STUDY OF THE AFFERENT PATHWAYS FROM THE RECTUM WITH A NEW DISTENSION CONTROL DEVICE

Quantitative studies of the afferent pathways from hollow viscera have been limited by the lack of an easily controlled, reproducible viscer al stimulus. We adapted a slow distention device to allow for rapid di stention to study the afferent pathways from the rectum. The device pr oduced a pressure increase of 10 mm Hg in 42 msec and of 20 mm Hg in 6 0 msec. We recorded cerebral evoked potentials (EPs) after rectal ball oon distention in 17 healthy subjects. Several averages of 25 to 50 re ctal distentions at 0.17-Hz frequency were recorded. The responses con sisted of multiple peaks within 200 msec after stimulation. The mean l atency of the initial positive peak was 44 msec, suggesting that a mye linated pathway was stimulated with mechanical rectal distention. Our device produced reliable and repeatable EPs that were independent-of b alloon characteristics or rectal pressures. EP recording after rectal stimulation may become a useful technique for the physiologic investig ation of disorders such as fecal incontinence, constipation, irritable bowel syndrome, and chronic intestinal pseudo-obstruction.