Sistema adaptativo para redução do efeito de oclusão em aparelhos auditivos

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia ElétricaA deficiência auditiva é um mal que atinge parcela significativa da população mundial. Sistemas de auxílio à audição têm se apresentado como importantes aliados na redução dos problemas de comunicação decorrentes dessa deficiência. No entanto, ainda hoje apresentam consideráveis limitações, tais como problemas de realimentação acústica e efeito de oclusão. Esse trabalho apresenta a proposta de um sistema adaptativo de controle ativo de ruído para redução do efeito de oclusão em aparelhos auditivos. O efeito de oclusão é causado pelas vibrações das porções cartilaginosas nas paredes do canal auditivo e acarreta desconforto acústico durante a fala do usuário. Para reduzir esse problema, um microfone posicionado internamente ao canal auditivo e um filtro adaptativo são utilizados de forma a produzir uma estimativa do sinal de oclusão em anti-fase. Esta estimativa é aplicada conjuntamente com o sinal processado de fala no alto-falante do dispositivo. Como resultado, obtém-se uma diminuição do desconforto acústico. Resultados de simulações e de experimentos em condições reais demonstram a viabilidade e a funcionalidade da arquitetura proposta.Hearing impairment is a disease that affects a significant amount of the world's population. Hearing aids have become important allies in reducing communication problems arising from such disabilities. However, hearing aids present some limitations, such as acoustic feedback and occlusion effect. This work presents a proposal of an adaptive active noise control system to reduce the acoustic occlusion effect in hearing aids. Occlusion effect is caused by vibrations at the cartilaginous ear canal walls, and causes discomfort, especially during user's speech. To reduce this problem, a microphone is placed inside the ear canal and an adaptive filter are used to generate an anti-phase estimate of the occlusion signal. This estimate and the processed speech signal are applied to the hearing aid's receiver. The end result of this process is the reduction of the acoustic discomfort. Computer simulations and experiments under real operation conditions illustrate the feasibility and functionality of the proposed architecture

Uma proposta para a redução do efeito de oclusão em aparelhos auditivos

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Elétrica, Florianópolis, 2017.A deficiência auditiva, também conhecida como surdez, consiste na perda parcial ou total da capacidade de audição de um indivíduo. De forma geral, essa limitação pode ser compensada pela utilização de aparelhos auditivos. Esses dispositivos são projetados não apenas para amplificar o campo acústico nas adjacências do ouvido, mas também para aumentar a inteligibilidade e o conforto acústico do usuário. Apesar do avanço da tecnologia digital, estudos recentes relatam a insatisfação dos usuários com relação a diferentes aspectos, entre eles: a amplificação do ruído ambiente, a realimentação acústica e o efeito de oclusão. Essas características tendem a reduzir o tempo de uso diário do aparelho pelos usuários.A realimentação acústica decorre do acoplamento acústico entre o alto-falante e o microfone do aparelho auditivo e se manifesta na forma de um apito estridente que causa desconforto físico ao usuário, podendo ser ouvido por pessoas no seu entorno. A prevenção da realimentação acústica usualmente é realizada através da limitação do ganho máximo do dispositivo, da utilização de canceladores ativos de realimentação ou do estreitamento ou fechamento do canal auditivo por um molde (de forma a aumentar a impedância acústica entre alto-falante e microfone). Embora o estreitamento ou fechamento do canal auditivo seja o método mais usual e efetivo, sua utilização resulta no chamado efeito de oclusão. O efeito de oclusão ocorre quando o aparelho auditivo, posicionado na porção cartilaginosa do canal, possui uma abertura de ventilação com tamanho insuficiente para promover a necessária dissipação de energia sonora conduzida ao canal auditivo através do crânio e da mandíbula, causando aumento significativo de potência em baixas frequências (predominantemente na faixa de 200 a 500 Hz) e fazendo com que o usuário ouça sua própria voz de forma abafada. Este trabalho apresenta, inicialmente, a análise de um sistema de cancelamento de realimentação na presença do efeito de oclusão. Simulações para validação do modelo mostraram que o efeito de oclusão não altera o desempenho do sistema de cancelamento. Como contribuição principal, um novo sistema adaptativo de controle ativo de ruído para reduzir o efeito de oclusão em aparelhos auditivos sem duto de ventilação é proposto. Em contraste com os canceladores de efeito de oclusão previamente desenvolvidos, esse sistema oferece uma estrutura de cancelamento não realimentada, que permite a análise de seu comportamento como um problema de identificação de um filtro linear com resposta ao impulso finita. Equações recursivas determinísticas foram derivadas para predição do erro quadrático médio e comportamento médio dos coeficientes, tanto para transitório como em regime permanente. Tais modelos são de particular interesse para os projetistas de aparelhos auditivos como ferramentas de guia para definir parâmetros ótimos, de forma a obter o desempenho desejado. As simulações computacionais concordam com as predições teóricas obtidas pelas equações derivadas, indicando uma redução média de 5,4 dB do efeito de oclusão na faixa de 200-500 Hz. Experimentos subjetivos corroboram a funcionalidade da arquitetura proposta.Abstract : Hearing loss is the partial or total loss of hearing ability of an individual. In general, this limitation can be compensated by the use of hearing aids. These devices are designed not only to amplify the sound field in the vicinity of the ear, but also to increase the intelligibility and acoustic comfort of the user. Even with the advancement of digital technology, recent studies have reported the dissatisfaction of users with respect to several aspects, including: environmental noise amplification, acoustic feedback and occlusion effect. Such characteristics tend to reduce the daily use of the device by users.The acoustic feedback results from the acoustic coupling between the loudspeaker and the microphone of the hearing aid, and is manifested as a shrill whistle that causes physical discomfort to the user and it is perceived by the user and people around as an unpleasant sound. Prevention of acoustic feedback is usually accomplished by limiting the maximum gain of the device, the use of active feedback cancellers or by narrowing or closing of the auditory canal by a mould (in order to increase the acoustic impedance between loudspeaker and microphone). The narrowing or closure of the auditory canal is the most common and effective method, but its use reinforces the occlusion perception. The occlusion effect occurs when the earmould, placed in the cartilaginous part of the ear canal, has a ventilation oppening insufficient to dissipate the necessary acoustical energy conducted to the ear canal through the skull and jaw, resulting in a power increase at low frequencies (predominantly in the range of 200 to 500 Hz), leading the user to perceive a muffled version of his own voice.This work presents, initially, an analysis of a feedback system cancellation in the presence of the occlusion effect. The predicted results of the mean weight behaviour are compared with simulations to show that the occlusion effect does not affect the feedback system performance. Following, a new adaptive active-noise-control system to reduce the occlusion effect in unvented hearing aids is proposed. In contrast to previously developed occlusion-effect cancellers, this system is based on a feedforward cancelling structure that permits the analysis of its behaviour as a finite-impulse-response linear-filter identification problem. Deterministic recursive equations were derived with the aim to theoretically predict its mean square error and mean coefficient behaviour, both in transient and steady state conditions. Such models are of particular interest to hearing aid designers as guide tools for setting parameters to obtain a desired performance. Computational simulations accurately agree with theoretical predictions obtained by the derived equations, indicating a mean reduction of 5.4 dB of the occlusion effect in the range of 200?500 Hz. Subjective experiments corroborate the functionality of the proposed architecture

