Monitoring of nocturnal penile tumescence in healthy volunteers by the “Androscan MIT” registrar to establish reliable normal physiological values in a multicenter study

Aim. To evaluate the normal numerical and graphic values of nocturnal penile tumescence (NPT) test using Androscan MIT in healthy males in order to use the collected data as reference standard. Materials and methods. NPT monitoring was carried out in 38 healthy male volunteers by fixing a sensor designed for 20 measurements on their penis. During the NPT test the following parameters were recorded: 1) total sleep time; 2) minimal penis diameter (PD) in the flaccid state recorded by the apparatus; 3) maximum PD during effective penile tumescence; 4) absolute PD increase during effective erections; 5) increase in PD in %; 6) the overall time of the rigid-erection phase; 7) the number of penile rigidity episodes; 8) the average duration of each effective erection; 9) the percentage of rigid erections during the whole monitoring period. Results. Based on the data collected by Androscan MIT, we have specified the numerical values which characterize normal physiological NPT indices in healthy male volunteers. The number of tests performed and similar inclusion criteria contribute to the objectiveness of the presented data. Normal sleep time was from 7.3 to 9.5 hours. Monitoring during sleeping reflected the upper and lower limits of the minimal PD value recorded by Androscan MIT, which was from 23.5 mm to 30.2 mm. The maximum PD increase during the most effective erection varied from 35.3 mm to 44.3 mm. Total PD increase was from 10.6 mm to 15.4 mm (from 35.6% to 59.2%). In all cases a significant difference in PD increase between flaccid state and effective erection during sleeping was seen. The number of penile rigidity episodes varied from 3 to 7 a night. The overall time of effective erections was from 62.3 to 206.7 minutes, while the minimum duration of a single erection episode was 16.4 minutes and the maximum duration reached 35.8 minutes. The ratio of effective NPT to the total sleep time (the percentage of penile rigidity episodes) varied from 11.9% to 41.3%. Conclusion. Our results allowed to define reference qualitative and quantitative values of NPT in healthy male volunteers recorded by Androscan MIT which can be considered as normal and physiological and used for differential diagnostics of erectile dysfunction.

nocturnal penile tumescence, penile tumescence monitor, Androscan MIT, normal values of nocturnal penile tumescence