Chiarioni, G., Salandini, L., & Whitehead, W.E. (2005). Biofeedback benefits only patients with outlet dysfunction, not patients with isolated slow transit constipation. Gastroenterology, 129, 86–97.

To compare the efficacy of biofeedback in pelvic function dyssynergia–induced constipation (PFD) versus slow transit constipation (STC).

All subjects received five weekly biofeedback lessons and were assessed at 1, 6, 12, and 24 months.

• The study reported on a sample of 75 consecutive patients who were referred to a gastroenterology clinic hospital for refractory, long-standing constipation and met inclusion criteria.
• Fifty-two patients had delayed whole-gut transit issues, 34 had PFD, and 12 had STC.

Gastroenterology Clinic of the Division of Gastrointestinal Rehabilitation of the University of Verona in Valeggio sul Mincio, Italy

This was a quasi-experimental study.

• Anorectal manometry at one and six months
• Questionnaire and balloon defecation test at 1, 6, 12, and 24 months

At six months, greater improvements were seen in patients with PFD compared to those with STC: 71% versus 8% reported improved satisfaction (p = 0.001), and 76% versus 8% reported three or more bowel movements per week (p ≤ 0.001).

Patients with PFD received greater benefit from biofeedback than those with STC.

• The sample size was small (less than 100).
• The study design was not randomized and used a two-group comparison without controls.