Electrococleografía en implante coclear / Electrocochleography in cochlear implant

La electrococleografía es una técnica electrofisiológica desarrollada en modelos animales hace más de 90 años. En la actualidad se utiliza en la práctica clínica en audiolo-gía y otoneurología, ya que permite evaluar la función coclear, a través del registro del potencial microfónico coclear, y la funcionalidad del nervio auditivo por medio del registro del potencial de acción compuesto. Debido al avance de la tecnología de los implantes cocleares, actualmente existe la posibilidad de realizar mediciones clínicas a tiempo real con electrococleografía intraoperatoria, por lo que se puede monitorizar la función auditiva residual durante la inserción de los electrodos del implante coclear. En este artículo se presenta una revisión narrativa del uso y aplicación clínica de la electrococleografía en la evaluación de pacientes con implante coclear para predecir el desempeño auditivo y la percepción del habla. La literatura muestra que la electroco-cleografía es una técnica que se encuentra, plenamente, vigente para evaluar la función auditiva en pacientes usuarios de implantes cocleares. Si bien las respuestas cocleares han demostrado ser un buen predictor de los umbrales perceptuales auditivos y del habla en silencio en adultos, aún es una técnica que requiere más desarrollo para ser una herramienta clínica que permita predecir el habla en ruido y la función auditiva en niños y adultos mayores.

Electrocochleography is an electrophysiological technique developed in animal models more than 90 years ago. It is currently used in clinical practice in audiology and otoneurology, since it allows the evaluation of cochlear function, through the recording of the cochlear microphonic potentials, and the functionality of the auditory nerve by means of compound action potential recordings. Due to the advancement of cochlear implant technology, there is currently the possibility of real-time clinical measurements with intraoperative electrocochleography, so that residual hearing function can be monitored during the insertion of the cochlear implant electrodes. This article presents a narrative review of the use and clinical application of electrocochleography in the evaluation of patients with cochlear implants to predict auditory performance and speech perception. The literature shows that electrocochleography is a technique that is fully in force to assess hearing function in patients who use cochlear implants. Although cochlear responses have been shown to be a good predictor of auditory perceptual thresholds and speech in quiet in adults, it is still a technique that requires further development to become a clinical tool for predicting speech in noise and auditory function in children and older adults.

Comparison between chloral hydrate and propofol-ketamine as sedation regimens for pediatric auditory brainstem response testing / Comparação entre o uso de hidrato de cloral e propofol-quetamina como formas de sedação para exames de potenciais evocados auditivos de tronco encefálico

Abstract Introduction: The use of diagnostic auditory brainstem response testing under sedation is currently the "gold standard" in infants and young children who are not developmentally capable of completing the test. Objective: The aim of the study is to compare a propofol-ketamine regimen to an oral chloral hydrate regimen for sedating children undergoing auditory brainstem response testing. Methods: Patients between 4 months and 6 years who required sedation for auditory brainstem response testing were included in this retrospective study. Drugs doses, adverse effects, sedation times, and the effectiveness of the sedative regimens were reviewed. Results: 73 patients underwent oral chloral hydrate sedation, while 117 received propofol-ketamine sedation. 12% of the patients in the chloral hydrate group failed to achieve desired sedation level. The average procedure, recovery and total nursing times were significantly lower in the propofol-ketamine group. Propofol-ketamine group experienced higher incidence of transient hypoxemia. Conclusion: Both sedation regimens can be successfully used for sedating children undergoing auditory brainstem response testing. While deep sedation using propofol-ketamine regimen offers more efficiency than moderate sedation using chloral hydrate, it does carry a higher incidence of transient hypoxemia, which warrants the use of a highly skilled team trained in pediatric cardio-respiratory monitoring and airway management.

Resumo Introdução: O uso de testes diagnósticos de potencial evocado auditivo de tronco encefálico sob sedação é atualmente o padrão-ouro em lactentes e crianças pequenas que não têm desenvolvimento suficiente para realizar o exame. Objetivo: O objetivo do estudo foi comparar a sedação de crianças submetidas a testes de potencial evocado auditivo de tronco encefálico com propofol-quetamina e com hidrato de cloral por via oral. Método: Pacientes entre 4 meses e 6 anos de idade que necessitaram de sedação para a realização do potencial evocado auditivo de tronco encefálico foram incluídos nesse estudo retrospectivo. Foram revisadas as doses dos medicamentos, os efeitos adversos, os tempos de sedação e a eficácia das formas de sedação. Resultados: 73 pacientes foram submetidos à sedação oral com hidrato de cloral, enquanto 117 receberam sedação com propofol-quetamina; 12% dos pacientes do grupo hidrato de cloral não alcançaram o nível desejado de sedação. Os tempos médios de procedimento, recuperação e o tempo total de cuidados de enfermagem foram significativamente menores no grupo propofol-quetamina, entretanto este grupo experimentou maior incidência de hipoxemia transitória. Conclusão: Ambos os regimes de sedação podem ser utilizados com sucesso para sedar crianças para realização do exame de potencial evocado de tronco encefálico. Embora a sedação profunda com propofol e quetamina ofereça mais eficiência do que a sedação moderada com hidrato de cloral, ela apresenta maior incidência de hipoxemia transitória, o que requer uma equipe altamente qualificada, treinada em monitoramento cardiorrespiratório pediátrico e manejo de vias aéreas.

