Combining Animal-assisted Intervention and Placebo-induced Analgesia

Study Overview
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Brief Summary
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An increased interest of animal-assisted interventions (AAI) can be observed within clinical practice, even though it is still not entirely clear how the presence of an animal contributes to the outcome of a treatment. One theory maintains that the mere presence of an animal influences the therapeutic alliance between therapist and client. However, results from a recent study suggest that a relationship between patient and health-provider alone is not sufficient to influence treatment outcomes, but that a therapeutic rationale is needed and that verbal instructions and suggestions are highly important in shaping participants' treatment expectations. To investigate this theory, this study will combine AAI with a placebo intervention, as placebo interventions offer the basic form of intervention working through relationship and expectancy. The effects of the presence of a dog will be assessed with a standardized experimental heat pain paradigm (TSA-II) in a randomized controlled trial in healthy participants (N=128). After a baseline measurements of heat pain threshold and tolerance, participants will be randomly assigned to one of the following four conditions: a) placebo intervention , no dog present, b) placebo intervention, dog present, c) no placebo intervention, no dog present and d) no placebo intervention, dog present. The dog will be introduced after randomization. Expectancy will be induced by telling participants that the contact to an animal increases the oxytocin level, which has an non inflammatory effect. The placebo intervention will be a deceptive cream which is said to helps against pain. Afterwards, posttreatment measurements will be conducted and participants fill in questionnaires about their perceptions of the experimenter.

Detailed Description
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A growing body of literature suggests that animal-assisted interventions (AAI) have important clinical effects on humans, e.g. decreased physiological stress, reduction of depression and anxiety symptoms and reduction in pain perception and experience. Such evidence leads to an increased interest in using AAI in clinical practice. However, it is still not quite clear how AAI works or in other words what it is that makes AAI effective. Therefore, it is crucial to investigate how the inclusion of animals in clinical practice contributes to beneficial therapeutic outcomes. In this regard, it has been assumed that the presence of an animal enhances the development of the therapeutic alliance, which, in turn, has been shown to play a crucial role in the outcome of the treatment. However, results from a recent study suggest that a relationship between patient and health-provider alone is not sufficient to influence treatment outcomes, but that a therapeutic rationale is needed and that verbal instructions and suggestions are highly important in shaping participants' treatment expectations. As placebo effects are related to therapeutic rationale and relationship, the investigators would like to use an expectancy-induced placebo intervention to identify if animal-assisted intervention also works through these two components. Given that placebo analgesia works well through therapeutic rationale the investigators decided to employ an animal-integrated placebo intervention study with healthy participants (N=128) in a standardized experimental heat pain paradigm. Even though a growing body of evidence highlights the positive effects of animal-assisted interventions until this day little is known about the mechanisms. There exist various hypotheses trying to explain why AAI works, most focusing on the crucial role of the animal in the intervention. However, to the best of the investigator's knowledge there has been no study which examined if the effectiveness of animal-assisted interventions could simply be explained by the power of the therapeutic rational and the relationship. Therefore, it is still unknown if AAI is effective because of the animal or because of its influence on the therapeutic relationship and the given therapeutic rationale. It is important to understand how AAI works. Moreover, if AAI, like other interventions, is about expectation and relationship, this could have important implications for clinical practice and a better understanding of how AAI must be used to be effective. If AAI works through similar mechanisms as the placebo, then both interventions should have a similar impact on the outcome of the intervention (reduced pain perception, increased placebo analgesia). Findings of this study could have important implications, not only for clinical practice of AAI but also for intervention in general as the results could help to better understand the importance of these two components.

Official Title
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Combining Animal-assisted Intervention and Placebo-induced Analgesia: The Dog as Treatment in a Randomized Controlled Trial

Conditions
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Pain, Therapeutic Alliance, Placebo

Intervention / Treatment
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* Other: Animal-assisted placebo condition
* Other: Placebo condition
* Other: Dog only condition
* Other: Control Condition


