RESUMEN Se desarrolló un agregado de plástico reciclado (APR) usando la estrategia de núcleo-coraza en que la fracción plástica de residuos de aparatos eléctricos y electrónicos (RAEE) es el núcleo o corazón y una mezcla de cemento y aditivos estabilizantes actúa como coraza. La cantidad de retardantes de fuego bromados (principalmente tetrabromobisfenol-A) lixiviados en agua para el curado de APR se mediante extracción con solventes orgánicos y cromatografía gaseosa (CG-FID). Se logró establecer una relación clara entre las características del aditivo estabilizante y la cantidad de tetrabromobisfenol-A y bisfenol-A lixiviados. Se utilizó como aditivo carbón activado, que en producción de gran escala puede ser provisto por diferentes proveedores comerciales con diferentes características de mesoporo. Esta característica puede evaluarse fácilmente mediante el número de iodo y es determinante en la capacidad de estabilización del carbón activado. El análisis propuesto puede utilizarse de manera efectiva con la tecnología desarrollada para determinar la capacidad estabilizante del carbón empleado como materia prima en la producción de RPA.

ABSTRACT A recycled plastic aggregate (RPA) was developed using the core-shell strategy, where the core is the plastic fraction of Waste of Electrical and Electronic Equipment (WEEE) and a cement matrix with stabilizing additives acts as the shell. The amount of brominated flame retardant (mainly tetrabromobisphenol-A) leached in curing water of RPAs was quantified using extraction with an organic solvent and gas chromatography methods (CG-FID). A clear relationship can be established between the characteristics of the stabilizing additive used and the amount of tetrabromobisphenol-A and bisphenol-A leached. The additive used was activated carbon, which in a manufacture scale may be provided by different suppliers with different mesoporous characteristics, which can be easily determined by the iodine number. The analysis proposed can be an effective way to determine if a particular activated carbon can be used as stabilizing additive in the production of RPAs with the developed technology.

Resumo O trabalho surge a partir do relevamento de informação que permitiu avaliar a situação atual dos resíduos elétricos e eletrônicos (RAEE) em Chile. Identificando os métodos de caracterização em cada material para estabelecer condições, valorizações e procedimentos na gestão adequada de estes em favor da nova Lei de Responsabilidade estendidas do Produtor (REP). O resultado obtido estabelece um modelo procedimental aplicável à engenharia e o design entre outras disciplinas, que permitirá sistematizar a tomada de decisões e o planejamento desde uma perspectiva eco - eficiente, potenciando deste modo projetos de interesse tecnológico e econômico para o manejo sustentável dos resíduos elétricos e eletrônicos.

Abstract The following work arises from the survey of information that allowed to evaluate the current situation of electrical and electronic waste (WEEE) in Chile. Identifying the characterization methods in each material to establish conditions, appraisals and procedures in the proper handling of these in post of the new Law of Extended Producer Responsibility (EPR). The result obtained establishes a procedural model applicable to the Teaching of Engineering and Design among other disciplines, which will systematize decision making and planning from an ecoefficient perspective, thus promoting projects of technological and economic interest for sustainable management of electrical and electronic waste.

Resumen El siguiente trabajo surge a partir del relevamiento de información que permitió evaluar la situación actual de los residuos eléctricos y electrónicos (RAEE) en Chile. Identificando los métodos de caracterización en cada material para establecer condiciones, valorizaciones y procedimientos en el manejo adecuado de éstos en post de la nueva Ley de Responsabilidad extendida del Productor (REP). El resultado obtenido establece un modelo procedimental aplicable a la Enseñanza de la Ingeniería y el Diseño entre otras disciplinas, que permitirá sistematizar la toma de decisiones y la planeación desde una perspectiva Ecoeficiente, potenciando de esta forma proyectos de interés tecnológico y económico para el manejo sostenible de los residuos eléctricos y electrónicos.