Atrial fibrillation classification based on MLP networks by extracting Jitter and Shimmer parameters

Atrial fibrillation (AF) is the most common cardiac anomaly and one that potentially threatens human life. Due to its relation to a variation in cardiac rhythm during indeterminate periods, long-term observations are necessary for its diagnosis. With the increase in data volume, fatigue and the complexity of long-term features make analysis an increasingly impractical process. Most medical diagnostic aid systems based on machine learning, are designed to automatically detect, classify or predict certain behaviors. In this work, using the PhysioNet MIT-BIH Atrial Fibrillation database, a system based on MLP artificial neural network is proposed to differentiate, between AF and non-AF, segments and ECG’s features, obtaining average accuracy of 80.67% in test set, for the 10-fold cross-validation method. As a highlight, the extraction of jitter and shimmer parameters from ECG windows is presented to compose the network input sets, indicating a slight improvement in the model's performance. Added to these, Shannon's and logarithmic energy entropies are determined, also indicating an improvement in performance related to the use of fewer features.This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UIDB/05757/2020.info:eu-repo/semantics/publishedVersio

Mechanical and optical properties of conventional restorative glass-ionomer cements - a systematic review

Objectives To perform a systematic review of test methodologies on conventional restorative glass-ionomer cement (GIC) materials for mechanical and optical properties to compare the results between different GICs. Material and Methods Screening of titles and abstracts, data extraction, and quality assessments of full-texts were conducted in search for in vitro studies on conventional GICs that follow the relevant specifications of ISO standards regarding the following mechanical and optical properties: compressive strength, flexural strength, color, opacity and radiopacity. Sources The Latin American and Caribbean Health Sciences (LILACS), Brazilian Bibliography of Dentistry (BBO) databases from Latin-American and Caribbean System on Health Sciences Information (BIREME) and PubMed/Medline (US National Library of Medicine - National Institutes of Health) databases were searched regardless of language. Altogether, 1146 in vitro studies were selected. Two reviewers independently selected and assessed the articles according to pre-established inclusion/exclusion criteria. Among all the properties investigated, only one study was classified as being of fair quality that tested compressive strength and was included. It was observed that many authors had not strictly followed ISO recommendations and that, for some properties (diametral tensile strength and microhardness), there are no guidelines provided. Conclusions It was not possible to compare the results for the mechanical and optical properties of conventional restorative GICs due to the lack of standardization of studies

