The role of PPG in sexological assessment and treatment of sexual offenders: a comparison of British and Czech practice

Derek Perkins, Marek Pdv and Petra Skfivankova

Introduction

Phalopletysmographic examination (Czech Republic), also known as penile plethysmographic assessment (UK), was invented by Kurt Freund in 1957 in Prague when he measured volume changes in the penis during exposition of sexual and nonsexual stimuli (Freund, 1963). In the UK, PPG assessment was first introduced into the prison service and high secures forensic mental health services in the 1970s. In the Czech Republic, PPG use is deeply rooted in the practice of sexology diagnosis and treatment, further developed by Freund with his co-workers (Kolafsky, Madlafousek, & Novotna, 1978).

The PPG is a laboratory procedure for assessing sexual preferences by penile tumescence measurement. PPG assessment involves the presentation of sexual stimuli to a male subject and the concomitant measurement of changes in the penis circumference, length, or volume. PPG findings are based on analyses of relative penile responses to different categories of stimuli - child vs. adult, consent vs. coercion etc. The PPG is used for both clinical and research purposes. Clinically, it is used to: assist with case formulation; risk management; treatment planning; evaluation of treatment effects and engaging offenders with case formulation and treatment (Dean & Perkins, 2008). The PPG provides an assessment of the mans current sexual arousal profile within the laboratory setting, from which it is posited that this profile may be indicative of his more general pattern of sexual interests, together with indications of whether he may have difficulty managing any offence-related arousal. Both findings can be relevant in planning treatment and managing risks.

If conducted sensitively and collaboratively, PPG assessments also provide a useful method for engaging subjects - offenders, patients, clients - in further relevant assessments and treatment interventions based on a shared understanding of any offence-related sexual interests that are identified. For example, a sexual preference for children, or for sexual violence, or any other problematic paraphilia, can begin to be addressed through an agreed understanding between patient and therapist, aided by the relevant PPG profiles. This is perhaps analogous, within the sphere of physical medicine, to patient and doctor reviewing X-rays or MRI scans, as part of the clinical decisionmaking and treatment planning process.

Materials and methods

Comparative analysis of PPG purposes and methodologies in the assessment of paraphilic sexual offenders was undertaken between Broadmoor Hospital UK, and Bohnice Hospital, Czech Republic. This was carried out within the broader context of national consensus in each country concerning PPG use, based on relevant literature, national guidelines and expert opinions.

Results

Sexual aggression in classifications systems DSM-5 and MKN-11

Only a minority of individuals who have sexually offended have a diagnosed paraphilia. Most sexual aggressions are committed by men with histories of disrupted early lives and attachments (Ward, Hudson, & Marshall, 1996), personality disorder(s), alcohol and drug abuse histories or by people suffering other psychiatric disorders. The term paraphilia (from Greek para-, means out of, a philia, means love) is a biomedical term which was first used by I.F. Krause and introduced in sexology by W. Stekel (Weiss, 2010). The term paraphilia is in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) described as an intense and persistent sexual interest other than sexual interest in genital stimulation or preparatory fondling with phenotypically normal, physically mature, consenting human partners. In some circumstances, the criteria ‘intense and persistent’ may be difficult to apply, such as in the assessment of persons who are very old or medically ill and who may not have ‘intense’ sexual interests of any kind. In such circumstances, the term paraphilia may be defined as any sexual interest greater than or equal to nor-mophilic sexual interests (American Psychiatric Association, 2013).

In preparation of the fifth DSM revision, discussions were held on the inclusion of the Paraphilic Coercive Disorder (PCD) in the DSM-5 classification to clarify the current diagnosis of the undetermined paraphilia (Quinsey, 2010). The proposed general diagnostic criteria were analogous to other paraphilia- present for at least six months, repeated sexual fantasies; the person is seriously distressed by these fantasies, or forced sexual stimulation or violent sex with at least three disagreeing partners has occurred (Stern, 2010). Clinical experience with men who repeatedly sexually offend led a number of authors to propose the inclusion of this subgroup of aggressors, different from typical sadists, into this separate diagnostic category (Quinsey, 2010; Stern, 2010; Thornton, 2010). Phallometric data support this by demonstrating that, while only 10% of non-rapists show responses to depictions of rape, 60% of men who have committed rape show equal or greater arousal (Lalumiere, Quinsey, Harris, Rice, & Trautrimas, 2003). However, another group of authors argue that there is not enough evidence to confirm the stability of this diagnostic construct and nonexistence of the robust data for its introduction (Balon, 2013; Knight, 2010). PCD was not ultimately included as a DSM-V classification, and remains among the categorical units requiring further investigation and acquisition of additional data (Agalaryan & Rouleau, 2014).

