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Consecutive nightly recordings are required for the accurate monitoring of nocturnal erections

Zhang, Y1; Chen, S1; Ma, G1; Lai, Y1; Yang, X1; Feng, J1; Zang, Z1; Qi, T1; Wang, B1; Ye, L1

1: The Third Affiliated Hospital, Sun Yat-sen University, China

Objective: Nocturnal penile tumescence (NPT) occur spontaneously in males during sleep. NPT occurrence is based largely on the quality of sleep, and a first-night effect may be concerned. It is an incontestable fact that consecutive measurement of NPTR is already included in the international guidelines and widely accepted. However, the influence of "first-night effect" on NPTR monitoring has not been proved directly. Also, there is still voices of opposition. The aim of our study was to evaluate the effect and determine the necessity of monitoring nocturnal penile tumescence and rigidity (NPTR) for two consecutive nights.

Material and Method: The study included 105 patients with erectile dysfunction (ED) who were enrolled in our clinic for normal medical treatment and underwent two consecutive nights of NPTR measurement using a RigiScan Plus device. Numbers of normal erectile episodes, rigidity activated units (RAUs) at the tip, tumescence activated units (TAUs) at the tip, average event rigidity at the tip (%) and durations in minutes of erectile episodes with rigidity >60% were retrieved and analyzed.

Result: Among the 105 examined patients (mean age, 32.04±8.15 y), 68 men (mean age, 32.32±8.74 y) had at least one effective erection during the first night; 21 men (mean age, 30.52±7.31 y) had no effective erections during the first night but exhibited an effective erection during the second night; and the remaining 16 men(mean age, 32.81±6.60 y) did not exhibit any effective erections during the two nights of monitoring. There was no statistically significant difference in age between these subgroups. When the duration of erectile episodes with rigidity >60% (at the tip) was used as an evaluation index, outcomes were better for 65 (61.9%) patients, worse for 34 (32.4%) patients and equal for 6 (5.7%) patients.

Conclusion: Based on the results of our study, we advise consecutive nightly measurements to avoid the influence of the first-night effect and obtain more accurate data for diagnostic interpretations of NPTR results.


Work supported by industry: no.

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