Mechanical and optical properties of conventional restorative glassionomer cements - a systematic review

Objectives: To perform a systematic review of test methodologies on conventional restorative glass-ionomer cement (GIC) materials for mechanical and optical properties to compare the results between different GICs. Material and Methods: Screening of titles and abstracts, data extraction, and quality assessments of full-texts were conducted in search for in vitro studies on conventional GICs that follow the relevant specifications of ISO standards regarding the following mechanical and optical properties: compressive strength, flexural strength, color, opacity and radiopacity. Sources: The Latin American and Caribbean Health Sciences (LILACS), Brazilian Bibliography of Dentistry (BBO) databases from Latin-American and Caribbean System on Health Sciences Information (BIREME) and PubMed/Medline (US National Library of Medicine - National Institutes of Health) databases were searched regardless of language. Altogether, 1146 in vitro studies were selected. Two reviewers independently selected and assessed the articles according to pre-established inclusion/exclusion criteria. Among all the properties investigated, only one study was classified as being of fair quality that tested compressive strength and was included. It was observed that many authors had not strictly followed ISO recommendations and that, for some properties (diametral tensile strength and microhardness), there are no guidelines provided. Conclusions: It was not possible to compare the results for the mechanical and optical properties of conventional restorative GICs due to the lack of standardization of studies

Epidemiology of vulvar lichen sclerosus and its correlation with other conditions

OBJECTIVES: To investigate some epidemiological data of lichensclerosus patients; to verify its association with other conditionsand compare these data with the literature. METHODS:Retrospective analysis of medical records of patients submitted to12,724 vaginal/cervical examinations and vulvoscopies, at Hospitaldo Servidor Público Estadual “Francisco Morato de Oliveira” – SãoPaulo, from August 1998 to August 2001. RESULTS: The frequencyof lichen sclerosus confirmed by pathological examination was0.73% among these patients. Mean age was 63.6 years. Mostpatients presenting the condition were aged over 50 years (81/93), and the difference was statistically significant as comparedwith younger subjects (12/93). Caucasian women represented91.4% of the sample and black, 8.6%. Smokers accounted for 8.6%of the cases. Autoimmune diseases were detected in 31.2%,psychiatric disorders in 17.2%, and neoplasms in 11.8% of thosesuffering from lichen sclerosus. The colpocytology of one patientwas classified as Papanicolaou class V. CONCLUSION: These datashow the population studied presented findings similar to thosereported in the literature

Programa de Educación Tutorial en salud bucal : la experiencia en atención primaria en el centro de salud de Itapoã-DF

Este artigo apresenta o relato de experiência do Programa de Educação Tutorial em Odontologia da Universidade de Brasília, durante o período de março a dezembro de 2010. O cenário de prática das atividades de campo é a Regional Administrativa do Itapoã, no Distrito Federal, e a atuação do grupo tutorial acontece junto às Equipes de Saúde da Família por meio de rotinas educativo-preventivas em saúde bucal durante as visitas domiciliares, atividades clínicas e desenvolvimento de pesquisas. Alunos e preceptores estão sendo capazes de reconhecer os determinantes sociais do processo saúdedoença, analisar os indicadores de saúde bucal da população, aprimorar práticas educativas utilizadas na Estratégia Saúde da Família e promover saúde no âmbito da comunidade. As principais dificuldades encontradas dizem respeito a limitação de espaço físico e de recursos capazes de atender a demanda do grupo tutorial e das famílias assistidas. Esta experiência tutorial junto à Estratégia Saúde da Família possibilita um aprendizado que vai muito mais além do que a tradição de ensino bio-tecnicista da odontologia, bem como permite aos discentes de odontologia da UnB ‘vivenciar uma experiência real’ e refletir sobre os conhecimentos teóricos obtidos nos ‘bancos da universidade’. _________________________________________________________________________________________________________________ ABSTRACTThis paper presents an experience report of the Tutorial Program in Dentistry from the University of Brasília, during the period from March to December, 2010. The scenario of practice is the Itapoã - an Administrative Area of the Distrito Federal - and the activities of the tutorial group take place in partnership with the Family Health Team through a preventive educational oral health routine during home visits, as well as clinical activities and development of research. Students and preceptors are being able to recognize the social determinants of the health-disease process, analyze oral health indicators of the population, improve educational practices and promote health within the community. The main barriers of the tutorial group are the lack of physical space and dental equipment capable of meeting the demand of the tutorial group and assisted families. This tutorial experience within the Family Health Strategy provides a learning experience that goes far beyond the tradition of teaching bio-technicalities of dentistry, as well as allows dental students real to live through a real field experience and reflect on the theoretical knowledge obtained from the ‘university seats’. _________________________________________________________________________________________________________________ RESUMENEste documento presenta el relato de la experiencia del Programa de Educación Tutorial en Odontología de la Universidad de Brasília, durante el período de Marzo a Diciembre de 2010. El escenário de práctica de las actividades de campo es el Sector Regional Administrativo de Itapoã, en el Distrito Federal, donde el trabajo del grupo tutorial acompaña el trabajo de los Equipos de Salud de la Família a través de la educación preventiva de rutina en la salud bucal de la población, mejorando las prácticas educativas utilizadas en la estrategia de salud familiar y promoviendo la salud en la comunidad. Las principales dificultades se refieren a la limitación del espacio físico y el equipo dental capaces de satisfacer la demanda del grupo tutorial y de las famílias atendidas. Esta actividad tutorial con la Estrategia de Salud de la Família ofrece una experiencia de aprendizaje que vá más allá de la tradición de la enseñanza de técnicas bio-odontológicas, así como permite a los estudiantes de odontología de la UnB “pasar una verdadera experiencia” y reflexionar sobre el conocimiento teórico obtenido en “los bancos de datos de la universidad”

