Anorectal physiology validated: a repeatability study of the motor and sensory tests of anorectal function.

Sixteen subjects (mean (s.d.) age 50.7 (12.8) years, three men) were studied on two separate occasions by two experienced investigators in random order. A standard protocol of anatomical, manometric and electrophysiological assessments of anorectal motor and sensory function was followed. No significant differences were found between the results obtained by the two investigators in the measurements of perineal descent, anal canal length, and canal resting pressure and squeeze pressure, pudendal nerve terminal motor latency, single-fibre electromyography fibre density of the external anal sphincter, and thresholds of mucosal electrosensitivity. This study shows that the standard tests of anorectal sensorimotor function are repeatable by different investigators. In addition, it suggests that comparison of data obtained in different centres using these techniques is valid.