seems too moderate for explaining hyperacusis, which is more likely produced by impaired temporo-spatial loudness coding with a brainstem origin. Hyperacusis is one of the perceptual disorders found in migraine. We studied auditory physiological changes in an animal model of migraine induced by extradural administration of inflammatory soup. In a migraine context, none of the salicylate-induced changes was observed so that the reaction to sound is likely closer to phonophobia, an emotional response to sound resulting from abnormal activation of the limbic system and the autonomic nervous system.

No description available.

Schleiereulen sind gute Nachtjäger und finden ihre Beute vor allem durch den Hörsinn. Die auditorische Lokalisierung in der horizontalen Ebene basiert dabei auf interauralen Zeitdifferenzen. Diese werden im Hirnstamm durch das Netzwerk von nucleus magnocellularis (NM) und nucleus laminaris (NL) in Orte umkodiert. Im NL kann ein extrazelluläres Potential (EP), das Neurophonpotential (NP) gemessen werden. Dieses hat eine erstaunliche zeitliche Präzision von unter 10 Mikrosekunden, und spiegelt den für die Stimulation benutzten Ton bis zu Frequenzen von 9 kHz wider. Wie kann eine solche Präzision erzeugt werden, und was kann man über den Ursprung des Potentials in dieser neuronalen Struktur lernen? Um diese Fragen zu klären, studiere ich in vivo gemessene NPs. Dadurch kann in Zukunft die Verbindung von neuronaler Aktivität und EP besser verstanden werden. Hunderte neuronale Stromquellen, die alle kohärent mit einer hohen Feuerrate aktiv sind, sind nötig, um ein solches NP zu erzeugen. Dabei sind Anzahl und Stromstärke der Neuronen im NL nicht ausreichend, um das NP zu erzeugen. Der Hauptanteil der Quellen besteht aus den Signalen, die den Input des NL formen: die Ströme der Ranvierschen Schnürringe entlang der Axone aus dem NM, sowie die synaptischen Ströme zu den Dendriten von NL Neuronen. Weiterhin können NPs, die als Antwort auf monaurale Stimulierung aufgenommen wurden, linear addiert werden, um die Antwort auf binaurale Stimulation zuverlässig vorherzusagen. Leichte Abweichungen von der Vorhersage könnten damit erklärt werden, dass einzelne, sehr nah an der Elektrode befindliche Neurone nichtlinear zum NP beitragen. Im Gegensatz zu anderen bisher untersuchten neuronalen Strukturen - auch homologer Hirnregionen - spiegelt das NP der Schleiereule Eingangs- statt Ausgangssignale wider. Dieser strukturelle Unterschied könnte erklären, wieso das Schleiereulengehirn höhere Genauigkeit erreicht, als das anderer Tiere. / The barn owl is a good night hunter and mainly localizes the prey with its auditory system. The auditory localization in the horizontal plane, based on interaural time differences, depends on the auditory brainstem circuit consisting of nucleus magnocellularis (NM) and nucleus laminaris (NL). An extracellular field potential (EFP), named neurophonic, can be recorded in the NL. It has a very high temporal precision of below 10 microseconds and replays the stimulating sound up to 9 kHz. In this thesis I study how an EFP with such a precision can be generated. Furthermore, what can we learn about the system and about the origin of the neurophonic in NL from these recordings? The answers will help connecting the neural activity to the EFP also in general. Firstly, hundreds of sources, all firing with a high rate and in a highly phase-locked manner, are needed to generate the neurophonic in NL. The number of the neurons in NL and the magnitude of their output currents are not high enough to alone give rise to the neurophonic. The majority of the neural sources conveys the input from NM to NL, i.e., the currents from the nodes of Ranvier in the afferent axons from NM, and the synaptic currents to the dendrites of the NL neurons. Furthermore, the neurophonics in response to monaural stimulation sum up linearly and predict accurately the neurophonics in response to binaural stimulation. This implies that the non-linear response of the NL neurons usually cannot be detected in the neurophonic, but that there might be a minor contribution from a single NL neuron when in the immediate vicinity of the electrode. All in all, the neurophonic in the barn owl''s NL seems to reflect the inputs to the nucleus, whereas usually the output is well represented in the EFP. Even in the homologue nuclei in chick and mammals the neurophonic is thought to reflect the output instead of the input. Thus, the exceptionality of the barn owl might be needed for the high precision in its NL.

