Intestinal motor function in irritable bowel syndrome.

Irritable bowel syndrome is widely considered to be associated with disordered gastro-intestinal motility. The evidence for a motor disorder in the colon and small intestine of patients with irritable bowel syndrome is reviewed. Results of myoelectric, motility and transit studies in both the colon and small intestine are inconsistent. Difficulties in interpreting colonic motility have led investigators to address the small intestine as a possible site of dysmotility. An increase in the number of clustered contractions in the proximal small intestine has been reported by some, but not all investigators. Methodological differences as well as patient selection, symptom severity and fluctuation may all contribute to discrepancies between the results of different studies. Motility disturbances may be present which are currently unrecognised due to an inadequate understanding of the propagation of colonic contractions, and of small intestinal contractions during phase II and postprandially. Whether the reported motor disturbances arise locally in the gut or originate from higher centres in the central nervous system has not been established.