Automatic wheeze detection based on auditory modelling

Automatic wheeze detection has several potential benefits compared with reliance on human auscultation: it is experience independent, an automated historical record can easily be kept, and it allows quantification of wheeze severity. Previous attempts to detect wheezes automatically have had partial success but have not been reliable enough to become widely accepted as a useful tool. In this paper an improved algorithm for automatic wheeze detection based on auditory modelling is developed, called the frequency- and duration-dependent threshold algorithm. The mean frequency and duration of each wheeze component are obtained automatically. The detected wheezes are marked on a spectrogram. In the new algorithm, the concept of a frequency- and duration-dependent threshold for wheeze detection is introduced. Another departure from previous work is that the threshold is based not on global power but on power corresponding to a particular frequency range. The algorithm has been tested on 36 subjects, 11 of whom exhibited characteristics of wheeze. The results show a marked improvement in the accuracy of wheeze detection when compared with previous algorithms

Computerised lung sound analysis to improve the specificity of paediatric pneumonia diagnosis in resource-poor settings: protocol and methods for an observational study

Introduction: WHO case management algorithm for paediatric pneumonia relies solely on symptoms of shortness of breath or cough and tachypnoea for treatment and has poor diagnostic specificity, tends to increase antibiotic resistance. Alternatives, including oxygen saturation measurement, chest ultrasound and chest auscultation, exist but with potential disadvantages. Electronic auscultation has potential for improved detection of paediatric pneumonia but has yet to be standardised. The authors aim to investigate the use of electronic auscultation to improve the specificity of the current WHO algorithm in developing countries. Methods: This study is designed to test the hypothesis that pulmonary pathology can be differentiated from normal using computerised lung sound analysis (CLSA). The authors will record lung sounds from 600 children aged ≤5 years, 100 each with consolidative pneumonia, diffuse interstitial pneumonia, asthma, bronchiolitis, upper respiratory infections and normal lungs at a children\u27s hospital in Lima, Peru. The authors will compare CLSA with the WHO algorithm and other detection approaches, including physical exam findings, chest ultrasound and microbiologic testing to construct an improved algorithm for pneumonia diagnosis. Discussion: This study will develop standardised methods for electronic auscultation and chest ultrasound and compare their utility for detection of pneumonia to standard approaches. Utilising signal processing techniques, the authors aim to characterise lung sounds and through machine learning, develop a classification system to distinguish pathologic sounds. Data will allow a better understanding of the benefits and limitations of novel diagnostic techniques in paediatric pneumonia

Outcome Measures for Respiratory Physiotherapy in Cystic Fibrosis — Challenges and Advances

Respiratory physiotherapy is part of the routine management of patients with cystic fibrosis. It normally consists of airway clearance techniques and exercise training. The evidence of such interventions has been questioned. Nevertheless, the lack of evidence should not be interpreted as lack of benefit. Instead, attention to methodological issues, such as the selection of the outcome measures, is needed, as they may hamper the establishment of the effectiveness of respiratory physiotherapy techniques. Hence, this chapter presents and discusses the strengths and weaknesses of conventional and emerging outcome measures possibly to be used (i) in clinical practice before, during and after each session of respiratory physiotherapy to monitor its effectiveness; (ii) before and after the respiratory physiotherapy treatment (i.e., normally characterised by weeks of intervention) and (iii) in applied research in respiratory physiotherapy used in the management for cystic fibrosis. A comprehensive overview of the available outcome measures is provided, with particular emphasis on their strengths and limitations that should be recognised when interpreting the results

Wheezes, crackles and rhonchi:simplifying description of lung sounds increases the agreement on their classification: a study of 12 physicians' classification of lung sounds from video recordings

Background: The European Respiratory Society (ERS) lung sounds repository contains 20 audiovisual recordings of children and adults. The present study aimed at determining the interobserver variation in the classification of sounds into detailed and broader categories of crackles and wheezes.Methods: Recordings from 10 children and 10 adults were classified into 10 predefined sounds by 12 observers, 6 paediatricians and 6 doctors for adult patients. Multirater kappa (Fleiss'. kappa was calculated for each of the 10 adventitious sounds and for combined categories of sounds.Results: The majority of observers agreed on the presence of at least one adventitious sound in 17 cases. Poor to fair agreement (kappa &lt;0.40) was usually found for the detailed descriptions of the adventitious sounds, whereas moderate to good agreement was reached for the combined categories of crackles (kappa = 0.62) and wheezes (kappa = 0.59). The paediatricians did not reach better agreement on the child cases than the family physicians and specialists in adult medicine.Conclusions: Descriptions of auscultation findings in broader terms were more reliably shared between observers compared to more detailed descriptions.</p

Sons respiratórios computorizados em crianças com infeção respiratória do trato inferior : um estudo comparativo