Forensic medical identification of 355 cases with hearing impairment / 法医学杂志

OBJECTIVE@#To analyze the difference of subjective hearing threshold and objective hearing threshold, and to discuss the importance of standard for hearing evaluation in forensic medicine.@*METHODS@#Three hundred and fifty-five cases (387 ears) of forensic medical identification with hearing impairment were retrospectively analyzed including the items entrusted and hearing test results. All cases were collected from 2004 to 2012 in the forensic science center.@*RESULTS@#In the 387 ears, 218 ears (56.3%) were evaluated the degree of disability and 106 ears (27.4%) were identified the degree of damage. In the disability degree evaluation, the subjective hearing threshold and the objective hearing threshold were significant different in 120 ears (55.0%), while in damage degree evaluation, the subjective hearing threshold and the objective hearing threshold were significant different in 69 ears (65.1%).@*CONCLUSION@#Because of camouflaging or exaggerating the hearing impairment by the wounded, the subjective hearing threshold can't accurately assess the existence and the degree of hearing impairment. In the forensic identification, auditory brainstem response, 40 Hz auditory event related potential and auditory steady-state response should be combined in the application to evaluate the hearing impairment for the wounded in order to ensure the reliability of the evaluation of hearing impairment.

Comparisons among three frequency-specific auditory evoked potentials in normal hearing adults / 法医学杂志

OBJECTIVE@#To provide supports for the application of auditory evoked potential (AEP) in the evaluation of behavioral threshold, by studying the difference and relevance between the pure tone audiometry (PTA) and three frequency-specific auditory evoked potentials, including 40 Hz auditory event related potentials (40 Hz AERP), tone burst auditory brainstem response (Tb-ABR) and auditory steady-state response (ASSR).@*METHODS@#Three frequency-specific AEP and PTA thresholds were recorded at speech frequency (0.5, 1, 2, 4 kHz) from thirty-four adults with normal hearing (68 ears). Then, the relationship between the AEP thresholds and PTA thresholds were analyzed respectively.@*RESULTS@#There were good correlations between three frequency-specific AEP thresholds and PTA thresholds at speech frequency. However, the difference of thresholds between each frequency-specific AEP and PTA was not same. The difference of thresholds were the smallest and the relevance were the best between 40 Hz AERP and PTA at 0.5 kHz, and between ASSR and PTA at 2, 4 kHz. At 1 kHz, there were not statistical difference between ASSR, 40 Hz AERP and PTA, while the relevance of 40 Hz AERP was better than ASSR.@*CONCLUSION@#Different methods should be chosen to assess the objective behavioral thresholds at different frequency.

Temporal resolution with click and pure tone stimuli in youngsters with normal hearing sensitivity / Resolução temporal com estímulos clique e tom puro em jovens com sensibilidade auditiva normal

PURPOSE: To assess the auditory ability of temporal resolution and to compare the random gap detection test (RGDT) versions with pure tone and clicks stimuli. METHODS: Participants were 40 young individuals of both genders with ages between 18 and 25 years, and normal hearing thresholds for the sound frequencies of 250 Hz to 8 kHz. Initially, participants were submitted to the basic audiological evaluation. Then they underwent the RGDT with pure tone and clicks stimuli. Finally, we obtained the temporal acuity threshold, which corresponds to the shorter silence interval in which the patient perceives two sounds, for each type of stimulus, called final temporal acuity threshold for pure tones (mean of the thresholds obtained for 500 Hz, 1k, 2k and 4 kHz), and temporal acuity threshold for clicks. RESULTS: The mean temporal acuity threshold for the sound frequency of 500 Hz was 7.25 ms; for the frequency of 1 kHz was 7.25 ms; for 2 kHz was 6.73 ms; for the frequency of 4 kHz was 6.03 ms. The final temporal acuity threshold was 6.72 ms. The mean temporal acuity threshold for clicks was 6.43 ms. No difference was found between the temporal acuity thresholds obtained with pure tone and clicks stimuli. CONCLUSION: There is no difference in the performance of individuals on the auditory ability of temporal resolution, regardless of the auditory stimulus used.

