The idea behind this work is linked to the experience gained from the long use of the stethoscope, and to the fact that sound originating from the body is a mechanical fingerprint, reflecting the human body functions.
The aims of this thesis have been to develop bioacoustic systems using modern medical signal processing in three applications. The first was to develop a method for monitor the respiration, the second was to develop a detection method for the third heart sound and, the third was to study a swallowing detection technique and look into the potential of bioacoustic development in this area.
Respiratory monitoring is of vital importance in several clinical situations. A bioacoustic signal analysis approach has been developed for monitoring of respiration. This approach includes strategies to differentiate between inspiration and expiration. In two different patient groups, the method has managed to detect 98% of the respiratory cycles.
The third heart sound has been found to be related to heart failure. A tailored wavelet technique has been developed fur detection of the third heart sound. The method has been used in children and in patients with heart failure. The wavelet metod detected 87% of the third heart sounds and only 2% were classified as false positive.
An investigation of an existing method for swallowing detection, computerized laryngeal analyser (CLA), was performed toghether with a pilot study involving swallowing sounds for the detection. The CLA technique was found to be inadequate for swallowing detection. The bioacoustic approach showed promise for detection of swallows.
We expect in the future that bioacoustics will be an important medical field, for diagnosis, monitoring, rehabilitation and education. The methods show potential for increased use, both in hospital and primary care.
Linköping: Linköpings universitet , 2002. , 72 p.
2002-11-08, Aulan, Administrationshuset, Universitetssjukhuset, Linköping, 10:15 (Swedish)