Test-retest repeatability of anorectal physiology tests in healthy volunteers

PURPOSE: This study was undertaken to evaluate repeatability of tests of anorectal function in 58 healthy female volunteers, mean age 50 (range, 45-57) years. METHODS: Participants were studied on two separate occasions by one investigator in one laboratory using the same equipment. RESULTS: Mean difference for perineal position was 0.1 (95 percent confidence interval, -0.1-0.3) cm, and for perineal descent it was 0.02 (-0.2-0.3) cm. For anal mucosa electrosensitivity, mean difference was -0.1 (-0.4-0.1) mA, for maximum anal resting pressure it was 2.2 (-3.5-7.8) cm H2O, for maximum anal squeeze pressure it was -1 (-6.5-4.5) cm H2O, and for pudendal nerve terminal motor latency it was 0.04 (-0.02-0.09) msec. Coefficients of variation varied from 8 percent for pudendal nerve terminal motor latency to 49 percent for perineal descent. CONCLUSION: There was no systematic variation in repeated measurements for any of the parameters studied; however, the nonsystematic variation was generally large.