Variability and repeatability of perineal sound recording in a population of healthy male volunteers

Abstract

In a population of 16 healthy male volunteers we studied the variability and repeatability of perineal sound recording as a non-invasive method for diagnosing bladder outlet obstruction. The volunteers had a flat age-distribution (22-62 years), a median IPSS-score of 1 (range: 0-18) and voided at least 10 times. From each perineal sound recording the frequency spectrum was calculated and characterized by its weighted average frequency, standard deviation and skewness. We assessed the variability of these parameters using the Kruskal-Wallis test, differences between volunteers using Dunn's test and the repeatability by the normalized standard deviation of the differences between pairs of recordings in each volunteer. For each parameter the variability within volunteers was significantly smaller than the variability between volunteers (Kruskal-Wallis, P < 0.05). For each parameter more than one volunteer was significantly different from three or more volunteers (Dunn's test, P < 0.05). The repeatability of each parameter was comparable to that of the maximum flow rate. Perineal sound recording gives repeatable results, which are significantly different between volunteers. In combination with the earlier published results from model-experiments the present results increase the probability that perineal sound recording can be used as a very simple and cheap method to non-invasively diagnose BOO. Clinical testing of this method is therefore strongly indicated.