Resumen El proceso de recuperación de Residuos de Aparatos Eléctricos y Electrónicos (RAEE) crece día a día. Desde el punto de vista académico y empresarial, este presenta una notable importancia económica, ambiental y tecnológica, y su estudio en nuestro país aún está en su etapa inicial. El presente estudio tiene como objetivo la validación y entendimiento de un modelo de logística inversa para la recuperación de RAEE a partir del diseño y la construcción de un modelo de simulación continua basado en la perspectiva del pensamiento sistémico soportado con la dinámica de sistemas; Las proyecciones de este estudio se construyeron con base en la información del proceso de recuperación en forma artesanal que utilizan empresas de la región, así como empresas del sector que poseen niveles aceptables de tecnología para realizar las actividades de recuperación. Puntualmente, se tomó como referencia una empresa del sector, que presenta el proceso de recuperación del plástico PET, el cual es adaptable a cualquier proceso de recuperación de diferentes tipos de plástico. Esta primera aproximación permitió iniciar el proceso para la formulación de un sistema de logística inversa para el tratamiento de los residuos que generan los aparatos de las tecnologías de la información. Los resultados obtenidos en el modelo propuesto muestran comportamientos coherentes y este puede ser usado en diferentes escenarios y en otros procesos productivos para la recuperación de los RAEE. El estudio del sistema para la Recuperación de Aparatos Eléctricos y Electrónicos presenta altos niveles de variabilidad e incertidumbre, que lo convierten en algo complejo; esto obliga a la utilización de herramientas consideradas robustas, como la dinámica de sistemas, para su análisis.

Abstract The recovery of waste electrical and electronic equipment (WEEE) continues to grow every day. From the academic and business perspective, this process has gained a remarkable economic, environmental, and technological importance. In Colombia, however, its study is still incipient. In this paper, we aim to understand and validate a reverse logistics model for the recovery of waste electrical and electronic equipment (WEEE) based on the design and construction of a continuous simulation strategy. This strategy adopts the systems thinking approach supported by system dynamics. The projections in this study were calculated using information about the traditional recovery processes implemented by companies in the region and about companies in the sector that use acceptable technologies to carry out recovery activities. In particular our baseline model was a company that recycles PET plastic and whose recycling process can be adapted to different types of plastic. This first step allowed us to develop a reverse logistics system to manage the waste generated by discarded IT devices. Our findings showed consistent behaviors and suggest that the proposed model can be used in different scenarios and other production processes for WEEE recovery. The study of WEEE recovery systems is highly variable and uncertain, which makes it a complex task. Therefore, tools that are considered robust, such as system dynamics, must be used for that purpose.

Abstract Introduction Schwannomas are benign, solitary, encapsulated tumors that may originate at any site of the peripheral nervous system, with the exception of the olfactory and optic nerves. Schwannomas of the base of tongue are very rare, and only sporadic cases are documented. The tongue base represents a challenge for surgeons. Carbon dioxide (CO2) laser might provide an effective surgical option for such lesions because of the easy access to the lesion, the bloodless surgical field and optimum epithelization of wounds. Objective We present an unusual case of pedunculated schwannoma of the tongue base treated via transoral CO2-assisted excision. We also provide a review of the available literature, in English language, on humans. Data synthesis The authors searched the PubMed database and Google up to July 2018. The following search terms were applied: tongue and lingual, combined with schwannoma and neurilemmoma. Titles and abstracts were screened, and, then, only supraglottic (hypopharyngeal) tongue base masses were considered. Fourteen articles were included in this review, reporting 17 cases. The age of the patients ranged from 9 to 39 years, affecting predominantly females. Dysphagia and lump sensations were the most common presenting symptoms, and the mean follow-up period range was 1.5 to 60 months (mean = 13 months). There was no evidence of recurrence in any of the cases. Conclusion We could conclude that tongue base schwannomas are rare. Transoral complete excision of the tumor is the treatment of choice. CO2 laser surgery is a minimally invasive treatment option that has been performed in few reports with no recurrence and with favorable outcomes.