Some authors, therefore, sought to define a new subgroup of patients with a sadistic disorder. Such individuals are focused on humiliating and dominating the victim, causing pain and suffering, sometimes causing injuries or death. However, the sadistic spectrum is quite broad, and, as a diagnostic unit, suffers by a weak consistency, so a dimensional classification of sadism is more appropriate, with dimensions of control and domination, aggression, humiliation, cruelty without sexuality, and torture (Longpre, Guay, Knight, & Benbouriche, 2018). Knight proposed sexual sadism as an ‘agonistic continuum’ (spectrum) ranging from mere fantasies (ideational sadism) to consensual sadistic (or complementary sadomasochistic) activities over sexually violent behaviour to clearly and explicitly expressed sexually sadistic behaviour (Knight, 2010; Knight, Sims-Knight, & Guay, 2013).

The World Health Organization (WHO) published the 11th revision of the ICD on 18 June 2018 to allow translation into national languages. It will be submitted for approval by the World Health Assembly 2019 and Member States will use it for statistical purposes from 2022. The expected ICD-11 category F65 - ‘Sexual preference disorders’ are renamed Paraphilic Disorders and would be limited to disorders that involve sexual arousal patterns that focus on non-consenting others or are associated with substantial distress or direct risk of injury or death. A person with paraphilia is strongly stressed by the nature of his sexual arousal, not only fear of rejection by others. The WGS-DSH Working Group on Classification of Sexual Disorders and Sexual Health (WGSDSH) took into account the needs of public health, health services and the legal tradition of the member countries (namely Brazil, India, South Africa, Lebanon, Mexico, Germany) and invited other experts to discuss (Kaplan & Krueger, 2012). It introduces ICD-10 as well-grounded with a well-needed new diagnosis in forensic sexology: Coercive Sexual Sadism Disorder, Sadistic Force Disorder, and Other Paraphilic Disorder Involving Non-Consenting Individuals, or Another Paraphilic Disorder involving Non-Conscious Individuals. Designed kernels to identify the sexual arousal that causes physical or psychological harm to reluctant or incompetent subjects. The reason for classifying new diagnoses is specific forensic applicability because this persistent pattern of sexual arousal has been found to be an important factor, for example, among individuals treated in forensic institutions (Briken, Bourget, & Dufour, 2014; Kaplan & Krueger, 2012). In contrast to DSM 5, ICD-11 postulates the persistence of paraphilia, not just 6 months of manifestation.

PPG - test or tool}

Dean and Perkins (2008) set out reasons why the PPG should be regarded as a clinical tool rather than a psychological test. To meet the criteria for a psychological test, it must be: standardized in application, and reliable and valid in predicting future behaviour. PPG assessments currently lack the degree of uniform stimuli and testing methods to meet these requirements. More important, however, is the question of whether PPGs are measuring stable traits, as in the case of intelligence for example, or whether relative levels of sexual arousal to different stimuli/situations are at least partly state-based. For example, if an individual’s propensity to be aroused by sexual violence were dependent on feeling angry and alienated (e.g. see Yates, Barbaree, & Marshall, 1984), then the presence of such a state would be expected to influence findings at two time periods; one where the individual was angry/alienated and at the other where he was not. One of the authors carried out assessment with a male individual convicted of a sexual homicide (binding, rape and beating to death) where a sadistic PPG profile at initial testing ameliorated during a period when the individual was reportedly in love with another person; only to revert to the earlier sadistic profile after this loving emotional state had ended.

