The Penile Sensitivity Ratio: A Novel Application of Biothesiometry to Assess Changes in Penile Sensitivity

Abstract

IntroductionBiothesiometry allows for evaluation of penile vibratory sensitivity and can be used as a non-invasive and rapid surrogate test of penile sexual sensitivity. However, no standardized measurement methodology currently exists. AimTo describe and optimize a novel, standardized biothesiometry parameter—the penile sensitivity ratio (PSR). MethodsWe reviewed all biothesiometry data from men presenting to our institution from July 2013–May 2017. 3 iterations of the PSR were evaluated using the threshold for vibratory detection from a combination of different input variables including the penile glans, penile shaft, index finger, and thigh. Numerator values for the PSR included the penile glans and penile shaft, whereas denominator inputs included the index finger and thigh. PSR is inversely correlated with penile sensitivity. Main Outcome MeasureThe primary outcome measure was the association between reported diminished penile sensitivity and PSR value. Secondary outcome measures were the association between PSR and age, diabetes, ejaculatory dysfunction, and Peyronie’s disease (PD). ResultsBiothesiometry data were evaluated from 1,239 men. Mean age was 53.2 years (SD 14.0 years). Diabetes was present in 7.4% (n = 92); 52.0% (n = 644) had PD. Ejaculatory dysfunction was identified in 15.8% (n = 196), with 12.2% (n = 151) having premature ejaculation and 3.6% (n = 45) reporting delayed ejaculation. Decreased penile sensitivity was reported in 20.3% (n = 252). 3 PSR iterations were analyzed to identify associations with decreased penile sensation. On univariate and multivariate analysis controlling for age, diabetes, ejaculatory dysfunction, and PD, only the PSR iteration, which included data from the penile glans and finger (PSRG/F), was significantly different between patients reporting diminished penile sensitivity and those without reported diminished sensitivity (univariate P < .01, multivariate P = .03). On univariate analysis, a higher PSRG/F was associated with older age (P < .01) and diabetes (P < .01), whereas men with PD had a lower PSRG/F (P < .01). On multivariate analysis, PSRG/F remained increased for age (P < .01) and decreased for PD (P = .01); however, there was no association with diabetes (P = .12). No association existed between ejaculatory function and PSRG/F on univariate (P = .25) or multivariate analysis (P = .35). Clinical ImplicationsThe PSR may be used as a standardized biothesiometry parameter to evaluate penile sensitivity. Strength & LimitationsThis study included a large cohort of men undergoing biothesiometry (n = 1,239); however, it is limited by the multifactorial nature of perceived diminished penile sensitivity. ConclusionThe PSR using penile glans and index finger input variables is a non-invasive, painless, office-based, standardized biothesiometry parameter that is a clinically useful tool for measuring penile sexual sensitivity.Wiggins A, Farrell MR, Tsambarlis P, et al. The Penile Sensitivity Ratio: A Novel Application of Biothesiometry to Assess Changes in Penile Sensitivity. J Sex Med 2019;16:447–451.