OBJETIVO: Avaliar a habilidade auditiva de resolução temporal e comparar as versões do teste de detecção de intervalos aleatórios (RGDT) com estímulos do tipo tom puro e clique. MÉTODOS: Participaram deste estudo 40 indivíduos jovens com idades entre 18 e 25 anos, de ambos os gêneros e limiares auditivos normais para as frequências sonoras de 250 Hz a 8 kHz. Inicialmente, os participantes foram submetidos à avaliação audiológica básica. Posteriormente, foram submetidos ao teste RGDT com estímulos auditivos do tipo tom puro e clique. Ao final obteve-se o limiar de acuidade temporal, que corresponde ao menor intervalo de silêncio no qual o paciente percebe que está ouvindo dois sons, para cada tipo de estímulo, denominados limiar de acuidade temporal final para tons puros (média dos limiares obtidos para 500 Hz, 1k, 2k e 4 kHz), e o limiar de acuidade temporal para clique. RESULTADOS: A média do limiar de acuidade temporal para a frequência sonora de 500 Hz foi de 7,25 ms; para a frequência de 1 kHz foi de 7,25 ms; para a frequência de 2 kHz foi de 6,73 ms; para a frequência de 4 kHz foi de 6,03 ms. O limiar de acuidade temporal final foi de 6,72 ms. A média do limiar de acuidade temporal para clique foi de 6,43 ms. Não foi encontrada diferença quanto aos limiares de acuidade temporal ao comparar estímulos dos tipos tom puro e clique. CONCLUSÃO: Não há diferença no desempenho dos indivíduos para a habilidade auditiva de resolução temporal, independente do estímulo auditivo utilizado.

Auditory evoked potentials in premature and full-term infants / Potenciais evocados auditivos em lactentes pré-termo e a termo

Accurate information about type, degree, and configuration of hearing loss are necessary for successful audiological early interventions. Auditory brainstem response with tone burst stimuli (TB ABR) and auditory steady-state response (ASSR) exams provide this information. AIM: To analyze the clinical applicability of TB ABR and ASSR at 2 kHz in infants, comparing responses in full-term and premature neonates. MATERIAL AND METHOD: The study was cross-sectional, clinical and experimental. Subjects consisted of 17 premature infants and 19 full-term infants. TB ABR and ASSR exams at 2000 Hz were done during natural sleep. RESULTS: The electrophysiological minimum response obtained with TB ABR was 32.4 dBnHL (52.4 dBSPL); the ASSR minimum was 13.8 dBHL (26.4 dBSPL). The exams required 21.1 min and 22 min, respectively. Premature and full-term infant responses showed no statistically significant differences, except for auditory steady-state response duration. CONCLUSIONS: Both exams have clinical applicability at 2 kHz in infants, with 20 min of duration, on average. In general, there are no differences between premature and full-term individuals.

O sucesso de uma intervenção audiológica precoce depende de informações precisas quanto ao tipo, grau e configuração da perda auditiva. O potencial evocado auditivo de tronco encefálico com o estímulo tone burst (PEATE TB) e a resposta auditiva de estado estável (RAEE) proporcionam tais informações. OBJETIVO: Investigar a aplicabilidade clínica, em lactentes, do PEATE TB e da RAEE na frequência de 2 kHz, comparando as respostas dos lactentes nascidos a termo e prétermo. MATERIAL E MÉTODO: O estudo (transversal, clínico e experimental) foi realizado com uma casuística de 17 lactentes pré-termo e 19 a termo submetidos ao PEATE TB e RAEE em 2000 Hz. RESULTADOS: A resposta eletrofisiológica mínima obtida com o PEATE TB foi de 32,4 dBnNA (52,4 dBNPS) e com a RAEE de 13,8 dBNA (26,4 dBNPS), com duração média de 21,1 min e 22 min, respectivamente. A comparação das respostas dos lactentes pré-termo e a termo não apresentou diferenças estatisticamente significantes, com exceção do tempo de duração da RAEE. CONCLUSÃO: As duas metodologias têm aplicabilidade clínica na frequência de 2 kHz em lactentes, com duração média de 20 min. Lactentes nascidos pré-termo, no geral, não apresentam diferenças em relação aos lactentes nascidos a termo.

Graphic angle measure as an electrocochleography evaluation parameter / A medida angular gráfica como parâmetro de avaliação da eletrococleografia

To improve electrocochleography's diagnostic sensitivity in Meniére's disease - new assessment methods are being studied. AIM: To determine whether or not graphic angle measurement is sensitive and specific to Menière's disease laboratorial diagnosis and if there is an increase in the electrocochleography's sensitivity and specificity when graphic angle measurements are associated with Summating Potential-Action Potential ratio (SP/AP ratio). METHODS: Electrocochleography's was used to analyze 71 ears from 55 subjects: 41 patients with clinical diagnosis of Menière's disease (MD group), and 14 healthy individuals as control (Group C). Graphic results were analyzed initially to obtain the SP/AP ratio; afterwards, through another program graphic angle measurements were calculated. RESULTS: Sensitivity and specificity values of angle measures, SP/AP ratio, and the association between them varied according to the cutoff point, the highest equilibrium between sensitivity and specificity was observed with the values of 166.25 for angle measurement and 27 percent for SP/AP relation; 62.79 percent / 60.71 percent and 74.42 percent / 67.86 percent, respectively. The association between measurements showed a sensitivity increase due to the specificity decrease; 88.37 percent and 50 percent, respectively. CONCLUSION: Angle graphic measurement is not sensitive and specific enough for the laboratorial diagnosis of MD. Angle graphic measurement and SP/AP ratio association proved to be higher in sensitivity, in detriment of exam specificity.

