Which of the following statements about anorectal functional testing is/are true?

A. Anorectal manometry is often performed through open-tipped multilumen catheters perfused with fluid

B. Anorectal manometry can differentiate between segmental and global defects of the anal sphincter in patients with incontinence.

C. Electromyography can demonstrate persistent contraction of the pubis rectalis muscle during defecation, which is diagnostic of paradoxical pelvic floor contraction.

D. Measurement of sensory thresholds may reveal insensitivity in patients with chronic constipation.

DISCUSSION: Anorectal manometry is most commonly performed through open-tipped multilumen catheters perfused with fluid. These catheters are connected to a transducer and register internal and external sphincter pressures and presence of the anorectal inhibitory reflex. Anorectal manometry is particularly useful in patients with fecal incontinence since it can differentiate between segmental and global defects of the anal sphincter. Electromyography records the action potential derived from the different muscles involved in defecation through endoscopically placed mucosal electrodes along the colon. Electromyography can demonstrate persistent contraction of the pubis rectalis muscle during defecation, which is diagnostic of paradoxical pelvic floor contraction. Sensory threshold measurements may disclose a high rectal threshold (insensitivity) in patients with idiopathic constipation, extent of denervation, or myopathy in the colon wall.