From Attention to Behavior: Increasing Behavioral Inhibition
NCT ID: NCT03825627
Last Updated: 2019-08-13
Study Results
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Basic Information
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UNKNOWN
NA
76 participants
INTERVENTIONAL
2019-06-01
2020-12-31
Brief Summary
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Detailed Description
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A promising line of research has examined the neurocognitive basis of pedophilia. Pedophilic individuals display altered activity in the dorsolateral prefrontal cortex (dlPFC) when attending to child-related stimuli. This brain area is involved in the cognitive control of sexual arousal. Transcranial Direct Current Stimulation (tDCS) has been examined as a non-invasive method to increase activity in the dlPCF, ultimately increasing inhibitory control over impulses. Accumulating evidence also shows that individuals have an attentional bias towards sexually preferred stimuli. These attentional processes can be investigated by recording eye movements. Early automatic eye movements are particularly relevant in discriminating individuals with pedophilia from those without pedophilia.
The proposed study will examine the effects of tDCS over the dlPFC of pedophilic individuals and healthy controls, while they complete a task requiring controlled attention to virtual (computer-generated) images of children and adults. In two separate sessions, participants will be randomly assigned to an active and a placebo (sham) tDCS condition. Eye movements will be recorded during the task.
The investigators expect to observe a conflict between automatic and controlled attention when participants are presented with their sexually preferred stimuli. Specifically, the investigators expect pedophiles to show an attentional bias towards virtual child stimuli. The investigators predict that the attentional conflict will be reduced when tDCS is applied, compared to the sham condition. If the attentional bias is a key cognitive feature of sexual interest, the investigators expect to measure changes in reported or indirectly assessed sexual preferences.
Conditions
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Study Design
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RANDOMIZED
PARALLEL
TREATMENT
DOUBLE
Study Groups
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Antisaccade Task (active tDCS)
During the antisaccade task, the investigators will show participants computer-generated images depicting clothed and sexually relevant (nude) children, young adults and adults of both genders. Images will be drawn from the Virtual People Set and the Not-Real-People Set (Pacific Psychological Assessment Corporation, 2004). Pedophilic participants are expected to show a sexual preference towards a prepubescent body scheme whereas stimuli displaying adolescence and adulthood (sexual maturity) are expected to be sexually preferred by the teleiophilic control participants. In this arm active Transcranial Direct Current Stimulation will be used to influence performance.
Transcranial Direct Current Stimulation
Conductive saline-soaked rubber electrodes super-imposed on sponge plates will be placed on the scalp at F3 (active electrode, 4.4×4.4cm) and on the contralateral supraorbital area (reference electrode, 5.1×10.2cm).
Stimulation will be applied using a battery-driven constant-current regulator (Oasis Pro, Edmonton, Alberta, Canada). For each stimulation, the direct current is initially increased in a ramp-like fashion over 10 s until reaching 2 milliampere (mA) and will be similarly decreased at the end of stimulation.
In the active tDCS condition, stimulation will be maintained for 20 min; in the sham condition, it will be turned off after 15 s of stimulation, with a ramp-up/down of 10 s (i.e., 35 s total).
Antisaccade Task (sham tDCS)
During the antisaccade task, the investigators will show participants computer-generated images depicting clothed and sexually relevant (nude) children, young adults and adults of both genders. Images will be drawn from the Virtual People Set and the Not-Real-People Set (Pacific Psychological Assessment Corporation, 2004). Pedophilic participants are expected to show a sexual preference towards a prepubescent body scheme whereas stimuli displaying adolescence and adulthood (sexual maturity) are expected to be sexually preferred by the teleiophilic control participants. In this arm sham Transcranial Direct Current Stimulation will be used during the task.
Transcranial Direct Current Stimulation
Conductive saline-soaked rubber electrodes super-imposed on sponge plates will be placed on the scalp at F3 (active electrode, 4.4×4.4cm) and on the contralateral supraorbital area (reference electrode, 5.1×10.2cm).
Stimulation will be applied using a battery-driven constant-current regulator (Oasis Pro, Edmonton, Alberta, Canada). For each stimulation, the direct current is initially increased in a ramp-like fashion over 10 s until reaching 2 milliampere (mA) and will be similarly decreased at the end of stimulation.