A pesquisa dos potenciais evocados auditivos de tronco encefálico (PEATE) foi indicada para os casos onde há suspeita ou presença de síndromes genéticas pelo Joint Committee on Infant Hearing em 2007. O comitê fornece as diretrizes para a detecção das perdas auditivas na infância, para as quais as síndromes são fator de risco. A alta prevalência da SD e de alterações auditivas nesta população reforça a importância da identificação das perdas auditivas até os três meses de idade, como forma de minimizar os decorrentes prejuízos na comunicação. Este estudo, aprovado pela Comissão de Ética para análise de projetos de pesquisa do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HCFMUSP), teve como objetivo descrever as avaliações da audição de 30 crianças com SD, sem queixas otológicas, das quais 25 bebês (idade média de 2,47 meses) compuseram a amostra. Método: Foram pesquisados os PEATE durante o sono natural. A amostra foi analisada por bebês e por orelhas. Os bebês e as orelhas foram agrupados por intensidade de limiar eletrofisiológico: G1 (<= 30 dBNA), G2 (30 | 40 dBNA), G3 (> 40 dBNA) e registradas as latências absolutas I, III e V e as inter-latências I-III, III-V e I-V. Resultado: Dos 25 bebês, 3 apresentaram alteração neurossensorial ao menos unilateral (12%), 5 alteração condutiva (20%) e 17 (68%) indicaram resultados normais ao PEATE. Limiares eletrofisiológicos foram encontrados em 76% (n=38) das orelhas estavam abaixo, e em 24% (n=12), acima de 40 dBNA. Os grupos G1 e G2 apresentaram respostas equivalentes exceto para a latência absoluta da onda V e inter-latência III-V, que estiveram encurtadas no G2 em relação ao G1 (p<0,02;p=0,04) Discussão: Vários autores sugerem maior ocorrência de alterações condutivas entre portadores de SD. A prevalência de alterações auditivas condutivas e neurossensoriais encontradas nos bebês neste estudo apontam para a importância da investigação da via auditiva até os três meses de idade. Conclusão: A perda auditiva é uma alteração frequente em bebês com SD. Ocorreram alterações tanto condutivas quanto neurossensoriais nas orelhas com limiar alterado. As alterações neurossensoriais encontradas neste estudo reforçam a importância da adoção de procedimentos preventivos de avaliação da audição em bebês com SD e consequente intervenção / Introduction: The study of evoked auditory brainstem response (ABR) was indicated for cases of genetic syndromes by the Joint Committee on Infant Hearing in 2007. These guidelines indicate the detection of hearing loss in the childhood, for which genetic syndromes are a risk factor. The high prevalence of DS and of hearing disorders in this population reinforces the importance of identifying hearing loss by 3 months of age, to minimize the losses arising in communication. The main objective of this study, approved by the Ethics Committee of University of São Paulo, School of Medicine, Clinical Hospital (HCFMUSP) was to characterize the hearing ability of 30 children with Down syndrome, of which 25 babies (mean age 2.47 months), with no history of ear disease, comprised the sample. Method: ABR test has been performed during natural sleep. The babies and the ears were put together in groups by threshold level: G1 (<= 30 dB HL), G2 (30 |40 dB HL), G3 (over 40 dB HL). Results: Out of 25 babies, 3 (12%) had sensory neural hearing disorder in at least one ear; 5 (20%) had conductive hearing disorder in at least one ear and 17 (68%) had normal results on the ABR. Electrophysiological thresholds under 40 dB HL have been obtained in 76% (n = 38) of tested ears under, and in 24% (n = 12) over 40 dB HL. Groups G1 and G2 have had similar response, except for III-V interval shortened in G2 when compared to G1. Discussion: Many authors suggest conductive losses are more frequent than sensory neural losses in this population. The prevalence of sensory neural hearing disorder found in these babies point to the importance of investigating the auditory pathway. The group with thresholds between 30 and 40 dB HL was similar to the normal group, except for shortening of interval III-V. Statistically significant differences were found between normal and abnormal in the ABR. Conclusion: Sensory neural losses found in this study reinforce the importance of adopting preventive procedures for evaluating the hearing and subsequent intervention