RESUMEN El avance tecnológico ha traído consigo la generación de residuos de celulares y tabletas. Esta tendencia seguirá en aumento, dado el fácil acceso a estos dispositivos. En el siguiente estudio, se relaciona la incidencia del nivel de escolaridad, sobre las actitudes y las percepciones, que se tienen sobre el manejo de los residuos provenientes de celulares y de tabletas, con el fin de ahondar en esta problemática y aportar insumos para la creación de estrategias y de políticas encaminadas al desarrollo sustentable. Para esto, se aplicó una encuesta a 450 personas que habitan en la ciudad de Florencia - Caquetá, Colombia. Se realizó un test de independencia, que permitió decidir si el nivel de escolaridad incide sobre las actitudes y las percepciones. Los resultados obtenidos indicaron que no existe tal dependencia con las actitudes, pero sí con las percepciones, lo que demuestra la inconsistencia del ser humano entre lo que piensa y cómo actúa. Un hallazgo relevante en el presente estudio es que, en su gran mayoría, estos dispositivos o sus partes, después de un tiempo, terminan en la basura, junto con los residuos convencionales.

SUMMARY The technological advance has brought with it the generation of cell and tablet waste. This trend will continue to increase, given the easy access to these devices. In the following study, the incidence of schooling level is related to attitudes and perceptions about the handling of cell and tablet waste, in order to deepen this problem and provide inputs for the creation of strategies and policies aimed at sustainable development. For this, a survey was applied to 450 people living in the city of Florencia Caquetá Colombia. An independence test was carried out, which allowed to decide if the level of schooling affects attitudes and perceptions. The results obtained indicated that there is no such dependence on attitudes, but with perceptions, this shows the human being’s lack of balance between what he thinks and how he acts. A relevant finding in the present study, is that the vast majority of these devices or their parts, after a while end up in the trash, along with conventional waste.

RESUMO Objetivo Verificar como os limiares obtidos pelas respostas auditivas de estado estável (RAEE) podem estimar os limiares obtidos pela audiometria com reforço visual (VRA), em crianças com audição normal e perda auditiva de diversos graus. Métodos Foram avaliadas 41 crianças de ambos os sexos (28 crianças do sexo masculino e 13 do sexo feminino), com faixa etária de 18 a 48 meses. Foram pesquisadas as frequências de 500, 1000, 2000 e 4000 Hz, em ambos os métodos de avaliação, e avaliadas as orelhas separadamente, totalizando 82 orelhas, sendo 20 com audição normal e 62 com perda auditiva. Os limiares foram analisados para calcular suas correlações e outras variáveis. Resultados Os limiares não variaram significativamente, nem com a idade, nem com o sexo. Em média, foram observados limiares eletrofisiológicos maiores que os limiares comportamentais. Conclusão A técnica da RAEE possibilita a determinação dos limiares auditivos objetivamente, com uma considerável correlação com os limiares psicoacústicos, concordando com a literatura. Recomenda-se, entretanto, a realização de novos estudos brasileiros, que visem ao estabelecimento de critérios mínimos necessários para o planejamento e aplicação de protocolos, com fins de padronização, contribuindo com a validação diagnóstica.

ABSTRACT Purpose The objective of the following study was to verify how the thresholds obtained by ASSR can estimate the thresholds obtained by the VRA in children with normal hearing and hearing loss of different degrees. Methods Were evaluated 41 children of both sex (28 boys and 13 girls), on ages between 18 and 48 months. The thresholds were obtained with ASSR with multiple and simultaneous stimulation on frequencies of 500, 1000, 2000 and 4000Hz. The thresholds were obtained with VRA on each ear separately on frequencies of 500, 1000, 2000 and 4000Hz. Were evaluated 82 ears, 20 with normal hearing and 62 with hearing loss. The correlation between the thresholds was calculated. Results The findings of this study demonstrate that the thresholds didn’t have a statistic relevant relation with variables of age and sex. Considering the mean, the eletrophysiological thresholds were higher than the behavioral. These findings suggest ASSR can determinate hearing thresholds objectively and with a high correlation with psychoacoustic thresholds obtained by the behavioral method. Conclusion We recommend, however that another Brazilian studies be made, so it can be established a minimum criteria necessary for the planning and application of pattern protocols, contributing with diagnostic validation of ASSR technique.

