Apr. 5, 2007 Chronic constipation affects 15 to 20 percent of the U.S. population. Nearly one-third of affected people have dyssynergic defecation, in which muscles used for bowel movements do not work well, but there's some good news. University of Iowa research shows biofeedback treatment can successfully retrain muscles.
The biofeedback approach was better than standard treatment of laxatives, diet and exercise or another treatment (sham) that included muscle relaxation and coping strategies. The findings appear in the March issue of the journal Clinical Gastroenterology and Hepatology.
Many people with dyssynergic defecation have life-long constipation and experience significant difficulty with passing stools but are unaware that they have this particular type of chronic constipation, said Satish Rao, M.D., professor of internal medicine at the UI Roy J. and Lucille A. Carver College of Medicine.
"People with dyssynergic defecation cannot sense stool in their bowel or have difficulty using bodily mechanisms to expel the stool. However, they often don't seek help beyond using over-the-counter laxatives, and some doctors aren't aware of the condition either," Rao said.
The biofeedback technique involves making people more aware of unconscious or involuntary bodily functions involved in defecation. The technique includes placing a pencil-thin probe into the rectum to provide feedback information about how the body muscles are performing. This data, as well as visual and verbal feedback techniques, help individuals relearn the normal process of having a bowel movement.
The study included 79 adults, with an average age of 43, who had dyssynergic defecation. The 69 female and eight male participants were randomly assigned to one of three study groups: standard, biofeedback or "sham" biofeedback.
In the biofeedback group, 79 percent of the individuals had corrected bowel function at the end of the study. In contrast, only 4 percent of the sham group and slightly more than 8 percent of the standard group showed corrected muscle function.
"We did the study to find out: Is it medical attention and coping strategies or alterations in muscle-function that really make a difference with biofeedback?" Rao said. "The study results show that bowel movement improvement is possible in nearly 80 percent of patients through biofeedback."
Standard treatment included use of laxatives, education about bowel habits, exercise for overall physical and abdominal muscle strengthening, and dietary advice such as increasing fiber and fluid intake.
The biofeedback group received standard treatment plus six training sessions over three months in which the participants practiced pushing with a probe in the rectum and pushing out artificial stools.
"We showed the biofeedback group how to improve their pushing effort and relax the pelvic floor and anal sphincter muscles so that they can poop normally and easily," Rao said. "The probe gives us information about how the muscles are working."
The sham biofeedback group received standard care plus six training sessions over three months. They practiced pushing using the probe but, unlike the true biofeedback group, did not use the artificial stool and were not instructed in how to push or relax muscles. They were provided attention in the form of coping strategies and muscle relaxation tapes.
In addition to using objective anal/rectal muscle function measures, the team used a second objective measure and found that people in the biofeedback group were able to expel an artificial stool in less time than it took participants in the other groups.
"There's no question from the objective data that the biofeedback treatment is far superior than standard treatment," Rao said.
The study also included two subjective measures of differences among the three treatments. Entries from participants' diaries indicated that people in the biofeedback group, not standard or sham groups, had more spontaneous bowel movements. All groups reported more satisfaction overall with their bowel habits. However, 85 percent of the biofeedback group reported improvement, compared to 45 percent of the "sham" group.
The researchers are now developing a home-based biofeedback program to assist more people. They also are studying the mechanism by which the biofeedback succeeds.
"Biofeedback works, but we don't know exactly why it does," Rao said. "We'll study how the gut and brain 'talk to each other'. Somewhere in between is where the problem lies, so improving communication, if you will, between the gut and brain will improve bowel function."
The study was supported in part grants from the National Institutes of Health and the General Clinical Research Centers Program at the National Center for Research Resources.
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