21.   Stimulation of the sympathetic nerves is known to increase internal anal sphincter tone and inhibit colorectal contraction.

22.   The external anal sphincter response to rectal distension is very closely associated with both rectal sensation and rectal contraction in normal subjects, and presumably acts to prevent soiling.

23.   These observations support previous conclusions that the external anal sphincter response to rectal distension is a spinal reflex, that has become extensively modulated by conscious mechanisms.

24.   Patients were trained in increasing strength and duration of external anal sphincter contractions in response to rectal distension.

25.   There was no significant difference in threshold of internal anal sphincter relaxation between controls and incontinent patients with only three patients showing values outside the control range.

26.   The threshold of external anal sphincter contraction was the same in incontinent patients and in controls and only three patients showed a value above the upper limit of normal.

27.   The first session of biofeedback conditioning was associated with an improvement in external anal sphincter function in all subjects.

28.   The good responders showed a persistent improvement in external anal sphincter function, while in the poor responders it had reverted to prebiofeedback values.

29.   At diagnostic anorectal manometry, they showed an isolated alteration of squeeze duration without any impairment of internal anal sphincter function.

30.   A motor deficit of the external anal sphincter was seen in most of our patients with liquid stool incontinence and suvere urgency.