The penile plethysmograph (PPG; also known as erectometer) is a controversial type of plethysmograph that measures changes in blood flow in the penis. Cavernous nerve penile plethysmograph measures changes in response to inter-operative electric stimulation during surgery.
For sexual offenders, it is typically used to determine the level of sexual arousal as the subject is exposed to sexually suggestive content, such as photos, movies or audio. It has been demonstrated by most studies to be the most accurate method of identifying which sexual offenders will go on to commit sexual crimes against children, although there are clinicians who have noted that this does not mean the test is appropriate for the evaluation of sexual preferences or treatment effects.
For prostatectomy nerve-sparing surgery, the surgeon applies a mild electrical stimulation near the Cavernous nerves of penis to verify their locations and avoid operative trauma. Damage to these difficult to see nerves can cause erectile dysfunction outcomes. At the surgery's conclusion, the electrical stimulation penile plethysmograph result is a prognostic which helps to manage the erectile function outcomes earlier than the many months required for recovery. 
There are two types of penile plethysmograph:
- Volumetric air chamber
- When this is placed over the subject's penis, as tumescence increases, the air displaced is measured.
- Circumferential transducer
- This uses a mercury-in-rubber or indium/gallium-in-rubber ring strain gauge and is placed around the shaft of the subject's penis to measure changes in circumference.
Significant suppliers of PPG machines include Behavioral Technology Inc. and Medical Monitoring Systems. The device is known to be used in Brazil, Britain, Canada, China, Czech Republic, Hong Kong, New Zealand, Norway, Slovak Republic, Spain, and the United States.
The surgical machine is supplied as CaverMap by Blue Torch Medical Technology, Inc.
The original air device was developed by researcher Kurt Freund in Czechoslovakia during the 1950s. He later wrote, "In the early fifties homosexual interaction was still an indictable offense in Czechoslovakia. I was of course opposed to this measure, but I still thought, as did my colleagues at the psychiatric university hospital in Prague where I was working, that homosexuality was an experientially acquired neurosis" (p. 223) He then developed phallometry to replace psychoanalytic methods of assessment because "[P]sychoanalysis had turned out to be a failure, virtually unusable as an instrument for individual diagnosis or research....When phallometry began to look promising as a test of erotic sex and age preferences, we started using it mainly as a test of pedophilia, that is determining who has an erotic preference for children over adults" (p. 223-224).
In post-World-War-II Czechoslovakia, Freund was assigned by the communist government the task of identifying among military conscripts men who were falsely declaring themselves to be gay. "Freund (1957) developed the first device, which measured penile volume changes... to distinguish heterosexual and homosexual males for the Czechoslovakian army."  When he escaped Europe for Canada, Freund was able to pursue his research using phallometry for the assessment of sexual offenders. At that time, attempts to develop methods of changing homosexual men into heterosexual men were being made by many sexologists, including John Bancroft, Albert Ellis, and William Masters of the Masters and Johnson Institute. Because phallometry showed that such methods were failures, Freund was among the first sexologists to declare that such attempts were unethical.
Reliability and validityEdit
The Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) of the American Psychiatric Association states:
Penile plethysmography has been used in research settings to assess various paraphilias by measuring an individual's sexual arousal in response to visual and auditory stimuli. The reliability and validity of this procedure in clinical assessment have not been well established, and clinical experience suggests that subjects can simulate response by manipulating mental images.—
The penile plethysmograph has value in screening organic versus psychogenic erectile dysfunction in urological polysomnography centres. Lack of sexual response during REM sleep may indicate that further evaluation by a urologist is required. 
When applied during nerve-sparing surgery, electrical stimulation penile plethysmograph is an erectile dysfunction prognostic. The patient is provided with objective information on their specific outcome which aids in planning for further erectile function therapies.
One study showed that homophobic men who have claimed to be heterosexual undergo arousal when given homosexual stimuli. 
Bradford's penile tumescence testing on 100 admitted child molesters correctly classified 62% of the admitted homosexual child molesters and 52% of the admitted heterosexual child molesters he tested. A 52% rate is nearly as accurate as tossing a coin.
In a study by Wormith, 42% of the paedophiles were classified as having normal sexual preferences. 
