Reference values of motor unit potentials (MUPs) of the external anal sphincter muscle.

Objective: To provide reference values for the isolated motor unit potentials (MUPs) in the external anal sphincter (EAS) muscle, as mean duration, mean amplitude, mean area, number of turns and number of phases, related to the age of the patient. These data are not available in worldwide literature in spite of the fact that the EAS muscle is being increasingly mentioned in relation to differential diagnosis.

Methods: Study of 235 subjects aged 0-80 years using an automated analysis program.