Introdução: O Acidente Vascular Cerebral do tipo isquêmico é um quadro clínico que afeta milhares de pessoas no mundo. Como resultado dessa injúria observamos morte neuronal, e no decorrer natural de recuperação, o indivíduo pode desenvolver a sepse. A sepse é uma resposta inflamatória sistêmica que pode levar o indivíduo a morte. No seu desenvolvimento há a produção de diversas citocinas que caracterizam o processo inflamatório no organismo. Para avaliar as condições clínicas de um paciente com esse quadro o Potencial Evocado Auditivo de Tronco Encefálico (PEATE) pode ser útil,uma vez que ele não é um procedimento invasivo, sua técnica é rápida e pode ser feita à beira do leito. Porém, por outro lado, o PEATE pode ser sensível ao uso de alguns anestésicos. Objetivos: Fazer análise das citocinas IL-6, IL-10 e TNF- no decorrer da sepse; verificar os valores de latência do PEATE em gerbils submetidos à isquemia e sepse; e verificar a influência do anestésico ketamina associado à xilazina nos valores do PEATE desses animais. Método: Foram coletados os PEATEs de 72 gerbils machos adultos que foram divididos em 6 grupos, a saber: controle, sepse, isquemia, sham, isquemia com sepse e sham com sepse. Para a indução de sepse foi aplicado Lipopolissacarídeo (LPS) intraperitoneal nos gerbils. Os animais foram anestesiados antes das coletas com ketamina associada à xilazina, seus PEATEs foram coletados antes de qualquer procedimento (coleta base), após isquemia e 2, 4, 8 e 24 horas após a aplicação de LPS. Foi avaliada a latência absoluta da onda V, e os valores foram comparados intra e intergrupos. As citocinas IL-6, IL-10 e TNF- foram analisadas e comparadas em cada grupo estudado. Resultados: Foi observado aumento das citocinas IL-6, IL-10 e TNF- no decorrer da sepse. Houve diferença estatisticamente significante nos grupos submetidos à sepse no valor da latência da onda V em relação aos demais grupos. Observou-se, também, aumento da latência da onda V após a aplicação sucessiva do anestésico ketamina/xilazina em todos os grupos estudados. Conclusão: Houve aumento dos níveis das citocinas IL-6, IL-10 e TNF- nos animais que sofreram aplicação de LPS, revelando uma alteração de expressão gênica de moléculas pró (IL-6 e TNF-) e anti-inflamatória (IL-10) no decorrer da sepse.O PEATE se mostrou sensível a sepse com aumento de latência da onda V no desenvolver da doença no modelo experimental utilizado. O uso de Ketamina associada à xilazina influenciou o resultado do PEATE, aumentando o valor de latência absoluta da onda V do PEATE / Introduction: The Cerebrovascular Accident of ischemic type is a clinical condition affecting thousands of people around the world. As a result of this injury we observe neuronal death, and along the natural course of recovery individuals may develop sepsis. Sepsis is a systemic inflammatory response that may lead to death. Along its development, several cytokines are produced that characterize the inflammatory process on the body. To assess the clinical conditions of a patient with this condition the Auditory Brainstem Response (ABR) may be useful, as it is not an invasive procedure, it is fast to perform, and may be done at the patients bedside. On the other hand, the ABR may be sensitive to the use of some anesthetics. Objectives: To perform an analysis of the IL-6, IL-10 and TNF- cytokines in the course of sepsis; to verify the ABR latency values in gerbils submitted to ischemia and sepsis; and to verify the influence of the ketamine/xylazine anesthetic on the ABR values in these animals. Method: ABRs were collected for 72 adult male gerbils divided into 6 groups, namely: control, sepsis, ischemia, sham, ischemia with sepsis and sham with sepsis. For induction of sepsis, intraperitoneal lipopolysaccharide (LPS) was injected into the gerbils. The animals were anesthetized prior to the collections with ketamine/xylazine, theirs ABRs were collected before any procedure (base collection), after ischemia and 2, 4, 8 and 24 hours after the LPS injection. The absolute latency of the V wave was assessed, and values were compared within and among groups. The IL-6, IL-10 and TNF- cytokines were analyzed and compared in each study group. Results: An increase was observed in IL-6, IL-10 and TNF- cytokines in the course of sepsis. There was a statistically significant difference in the groups submitted to sepsis in the value of the V wave latency compared to the other groups. An increase in the V wave latency was also observed after successive injection of the ketamine/xylazine anesthetic in all study groups. Conclusion: There was an increase in the levels of IL-6, IL-10 and TNF- cytokines in the animals injected with LPS, revealing a change of the gene expression of the pro- (IL-6 and TNF-) and anti-inflammatory (IL-10) molecules in the course of sepsis. The ABR proved to be sensitive to sepsis with an increase of the V wave latency in the course of the disease on the experimental model used. The use of ketamine/xylazine influenced the results of the ABR, increasing the absolute latency value for the V wave of the ABR

