Abdominal Sound

Analysis of abdominal sound/vibration


This project is to advance the state of understanding of the activity of the bowel, which would lead to the development of improved monitoring techniques and better and more rapid diagnosis.

The Research Team

Dr. Brendan McCormack Principal Researcher Department of Engineering, IT, Sligo. Mr. Martin Caldwell Consultant Sligo General Hospital. Mr. John Hession Research Student Department of Engineering, IT, Sligo.


Abdominal sound (bowel sounds) accrue from movement of the intestines as they push food through. The intestines are hollow, causing the bowel sounds to propagate throughout the abdomen. The great majority of the bowel sounds are low toned and simply indicate that the gastrointestinal tract is working. Abdominal sounds are evaluated by listening to the abdomen with at stethoscope (Auscultation).

The absence of bowel sounds is known as ileus, this condition in which the examiner in unable to detect sounds from the bowel after listening to each area of the abdomen (the examiner usually listens for 5 minutes in each location). This indicates a lack of intestinal activity, which can quickly become life threatening because gas, secretions, and intestinal contents can accumulate to the point where the bowel wall ruptures.

Reduced bowel sounds (hypoactive) include a reduction on the loudness, tone or reqularity of the bowel sounds. They indicate a slowing or intestinal activity. Hypoactive bowel sounds are normal during sleep, and also occur normally for a short time after the use of certain medications and after abdominal surgery.

In many cases, hyperactive bowel sounds occur as the intestines respond to a problem (such as an obstruction). Then the bowel sounds can become hypoactive, indicating progression of the condition. They may quickly disappear (absent bowel sounds), indicating potentially life -threatening situation.

The clinical method currently employed to monitor bowel sounds is the stethoscope, applied typically in four different locations for five minutes. This practice is not only time consuming but also subjective, which can lead to inaccurate diagnoses. The stethoscope is used daily by almost every physician, the full potential of the art of using this instrument is seldom fully exploited.

Project Details

This project is to advance the state of understanding of the activity of the bowel, which would lead to the development of improved monitoring techniques and better and more rapid diagnosis. As this is a relative new area of research further investigation is required in a number of directions, and the following objectives have been identified:-

Conduct experiments on animal abdominal tissue to establish transmission characteristics. Using a known source of sound as a point of reference, this information could be used to establish the losses in the signal due to tissue damping.

Develop a model, which relates sounds generated inside the abdomen to sounds detected outside on the surface of the abdomen. The model would incorporate the characteristics of the detected signal and the tissue properties and anatomy.

Monitor human abdomen clinically. Conduct a survey into a group of normal subjects abdominal sounds and draw a comparison with groups having known abdominal clinical conditions.

Investigate the correlation between the sounds from ‘fed’ and a fasting abdominal feeding subjects and fasting in relation to return to normal state of the bowel.

Investigate the correlation if any between what one physician is listening, to compare to other physicians. Develop a database of sounds produced by the abdomen; this would be an attempt to establish the accuracy and repeatability of the diagnosis.

Investigate what bowel sounds are not detected by physicians using conventional auscultation (i.e. outside the audible range) and determine the properties.