ABSTRACT The main objective of the research group is the recovery of valuable metals (contained in PCB’s) such as Cu, Au, Ag, Pt, Pd, etc., by hydrometallurgical alternatives to the current ones used in mining. One of the biggest difficulties that has encountered the research group is the lack of availability of an adequate, simple and reliable quantitative and qualitative determination technique of such metal values contained in the experimental technical solutions. This paper presents the preliminary results obtained in carrying out various laboratory experiments aimed at building calibration curves and patterns to determine gold contents by UV/VIS absorption spectrophotometry technique. These experiments where carried on by dissolution of pure gold in an aqua regia solution (made with three parts of HCl per each of HNO3). Afterwards, the gold was extracted from the aqueous solution by an organic solvent (methyl-isobutyl-ketone or MIBK) and diluted solutions were analyzed with the spectrophotometer. Both direct absorbance spectra and second order derivative spectra were taken into consideration. Besides, it was evaluated the feasibility of applying this analysis technique on shredded samples of PCB’s. The results showed that it is possible the construction of a standard curve using wavelengths around 332 nm and the analytical method is applicable to shredded electronic cards.

RESUMEN La recuperación de metales valiosos (como el Cu, Au, Ag, Pt, Pd, etc.), contenidos en las placas de circuito impreso (PCB’s) provenientes de chatarra electrónica, mediante vías hidrometalúrgicas alternativas a las actualmente empleadas en la minería, constituye el principal objetivo del grupo de investigación. Una de las mayores dificultades que enfrentan los investigadores del proyecto, radica en la falta de disponibilidad de una técnica adecuada, simple, confiable y rápida para la determinación cuantitativa y cualitativa de dichos valores metálicos contenidos en las soluciones experimentales. En este trabajo se informan los resultados preliminares obtenidos al llevarse a cabo distintas experiencias de laboratorio orientadas a la construcción y calibración de curvas patrones para la determinación de oro, a partir de la espectrofotometría de absorción UV-Visible. Tales experiencias se realizaron mediante el empleo de oro puro disuelto en una solución de agua regia (preparada con tres partes de HCl y una de HNO3), la ulterior extracción del mismo con un solvente orgánico (metil-isobutil-cetona o MIBK) y la observación en el espectrofotómetro de las soluciones orgánicas diluidas. En esta última etapa se han tenido en cuenta tanto espectros de absorción directa como derivativa de segundo orden. Además, se ha comprobado la aplicabilidad de la técnica de análisis en muestras trituradas de PCB’s. Los resultados obtenidos indican que es posible la construcción de una curva patrón utilizando longitudes de onda en torno a los 332 nm y el método se puede llevar a cabo con muestras de tarjetas electrónicas trituradas.

Resumo Introdução O desempenho da resposta auditiva de estado estável (RAEE) em testes de limiar com registros ipsilateral e contralateral e modulações em frequências (MFs) não tem sido sistematicamente estudado. Objetivo Verificar a influência do modo de registro (ipsilateral vs. contralateral) e da modulação em frequências (40 Hz vs. 90 Hz) nos limiares de RAEE. Método Foram estudados 15 mulheres e 14 homens (18-30 anos) com audição bilateral normal. Estímulos CE-chirp® de banda estreita (centrados em 500, 1.000, 2.000 e 4.000 Hz) modulados em 40 e 90 Hz de MF foram apresentados à orelha direita dos participantes. Em seguida, os limiares de RAEE foram registrados em cada frequência de teste nos canais ipsilateral e contralateral. Resultados Devido aos pronunciados efeitos de interação entre o modo de registro e MF (p < 0,05 por variância com dois fatores para medidas repetidas – Anova duas vias), os limiares médios de RAEE foram então comparados entre quatro condições (Ipsi-40 Hz, Ipsi-90 Hz, Contra-40 Hz e Contra-90 Hz), com o uso de variância e com um fator para medidas repetidas (Anova uma via). Nas frequências de teste de 500 e 1.000 Hz, a condição Contra-40 Hz produziu os mais baixos limiares médios de RAEE. Em contraste, em altas frequências (2.000 e 4.000 Hz), a condição Ipsi-90 Hz revelou os mais baixos limiares médios de RAEE. Na maioria das frequências de teste, a condição Contra-90 Hz produziu os mais elevados limiares médios de RAEE. Conclusões Com base nos achados do presente estudo, os autores recomendam dois protocolos diferentes para um teste de limiares ideal com RAEE, pelo menos em adultos jovens. Isso inclui o uso do modo de registro Contra-40 Hz, devido ao seu desempenho promissor nas estimativas do limiar auditivo.

