Anorectal sensorimotor dysfunction in fecal incontinence and diabetes mellitus. Modification with biofeedback therapy.

We studied anorectal sensory and motor function in 14 diabetics with fecal incontinence and compared the results with those in 13 continent diabetics, 31 nondiabetics with fecal incontinence, and 11 continent nondiabetics. The threshold volume at which diabetic patients with fecal incontinence experienced rectal sensation was higher (25.0 +/- 3.4 ml [mean +/- S.E.M.]) than that in continent diabetics (13.0 +/- 2.4 ml) or nondiabetics with or without incontinence (14.5 +/- 1.5 and 12.5 +/- 1.8 ml, respectively; P less than 0.02). Biofeedback conditioning in 11 incontinent diabetics led to normal sensory thresholds in six of seven patients with pretreatment thresholds above 20 ml; five of these six became continent. Biofeedback also improved external-sphincter function in nine diabetics, eight of whom became continent. Overall, 8 of 11 diabetics had a reduction in fecal soiling after biofeedback therapy. We conclude that fecal incontinence in diabetics may be caused by decreased rectal sensation or impaired function of the external sphincter or both, and that these abnormalities can often be improved by biofeedback therapy with resultant reestablishment of bowel control.