Made available in DSpace on 2016-04-27T18:11:55Z (GMT). No. of bitstreams: 1 Daniela Veronese Bento.pdf: 1507917 bytes, checksum: 505321b79ebbf90c862cd111179b4352 (MD5) Previous issue date: 2012-02-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / INTRPDUCTION: Many different rates for ABR can be used to sensitize the exam. However, due to possible differences that can occur in the latencies and amplitudes when using ABR, it is necessary to carry out research to support the audiological diagnosis and help the clinical decision-making process. AIM: To study the influences at the two different repetition stimulus rates in the ABR in adults, neonates and premature infants. METHOD: ten normal-hearing neonates (GI), adults (GII) and premature infants (GIII) were subjected to ABR registration by air with repetition rates from 27.7 to 61.1 clicks per second (intensities: 80, 60, 40 and 20 dBHL). RESULTS: The arithmetic means and medians showed adjacent values for each combination of repetition rate and groups, which suggests that the distribution of the variables shows symmetry. Nevertheless, at 80 dBHL, the repetition rate of 61.1 clicks per second attained an absolute latency in waves I, II and V augmented in the groups GI and GIII (P=0.003, P=0* and P=0, respectively) and the amplitude in waves III and V reduced in the GI and GII (P=0.014 and P=0*). Wave III had the most reduced amplitude with a rarefied polarity (P=0.014). Moreover, the latency time during interpeak intervals I-III were higher for GI and GIII (P=0.0035); during III-V were higher for GIII (P=0*) and during I-V were higher for GI (P=0*). At 60 dBHL, the latency was higher for GI and GIII, -at 61.1 clicks per second in the three groups (P=0+)-, and the amplitude was more reduced for GI and GII (P=0,001). At 40 dBHL, two repetition rates attained a higher latency and reduced amplitude for GI and GII (P=0,005 and P=0,001, respectively); however, the three groups presented a higher latency time at 61.1 clicks per second (P=0,005). At 20 dBHL, the latency was higher for GII and GIII - 61.1 clicks per second (p=0,020)-, and the amplitude was smaller for GI and GIII (P=0,002). The exam length was higher - 27.7 click per second (P=0*)- in the three groups. CONCLUSION: Despite the latency increase and amplitude reduction, the method of raising the repetition rate of the acoustic stimuli to register electrophysiological hearing responses can be incorporated to sensitize the exam and decrease its duration / INTRODUÇÃO: O estímulo clique é utilizado para avaliar a integridade do sistema auditivo e verificar a sincronia neural. No registro do Potencial Evocado Auditivo de Tronco Encefálico (PEATE) podem ser utilizadas diferentes taxas de apresentação do clique para sensibilizar o exame. Entretanto, devido a possíveis diferenças que podem ocorrer nas latências e amplitudes no PEATE, faz-se necessária a realização de um estudo que forneça dados normativos, para fundamentar o diagnóstico audiológico e auxiliar na tomada de decisões quanto aos protocolos utilizados na prática clínica. OBJETIVO: Estudar a influência de duas taxas diferentes de repetição do estímulo clique no PEATE, em adultos, neonatos-termo e prematuros. MÉTODO: Dez neonatos-termo (GI), dez adultos (GII) e dez neonatos prétermos (GIII) com audição normal foram submetidos ao registro do PEATE por via aérea nas taxas de repetição de 27.7 e 61.1 cliques/segundo nas intensidades de 80, 60 40 e 20 dBnNA. RESULTADOS: As médias e medianas apresentaram valores próximos para cada combinação de taxa de repetição e grupos, sugerindo que a distribuição das variáveis estudadas apresenta simetria. Entretanto, na intensidade de 80 dBnNA, a taxa de repetição de 61.1 cliques/segundo obteve a latência absoluta das ondas I, III e V aumentada nos grupos GI e GIII (valor P=0,003, valor P=0+ e valor P=0+, respectivamente) e amplitude das ondas III e V reduzida no GI e GII (valor P=0,014 e valor P=0+), sendo que a onda III teve amplitude mais reduzida com a polaridade rarefeita (valor P=0,014). Além disso, o tempo de latência dos intervalos interpicos I-III foi maior para o GI e GIII (valor P=0,035); em III-V foi maior para o GIII (valor P=0+) e em I-V foi maior para o GI (valor P=0+). Em 60 dBnNA, a latência foi maior para GI e GIII, e em 61.1 cliques/segundo nos três grupos (valor P=0+), e a amplitude foi menor para GI e GIII (P=0,001). Em 40 dBnNA, as duas taxas de repetição obtiveram latência maior e amplitude menor em GI e GIII (valor P=0,005 e valor P=0,001, respectivamente); entretanto, os três grupos apresentaram tempo de latência maior em 61.1 cliques/segundo (valor P=0,005). Em 20 dBnNA, a latência foi maior para GII e GIII em 61.1 cliques/segundo (valor P=0,020), e a amplitude foi menor para GI e GIII (valor P=0,002). A média de duração do exame foi maior em 27.7 cliques/segundo (valor P=0+) nos três grupos. CONCLUSÃO: Apesar do aumento da latência e da diminuição da amplitude, o método de elevar a taxa de repetição do estímulo acústico para registrar respostas eletrofisiológicas da audição pode ser incorporado para sensibilizar o exame, investigando a integridade do sistema auditivo e a sincronia neural, com tempo de realização do exame diminuído