[Colonic motility and irritable colon]

The importance of colonic motility disorders in the irritable bowel syndrome is now well accepted, but an accurate description of these abnormalities is still wanting. The insufficiency of investigational methods and, mainly, the heterogeneity of the disorders can explain this need. Twenty-four hour recordings of colonic myoelectrical activity can now provide a better knowledge of motor disturbances. No evidence of a specific basic disorder has been presented, and the effects of stress produce contradictory results depending on the method used. In contrast, motility patterns recorded during sleep and after a meal show segmental hyperactivity in painful constipation, abnormalities of the colonic response to feeding in painful abdominal distension, propulsive hyperactivity with absence or reduction of the "sigmoidal brake" in painless diarrhea. However, it appears clearly that myoelectrical activity disturbances can only be observed in two thirds of the patients presenting with functional digestive disorders. "Sensitivity" or personality disorders and disturbances of other organs can explain the physiopathology of "irritable bowels" where no evidence can be found that the colon is involved.