28.01.2015 change 28.01.2015

21st century stethoscope

Photo: Fotolia Photo: Fotolia

Maybe it\'s time to put traditional stethoscope - the basic attribute of a doctor - to rest? Polish researchers are working on a modern digital stethoscope, which will process the sounds of the body so that the doctor can clearly heard disturbing signals.

Every patient knows what a stethoscope looks like. This instrument hanging on the neck has long since become a symbol of the medical profession. This fairly simple device allows physicians to quickly and easily listen to a patient and initially diagnose structural heart defects, diseases of lungs, abdomen, or even thyroid and arteries.

Traditional stethoscope is not a complicated device - a membrane and a funnel hidden behind it transfer sounds from the patient to the doctor’s ear. "The flow of blood and air in our body is accompanied by noise, which travels through the tissue and it can be picked up on the skin. These sounds may contain information about certain pathological conditions" - explained in an interview with PAP Dr. Łukasz Nowak of the Institute of Fundamental Technological Research PAS in Warsaw, who conducts research on a new generation of stethoscopes.

Dr. Łukasz Nowak is convinced that traditional stethoscopes do not allow picking up sounds from the body in an optimal way. He believes that the acoustic signals can be digitally processed, so that the doctor can more specifically determine what is going on in your body. The stethoscope would enhance the most important features of the sound so that the human ear can perceive it better, and make any deviations from the norm easier to notice during a quick examination, even in noisy environments.

The processing Nowak wants to apply to sound can be compared to photo editing. Specialists working with photos can extract new information from images by using filters - for example by increasing image contrast or saturation. This may reveal certain previously unnoticeable details. Similar procedure may be applied to sound: filters and digital processing may make some details become clearer to the human ear. First, however, researchers have to find algorithms that will help in the work of doctors. That is exactly the objective of Dr. Nowak’s team.

"We\'re going against grain" - admitted the acoustics expert. He explained that although many research groups worldwide are working on new generations of stethoscopes, their ideas are usually based on collect acoustic signals from the body and feeding them to a computer, which - instead of a doctor - would interpret these signals and diagnose. Meanwhile, according to Dr. Nowak, this solution would not satisfy doctors nor patients. According to the acoustics expert, it is important that the stethoscope remains a simple, portable device that would help the physician to quickly make initial diagnosis.

Polish team focused on a different aspect of improving the stethoscope - on adjusting the signal from the device to the physical capacity of the human ear and to how sounds are received in the brain. This would leave diagnosis and interpretation of the results in the hands of doctors. After all, diagnosis is based not only on the acoustic signals from the body, but also on the observation of the patient and interview.

"Our problem is that in our research we need to combine their clinical knowledge with knowledge of acoustics, psychoacoustics, and sound propagation in the human body" - said Dr. Nowak. He admitted that it is difficult to find in the common language. "For example, doctor tells us that in the acoustic signal from a stethoscope it is important whether he can hear any wheezing. We must determine what kind of wheezing he meant and examine what these sounds are characterized by" - said Dr. Nowak.

Dr. Nowak reminded that today doctors use stethoscope examination to initially detect cardiac murmurs in newborns. Only in 40 percent children who are referred for further examination, a significant disorder is confirmed. "I know first hand what the parents are going through while waiting to see a cardiologist with their child. In my daughter - on the basis of a stethoscope examination - doctor also wrongly suspected a heart defect" - admitted the acoustics expert. He added that the device imperfections sometimes may result in the opposite situation: doctors may miss defects in children who should be referred for further treatment. According to Dr. Nowak, effectiveness of these preliminary examinations could be improved by modern devices that he is developing.

"Perhaps because of our research, in some time it turns out that a doctor with classic stethoscope will look like an engineer with a slide rule looks today?" - concluded the scientist.

The project "New Methods and Technologies of Acoustic Medical Diagnosis" is implemented under the LEADER program of the National Center for Research and Development. The work is only starting, and it will continue for three years.

PAP - Science and Scholarship in Poland, Ludwika Tomala

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