Abstract Introduction The performance of auditory steady state response (ASSR) in threshold testing when recorded ipsilaterally and contralaterally, as well as at low and high modulation frequencies (MFs), has not been systematically studied. Objective To verify the influences of mode of recording (ipsilateral vs. contralateral) and modulation frequency (40 Hz vs. 90 Hz) on ASSR thresholds. Methods Fifteen female and 14 male subjects (aged 18–30 years) with normal hearing bilaterally were studied. Narrow-band CE-chirp® stimuli (centerd at 500, 1000, 2000, and 4000 Hz) modulated at 40 and 90 Hz MFs were presented to the participants' right ear. The ASSR thresholds were then recorded at each test frequency in both ipsilateral and contralateral channels. Results Due to pronounced interaction effects between mode of recording and MF (p < 0.05 by two-way repeated measures ANOVA), mean ASSR thresholds were then compared among four conditions (ipsi-40 Hz, ipsi-90 Hz, contra-40 Hz, and contra-90 Hz) using one-way repeated measures ANOVA. At the 500 and 1000 Hz test frequencies, contra-40 Hz condition produced the lowest mean ASSR thresholds. In contrast, at high frequencies (2000 and 4000 Hz), ipsi-90 Hz condition revealed the lowest mean ASSR thresholds. At most test frequencies, contra-90 Hz produced the highest mean ASSR thresholds. Conclusions Based on the findings, the present study recommends two different protocols for an optimum threshold testing with ASSR, at least when testing young adults. This includes the use of contra-40 Hz recording mode due to its promising performance in hearing threshold estimation.

Actualmente, el manejo integral de los residuos sólidos ordinarios resulta un reto para todas las naciones del mundo, con implicaciones ambientales en el suelo, agua y atmosfera. Por lo tanto, el objetivo de este estudio fue realizar un primer análisis de los residuos sólidos (plástico, vidrio, papel, y RAEE) registrados en un pequeño relicto de bosque del área de interés paisajístico Alonso Vera, localizado en el municipio de Girardot (Cundinamarca). La recolección y clasificación de los residuos se realizó el 14 de marzo de 2013 desde las 8:00 a.m. hasta las 11:00 a.m. con un esfuerzo de captura de 10 personas/sendero-márgenes, empleando elementos de protección como guantes y tapabocas para el pesaje de los residuos. En el relicto de bosque se recolectó en un día un total de 94 kg de residuos sólidos, siendo los RAEE y plásticos los más abundantes con 24,5 kg y 17 kg respectivamente. De este modo, se concluye preliminarmente que el relicto de bosque está siendo alterado principalmente por la disposición de plásticos y RAEE, siendo preocupante que la descomposición de estos residuos representa un riego para la salud humana e integridad de los ecosistemas.

Currently, the comprehensive management of ordinary solid waste becomes a challenge for all nations in the world, with environmental implications in soil, water and atmosphere. Therefore, the objective of this study was to perform a first analysis of solid waste (plastic, glass, paper, and WEEE) registered in a small relict forest of the Alonso Vera landscape zone, located in the municipality of Girardot (Cundinamarca). The collection and classification of waste was carried out on March 14, 2013 from 8:00 am until 11:00 am, with a capture effort of 10 people / forest trails, using protective gear such as gloves and masks for weighing the residue..In the forest relict a total of 94 kg of solid waste was collected in one day, being WEEE and plastic the most abundant with 24.5 kg and 17 kg respectively. This way, it is preliminarily concluded that the forest relict is being influenced mainly by the disposal of plastics and WEEE, matter of concern since the decomposition of this waste represents a risk to human health and the ecosystem integrity.