The implication is that, while for some individuals, PPG findings may be measuring a stable trait, for others it may be measuring a combination of state and trait factors, and hence the psychological test principle of reliability will not be achieved. While this would negate the PPG as meeting one important criterion for it to be viewed as a psychometric test, PPG can still be viewed as a useful clinical tool.

In relation to the final test criterion of validity in predicting future behaviour, while offence-related sexual interest has consistently been identified as a risk predictor for sexual offending against children (Hanson & Morton-Bourgon, 2005), such offences arise through a combination of interacting factors, notably sexual deviance (as above), offence-supportive attitudes and beliefs, and antisocial/psychopathic traits. Hence, not all deviant PPGs will predict reoffending in individual cases. For example, in the case of paedophilia, Finkelhor’s (1984) Preconditions Model of child sexual abuse highlights that the motivation to offend (the first precondition) might be paedophilic sexual interest. However, it might alternatively, or additionally, be emotional congruence with children. Hence, not all men who have sexually abused a child will have a deviant PPG. Similarly, while men who use child sexual exploitation material (CSEM) (sometimes referred to as child pornography offenders) typically display higher levels of paedophilic sexual interest than those who commit contact sexual abuse against a child, the majority do not reoffend with CSEM offences and even fewer commit future contact sexual offences (Babchishin, Hanson, & VanZuylen, 2015; Seto, Lalumiere, Harris, & Chivers, 2012;).

PPG examination description-methods

PPG examination is often used to investigate paraphilia and other offence-related sexual deviance and involves having a measurement device fitted around the penis, with penile tumescence measured in response to visual or auditory stimuli explicit stimuli (Dean & Perkins, 2008; Mackaronis, Byrne, & Strassberg, 2016). PPG assessment was initially undertaken by a volumetric method using an uncomfortable cylinder, which stimulated further development of alternative measurement methods, notably those using circumferential measures. Disadvantages of these alternatives are that they are less sensitive in measurement: comparison of both methods shows, that while the volumetric method is more movement prone, circumferential methods are less expensive, more user-friendly with clinically sufficient reliability (Laws, 2009).

Issues in PPG use

Dean and Perkins (2008) noted some practical challenges in PPG use: (a) achieving subject engagement with the procedure, as PPGs can be seen as invasive, embarrassing or anxiety provoking; (b) it is time-consuming, generally taking about two hours including preparation, carrying out the assessment and debriefing; and (c) it is costly to administer, due to the complex and demanding requirements of the laboratory procedure. As such, they argued that PPG assessment is unsuited to wide-scale application across the full spectrum of criminal justice and forensic mental health services.

PPG testing is not used in a number of countries because of ethical’ issues (Babchishin, Nunes, & Hermann, 2013), and concerns have also been raised about: (a) a lack of procedural and stimulus standardization (Laws, 2009); (b) poor test-retest reliability (Renaud et al., 2010); and (c) the capacity of those undertaking PPGs to suppress their responses (Renaud et al., 2009).

Nevertheless, PPG assessment has for many years been the most commonly used method of assessing male sexual interest, and has been evaluated in comparative reviews as having the best combination of accuracy and robustness in the face of counter-measures (Akerman & Beech, 2012; Fromberger et al., 2013; Kalmus & Beech, 2005). While subjects’ attempts at faking through response suppression need careful consideration, subjects who are unresponsive (‘flat-lining’) have not successfully ‘faked’ the results, which would be regarded as uninterpretable. To truly fake the test, a subject would need to consistently suppress sexual responses to the preferred stimulus (e.g. child) and generate a high response to a non-preferred stimulus (e.g. adult), arguably a complex and difficult feat to accomplish.