Para melhorar a sensibilidade diagnóstica da eletrococleografia na doença de Ménière têm-se estudado novos métodos de mensuração. OBJETIVOS: Verificar se a técnica da medida angular gráfica é sensível e específica para o diagnóstico laboratorial da doença de Ménière e se existe incremento na sensibilidade e especificidade da eletrococleografia, quando da associação da medida angular gráfica com o valor da relação SP/AP. CASUÍSTICA E MÉTODO: Foram analisadas a eletrococleografia de 71 orelhas: 41 pacientes com diagnóstico clínico de doença de Ménière e 14 controles sadios. Os traçados foram analisados inicialmente para a obtenção do valor da relação SP/AP, posteriormente foi calculada a medida angular gráfica. RESULTADOS: O valor da sensibilidade e especificidade da medida angular, da relação SP/AP e da associação de ambas variou de acordo com o ponto de corte, os valores 166,25 para a medida angular e 27 por cento para SP/AP foram os que demonstraram maior equilíbrio entre sensibilidade e especificidade, 62,79 por cento / 60,71 por cento e 74,42 por cento / 67,86 por cento, respectivamente. A associação das medidas mostrou incremento da sensibilidade à custa da diminuição da especificidade, 88,37 por cento e 50 por cento, respectivamente. CONCLUSÕES: A medida angular gráfica não é sensível e específica suficiente para o diagnóstico laboratorial DM. A associação da relação SP/AP e medida angular gráfica apresentou melhora da sensibilidade em detrimento da especificidade do exame.

The progress in the study on auditory evoked potentials / 法医学杂志

Auditory evoked potential (AEP) is the electric activities originating from auditory systems evoked by sound stimulus. AEP include cortical electric response audiometry (CERA), auditory brainstem evoked response (ABR), 40 Hz auditory event related potentials (40 Hz AERP), auditory steady-state response (ASSR), etc. For the subjects who cannot provide reliable or accurate behavioral hearing threshold, those techniques have been explored to evaluate the behavioral hearing threshold objectively. These techniques are reviewed in this article and are found that they could reflect the behavioral hearing threshold very well. CERA is difficult to operate because it is affected by the subject's wakefulness. ABR is the most widely used method currently and is not affected by the subject's consciousness, but it only reflects high frequencies. 40 Hz AERP has good sensitivity, while its results highly depend on the subject's consciousness. ASSR can be operated by using multiple frequency stimuli simultaneously to both ears and the test time is short. It is still a very difficult task to combine different techniques according to their characteristics in forensic audiology.

Sensitivity and specificity of auditory steady-state response testing

INTRODUCTION: The ASSR test is an electrophysiological test that evaluates, among other aspects, neural synchrony, based on the frequency or amplitude modulation of tones. OBJECTIVE: The aim of this study was to determine the sensitivity and specificity of auditory steady-state response testing in detecting lesions and dysfunctions of the central auditory nervous system. METHODS: Seventy volunteers were divided into three groups: those with normal hearing; those with mesial temporal sclerosis; and those with central auditory processing disorder. All subjects underwent auditory steady-state response testing of both ears at 500 Hz and 2000 Hz (frequency modulation, 46 Hz). The difference between auditory steady-state response-estimated thresholds and behavioral thresholds (audiometric evaluation) was calculated. RESULTS: Estimated thresholds were significantly higher in the mesial temporal sclerosis group than in the normal and central auditory processing disorder groups. In addition, the difference between auditory steady-state response-estimated and behavioral thresholds was greatest in the mesial temporal sclerosis group when compared to the normal group than in the central auditory processing disorder group compared to the normal group. DISCUSSION: Research focusing on central auditory nervous system (CANS) lesions has shown that individuals with CANS lesions present a greater difference between ASSR-estimated thresholds and actual behavioral thresholds; ASSR-estimated thresholds being significantly worse than behavioral thresholds in subjects with CANS insults. This is most likely because the disorder prevents the transmission of the sound stimulus from being in phase with the received stimulus, resulting in asynchronous transmitter release. Another possible cause of the greater difference between the ASSR-estimated thresholds and the behavioral thresholds is impaired temporal resolution. CONCLUSIONS: The overall sensitivity of auditory steady-state response testing was lower than its overall specificity. Although the overall specificity was high, it was lower in the central auditory processing disorder group than in the mesial temporal sclerosis group. Overall sensitivity was also lower in the central auditory processing disorder group than in the mesial temporal sclerosis group.