Introdução: As respostas auditivas de estado estável permitem avaliar de forma objetiva limiares auditivos frequência-específica. A audiometria tonal é o exame padrão-ouro; no entanto, nem sempre pode ser conclusiva, principalmente em crianças e adultos não colaborativos. Objetivo: Comparar os limiares auditivos da RAEE aos da audiometria tonal em indivíduos com audição normal. Materiais e métodos: Foram incluídos neste estudo prospectivo de corte transversal 26 adultos (52 orelhas), de ambos os gêneros, com audiometria normal e sem queixas otológicas. Os pacientes foram submetidos a anamnese, otomicroscopia, audiometria e imitanciometria. A seguir, realizou-se avaliação de respostas auditivas de estado estável. Os resultados obtidos foram analisados estatisticamente e comparados entre si. Resultados: A diferença entre os limiares (em dB NA) obtidos em ambos os exames para cada frequência testada foi de 7,12 dB para 500 Hz; 7,6 dB para 1000 Hz; 8,27 dB para 2000 Hz e 9,71 dB para 4000 Hz, com limiares mais elevados na RAEE, em todas as frequências. Não houve diferença estatística entre as médias para cada frequência testada. Conclusão: Os limiares obtidos na RAEE foram comparáveis aos da audiometria tonal em indivíduos normouvintes; entretanto, não deve ser usado como único método de avaliação auditiva.

Introduction: Auditory steady-state responses (ASSR) are an important tool to detect objectively frequency-specific hearing thresholds. Pure-tone audiometry is the gold-standard for hearing evaluation, although sometimes it may be inconclusive, especially in children and uncooperative adults. Aim: Compare pure tone thresholds (PT) with ASSR thresholds in normal hearing subjects. Materials and methods: In this prospective cross-sectional study we included 26 adults (n = 52 ears) of both genders, without any hearing complaints or otologic diseases and normal puretone thresholds. All subjects had clinical history, otomicroscopy, audiometry and immitance measurements. This evaluation was followed by the ASSR test. The mean pure-tone and ASSR thresholds for each frequency were calculated. Results: The mean difference between PTand ASSR thresholdswas 7,12 for 500 Hz, 7,6 for 1000 Hz, 8,27 for 2000 Hz and 9,71 dB for 4000 Hz. There were no difference between PT and ASSR means at either frequency. Conclusion: ASSR thresholds were comparable to pure-tone thresholds in normal hearing adults. Nevertheless it should not be used as the only method of hearing evaluation.

This is a summary of the author's PhD thesis supervised by Jose Luis González-Velarde (Tecnológico de Monterrey, Mexico) and Belarmino Adenso-Díaz (Universidad de Oviedo, Spain) and defended on October 11, 2010 at the Tecnológico de Monterrey. The thesis is written in English and is available from the author upon request. This research focuses on Reverse Logistics. Its main objective is to develop mathematical programming models and algorithms to optimize emerging Waste of Electric and Electronic Equipment (WEEE) collection systems. The thesis begins with an overview of the WEEE collection process and identifies key strategic decision areas which impact the performance of a collection system. It specifically identifies three closely interrelated problems within the logistics-manufacturing interface: network design, vehicle routing and cellular manufacturing (disassembly). Even though there is plenty of published literature on each of these individual problems, this research bridges a gap in existing literature on vehicle routing and cellular disassembly systems. The research aims to provide efficient solution approaches to optimize WEEE collection systems, therefore it uses real-world data and case studies (when possible) to test the proposed solution procedures. Computational results using real data show that the proposed methods outperform real existing approaches to reverse logistics.

