About the Penile Plethysmograph

Penile plethysmography (PPG) is advanced state-of-the-art technology that is recognized as the most accurate means of identifying deviant sexual arousal. Arizona Forensic Services, LLC operates one of only two PPG labs in the state of Arizona. The other is housed at the Arizona State Hospital for their SVP program.  

  1. The PPG is an FDA approved instrument that has been classified as a Class II medical device.
  2. The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-5) specifically recommends the use of the PPG. “Psychophysiological measures of sexual interest may sometimes be useful . . . The most thoroughly researched and longest used of such measures is penile plethysmography,”. (DSM-5, pp.698-699)
  3. The Association for the Treatment of Sexual Abusers (ATSA) is the world’s leading professional organization for assessing and treating sex offenders. In its Standards of Care, the PPG is considered a necessary component of an evaluation. 
  4. Published research demonstrates high sensitivity, specificity, positive predictive power (PPP) and negative predictive power (NPP).  The NNP is particularly important for predicting the absence of pedophilia.  
  5. A recent meta-analysis that included 16 samples and 2,709 sexual offenders replicated and extended previous findings that phallometric responding to both male and female pedophilic and hebephilic stimuli predict sexual re-offence. Further, this meta-analysis showed that phallometric testing predicts sexual re-offence in distinct subgroups of sexual offenders against children. (McPhail, et.al., March 2017)
  6. An Arizona District Court decision (Olmos v. Ryan, 2013) and the Ninth Circuit upheld the use of the penile plethysmograph as a condition of supervised release. 
  7. The Eighteenth Judicial Circuit (Jeff C. Rivers-Finney, 2015) found that “PPG evidence is admissible . . . both under Frye and Daubert.