In the active tDCS condition, stimulation will be maintained for 20 min; in the sham condition, it will be turned off after 15 s of stimulation, with a ramp-up/down of 10 s (i.e., 35 s total).
Approach Avoidance Task (active tDCS)
During the Approach-Avoidance Task (AAT), participants will look at a series of images depicting children and adults wearing swimsuits. The images were sampled from internet advertisements and do not constitute legally objectionable material. When sourcing the images, rigorous attention was paid to meet the criteria for fair use indicated by the American Psychological Association. There are 160 images in total. Half of the images will be used in the active and the other half in the sham condition (i.e., 20 female adults, 20 female children, 20 male adults, and 20 male children per condition). In this arm active Transcranial Direct Current Stimulation will be used to influence performance.
Transcranial Direct Current Stimulation
Conductive saline-soaked rubber electrodes super-imposed on sponge plates will be placed on the scalp at F3 (active electrode, 4.4×4.4cm) and on the contralateral supraorbital area (reference electrode, 5.1×10.2cm).
Stimulation will be applied using a battery-driven constant-current regulator (Oasis Pro, Edmonton, Alberta, Canada). For each stimulation, the direct current is initially increased in a ramp-like fashion over 10 s until reaching 2 milliampere (mA) and will be similarly decreased at the end of stimulation.
In the active tDCS condition, stimulation will be maintained for 20 min; in the sham condition, it will be turned off after 15 s of stimulation, with a ramp-up/down of 10 s (i.e., 35 s total).
Approach Avoidance Task (sham tDCS)
During the Approach-Avoidance Task (AAT), participants will look at a series of images depicting children and adults wearing swimsuits. The images were sampled from internet advertisements and do not constitute legally objectionable material. When sourcing the images, rigorous attention was paid to meet the criteria for fair use indicated by the American Psychological Association. There are 160 images in total. Half of the images will be used in the active and the other half in the sham condition (i.e., 20 female adults, 20 female children, 20 male adults, and 20 male children per condition). In this arm sham Transcranial Direct Current Stimulation will be used during the task.
Transcranial Direct Current Stimulation
Conductive saline-soaked rubber electrodes super-imposed on sponge plates will be placed on the scalp at F3 (active electrode, 4.4×4.4cm) and on the contralateral supraorbital area (reference electrode, 5.1×10.2cm).
Stimulation will be applied using a battery-driven constant-current regulator (Oasis Pro, Edmonton, Alberta, Canada). For each stimulation, the direct current is initially increased in a ramp-like fashion over 10 s until reaching 2 milliampere (mA) and will be similarly decreased at the end of stimulation.
In the active tDCS condition, stimulation will be maintained for 20 min; in the sham condition, it will be turned off after 15 s of stimulation, with a ramp-up/down of 10 s (i.e., 35 s total).
Interventions
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Transcranial Direct Current Stimulation
Conductive saline-soaked rubber electrodes super-imposed on sponge plates will be placed on the scalp at F3 (active electrode, 4.4×4.4cm) and on the contralateral supraorbital area (reference electrode, 5.1×10.2cm).
Stimulation will be applied using a battery-driven constant-current regulator (Oasis Pro, Edmonton, Alberta, Canada). For each stimulation, the direct current is initially increased in a ramp-like fashion over 10 s until reaching 2 milliampere (mA) and will be similarly decreased at the end of stimulation.
In the active tDCS condition, stimulation will be maintained for 20 min; in the sham condition, it will be turned off after 15 s of stimulation, with a ramp-up/down of 10 s (i.e., 35 s total).
Eligibility Criteria
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Inclusion Criteria
* Diagnosed with pedophilia (further psychiatric illnesses possible)
* Sufficient German language skills
Controls:
* Not diagnosed with Pedophilia (or other psychiatric illnesses)
* Sufficient German language skills
Exclusion Criteria
* Prior head injury with loss of consciousness for at least 5 min
* Neurological diagnosis (including epilepsy) or prior medical conditions with possible central nervous system sequelae
* Metallic implants inside the brain or any electrical medical device (e.g. pacemaker) in the body
* Visual or hearing impairment, to the extent that it interferes with task instructions
Current medication in patients (antiandrogenic medication among the pedophilic subjects, in particular) will be recorded and acknowledged as a covariate.