Este artículo presenta un resumen de la tesis doctoral del autor, la cual fue supervisada por José Luis González-Velarde (Tecnológico de Monterrey, México) y Belarmino Adenso-Díaz (Universidad de Oviedo, España) y defendida el 11 de Octubre de 2010 en el Tecnológico de Monterrey. La tesis está escrita en inglés y disponible sobre petición directa al autor. Esta investigación se enfoca en el estudio de la logística inversa. Su principal objetivo consiste en desarrollar modelos de programación matemática y algoritmos para optimizar los emergentes sistemas de recolección de Residuos de Aparatos Eléctricos y Electrónicos (RAEE). La tesis comienza con una descripción general del proceso de recolección de RAEE, e identifica las principales áreas de decisión que impactan el rendimiento de los sistemas de recolección. De forma específica se identifican tres problemas altamente interrelacionados dentro de la interfaz logística-producción-manufactura: diseño de redes, ruteo de vehículos y manufactura (desensamble) celular. Aun cuando existe una plenitud de literatura publicada sobre cada uno de estos temas, esta investigación llena un vacío en la literatura de ruteo de vehículos y manufactura celular. La investigación tiene por meta proporcionar enfoques de solución eficientes para optimizar los sistemas de recolección de RAEE, por ello utiliza datos reales y casos de estudio para probar los procedimientos de solución propuestos. Los resultados computacionales muestran que los métodos sobresalen respecto a los enfoques actuales en logística inversa.

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.

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.

TEMA: a resposta auditiva de estado estável (RAEE) é um procedimento eletrofisiológico que permite avaliar ao mesmo tempo os limiares auditivos de várias freqüências em ambas às orelhas, reduzindo assim o tempo de teste, e permite estimular até níveis próximos a 125dB HL, caracterizando assim a audição residual. OBJETIVO: verificar a aplicabilidade da RAEE para determinar os limiares auditivos nos diferentes graus de perda auditiva neurossensorial coclear. MÉTODO: foram avaliados 48 indivíduos com idade entre sete e trinta anos e diferentes graus de perdas auditivas. A Audiometria Tonal Liminar (ATL) e a RAEE foram avaliadas nas seguintes freqüências portadoras, 0,5; 1; 2 e 4k Hz. As freqüências portadoras na RAEE foram moduladas em amplitude e freqüência, com estimulação múltipla e dicótica nas perdas auditivas de grau leve e moderado. Estimulação simples foi utilizada nos outros graus de perdas auditivas. RESULTADOS: houve associação significante (p < 0,01) entre os limiares obtidos na ATL e RAEE para todas as freqüências testadas, principalmente para perdas auditivas de grau profundo. Contudo em alguns pacientes o grau da perda auditiva pode ser super-estimado. CONCLUSÃO: a RAEE pode ser utilizada para predizer os limiares auditivos da ATL, porém não deve ser analisada de forma isolada, mas de forma complementar a avaliação audiológica comportamental.

BACKGROUND: the auditory steady state response (ASSR) is an electrophysiological procedure that evaluates, at the same time, the hearing thresholds of both ears at various frequencies. This procedure reduces the time of testing and enables the stimulation of levels close to 125dB HL, characterizing residual hearing. AIM: to verify the applicability of the ASSR to determine the hearing thresholds in different levels of sensorineural hearing loss. METHOD: 48 individuals aged 7-30 years, with different levels of hearing loss were assessed. The Pure tone Audiometry (PTA) and the ASSR were carried out in following carrier frequencies 0.5; 1; 2 and 4k Hz. The carrier frequencies in the ASSR were modulated in amplitude and frequency, with multiple dicotic stimulation for mild and moderate hearing loss. Simple stimulation was used to test the other hearing deficit levels. RESULTS: there was a significant association (p<0.01) between the thresholds obtained in the PTA and in the ASSR for all of the tested frequencies, especially for the severe levels. However, for some patients, the hearing loss level was overestimated in the ASSR. CONCLUSION: the ASSR can be used to estimate the PTA threshold; nevertheless, it should not be analyzed in an isolated way, but seen as a complementary procedure to the behavioral auditory assessment.