Nocturnal penile tumescence in healthy 20- to 59-year-olds: a revisit.Sleep. 1989 Aug; 12(4):368-73.S
This report presents data on normative nocturnal penile tumescence (NPT), based on a study of 48 healthy men aged 20-59 years, without complaints of erectile dysfunction. In general, the current measures show good concordance with those reported by Karacan and colleagues in 1976. The effect of "pathology-free" aging (from age 20 to 59) on electrographic measures of NPT is relatively modest, accounting for 8.4-14.4% of the variance. Furthermore, no age effect on visual estimates of erectile fullness or on buckling force estimates of penile rigidity were present. Maximum buckling force and maximum erectile fullness showed stability across the four decades of the Pittsburgh sample.