United States Edit
Use as trial evidenceEdit
In the United States, a scientific technique could not be used as evidence in court unless the technique was "generally accepted" as reliable in the relevant scientific community. This was known as the Frye standard, adopted in 1923. In 1993, the doctrine was rejected by the Supreme Court of the United States in favor of a more comprehensive "reliable foundation" test in Daubert v. Merrell Dow Pharmaceuticals. In the Daubert standard, the "generally accepted" test was no longer determinative. Several other factors could now be considered, including whether the technique had been published and peer reviewed. Myers notes, "Courts that have considered penile plethysmography generally rule that the technique is not sufficiently reliable for use in court." 
In United States v. Powers the court excluded the penile plethysmograph test because it failed to qualify under Daubert's scientific validity prong for two reasons: the scientific literature does not regard the test as a valid diagnostic tool, and "a vast majority of incest offenders who do not admit their guilt, such as Powers, show a normal reaction to the test. The Government argues that such false negatives render the test unreliable." 
According to Barker and Howell, penile plethysmography (PPG) does not meet the legal threshold for the guilt phase for the following reasons:
- No standardization
- Test results are not sufficiently accurate
- Results are subject to faking and voluntary control by test subjects
- High incidence of false negatives and false positives
- Results are open to interpretation 
They concluded, "Until a way can be devised to detect and/or control false negatives and false positives, the validity of the test data will be questionable." Responding to Barker and Howell, Simon and Schouten noted, "Our own analysis suggests that the standardization and faking issues, as well as other problems not addressed in the Barker and Howell paper, warrant much more guarded conclusions about the use of the plethysmograph in legal and clinical settings."  Prentky noted "the increased likelihood in forensic settings that dissimulation may compromise the validity of the assessment."  Hall and Crowther noted penile plethysmography "may be even more problematic than other [methods] in assessing susceptibility of the test to faking." 
In State of North Carolina v. Spencer, the court reviewed the literature and case law and concluded that penile plethysmography was scientifically unreliable: "Despite the sophistication of the current equipment technology, a question remains whether the information emitted is a valid and reliable means of assessing sexual preference."
More recently, a substantial amount of research data has been gathered and reviewed, and significant steps have been taken toward standardization.[How to reference and link to summary or text] According to Launay (1999), "[T]he validity of the technique for research and clinical assessment is now established;" it is only the use in guilt-determination proceedings that is inappropriate.[How to reference and link to summary or text] Fedoroff and Moran called it an "experimental procedure" and noted, "Virtually every expert who has written about phallometry has cautioned that it is insufficiently sensitive or specific to be used to determine the guilt or innocence of a person accused of a sex crime."
Phallometry is widely considered appropriate for treatment and supervision of convicted sex offenders: "Courts have permitted plethysmographic testing for monitoring compliance by convicted sex offenders with the conditions of their community placement as part of crime-related treatment for sexual deviancy." Its use for the treatment and management of sexual offenders is recommended by the Association for the Treatment of Sexual Abusers. Becker notes it "should never be used exclusively in forensic decision making." The sexual assault trial of basketball player Kobe Bryant in Colorado brought this device and its use to public attention before the case was dropped in 2004, because Colorado law would have required evaluation with this device following conviction. The United States Court of Appeals for the Ninth Circuit recently addressed the procedures required before a supervised release program could include penile plethysmograph testing.  The device is routinely used at civil commitment facilities, but "some clinicians and offenders say it is easy, particularly in a laboratory, to stifle arousal and thus cheat on a plethysmograph test."  This has been reported to occur in 16% of cases.
During the Catholic sex abuse cases, the reliability of the test was questioned by some officials in the Roman Catholic Archdiocese of Philadelphia. Later, these officials chose to seek therapy at an institution where the plethysmograph was not used. This, even though the officials were made aware of the fact that the test was used by most experts and was believed to be of value in diagnosing sexual disorders. Later, a Grand Jury found that the Archdiocese of Philadelphia's decision to do so "had the effect of diminishing the validity of the evaluations and the likelihood that a priest would be diagnosed as a pedophile or ephebophile."