Mestrado em FisioterapiaBackground: Lower respiratory tract infections (LRTI) are the main cause of health burden in the first years of age. To enhance the diagnosis and monitoring of infants with LRTI, researchers have been trying to use the large advantages of conventional auscultation. Computerised respiratory sound analysis (CORSA) is a simple method to detect and characterise Normal Respiratory Sounds (NRS) and Adventitious Respiratory Sounds (ARS). However, if this measure is to be used in the paediatric population, reference values have to be established first. Aim: To compare and characterise NRS and ARS in healthy infants and infants with LRTI. Methods: A cross-sectional descriptive-comparative study was conducted in three institutions. Infants were diagnosed by the paediatrician as presenting or not presenting an LRTI, healthy volunteers were recruited from the institutions. Socio-demographic, anthropometric and cardio-respiratory parameters were collected. Respiratory sounds were recorded with a digital stethoscope. Frequency at maximum intensity (Fmax), maximum intensity (Imax) and mean intensity (Imean) over the whole frequency range were collected to characterise NRS. Location, mean number, type, duration and frequency were collected to characterise ARS. All analysis was performed per breathing phase (i.e., inspiration and expiration). Results: Forty nine infants enrolled in this study: 25 healthy infants (G1) and 24 infants with LRTI. Inspiratory Fmax (G1: M 116.1 Hz IQR [107.2-132.4] vs G2: M 118.9Hz IQR [113.2-128.7], p=0.244) and expiratory frequencies (G1: M 107.3Hz IQR [102.9-116.9] vs G2: M 112.6Hz IQR [106.6-122.6], p= 0.083) slightly higher than their healthy peers. Wheeze occupation rate was statistically significantly different between groups in inspiration (G1: M 0 IQR [0-0.1] vs G2: M 0.2 IQR [0-5.2] p= 0.032) and expiration (G1: M 0 IQR [0-1.9] vs G2: M 1.5 IQR [0.2-6.7] p= 0.015), being the infants with LRTI the ones presenting more wheezes. Conclusion: Computerised respiratory sounds in healthy infants and infants with LRTI presented differences. The main findings indicated that NRS have Fmax higher in infants with LRTI than in healthy infant and Wh% was the characteristic that differ the most between infant with LRTI and healthy infant.Enquadramento: As infeções respiratórias do trato inferior (IRTI) constituem o principal problema de saúde nos primeiros anos de vida das crianças. Desta forma, a investigação tem-se focado no desenvolvimento de medidas objetivas para o diagnóstico de IRTI, utilizando essencialmente as vantagens da auscultação convencional incorporadas numa análise computorizada e automática. Contudo, apesar da análise computorizada de sons respiratórios ser um método simples de deteção e caraterização dos sons respiratórios normais (SRN) e adventícios (SRA), desconhecem-se quais os valores de referência dos sons respiratórios em crianças, o que limita a sua aplicação na prática clínica Objetivos: Caraterizar e comparar os SRN e os SRA em crianças saudáveis e com IRTI. Métodos: Estudo descritivo, comparativo e transversal realizado em três instituições. Eram elegíveis crianças diagnosticadas pelo pediatra com IRTI e voluntários para crianças saudáveis. Foram recolhidos dados sócio demográficos, antropométricos e parâmetros cardiorrespiratórios. Os sons respiratórios foram registados com um estetoscópio digital. Foram analisados diversos parâmetros para os SRN: a frequência na intensidade máxima (Fmax), a intensidade máxima (Imax) e a média da intensidade ao longo de toda a faixa de frequência (Imean). Nos SRA foram analisados: a taxa de ocupação por wheezes (Wh%), a média wheezes (Wh), o número e o tipo Wh, a frequência e a localização Wh por região; o número crackles (Cr), o tipo e a frequência Cr, a duração da deflexão inicial, da maior deflexão e dos dois ciclos de deflexão dos Cr. Todos estes dados foram analisados por fase do ciclo respiratório (i.e., inspiração e expiração). Resultados: Quarenta e nove crianças foram incluídas neste estudo: 25 saudáveis (G1) e 24 com IRTI (G2). A Fmax inspiratória (G1: M 116,1 Hz IQR [107,2-132,4] vs G2: M 118.9Hz IQR [113,2-128,7], p = 0,244) e expiratória (G1: M 107.3Hz IQR [102,9-116,9] vs G2: M 112.6Hz IQR [106,6-122,6], p = 0,083) foi superior nas crianças com IRTI relativamente às crianças saudáveis. A Wh% foi significativamente superior nas crianças com IRTI, relativamente às crianças saudáveis na inspiração (G1: M 0 IQR [0-0,1] vs G2: M 0,2 IQR [0-5,2] p = 0,032) e na expiração (G1: M 0 IQR [0-1,9] vs G2: M 1,5 IQR [0,2-6,7] p = 0,015). Conclusão: Os sons respiratórios computorizados de crianças saudáveis e com IRTI apresentam diferenças. Os principais resultados indicam que os sons respiratórios normais apresentam uma Fmax maior em crianças com IRTI do que em saudáveis e que Wh% é a característica que mais difere entre os dois grupos