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Erectile Dysfunction and Penile Skin Temperature : The Possibility of Continuous Penile Skin Temperature Measurements to Monitor Sleep-Related Erections

Edgar, R. (2021) Erectile Dysfunction and Penile Skin Temperature : The Possibility of Continuous Penile Skin Temperature Measurements to Monitor Sleep-Related Erections.

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Abstract:INTRODUCTION - Erectile Dysfunction (ED) is a frequently occurring disorder and affects the quality of life and sexual satisfaction of numerous men. The golden standard for diagnosing the either somatic or psychogenic cause of ED is by monitoring Sleep-Related Erections (SREs) by the RigiScan. This outdated sensing system has several drawbacks and needs replacement. In a previous study, we introduced several alternative methods for the monitoring of SREs, including the possibility of penile skin temperature monitoring. The objective of this study is to find out whether penile skin temperature measurements are suitable for the monitoring of SREs. HEAT TRANSFER MODEL - A mathematical model is set up to describe the thermal aspects that occur during a flaccid state and an erection. The heat transfer is described by means of conduction and convection in a closed system model with steady state, steady flow condition. Parameters and constants are found in literature or determined experimentally. According to our model, the temperature increase from flaccid to erect state is 1.4 °C, in naked condition. When wearing clothes (i.e. cotton underwear) and clothes plus a blanket, we calculated a temperature increase of 1.1 °C and 0.4 °C respectively. METHODS - Nighttime penile skin temperature monitoring is carried out in one healthy subject (age 28) with the TM-220 thermistor (iWorx Systems inc, Dover, USA), and compared to the outcomes of the RigiScan (GOTOP Medical Inc., St. Paul, Minnesota, USA). Low- and high-pass filters are applied to the temperature data to remove high-frequency noise and the circadian cycle. Next, time and temperature intervals are extracted that correspond to erections in the RigiScan data. These intervals are used for slope analysis. Wilcoxon signed-rank tests are applied to test for significant differences in the non-normal distributed data. RESULTS - In total, 22 erections are monitored during 7 nights. The penile skin temperature varies between 32 °C and 36 °C. The mean duration of the erections is 25.4 minutes (SD 12.8). The Wilcoxon signed-rank test reveals that the temperature at t = 10 minutes in every erection interval is significantly higher than the temperature at t = 0 minutes (p = 0.009). The temperature slopes of intervals where erections take place are not significantly different compared to the slopes of the non-erection intervals (complete interval; p = 0.306, first 10 minutes of each interval; p = 0.123). DISCUSSION AND CONCLUSION - Despite the promising results from our heat transfer model, we cannot distinguish an erection from a non-erection in one healthy subject by measuring skin temperature yet. The statistical proof of a temperature rise during an erection is poor, but we do see some changes. Unfortunately, the interquartile ranges exceed the medians. Probably, ambient temperature fluctuations resulted in too much disturbance which influenced the data obtained. Therefore, further research should focus on minimizing those fluctuations in the temperature measurements. All in all, the importance of our results lies both in pioneering in this field and the search towards a worthy successor of the RigiScan in general.
Item Type:Essay (Master)
Faculty:TNW: Science and Technology
Programme:Technical Medicine MSc (60033)
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