PPG in sexual aggression assessment in the Czech Republic

History

Based on courtship disorder postulated by Freund (1963), Czech investigators looked for deepened diagnostics distinguishing the reactions of exhibitionists, frotteurists, rapists, and sadists (Kolarsky et al., 1978). They wanted to understand the essence of individual deviations based on PPG stimuli presentation. At the end of the 1960s, they distinguished the aggressors from the sadists otherwise deviant (Kolarsky et al., 1978; Mellan, Nedoma, & Pondelickova, 1972). These authors have highlighted hunting stereotypes, lack of pre-touch interaction with the victim, hitting, crashing, or attempting to penetrate or directly immobilize victims in numerous non-sadistic delinquents’ cases. Such sudden attacks are unlike the sadistic offender’s prolonged torture of the victim. Zverina with Pondelickova (Zvefina & Pondelickova, 1984) found highly aggressive rapists as well as attackers not targeting coitus. For those who have committed non-sadistic sexual aggression, the pleonastic term ‘pathological sexual aggression’ was chosen in the Czech Republic, although we do not know whether or not there is ‘normal’ sexual aggression in human eroticism. However, the term ‘atypical aggressiveness’ for men who repetitively assault women but do not rape them (Brichcin, 1969) has not been taken up.

There has always been a specific group of men who sexually aggress (so-called ‘assault sadists’) who commit the most serious acts, brutally attacking their victims, immobilizing and manipulating them frequently to achieve sexual satisfaction (Weiss, 2010). The existence of this small subgroup sui generis is not questioned, and diagnostics also do not usually face any significant difficulties. Kolarsky and Brichcin (2000) also describe a combination of swift victim immobilization without victim torture. Such men perceive the victim as prey, having no sense of the victim as a human being with feelings and wishes.

The importance of PPG in sexology assessment of such offenders was realized from its beginning, using the volumetric method to measure penile responses to slides presenting various offence-relevant stimuli (Brichcin & Weiss, 1989). In forensic cases, phallometry is also used to assess the effect of complex sexology treatment, and as one of data sources in predicting the risk of recurrence. There was also research conducted on men with paraphilias, in which phallometry research also significantly contributed to appraising sexual motivation states theory (Kolarsky et al., 1978). Sexual motivation state theory equally influenced practical PPG examination procedure, the order of stimuli and of course their form and aesthetics (Kolarsky, Brichcin, & Holly, 2001).

Current practice

Nowadays, in the Czech Republic, mainly photos are used as stimuli during the PPG assessment. The usual setting is that individual is seated in a chair and watches the photographic images presented on the monitor and his sexual response is measured by PPG. There is a consensus, that photos from the major categories should be presented (adult men, adult women, preadolescents of both sexes, photos of violent scenes, consensual partner interactions scenes), and there should be an adjustment in the stimuli in response to further information about specific behaviour in a given case. Some units alternatively also use audio stimuli. Some experts prefer sorting stimuli sequentially (e.g. according to convergence of lovers based on motivation state theory); some workplaces use random presentation. Usual exposition length varies from 5 to 60 seconds, with a neutral stimulus presentation in between. There is a call to use video presentation as sexual stimuli for individuals, but it is not used due to the criminality of child pornography video, and lack of artificial material suitable to use.

Evaluation of the record is nowadays computerized, widely used is Z-score calculation discriminating level of reactions in specific stimuli category. There is also consensus about the necessity of comparison of reactions to stimuli within category and comparison between categories. There is also consensus concerning post exposition reaction. Taking these reactions into consideration is widely accepted. A critical approach to result evaluation is essential, as the validity of an examination - dependent on actual arousal (Howes & Howes, 2017) - does not necessarily reflect long-term reactivity; this holds naturally also for negative findings. The whole context of the clinical case must be therefore taken into account and phallometric findings should be coupled with documented conduct (Marshall & Fernandez, 2001), results of the clinical examination and or other instrumental methods as implicit association Tests (IAT) or polygraphy (Wilcox, 2000).