Brainstem auditory evoked potentials and electrocochleographic findings in patients with idiopathic sudden sensorineural hearing loss

To determine the status of cochlea, auditory pathway and hearing threshold by recording brainstem auditory evoked potential [BAEP] and electrocochleography in patients with idiopathic sudden sensorineural hearing loss [ISSNHL]. Observational study. Department of Clinical Physiology at King Abdul Aziz University Hospital, Riyadh, Saudi Arabia, from May 2002 to November 2007. Patients diagnosed with idiopathic sudden sensorineural hearing loss [ISSNHL] based on clinical features and pure tone audiometry were studied. Brainstem auditory evoked potential [BAEP] and electrocochleography [ECOG] was performed in them according to standard protocols for assessment of auditory pathway and hearing threshold. Out of 23 patients [14 males and 9 females] left ear was affected in 9 [39.1%] patients, right ear in 13 [56.5%] and both in 1 [4.3%]. Absolute latency of wave I and wave V were significantly prolonged in affected ear compared to unaffected ears [p=0.0031], while interpeak I-V latency was significantly higher in affected ears versus unaffected ears [p=0.0544]. Six patients [26.1%] had type II Diabetes mellitus, five cases [21.7%] had hypertension and 5 cases [21.7%] had dyslipidemia. ECOG revealed absence of summation potential [SP] and action potential [AP] response even at 95 dB in 17 out of 23 cases [73.9%]. Patients with ISSNHL had significant abnormalities in BAEP and ECOG recordings showing predominantly cochlear involvement. Thus, these tests provide useful diagnostic information in patients with ISSNHL in addition to pure tone audiometry

Padronização do potencial evocado auditivo de tronco encefálico utilizando um novo equipamento / Standardization of brainstem auditory evoked potential using a new device

TEMA: padronização do Potencial Evocado Auditivo de Tronco Encefálico (PEATE) utilizando um novo equipamento. OBJETIVO: padronizar as respostas do PEATE utilizando de um novo equipamento desenvolvido (NED) no Brasil. MÉTODOS: análise das latências absolutas, interpicos e das amplitudes das ondas do PEATE, por meio de um novo equipamento desenvolvido para estudar grupos de ouvintes normais (91 adultos) e outro com perda neurossensorial (15 adultos) com perda auditiva neurossensorial bilateral entre o equipamento EP15 / Interacoustis e o NED. Utilizando o clique não filtrado, com duração de 100 microssegundo (µs), totalizando 2.000 estímulos, na polaridade rarefeita, frequência de estimulação de 13,1 cliques/s, intensidade de 80 decibels de nível de audição normalizado (dB NAn), com janela de 10 milissegundos e filtro passa-banda entre 100 e 3000 Hertz (Hz). Nível de significância de 0,05. RESULTADOS: as médias das latências absolutas e interpicos em 76 ouvintes normais no NED foram: onda I=1,50, III=3,57, V=5,53, I-III=2,06, III-V=1,96 e I-V=4,02. Ao separar por gênero houve diferença estatisticamente significante para as latências absolutas das ondas III e V e nos interpicos I-III e I-V. Valor médio da amplitude da onda I=0,384 microvolt (μV) e da onda V=0,825 μV. Não existiu diferença estatisticamente significante ao comparar as latências absolutas e interpicos entre dois equipamentos no mesmo indivíduo. CONCLUSÃO: os componentes do PEATE com o NED em ouvintes normais foram similares quanto às orelhas, com latências menores estatisticamente significantes nas mulheres. As latências do PEATE no mesmo indivíduo com o NED foram semelhantes às obtidas com o EP15 / Interacoustis. Foram obtidos os valores de normalidade para o PEATE em adultos ouvintes normais.

BACKGROUND: standardization of Brainstem Auditory Evoked Potential (BAEP) using a new device. AIM: to standardize BAEP responses using a new device developed (NDD) in Brazil. METHOD: analysis of absolute latencies, interpeaks and wave amplitudes of BAEP, using a new device developed to study normal-hearing groups (91 adults) and individuals (15 adults) with bilateral neurosensory hearing loss. Responses obtained in the EP15 hearing device/Interacoustics and the NDD were compared. For this, the following paramenters were used: non-filtered click of 100 microsecond (µs), totaling 2000 stimuli in rarefied polarity, stimulation frequency of 13.1 clicks/s, intensity of 80 decibels normalized hearing level (dB nHL), with a window of 10 milliseconds and bandpass filter between 100 and 3000 Hertz (Hz). Significance level was set at 0.05. RESULTS: absolute latency and interpeak means for 76 normal-hearing individuals with the NDD were: wave I=1.50, III=3.57, V=5.53, I-III=2.06, III-V=1.96 and I-V=4.02. When analyzing results according to gender, there was a statistically significant difference for the absolute latencies of waves III and V and in interpeaks I-III and I-V. Mean amplitude value of wave I=0.384 microvolt (µV) and of wave V=0.825 µV. There was no statistically significant difference between the absolute latencies and interpeaks of the two devices in the same individual. CONCLUSION: the components of BAEP with the NDD in normal-hearing subjects were similar regarding the tested ears, with statistically lower latencies in women. The BAEP latencies in the same individual with NDD were similar to those obtained with the EP15 / Interacoustics. Normal values of BAEP were obtained in normal-hearing adults.

