Put on Your Listening Shirt

Listening to the sounds our bodies make is a common part of a medical examination. With the help of a stethoscope, a trained medical professional can diagnose problems with heart or lung function. Some sounds do not occur in such regular or characteristic patterns as is the case with those produced by the heart and lungs, however. It may not be feasible to capture such body sounds during a brief examination in the office. Moreover, the presence of particular sounds may be dependent on various activities that occur during the day that are not easy or reasonable to reproduce in a clinical setting.

Bowel sounds are among those body sounds that are difficult to capture during a typical examination because they tend to occur sparsely and randomly. A collaboration between Friedrich-Alexander University and the University Hospital Erlangen has birthed a solution to this problem, in the form of a shirt they have very descriptively named GastroDigitalShirt.

GastroDigitalShirt is an off-the-shelf t-shirt made of elastane to provide the tight fit required to capture low amplitude bowel sounds. A matrix of eight I2S MEMS digital microphones (Knowles Sph0645lm4h) are strategically placed around the shirt following the pattern of an abdominal map that is used during medical examinations. Various sizes of GastroDigitalShirt are available to accommodate varied body shapes. Microphones are connected to a Radxa Rock Pi S single board computer. The computer and a 3500mAh capacity battery are stored in a custom 3D-printed case that can be worn on a belt.

In an experimental study, participants were asked to wear the shirt for several hours while performing a number of activities. From the data collected, a pair of study managers analyzed the audio and were able to identify four distinct bowel sounds, showing the device to be viable in real word use. The researchers did note that some recording data was lost, probably due to an improper fit of the shirt causing misalignment of, or poor surface contact with, the microphones.

In its current state, privacy is a significant issue with the design of the device. In addition to recording the target sounds, other sounds from the wearer and their environment (e.g. speech) are subject to being captured. This concern may be alleviated by processing the recorded audio on-device to remove any off target data before it is stored.

With some refinement, GastroDigitalShirt may represent another front for improving health through wearable sensing technologies. The longitudinal data acquired from large populations by this and similar wearable technologies has real potential to transform our understanding of health, disease, and treatment.