Application of clustering techniques for lung sounds to improve interpretability and detection of crackles

Due to the subjectivity involved currently in pulmonary auscultation process and its diagnostic to evaluate the condition of respiratory airways, this work pretends to evaluate the performance of clustering algorithms such as k-means and DBSCAN to perform a computational analysis of lung sounds aiming to visualize a representation of such sounds that highlights the presence of crackles and the energy associated with them. In order to achieve that goal, Wavelet analysis techniques were used in contrast to traditional frequency analysis given the similarity between the typical waveform for a crackle and the wavelet sym4. Once the lung sound signal with isolated crackles is obtained, the clustering process groups crackles in regions of high density and provides visualization that might be useful for the diagnostic made by an expert. Evaluation suggests that k-means groups crackle more effective than DBSCAN in terms of generated clusters.Debido a la subjetividad que involucra actualmente el proceso de auscultación pulmonar y su diagnóstico para evaluar la condición de las vías respiratorias de un paciente, este trabajo busca evaluar el desempeño de los algoritmos de clustering: k-means y DBSCAN para efectuar un análisis computacional de sonidos pulmonares con el objetivo de visualizar una representación de dichos sonidos que exalte la presencia de estertores y la energía contenida en ellos. Para este fin, se emplearon técnicas de descomposición y análisis Wavelet a diferencia del tradicional análisis en frecuencia dada la similitud entre la forma de onda de un estertor típico y la wavelet sym4. Obtenida la señal de sonido pulmonar con estertores aislados, el proceso de clustering agrupa estertores en regiones de alta presencia y ofrece una visualización que puede ser de utilidad para el diagnóstico hecho por un experto. La evaluación hecha sugiere que k-means agrupa conjuntos de estertores de forma más efectiva que DBSCAN en términos de clusters generados

Aplicación de Técnicas de Clustering en Sonidos Adventicios para Mejorar la Interpretabilidad y Detección de Estertores

Due to the subjectivity involved currently in pulmonary auscultation process and its diagnostic to evaluate the condition of respiratory airways, this work pretends to evaluate the performance of clustering algorithms such as k-means and DBSCAN to perform a computational analysis of lung sounds aiming to visualize a representation of such sounds that highlights the presence of crackles and the energy associated with them. In order to achieve that goal, Wavelet analysis techniques were used in contrast to traditional frequency analysis given the similarity between the typical waveform for a crackle and the wavelet sym4. Once the lung sound signal with isolated crackles is obtained, the clustering process groups crackles in regions of high density and provides visualization that might be useful for the diagnostic made by an expert. Evaluation suggests that k-means groups crackle more effective than DBSCAN in terms of generated clusters. Debido a la subjetividad que involucra actualmente el proceso de auscultación pulmonar y su diagnóstico para evaluar la condición de las vías respiratorias de un paciente, este trabajo busca evaluar el desempeño de los algoritmos de clustering: k-means y DBSCAN para efectuar un análisis computacional de sonidos pulmonares con el objetivo de visualizar una representación de dichos sonidos que exalte la presencia de estertores y la energía contenida en ellos. Para este fin, se emplearon técnicas de descomposición y análisis Wavelet a diferencia del tradicional análisis en frecuencia dada la similitud entre la forma de onda de un estertor típico y la wavelet sym4. Obtenida la señal de sonido pulmonar con estertores aislados, el proceso de clustering agrupa estertores en regiones de alta presencia y ofrece una visualización que puede ser de utilidad para el diagnóstico hecho por un experto. La evaluación hecha sugiere que k-means agrupa conjuntos de estertores de forma más efectiva que DBSCAN en términos de clusters generados

Automatic classification of adventitious respiratory sounds: a (un)solved problem?

(1) Background: Patients with respiratory conditions typically exhibit adventitious respiratory sounds (ARS), such as wheezes and crackles. ARS events have variable duration. In this work we studied the influence of event duration on automatic ARS classification, namely, how the creation of the Other class (negative class) affected the classifiers’ performance. (2) Methods: We conducted a set of experiments where we varied the durations of the other events on three tasks: crackle vs. wheeze vs. other (3 Class); crackle vs. other (2 Class Crackles); and wheeze vs. other (2 Class Wheezes). Four classifiers (linear discriminant analysis, support vector machines, boosted trees, and convolutional neural networks) were evaluated on those tasks using an open access respiratory sound database. (3) Results: While on the 3 Class task with fixed durations, the best classifier achieved an accuracy of 96.9%, the same classifier reached an accuracy of 81.8% on the more realistic 3 Class task with variable durations. (4) Conclusion: These results demonstrate the importance of experimental design on the assessment of the performance of automatic ARS classification algorithms. Furthermore, they also indicate, unlike what is stated in the literature, that the automatic classification of ARS is not a solved problem, as the algorithms’ performance decreases substantially under complex evaluation scenarios.publishe