Abstract
Gastrointestinal motility investigations involve the study of the motions of the bowel. Their goal is to understand the nature of the physical interactions that take place between the gut wall and its contents in both health and disease. The aim of this project was to develop a computerised system for the measurement, inspection, analysis and collation of prolonged, ambulatory manometric records from within the human small bowel. This was planned to evolve from existing analogue techniques using a specially commissioned digital data-logger. This thesis describes the testing of the data-logger by comparison with an accepted standard technique, investigating its long-term stability and the effect of different sampling rates. Then the development of a means of detecting intestinal contractions with minimal artefact is described. When validated against 6 experienced human observers the program had a sensitivity of between 84-95 % and a positive predictability of 98% in a noise free signal falling to 37% in a signal containing many movement artifacts and few contractions. The inter- and intra-observers response was found to be variable displaying a high degree of subjectivity in their assessment with respect to the computer. Further methods for the classification of intestinal activity in the temporal domain such as contraction frequency and the occurrence of clusters of contractions are described.. A new parameter, Psw is proposed which provides an indication of the relative inter-contractile separations. The effect of meals and disease on Psw, contraction and cluster incidence is investigated and all three parameters are found to be markedly affected by feeding. A program for the identification of contractile propagation across adjacent sites is described, with reference to both a computer model and data from healthy subjects. A cross-correlation method is devised for the accurate assessment of propagation velocities. Finally, the form of database currently used for the clinical reporting of routine small bowel motility investigations is described with suggestions for improvements and additions to this database which are planned.