Normal values in the interpretation of nocturnal penile erection

Kim, Young Chan; Choi, Hyung Ki; Kim, Jong Hyun

Abstract

Nocturnal penile erection monitoring(NPEM) is a widely used technique for the differential diagnosis of impotence. However. minimal requirements in various parameters of nocturnal penile erection monitoring. that is demanded for vaginal penetration. has not yet been elucidated. To delineate the minimal tumescence and rigidity for vaginal penetration we studied thirty-three candidates with normal sexual life and two hundred fifty nine erectile failure patients using RigiScan. All normal candidates performed one session per night for 3 days. The cut off values of average tumescence and duration of rigidity were determined based on the 95 percentiles of the norma1 candidates. The 95 percentiles of average-tumescence were 6.6cm in the base and 6.4cm in the tip or the penis. The 95 percentiles or the duration of rigidity more than 60% were 9 minutes in the base and 5 minutes in the tip. Those values of rigidity more than 40% were 11 and 6 minutes in the base and tip, respectively. We adopted the values of rigidity more than 60% rather than 40% as normal cut off value. With these cut-off values, two hundreds fifty nine impotence patients were evaluated for their features with the maximum figures of their tumescence and time of rigidity which measured in the same way. One hundred forty eight patients ( 57.1%) were in normal values. Among abnormal 42.9%, 92(35.5% ) cases showed insufficient rigidity, 61 (23.5%) cases of dissociation of rigidity between the tip and the base of penis and 59(22.8%) cases with uncoupling between rigidity and circumferential expansion. Therefore, we suggest that these cut-off values are acceptable to evaluate the performance of erectile failure patient.