Estudo dos potenciais evocados auditivos em autismo / Study of auditory evoked potentials in autism

Background: electrophysiological assessment of hearing in autistic individuals. AIM: to characterize the findings obtained in the electrophysiological assessments of autistic individuals, as well as to compare these to the results obtained for individuals of the same age who present typical development. Method: 16 individuals with autism (study group) and 25 normal individuals (control group), ranging in age from eight to 20 years underwent anamnesis, pure tone audiometry, speech audiometry, acoustic immitance measures, brainstem auditory evoked potential (BAEP), middle latency response (MLR) and cognitive potential (P300). Results: the study group presented altered results in all auditory evoked potentials, showing statistically significant differences when compared to the control group. Concerning the types of alterations found in the study group the following results were observed: higher occurrence of lower brainstem alteration in the BAEP, both (electrode and ear effects occurring simultaneously) in the MLR, and absence of response in the P300. In the quantitative data analysis, statistically significant differences between the groups were found only for the BAEP regarding the latencies of waves III and V and interpeaks I-III and I-V. Conclusion: autistic individuals present altered BAEP and P300, suggesting impairment in the brainstem auditory pathway and corticals / subcorticals areas.

Tema: avaliação eletrofisiológica da audição em indivíduos com autismo. Objetivo: caracterizar os achados das avaliações eletrofisiológicas da audição em indivíduos com autismo, bem como comparar seus resultados aos obtidos em indivíduos com desenvolvimento típico da mesma faixa etária. Método: foram realizadas anamnese, audiometria tonal, logoaudiometria, medidas de imitância acústica, potenciais evocados auditivos de tronco encefálico (PEATE) e de média latência (PEAML), e potencial cognitivo (P300), em 16 indivíduos com autismo (grupo pesquisa) e 25 normais (grupo controle), com idades entre oito e 20 anos. Resultados: o grupo pesquisa apresentou resultados alterados em todos os potenciais evocados auditivos, havendo diferença estatisticamente significante quando comparado ao grupo controle. Foi observada uma maior ocorrência de alteração do tipo tronco encefálico baixo no PEATE, do tipo Ambas no PEAML, e ausência de resposta no P300, para o grupo pesquisa. Na análise dos dados quantitativos, verificou-se que apenas para o PEATE ocorreu diferença estatisticamente significante entre os grupos, com relação às latências das ondas III e V e interpicos I-III e I-V. Conclusão: indivíduos com autismo apresentam alterações no PEATE e P300, sugerindo comprometimento da via auditiva em tronco encefálico, áreas subcorticais e corticais.

Potenciais evocados auditivos de estado estável em crianças com perdas auditivas cocleares / Auditory steady-state response in children with cochler hearing loss

Background: auditory steady-state response (ASSR) is indicated as a promising technique in the assessment of the hearing status of children. AIM: to investigate the level of agreement between the results of the ASSR and the visual reinforcement audiometry (VRA) in a group of children, thus examining the clinical applicability of this technique in hearing assessment of children. Method: participants were 14 children with ages between 4 and 36 months (mean 16 months) with the diagnosis of cochlear hearing loss. The ASSR was recorded in the frequencies of 0.5, 1, 2 and 4kHz for multiple simultaneous stimulation and the results were compared with the visual reinforcement audiometry (VRA). Results: the intraclass correlation coefficients between ASSR and VRA were 0.90, 0.93, 0.93 and 0.89 respectively for the frequencies of 0.5, 1, 2 and 4kHz, indicating a strong correlation between the techniques. Conclusion: the ASSR can provide accurate information to support the selection of hearing aids for children when it is not possible to perform the VRA.

Tema: os potenciais evocados auditivos de estado estável (PEAEE) têm sido apontados como uma técnica promissora na avaliação audiológica infantil. Objetivo: investigar o nível de concordância entre os resultados do PEAEE e a audiometria de reforço visual (VRA) em um grupo de crianças, averiguando assim a aplicabilidade clínica desta técnica na avaliação audiológica infantil. Método: foram avaliadas 14 crianças com idade entre 4 e 36 meses (média 16 meses) com diagnóstico de perda auditiva coclear. Os PEAEE foram registrados nas frequências de 0,5; 1; 2 e 4kHz pela estimulação múltipla simultânea, e os resultados obtidos foram comparados com os resultados da VRA. Resultados: os coeficientes de correlação intraclasse entre as respostas dos PEAEE e da VRA foram de 0,90; 0,93; 0,93 e 0,89 para as frequências de 0,5; 1; 2 e 4kHz, respectivamente, indicando forte concordância entre as técnicas. Conclusão: os PEAEE podem fornecer informações precisas para que se possa dar início à seleção e adaptação dos AASI em crianças nas quais ainda não é possível a realização da VRA.

The progress in the study on slow vertex response / 法医学杂志

Slow vertex response (SVR) is one of long latency auditory evoked potentials. It is a biological and electric response originating from brain cortical neuron evoked by sound stimulus with the latency from 50 to 500 milliseconds. Of all the neuroelectric physiological audiometries, it is the earliest method applied in assessing the function of the auditory neural conduction pathway. The concept, neural generators of SVR have been introduced in this article. Influencing factors on SVR were discussed such as stimulus parameters, consciousness state, age, maturation of the subject. Applications of SVR in clinical and forensic medicine identification were also discussed.