Controls
* Prior head injury with loss of consciousness for at least 5 min
* Neurological diagnosis (including epilepsy) or prior medical conditions with possible central nervous system sequelae
* Metallic implants inside the brain or any electrical medical device (e.g. pacemaker) in the body
* Visual or hearing impairment, to the extent that it interferes with task instructions
* Current or previous pedophilic sexual interest
For both groups further exclusion (prematurely) will occur if initial data shows that participants don't comply with instructions or if questionnaires hint toward a lack of sexual interest in general.
18 Years
65 Years
MALE
Yes
Sponsors
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University of Zurich
OTHER
Responsible Party
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Principal Investigators
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Nathalie Brackmann, Dr.
Role: PRINCIPAL_INVESTIGATOR
University Hospital of Psychiatry Zurich, Department of Forensic Psychiatry
Locations
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Psychiatrische Universitätsklinik Zürich
Zurich, , Switzerland
Countries
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Central Contacts
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Facility Contacts
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Nathalie Brackmann, PhD
Role: primary
References
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Dombert B, Mokros A, Bruckner E, Schlegl V, Antfolk J, Backstrom A, Zappala A, Osterheider M, Santtila P. The virtual people set: developing computer-generated stimuli for the assessment of pedophilic sexual interest. Sex Abuse. 2013 Dec;25(6):557-82. doi: 10.1177/1079063212469062. Epub 2013 Jan 7.
Cacioppo JT, Priester JR, Berntson GG. Rudimentary determinants of attitudes. II: Arm flexion and extension have differential effects on attitudes. J Pers Soc Psychol. 1993 Jul;65(1):5-17. doi: 10.1037//0022-3514.65.1.5.
Ettinger U, Ffytche DH, Kumari V, Kathmann N, Reuter B, Zelaya F, Williams SC. Decomposing the neural correlates of antisaccade eye movements using event-related FMRI. Cereb Cortex. 2008 May;18(5):1148-59. doi: 10.1093/cercor/bhm147. Epub 2007 Aug 28.
Fromberger P, Jordan K, Steinkrauss H, von Herder J, Witzel J, Stolpmann G, Kroner-Herwig B, Muller JL. Diagnostic accuracy of eye movements in assessing pedophilia. J Sex Med. 2012 Jul;9(7):1868-82. doi: 10.1111/j.1743-6109.2012.02754.x. Epub 2012 Apr 30.
Oberlader VA, Ettinger U, Banse R, Schmidt AF. Development of a Cued Pro- and Antisaccade Paradigm: An Indirect Measure to Explore Automatic Components of Sexual Interest. Arch Sex Behav. 2017 Nov;46(8):2377-2388. doi: 10.1007/s10508-016-0839-7. Epub 2016 Oct 17.
Phaf RH, Mohr SE, Rotteveel M, Wicherts JM. Approach, avoidance, and affect: a meta-analysis of approach-avoidance tendencies in manual reaction time tasks. Front Psychol. 2014 May 8;5:378. doi: 10.3389/fpsyg.2014.00378. eCollection 2014.
Poeppl TB, Nitschke J, Santtila P, Schecklmann M, Langguth B, Greenlee MW, Osterheider M, Mokros A. Association between brain structure and phenotypic characteristics in pedophilia. J Psychiatr Res. 2013 May;47(5):678-85. doi: 10.1016/j.jpsychires.2013.01.003. Epub 2013 Feb 9.
Weidacker K, Kargel C, Massau C, Weiss S, Kneer J, Krueger THC, Schiffer B. Approach and Avoidance Tendencies Toward Picture Stimuli of (Pre-)Pubescent Children and Adults: An Investigation in Pedophilic and Nonpedophilic Samples. Sex Abuse. 2018 Oct;30(7):781-802. doi: 10.1177/1079063217697134. Epub 2017 Mar 20.
Other Identifiers
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2018-02028
Identifier Type: -
Identifier Source: org_study_id
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