NOCTURNAL PENILE TUMESCENCE AND RIGIDITY MONITORING IN YOUNG POTENT VOLUNTEERS - REPRODUCIBILITY, EVALUATION CRITERIA AND THE EFFECT OF SEXUAL INTERCOURSE

Purpose: We studied the reproducibility of nocturnal penile tumescence , rigidity evaluation criteria and the possible effects of sexual inte rcourse in young, healthy, potent male volunteers. Materials and Metho ds: We recruited 12 male medical students 21 to 24 years old into the study. A disorder-free medical history, availability of a sexual partn er and normal erectile function were the inclusion criteria. All subje cts completed 3 sessions of 3 nights of recording using the RigiScan device with at least a 3-day interval between recordings. During the l ast S-night recording subjects were asked to have sexual intercourse a t least once. Analysis of the recordings was focused on the best erect ile event as well as on rigidity and tumescence activity units normali zed per hour. Results: The subjects completed 36, 3-night recordings. Of the total of 108 sessions 18 occurred after sexual intercourse. We analyzed 562 erectile episodes. All 3-night recordings included at lea st 1 episode of rigidity at the penile tip greater than 60% and more t han 10 minutes in duration. Sexual intercourse did not significantly a ffect nocturnal penile tumescence and rigidity. When rigidity and tume scence activity unit values were normalized by the hour and expressed as mean values of the 3-night sessions, documented values became repro ducible. Conclusions: At least 2 consecutive nights of recording are n ecessary to evaluate nocturnal penile tumescence and rigidity recordin gs. Nocturnal penile tumescence and rigidity with at least 1 erectile episode of tip penile rigidity greater than 60% and 10 minutes in dura tion may be associated with potency. Mean rigidity and tumescence acti vity unit values per hour of a recording may be used as objective para meters to measure overall erectile activity. In addition, sexual inter course seems to decrease nocturnal penile tumescence and rigidity meas urements, although not statistically significant. We anticipate that a pplication of these criteria for nocturnal penile tumescence and rigid ity evaluation will improve the diagnostic validity of the test. Futur e research will determine whether these criteria are too strict for th e evaluation of aging men.