Comparison of thresholds acquired with SVR and PTA in normal hearing subjects / 法医学杂志

OBJECTIVE@#To investigate the value of slow vertex response (SVR) for forensic appraisement of hearing dysfunction by comparing the thresholds acquired with SVR and pure tone audiometry (PTA).@*METHODS@#Forty-six subjects with normal hearing were tested with PTA (0.125-8 kHz) and SVR (0.5-4 kHz). Paired t-test analysis was performed on the thresholds of SVR and PTA at each frequency (0.5, 1, 2 and 4 kHz), and analysis of variance was performed on the difference between the pure tone audiometry threshold and the evoked potential threshold among different frequency.@*RESULTS@#At each frequency(0.5, 1, 2 kHz and 4 kHz), difference between the thresholds acquired with SVR and PTA was statistically significant(P < 0.05). The mean difference of the two thresholds were (5.98 +/- 6.72) dB HL at 0.5 kHz, (3.86 +/- 6.12) dB HL at 1 kHz, (7.12 +/- 6.56) dB HL at 2 kHz, (8.53 +/- 7.90) dB HL at 4kHz, and the mean difference at 1 kHz was the smallest. This variation between frequencies was also statistically significant.@*CONCLUSION@#The thresholds acquired with SVR were higher than those acquired with PTA. The adjusted thresholds should be established at each frequency, when the SVR thresholds are used to evaluate the behavioural hearing thresholds.

Os efeitos da polaridade do estímulo nos Potenciais Evocados Auditivos de Tronco Encefálico / Polarity stimulation effects on brainstem auditory evoked potentials

Os Potenciais Evocados Auditivos de Tronco Encefálico (PEATE) são considerados potenciais exógenos, ou seja, as respostas obtidas são altamente dependentes da característica do estímulo utilizado para evocá-los. OBJETIVO: Averiguar a influência da polaridade do estímulo clique na pesquisa dos PEATE em diferentes intensidades, utilizando-se fone de inserção. FORMA DE ESTUDO: Clínico. MATERIAL E MÉTODO: 33 indivíduos, idade entre 18 e 28 anos, sem alteração auditiva foram submetidos à pesquisa dos PEATE, com estímulo clique nas polaridades de rarefação, condensação e alternada, em diferentes intensidades. RESULTADOS: As latências absolutas da onda V mostraram-se menores na polaridade de rarefação quando comparadas às demais e na intensidade de 80 dBnHL houve diferença significante entre a rarefação e as demais polaridades para as latências interpicos III-V e I-V. Houve alta correlação entre as polaridades de condensação e alternada para as latências absolutas e interpicos na intensidade de 80 dBnHL. CONCLUSÃO: A polaridade do estímulo clique influência significativamente nos PEATE. Na rotina em que se utiliza o fone TDH 39, com apresentação de polaridade alternada, sugere-se que o uso da polaridade de condensação seja mais adequado para efeitos de comparação padronizada, devido à maior semelhança das latências encontradas nesse estudo com fone de inserção.

Brainstem Auditory Evoked Potentials are considered exogenous potentials, that is, the responses obtained are highly dependent upon the characteristic of the stimulus used to evoke them. AIM: To investigate the influence of the click stimulus polarity in the study of Brainstem Evoked Response Audiometry (BERA) at different intensities, using insertion-canal earphones. TYPE OF STUDY: Clinical. MATERIALS AND METHODS: 33 individuals, aged between 18 and 28, with no auditory alteration were submitted to BERA testing, with click stimulus on the rarefaction, condensation and alternate polarities, in different intensities. RESULTS: The absolute latencies of the V wave proved to be lower in the rarefaction polarity when compared to the others and, at 80 dBnHL, there was a significant difference between rarefaction and the other polarities for interpeak latencies III-V and I-V. There was a high correlation between the condensation and alternating polarities for absolute and interpeak latencies at 80 dBnHL. CONCLUSION: the click stimulus polarity has a significant influence on BERA. In the routine use of the TDH 39 earphone, with alternating polarity, we suggest that condensation polarity is more adequate for standardized comparison purposes, due to the higher similarity of the latencies found in this insertion earphone study.

Achado ocasional de doenças neurológicas durante a pesquisa da surdez infantil através do BERA / Occasional finding of neurological disorders during children hearing loss evaluation using the ABR

Uma das mais importantes aplicações clínicas dos potenciais evocados auditivos de tronco cerebral (BERA) é a sua utilização na avaliação da surdez infantil. Atualmente o BERA também é utilizado na triagem das síndromes cócleo-vestibulares a procura de lesões retro-cocleares, na monitoração dos estados de coma (morte cerebral), na monitoração do tronco cerebral em cirurgias da base do crânio, etc. Uma das qualidades do BERA é a sua capacidade de avaliar a integridade neurofisiológica das vias auditivas do tronco cerebral. Desta maneira, algumas vezes durante a pesquisa dos limiares auditivos infantis, nos deparamos com BERAs que sugerem a presença de lesões retro-cocleares das vias auditivas (assimetria de traçados, aumento dos intervalos interpicos), muitas vezes comprovadas através de exames de imagem. Trata-se de achado ocasional de moléstia neurológica por ocasião da pesquisa dos limiares auditivos infantis. Neste trabalho relataremos dois casos de doenças neurológicas, diagnosticadas ocasionalmente através do BERA realizado com o intuito de se pesquisar os limiares auditivos.

