Time-frequency detection and analysis of wheezes during forced exhalation.
The objective of the present work was to detect and analyze wheezes by means of a highly sensitive time-frequency algorithm. Automatic measurements were compared with clinical auscultation for forced exhalation segments from 1.2 to 0 liters/second (l/s). Sensitivities between 100% and 71%, as a function of flow level related to wheezing segments detection, were achieved. Time-frequency wheeze parameters were measured for the flow range from 1.2 to 0.2 l/s. Wheezes were detected in both analyzed groups; asthmatics (N = 16) and control subjects (N = 15). Significant differences between groups were found for the mean number of wheezes detected at basal condition (p = 0.0003). Frequency parameter differences were also significant (0.0112 < p < 0.0307). All these parameters were also studied after applying a bronchodilator drug (Terbutaline). Significant differences between patient groups were found when studying the changes in the number of wheezes for each patient (p = 0.0195). Finally, limited bandwidth parameters, which measure the bronchodilator response, were also studied.
Homs-Corbera
Antoni
A
Department of Automatic Control (ESAII), Biomedical Engineering Research Center (CREB), Technical University of Catalonia (UPC), 08028 Barcelona, Spain. homs@creb.upc.es
Fiz
José Antonio
JA
Morera
José
J
Jané
Raimon
R
D000465:Algorithms; D001249:Asthma / Q000150:complications / Q000175:diagnosis*; D001314:Auscultation / Q000379:methods*; D016000:Cluster Analysis; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D045853:Exhalation; D006801:Humans; D008875:Middle Aged; D010363:Pattern Recognition, Automated; D015203:Reproducibility of Results; D012135:Respiratory Sounds / Q000175:diagnosis* / Q000209:etiology; D012680:Sensitivity and Specificity; D013018:Sound Spectrography / Q000379:methods*