A new probe for measuring electromyographic activity from multiple sites in the anal canal.
A new multiple electrode probe (MEP) designed to measure surface electromyographic activity from the subcutaneous and deep portions of the external anal sphincter is described. Using the MEP, electromyographic activity was sampled in an asymptomatic subject and in three incontinent patients. Comparisons of electromyographic data between and within subjects, and across sessions, indicate that the MEP discriminates muscle activity from different sites along the anal canal. The recording method described is capable of identifying patterns of muscle recruitment which have not been reported before using surface electromyography. After a defecation maneuver, the distal and proximal portions of external and sphincter were observed to contract in what would seem to be a closing reflex. Moreover, the absence of this pattern may indicate abnormality. Accordingly, the MEP promises to be useful in the diagnosis, evaluation, and treatment of fecal and urinary incontinence and, particularly, in the biofeedback treatment of these and related disorders.