One of the most important applications of the Brainstem evoked response audiometry (ABR) is in the evaluation of hearing loss in children. Today the ABR is also indicated in the screening of cochleo-vestibular syndromes to detect retrocochlear lesions, to monitor patients in a coma (brain death), in monitoring the brainstem during skull base surgery, etc. Among the many BERA qualities, is its capacity to evaluate the neurophysiologic integrity of the auditory brainstem pathway. In doing so, sometimes while evaluating hearing function in children we are faced with ABR waves that suggest the presence of retrocochlear lesions (trace asymmetry, increased interpeak intervals), many times confirmed through image studies. These cases are seen as occasional findings of neurologic disorders during children hearing loss evaluation. In this study we report 2 cases of neurologic disorders diagnosed with the use of the ABR to evaluate hearing loss in children.

A implementação de programa de triagen auditiva neonatal universal em um hospital universitário brasileiro / Universak newborn hearing screeening program assessment in a Brazilian university

Objetivo: avaliar os resultados de implementação do Programa de Triagem Auditiva Neonatal Universal (PT aNU) no Hospital Universitário da Universidade de São Paulo (HU-USP), São Paulo, SP. Casuística e Métodos: Programaou-se a avaliação universal por triagem auditiva...

A audiometria tonal liminar e/ou avaliação instrumental confirmam posteriormente a audiometria de tronco cerebral obtida precocemente em crianças deficientes atuditivas? / Does Pure Tone Threshold Audiometry and/or Behavorial Auditory Assessment Confirm Subsequent Response Obtained Precociously in Children with Auditive Deficiency?

Esta pesquisa foi realizada a partir do levantamento dos diagnósticos audiológicos obtidos através da audiometria de tronco cerebral (ATC), realizada precocemente, e da audiometria tonal liminar (ATO e/ou avaliação instrumental (AI), realizadas anos depois nas mesmas 30 crianças com deficiência auditiva em atendimento no setor de Audiologia Educacional do Serviço de Atendimento Fonoaudiológico da Universidade Federal de Santa Maria, com o objetivo de compara-loa e verificar a concordância existente entre eles. Resultados: A comparação, levando em conta os graus de perda auditiva obtidos através dos três procedimentos de avaliação considerados, mostrou uma concordância de 97,30% dos diagnósticos nas perdas auditivas de grau profundo, 77,78% no grau severo, 57,15% no grau moderado e de 33,33% no grau moderadamente-severo. No geral, do ponto de vista clínico, verificou-se concordância diagnóstica em 57 (95,00%) das 60 orelhas pesquisadas.

This research was made after survey of the audiologics diagnostics obtained through of the auditory brainstem response (ABR), pure tone threshold audiometry (PTA) and/or behavioral auditory assessment (BAA) made in 30 children with auditive deficiency with the purpose of to compare and Check the agreement between them. Results: In the comparison of the diagnostics of the grades of hearing loss obtained watched a agreement of 97,30% of the diagnostics in the hearing losses of profound grade, 77,78% in the severe grade, 57,15% in the moderate grade and 33,33% in the moderately-severe; in general, of the clinical point of view, watched diagnostic agreement in 57 (95,00%) of the 60 ears researched.

Electrococleografía transoperatoria en cirugía de saco endolinfático / Intraoperative electrocochleography in endolumphatic sac surgery

Objetivos. Analizar los cambios en la relación potencial de suma-potencial de acción (PS/PA) en la Electrococleografía (EcoG) intraoperatoria a través de registros efectuados al descomprimir y abrir el saco endolinfático, tratar de identificar la posición del saco endolinfático en pacientes sometidos a cirugía de saco endolinfático con enfermedad de Meniére. Diseño. Prospectivo. longitudinal, comparativo, observacional. Material y métodos. En el periodo comprendido de Septiembre a Diciembre de 1998, en el servicio de Neurotología del Instituto Nacional de Neurología y Neurocirugía, se estudiaron 8 pacientes con diagnóstico de enfermedad de Meniére con falla a tratamiento médico, realizándoles audiometría, logoaudiometría, electronistagmografía y electrococleografía. Aceptaron se practicara cirugía de descompresión y apertura de saco endolinfático y 4 registros de electrococleografía transoperatoria. Resultados. La comparación de los valores obtenidos en el EcoG durante la descompresión y apertura del saco endolinfático mostró valores absolutos PS/PA, con una significancia del 99.9 por ciento, lo cual equivale a P. Los 8 (100 por ciento) pacientes mostraron disminución de la amplitud del PS en la EcoG intraoperatoria en algún momento del monitoreo. Todos los pacientes en su EcoG de control postquirúrgico mostraron una relación PS/PA a 30 por ciento, cuando en el registro prequirúrgico tenían registro a 35 por ciento. Conclusiones: Aunque nuestra muestra es pequeña, es significativa, ya que encontramos en el 100 por ciento de los pacientes disminución de la relación PS/PA en la EcoG intraoperatoria.