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ABSTRACT For computerized analysis of respiratory sounds to be effective, the acquired signal must be free from all the interfering elements. Different forms of noise which can degrade the quality of lung sounds are recording artifacts, power line/Radio Frequency (RF) interferences, ambient acoustic interferences, heart sound interference etc. Such interferences adversely affect the diagnostic interpretations. Powerful denoising techniques are necessary to resolve this issue. A denoising scheme for lung sounds, based on Savitzky-Golay (S-G) filter is proposed in this paper. The order and frame length of the SG filter is determined objectively using the Signal to Noise Ratio (SNR) and computational time as objective function. Maximum SNR is observed when the frame length is nearest to the value just higher than the polynomial order. This observation holds good for different levels of simulated addictive Gaussian noise. The polynomial order of 8 and frame size of 9 are found to be promising with SNR of 10.401db at computation time of 2.1ms.
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Objective By using lung sound spectrum analysis, the clinical efficacy of asthma -relieving manipulation, which is a gentle massage therapy mainly on the acupoints, on acute exacerbation of children asthma was evaluated. Methods We collected the lung sound of 11 children with acute asthmatic attack before and after asthma-relieving manipulation, and then input to the computer for obtaining lung sound spectrum signal data. The sound intensity, average respiratory muscle strength ( RMS) power, total RMS power and the volume of every 25 Hz frequency spectrum were extracted for comparison. Results After asthma-relieving manipulation, the sound intensity, average RMS power, and total RMS power of the children with acute asthmatic attack were significantly lower than those before the manipulation (P0.05). Conclusion Lung sound spectrum analysis can be applied to monitor lung function of asthmatic children objectively and quantitatively, and it is a new sensitive method for clinical detection. Asthma-relieving manipulation shows certain effect on acute exacerbation of children asthma.
ABSTRACT
BACKGROUND: Auscultation of lung sound is a fundamental component of physical examination of respiratory disease. It is difficult to teach lung sound to the medical student because of the observer variability and the lack of objective recording in auscultation. Multimedia education has became available in many fields due to rapid development of computer and its software. So we made multimedia program to teach the lung sound and evaluated the effect of this program on the self study of the lung sound by medical students. METHOD: We developed the multimedia title "Auscultation of lung sound" by integrating lung sounds, wave form display, radiographic findings and some explanations about various lung sounds including normal and abnormal lung sounds. Thirty students attending in the 2nd year of Medical school at the Hallym University was randomly divided into two groups. Each group studied on their own using either tape or multimedia title for one week. After the study, they were tested to describe the lung sound of real patients who were admitted to the Chun Cheon Sacred Heart Hospital. Multimedia group was asked to answer the questionnaire on multimedia title. RESULTS: 1) Test score of auscultation on real patients: The mean score of tape group and multimedia group was 1.20+/-1.08 and 1.54+/-0.74 respectively. But there was no significant difference between two groups (P=0.34). 2) Summary of questionnaire: Twelve out of 15(80%) students answered that multimedia title helped them to understand the lung sound and three students(20%) answered that this program was very helpful. For the visual display of wave form, eight out of 15(34%) students answered that it was helpful and three out of 15(34%) students answered that it was very helpful. Eighty seven percent of the students answered that visual display of sound wave form helped them to understand the lung sound. Fourteen out of 15 students answered that multimedia program was interesting and provocative. All student answered that they will recommend this title to other colleagues. CONCLUSON: Even though there was no stastical significant difference between two self study methods but student of multimedia group showed narrow range of score than tape group. Answer to the questionnaire supported the usefulness of multimedia for the self study of lung sound. Therefore we conclude that this program is helpful in the self-learninig of lung sound for medical students.