Sexual aggression diagnostics

When meeting the general criteria for paraphilia and taking into account the specific features of the individual’s behaviour and a proper analysis of the skipping in the perpetrators motivation system, this subgroup of perpetrators is clinically well distinguishable and classifiable. In recognition of the disorder, the sexological anamnesis is a significant source of information such as often atypical manifestations in childhood, accelerated sexual development, difficulty in maintaining partner relationships, or the long-term presence of fantasy of victim abuse can point to an anomaly in sexuality. It is also worthwhile to identify the characteristics of the perpetrators access to the victim, means of overcoming victim resistance and behaviour of the perpetrator after the committed offence. An important source of information is provided by a PPG examination recording the reactivity to conventional or atypical stimuli such as violent scenes (Seto et al., 2012). PPG is evident in distinguishing a subgroup of sadistic disorders in which also fMRI, when observing paindisplay scenes, specifically activates both the areas responsible for sexual arousal (amygdala, hypothalamus, ventral striatum) and for the treatment of pain (anterior cingulum and insula) (Harenski, Thornton, Harenski, Decety, &Kiehl, 2012)

Case example, Czech Republic

A boy, aged 16, was convicted of sexual assault on his classmate - a girl aged 15. He said that the sexual assault was planned. Three hours before their meeting he was thinking about how to get her drunk and overpower her. He had no previous convictions, but he had a lot of physical conflicts with his father. His personality had dissocial traits, he felt no remorse, his empathy was very low, and he was very shy. After the assault, he did not know what happened, why he was sexually thrilled by overpowering the girl and by the violence. He was confused.

PPG assessment showed a clear sexual preference for non-sexual violence to young women (scenes of overpowering, punching, kicking and strangling women). After that, he was comprehensively sexologically examined and the result was that he suffers from paraphilic sexual sadism disorder. It was very hard for him and his family to deal with this fact but on the other hand, they felt relief that they know what is going on. The boy started to be treated within group therapies working on the origins of his sexual interests, intimacy difficulties and shame of talking to not only girls but also to peers, followed by one-to-one therapy with psychologists and sexologist.

PPGs in the UK

History

PPGs were first used within the UK prison and secure hospital services in the 1970s as part of the range of psychological assessments carried out with men who had sexually offended, for the purpose of assisting risk assessment and treatment planning. Interestingly, its use within the UK Prison Service was banned in the 1980s by the then Director of Prison Medical Services, on the basis that its use was excessively intrusive. However, with the emergence of evidence-based treatment programmes for men who had sexually offended, the UK’s then Home Secretary set a policy direction in 1990 that saw PPGs reintroduced within some UK prisons as part of the pre- and post-sex offender treatment program (SOTP) assessment measures. At the time of writing, PPGs have ceased to be used within the UK prison system but continue to be used on an individualized referral basis within forensic psychiatric services.

Research on modifying offence-related sexual interests has yielded modest supportive evidence for both behavioural management techniques (Schmucker & Lbsel, 2015) and anti-libidinal medication (Bradford & Harris, 2003). Other research has suggested that certain sexual preferences, notably paedophilia in the forensic context, has a sufficiently biological basis that attempting to reshape sexual interest is less likely to be successful than selfmonitoring and self-management: see for example Bradford, Fedoroff, and Gulati (2013), Cantor (2015)' and Cantor (2015)² in response to Muller et al. (2014).

Current practice

PPGs in the UK are carried out in line with the British Psychological Society’s (BPS) professional guidelines for their use (wwwl.bps.org.uk/content/ penile-plethysmography-guidance-psychologists-1). This sets out, amongst other things, gaining informed consent, clearly specified assessment purposes, targeted and proportionate assessment stimuli, the legality and ethical appropriateness of stimuli, and the requirement that PPGs should only be carried out and interpreted in the context of a wider set of assessments. As described for CZ above, this typically includes file review, interview information, psychometric assessments and collateral behavioural observations. No decision should be made purely on the basis of PPG findings.

Case example

Mr A, aged 23, attacked a woman in a park at twilight, pushing her to the ground, punching her face and stealing her handbag. The woman said that, by the way he grabbed hold of her (i.e. touching her breasts and thighs), she thought she was going to be raped but Mr A denied that this was his intention. He had no previous convictions, but the social enquiry report said that he had been banned from visiting his aunt’s house when he was 15 and she caught him masturbating in her bedroom. PPG assessment assessed his relative responses to consenting heterosexual sex, rape (scenes of overpowering and forcing sex on a woman), and non-sexual violence to women (scenes of overpowering, punching, kicking and strangling women). The PPG results indicated that Mr A responded least to violence but at a higher and similar level to consent and rape as a percentage of his maximum response (as dia-grammatically illustrated in Figure 3.1)

Figure 3.1 PPG results for Mr A as mean maximum responses for consent, rape and violence stimuli as percentages of maximum response obtained during the assessment.