Courts in Canada came to a similar conclusion as the United States. The Supreme Court of Canada adopted the Daubert doctrine in R. v . J.-L.J.  2 S.C.R. 600, which upheld a lower court's decision to exclude testimony by a psychiatrist who had administered several tests on the accused, including a penile plethysmograph:
A level of reliability that is quite useful in therapy because it yields some information about a course of treatment is not necessarily sufficiently reliable to be used in a court of law to identify or exclude the accused as a potential perpetrator of an offence. In fact, penile plethysmography has received a mixed reception in Quebec courts: Protection de la jeunesse – 539,  R.J.Q. 1144; R. c. Blondin,  Q.J. No. 3605 (QL) (S.C.); L. Morin and C. Boisclair in "La preuve d'abus sexuel: allégations, déclarations et l'évaluation d'expert" (1992), 23 R.D.U.S. 27. Efforts to use penile plethysmography in the United States as proof of disposition have largely been rejected: People v. John W., 185 Cal.App.3d 801 (1986); Gentry v. State, 443 S.E.2d 667 (Ga. Ct. App. 1994); United States v. Powers, 59 F.3d 1460 (4th Cir. 1995); State v. Spencer, 459 S.E.2d 812 (N.C. App. 1995); J. E. B. Myers et al., "Expert Testimony in Child Sexual Abuse Litigation" (1989), 68 Neb. L. Rev. 1, at pp. 134-35; J. G. Barker and R. J. Howell, "The Plethysmograph: A Review of Recent Literature" (1992), 20 Bull. Am. Acad. of Psychiatry & L. 13.—
- ↑ Indiana University, Research & Creative Activity
- ↑ Hanson, R. K., & Bussière, M. T. (1998). Predicting relapse: A meta-analysis of sexual offender recidivism studies. Journal of Consulting and Clinical Psychology, 66, 348–362.
- ↑ 3.0 3.1 Simon WT, Schouten PG. The plethysmograph reconsidered: comments on Barker and Howell. Bull Am Acad Psychiatry Law. 1992;20(1):13-25.
- ↑ Kolotz, L, et al. A Randomized Phase 3 Study Of Intraoperative Cavernous Nerve Stimulation with Penile Tumescence Monitoring to Improve Nerve Sparing During Radical Prostatectomy. Journal of Urology 2000;164(5):1573-1578.
- ↑ Howes, R. J. (1995). A survey of plethysmographic assessment in North America. Sexual Abuse: A Journal of Research and Treatment, 7, 9-24.
- ↑ Kuban, M., Barbaree, H. E., & Blanchard, R. (1999). A comparison of volume and circumference phallometry: Response magnitude and method agreement. Archives of Sexual Behavior, 28, 345–359.
- ↑ Freund, K. (1991). Reflections on the development of the phallometric method of assessing sexual preference. Annals of Sex Research, 4, 221–228.
- ↑ 8.0 8.1 8.2 Wilson, R. J., & Mathon, H. F. (2006, fall). Remembering Kurt Freund (1914-1996). ATSA Forum. Beaverton, OR: Association for the Treatment of Sexual Abusers.
- ↑ W O'Donohue, E Letourneau. The psychometric properties of the penile tumescence assessment of child molesters. Journal of Psychopathology and Behavioral Assessment, 1992
- ↑ Bancroft, J. (1969). Aversion therapy of homosexuality. British Journal of Psychiatry, 115, 1417-1431.
- ↑ Ellis, A. (1956). The effectiveness of psychotherapy with individuals who have severe homosexual problems. Journal of Consulting Psychology, 20, 191-195.
- ↑ Schwartz, M. F., & Masters, W. H. (1984). The Masters and Johnson treatment program for dissatisfied homosexual men. American Journal of Psychiatry, 141, 173-181.
- ↑ http://archive.southcoasttoday.com/daily/10-96/10-29-96/c06wn888.htm
- ↑ DSM-IV, Paraphilias, at 524
- ↑ Patent
- ↑ Marshall P, Surridge D, Delva N (1981). The role of nocturnal penile tumescence in differentiating between organic and psychogenic impotence. Archives of Sexual Behavior 10, No. 1
- ↑ Klotz, L., Cavernosal Nerve mapping: current data and applications. BJU Int. 2004;93(1):9-13
- ↑ Adams, H. E., Mostinger, P., McAnulty, R. D., & Moore, A. L. (1992). Voluntary control of penile tumescence among homosexual and heterosexual subjects. Archives of Sexual Behavior, 21, 17–31.
- ↑ Freund, K. (1963). A laboratory method of diagnosing predominance of homo- and hetero-erotic interest in the male. Behaviour Research and Therapy, 1, 85–93.
- ↑ Freund, K. (1967). Diagnosing homo- or heterosexuality and erotic age preference by means of a psychophysiological test. Behavioral Research and Therapy, 5, 209–228.
- ↑ Adams H. E., Right L. W., & Lohr B. A. (1996). Is Homophobia Associated With Homosexual Arousal? Journal of Abnormal Psychology.
