INSTITUTE OF PHYSICS PUBLISHING PHYSIOLOGICAL MEASUREMENT Physiol. Meas. 23 (2002) 505–519 PII: S0967-3334(02)28140-X Non-invasive gastric motility monitor: fast electrogastrogram (fEGG) Ata Akin 1 and Hun H Sun 2 1 Institute of Biomedical Engineering, Boˆ gazic ¸i University, Bebek, ˙ Istanbul, Turkey 2 School of Biomedical Engineering, Drexel University, Philadelphia, PA 19104, USA E-mail: ataakin@boun.edu.tr Received 21 August 2001, in final form 27 March 2002 Published 23 May 2002 Online at stacks.iop.org/PM/23/505 Abstract We propose a new analysis method to extract the motility information from the electrogastrogram signal that has been recorded at a higher sampler rate than the conventional approaches. This technique utilizes a fourth order Butterworth bandpass filter in extracting the 50–80 cycles per minute (cpm) activity that was previously noted to represent the spike activity range of the cutaneous signals of dogs. Receiver operating characteristics (ROC) analyses have been applied to the processed data to compare the detection performance of our fEGG technique to the conventional approaches that use the slow wave as the reference. The areas under the ROC curves comparing the changes from postprandial stage to fed stage for the fEGG study was found to be 0.961 while for the slow wave it was 0.686. We offer our method as a complementary one to the existing methods. Keywords: Electrogastrogram, gastric motility, signal processing 1. Introduction Gastrointestinal motility is the combination of two activities: movement of food from the mouth to the anus and the mixing of food by breaking it into uniformly small particles (Silverthorn 2001). The control of motility is performed by neuronal and hormonal factors that modulate the smooth muscles in generating muscular contractions to perform these two activities. In gastroparesis (delayed emptying of the stomach), the timing and strength of these contractions are diminished or disrupted. Hence, it is clinically important to gain rapid and non-invasive access to the emptying pattern of the stomach to isolate the symptoms. The connection between the changes in the gastromyoelectric activity and gastric contractions has been observed to form a cause-effect relationship (Atanassova et al 1995, 0967-3334/02/030505+15$30.00 © 2002 IOP Publishing Ltd Printed in the UK 505