Figure 3.2 Mr A's PPG mean responses to consent, rape and violence stimuli over the duration of the stimulus presentations as percentages of maximum response obtained.

It was noted that he responded to initial scenes of overpowering women in both the rape and the violence scenes, and that this arousal declined as the violence scenes progressed but continued to rise in the rape scenes (as diagrammatically illustrated in Figure 3.2). This is consistent with a hypothesis that he was most sexually interested in overpowering and raping women (rape category) rather than in extreme violence such as kicking, punching and strangling (violence category). On the consent scenes, he responded most in the latter stages when sex was occurring, in contrast to the rape scenes where he responded to both the overpowering segments and the sex segments. He acknowledged in discussing the findings that they reflected his sexual interests, and it was possible, as in many such cases, to then move onto treatment planning more quickly and in a more informed way than would otherwise have been the case.

Discussion: comparison of both practice systems

Although the history of PPG is deeply rooted in the Czech Republic and although there are many experts in this field who use PPG, not only in forensic sex diagnosis and treatment diagnostics, it is still a method that is not standardized in the Czech Republic and its value is therefore potentially underestimated by some experts. There is no uniform approach in the sexodiagnostic examination in the Czech Republic and PPG examination is not always included.

PPG assessment also has a long history in the UK, dating back to the 1970s, but again standardization of procedures, stimulus and interpretations is not uniform. There are, however, some UK professional practice guidelines which have proved very helpful, and a number of these principles are also mirrored in Czech practice. After the 11th revision of the ICD comes into use, it will be possible to code paraphilic violence into separate diagnostic categories: namely, Coercive sexual sadism disorder and sui generis diagnosis Other Paraphilic Disorder Involving Non-Consenting Individuals. This latter subgroup is different from the subgroup of individuals who have sexually offended and have sadistic disorders and, of course, from all other people who commit sexual violence for reasons other than a paraphilic motivation (e.g. due to intoxication, personality disorder or other mental disorder); in other words, without the presence of paraphilia. Although motivation state theory is more descriptive than causal, it still gives a solid explanatory frame to sexodiagnostic differentiation between these two subgroups of individuals who have sexually offended. PPG examination can, in most cases, contribute to differentiation not only between individuals who are paraphilic and nonparaphilic, but also between the above mentioned paraphilias. Responses of both types of paraphilia are typically different and PPG assessment can, thus, significantly contribute to determining correct diagnosis.

Evidence-based conclusions in differential diagnosis cannot be reached by the currently inconsistent approach in sexodiagnosis. It is important to find common ground also in the legal and clinical framework of sexodiagnostic examination because the lack of data (despite apparent clinical experience in this field) also inhibits the therapeutic advancement in this area. In this situation, PPG standardization in the near future seems to be the optimal and logical follow-up process. Some countries have already implemented this, such as the UK, from which Czech practice can draw relevant guidelines and practices, and with whom it can cooperate. We can help to increase the unification, transparency and validity of the sexodiagnostic examination not only for clinicians in this area but also for the law system, and to increase benefits to patients by achieving greater standardization, efficiency and ethical acceptability of PPG examination.

Conclusion

The aim of this chapter was to describe the development and individual approaches in the implementation of PPG examinations in the Czech Republic and the UK in case formulations, diagnoses and treatment of men who have sexually offended. For future practice, it is important to introduce more targeted and complex stimuli into routine PPG assessments. Despite the different sexological assessment and treatment backgrounds of the Czech Republic and the UK, we can hopefully learn from and enrich our clinical sexological practice from each other. In this, we aim to obtain evidence-based and standardized methods for more effective sexological assessment and diagnosis, and to inform better treatments to not only protect victims of sexual offending, but also offer effective treatments for men who sexually offend and who suffer from paraphilias.

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