Nocturnal penile tumescence devices: past, present and future.

Erectile function is an important part of men's health that can significantly impact quality of life. Naturally occurring nighttime erections experienced by men throughout their lifespan provides insight into penile health as well as overall health. Nocturnal penile tumescence (NPT) and nocturnal penile tumescence and rigidity (NPTR) devices that can non-invasively evaluate the presence and quality of erections can have valuable diagnostic and clinical utility. Early devices have several limitations that limit their current use. New, wearable devices have promising applications for the evaluation of erectile function over time. Continued advancements in this technology have the potential to render future generations of these devices as invaluable tools that are useful for both men and healthcare professionals.