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥ 18 years Right-handedness Exclusion Criteria: Being scared of dogs by self-report dog hair allergy by self-report Any acute or chronic disease (chronic pain, hypertension, heart disease, renal disease, liver disease, diabetes) as well as skin pathologies, neuropathies or nerve entrapment symptoms, sensory abnormalities affecting the tactile or thermal modality Pregnancy Current medications (psychoactive medication, narcotics, intake of analgesics) or being currently in psychological or psychiatric treatment Insufficient German language skills to understand the instructions Previous participation in studies using pain assessment with Peltier Devices Current or regular drug consumption (THC, cocaine, heroin, etc.)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: randomized controlled parallel group within-subjects design
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Animal-assisted placebo condition<br>Participants receive verbal information that they are receiving an analgesic cream. Additionally, and before getting the dog, participants will get a therapeutic rationale for the presence of the dog. | Other: Animal-assisted placebo condition<br>* Participants receive the same verbal information as in the Placebo condition. Additionally, participants will receive the same verbal information as in the Dog only condition.<br>|
| Experimental: Placebo condition<br>Participants receive verbal information that they are receiving an analgesic cream. | Other: Placebo condition<br>* Participants receive verbal information that they are receiving an analgesic cream (i.e. Antidolor, containing Lidocain), which has been shown to produce significant pain reduction in previous clinical trials. However, they will receive an inert cream.<br>|
| Experimental: Dog only condition<br>Before meeting the dog, participants will get a therapeutic rationale for the presence of the dog. | Other: Dog only condition<br>* Participants will get a therapeutic rationale for the presence of the dog. The rationale is supported in the literature and therefore not invented for the purpose of this study. Participants will be told that: Studies have shown the presence of an animal can affect pain perception because the presence and the interaction with an animal can increase our Oxytocin level. Therefore, the investigators want to examine if the presence of a dog has an impact on your pain perception. While participants have to wait for the action time of the cream they are allowed to pet the dog. The intensity of interaction will be documented and be rated on a scale from 1-5 (1=very low degree of interaction, 5=very high degree of interaction). During the experiment the dog will be lying in the room with some distance to participants to avoid further physical interaction. The dog will always be lying at the same spot. Participants will still be able to see the dog.<br>|
| Other: Control condition<br>Participants in this condition will receive no intervention. | Other: Control Condition<br>* Participants in this condition will receive no intervention. All instructions will be conveyed in a standardized manner to ensure that the participant-experimenter relationship is comparable in terms of friendliness and attention across all four conditions.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Posttreatment objective heat pain tolerance | Heat stimuli will be administered to the right volar forearm using a 30x 30-mm Peltier device (Medoc, Ramatishai, Israel; TSA-II) placed at 2/3 of the distance from wrist to elbow. Pain tolerance will be determined by the method of limits: Participants will be asked to stop the increasing heat stimulus at the moment they cannot stand the heat any longer. Three measurements will start at 32 °C, with a rise of 0.5 °C/s. Heat tolerance will be defined as the average of the three measurements. | 10 minutes | 
| Corresponding subjective ratings of pain intensity and unpleasantness of pain tolerance | Subjective ratings of pain intensity and unpleasantness will be measured with a visual analogue scale (VAS): Following each pain stimuli with the TSA-II participants have to respond on a VAS how intense and unpleasant the pain is. The range of the scale is from 1-10 (1= not intense/unpleasant at all; 10= the most intense/unpleasant pain). | 5 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Posttreatment objective heat threshold | Heat pain threshold will be determined by the methods of limits. Temperature will be increased from the baseline (32°C) at a rate of 0.5°C /s. Participants are instructed to press the button to determine the turning point from perceiving warmth to the perception of pain. When the pain threshold has been reached, the device will resume from its baseline (32 °C) with a rise of 0.5 °C/s. This procedure will be repeated three times. Pain threshold will be defined as the average of the three measurements. | 10 minutes | 
| Corresponding subjective ratings of pain intensity and unpleasantness of pain threshold. | Subjective ratings of pain intensity and unpleasantness will be measured with a visual analogue scale. ): Following each pain stimuli with the TSA-II participants have to respond on a VAS how intense and unpleasant the pain is. The range of the scale is from 1-10 (1= not intense/unpleasant at all; 10= the most intense/unpleasant pain). | 5 minutes | 
| Pain expectancy and relief | The Expectancy of Relief Scale assesses how intensive and unpleasantness participants expect the pain to be after the treatment phase. The expectancy ratings are made on the same VAS (ranging from 1 to 10, (1= not intense/unpleasant at all; 10= the most intense/unpleasant pain) as those for pain intensity and pain unpleasantness. | 2 minutes | 
| Participants perception of the study conductor assessed by questionnaire | Participants perception of the study conductor will be assessed with the Counselor Rating Form (CRF) Short questionnaire. The CRF-S assesses participant's perception of the study conductor and if their perception changes in the presence of absence of a dog. The CRF-S is a brief 12-items questionnaire that has been developed to measure people's perception of a therapist on total three subscales: trustworthiness, expertness and attractiveness (Corrigan and Schmidt, 1983). The questionnaire contains item such as honest, likeable, trustworthy, friendly on a 7-point Likert scale ranging from 1 (not very) to 7 (very). This questionnaire will be used after baseline heat pain measurements and a second time after posttreatment heat pain measurements. | 10 minutes | 
| Attitude towards dogs assessed by questionnaire | Attitude towards dogs will be assessed with the questionnaire on the attitude towards dogs (AAPL). This questionnaire was designed for this study. This questionnaire assesses if participants like dogs and animals. This study developed this questionnaire for this study. | 2 minutes | 
| Kontextmodellfragebogen (KMF)/context model questionnaire | The KMF assesses the perception of participants of the study conductor and the credibility and expectation of the intervention. Participants fill out this questionnaire after the treatment phase. | 5 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Treatment Rationale, animal-assisted intervention