- ↑ Blanchard, R., Klassen, P., Dickey, R., Kuban, M. E., & Blak, T. (2001). Sensitivity and specificity of the phallometric test for paedophilia in nonadmitting sex offenders. Psychological Assessment, 13, 118–126.
- ↑ Freund, K., & Blanchard, R. (1989). Phallometric diagnosis of paedophilia. Journal of Consulting and Clinical Psychology, 57, 100–105.
- ↑ Murphy, W. & Barbaree, H. E. (1994). Assessments of sexual offender by measures of erectile response: Psychometric properties and decision making. Brandon, VT: Safer Society Press.
- ↑ Bradford JMW, Pawlak A, Curry SD. (1992) [Evaluation of the sexual behaviours clinic assessment of child molesters]. Unpublished raw data. Cited in Bouget D, Bradford JMW (2008) Evidential Basis for the Assessment and Treatment of Sex Offenders. Brief Treatment and Crisis Intervention 2008 8(1):130-146
- ↑ Wormith JS (1986). Assessing deviant sexual arousal: Physiological and cognitive aspects. Advances in Behavior Therapy. 1986;8:101–137.
- ↑ Buhrich, N., & McConaghy, N. (1977). The discrete syndromes of transvestism and transsexualism. Archives of Sexual Behavior, 6, 483–495.
- ↑ Freund, K., Seto, M. C., & Kuban, M. (1996). Two types of fetishism. Behaviour Research and Therapy, 34, 687–694.
- ↑ Seto, M. C., & Kuban, M. (1996). Criterion-related validity of a phallometric test for paraphilic rape and sadism. Behaviour Research and Therapy, 34, 175–183.
- ↑ Myers JEB (2005). Myers on Evidence in Child, Domestic, and Elder Abuse Cases. Aspen Publishers Online ISBN 0735556687
- ↑ United States v. Powers, 59 F.3d 1460 (4th Cir. 1995)
- ↑ 32.0 32.1 Barker and Howell, The Plethysmograph: A Review of Recent Literature, 20 Bull. Am. Acad. of Psychiatry and Law 13 (1992)
- ↑ Prentky RA, Knight RA, Lee AFS (1997) Risk factors associated with recidivism among extrafamilial child molesters. Journal of Consulting and Clinical Psychology.
- ↑ Hall GCN, Crowther JH (1991). Psychologists' involvement in cases of child maltreatment: additional limits of assessment methods. American Psychologist Jan Vol 46(1) 79-80
- ↑ North Carolina v. Spencer, 459 S.E.2d 812, 815 (N.C. Ct. App. 1995),
- ↑ Launay, G. (1999) "The phallometric assessment of sex offenders: an update," Criminal Behaviour and Mental Health, 9 (3) 254–274.
- ↑ Fedoroff JP, Moran B (1997). Myths and Misconceptions about Sex Offenders. The Canadian Journal of Human Sexuality, Vol. 6, 1997
- ↑ Sachsenmaier, S. J., & Peters, J. M. (2002). Sexual offender risk assessment methods and admissibility as expert witness evidence. In J. M. Peters (Ed.), Assessment and management of sex offenders: What prosecutors need to know. Washington, DC: United States Department of Justice, Child Exploitation and Obscenity Section
- ↑ Association for the Treatment of Sexual Abusers. (2004). ATSA Practice Standards and Guidelines for the evaluation, treatment and management of adult male sexual abusers. Beaverton, OR: Author.
- ↑ Becker JD, Murphy WD (1998). What we know and do not know about assessing and treating sex offenders. Psychology, Public Policy, and Law. Volume:4 Issue:1/2 Dated:March/June 1998 Pages:116 to 137
- ↑ Mark Shaw for USATODAY- Bryant's off-court issues may aid prosecution
- ↑ United States v. Weber, 2006 U.S. App. LEXIS 15111 (9th Cir. 2006).
- ↑ Goodnough A, Davey M (March 6, 2007). For Sex Offenders, a Dispute Over Therapy's Benefits. New York Times
- ↑ Blanchard, R., Klassen, P., Dickey, R., Kuban, M. E., & Blak, T. (2001). Sensitivity and specificity of the phallometric test for pedophilia in nonadmitting sex offenders. Psychological Assessment, 13, 118-126.
- ↑ Court of Common Pleas, First Judicial District of PA, County Investigating Grand Jury, 9-17-2003
- ↑ R. v . J.-L.J.,  2 S.C.R. 600