The Brazilian Registry of Adult Patient Undergoing Cardiovascular Surgery, the BYPASS Project: Results of the First 1,722 Patients

Objective: To report the early results of the BYPASS project - the Brazilian registrY of adult Patient undergoing cArdiovaScular Surgery - a national, observational, prospective, and longitudinal follow-up registry, aiming to chart a profile of patients undergoing cardiovascular surgery in Brazil, assessing the data harvested from the initial 1,722 patients. Methods: Data collection involved institutions throughout the whole country, comprising 17 centers in 4 regions: Southeast (8), Northeast (5), South (3), and Center-West (1). The study population consists of patients over 18 years of age, and the types of operations recorded were: coronary artery bypass graft (CABG), mitral valve, aortic valve (either conventional or transcatheter), surgical correction of atrial fibrillation, cardiac transplantation, mechanical circulatory support and congenital heart diseases in adults. Results: 83.1% of patients came from the public health system (SUS), 9.6% from the supplemental (private insurance) healthcare systemsand 7.3% from private (out-of-pocket) clinic. Male patients comprised 66%, 30% were diabetics, 46% had dyslipidemia, 28% previously sustained a myocardial infarction, and 9.4% underwent prior cardiovascular surgery. Patients underwent coronary artery bypass surgery were 54.1% and 31.5% to valve surgery, either isolated or combined. The overall postoperative mortality up to the 7th postoperative day was 4%for CABG was 2.6%, and for valve operations, 4.4%. Conclusion: This first report outlines the consecution of the Brazilian surgical cardiac database, intended to serve primarily as a tool for providing information for clinical improvement and patient safety and constitute a basis for production of research protocols.Univ Fed Sao Paulo UNIFESP EPM, Hosp Sao Paulo, Sao Paulo, SP, BrazilHosp Caridade Sao Vicente Paulo, Jundiai, SP, BrazilInst Med Integral Prof Fernando Figueira IMIP, Recife, PE, BrazilHosp Base FUNFARME & FAMERP, Sao Jose Do Rio Preto, SP, BrazilIMC, Sao Jose Do Rio Preto, SP, BrazilIrmandade Santa Casa Sao Paulo INCT HPV, Fac Ciencias Med Santa Casa Sao Paulo, Sao Paulo, SP, BrazilFundacao Univ Cardiol, Inst Cardiol Rio Grande do Sul, Porto Alegre, RS, BrazilInst Coracao Natal, Natal, RN, BrazilInst Cardiol Dist Fed, Brasilia, DF, BrazilUniv Fed Maranhao HU UFMA, Univ Hosp, Sao Luis, MA, BrazilHosp Evangelico, Cachoeiro De Itapemirim, ES, BrazilHosp Coracao Sergipe, Aracaju, SE, BrazilHosp Nossa Senhora Salete, Inst Cirurgia Cardiovasc ICCV, Cascavel, PR, BrazilHosp Wilson Rosado, Mossoro, RN, BrazilHosp Bosque Saude, Sao Paulo, SP, BrazilHosp Univ Santa Maria, Santa Maria, RS, BrazilHosp Coracao HCor, Sao Paulo, SP, BrazilHosp Coracao IP HCor, Ins Pesquisa, Sao Paulo, SP, BrazilInst Coracao InCor, Sao Paulo, SP, BrazilUniv Fed Sao Paulo UNIFESP EPM, Hosp Sao Paulo, Sao Paulo, SP, BrazilWeb of Scienc