Mechanisms of Affective Touch in Chronic Pain

Study Overview
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Brief Summary
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This study compares how different types of touch found in massage therapies impact pain perception, and whether these effects differ in individuals with and without chronic pain. This study also examines psychological factors that may predict differences in touch perception in individuals with chronic pain. This research will improve our understanding of whether and how massage therapies can benefit pain and health, and whether this differs in people who suffer from chronic pain.

Official Title
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Mechanisms of Affective Touch in Chronic Pain

Conditions
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Fibromyalgia

Intervention / Treatment
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* Behavioral: affective touch


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ages 18-65 fluent in English physician diagnosis of Fibromyalgia but no other chronic pain conditions (patients) or no evidence of chronic pain (healthy volunteers) Exclusion Criteria: Sensory, motor, or anatomic differences or injuries relevant to study procedures Known anomalies of the central nervous system (including stroke, dementia, aneurysm, or personal history of psychosis) Pregnancy Inability to rate pain or sensations Major medical conditions such as kidney, liver, cardiovascular (hypertension, preexisting cardiac arrhythmia), autonomic, pulmonary, or neurological problems (e.g., seizure disorder) or a chronic systemic disease (e.g., diabetes). History of blood clots or first-degree family members with clotting disorders Current use of opiate medication(s) Contraindications to MRI if participating in pilot MRI study Unable to identify a heat stimulus 50C or lower that generates a rating of a 7 on our VAS scale History of fainting or seizures History of frostbite Open cut or sore on hand to be immersed in cold water bath Fracture of limb to be immersed History of Reynaud's phenomenon (hands get white, then blue on exposure to cold, then red on warming)

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
Intervention Model: Single Group Assignment
Masking: Single


Arms and Interventions

| Intervention/Treatment |
| --- |
|Behavioral: affective touch|Various types of touch such as brushing, pressure, and tapping, as well as heat pain|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Chronic pain levels using the Chronic Pain Grade Questionnaire | The investigators will measure chronic pain levels using the Chronic Pain Grade Questionnaire. This measure will be included in a linear regression model to determine whether this measure significantly predicts differences in ratings of touch pleasantness. | Day 1 | 
| Trauma history using the Childhood Trauma Questionnaire | The investigators will measure trauma history using the Childhood Trauma Questionnaire. This measure will be included in a linear regression model to determine whether this measure significantly predicts differences in ratings of touch pleasantness. | Day 1 | 
| Current depression using the Hospital Anxiety and Depression Scale without chronic pain | The investigators will measure current depression using the Hospital Anxiety and Depression Scale. This measure will be included in a linear regression model to determine whether this measure significantly predicts differences in ratings of touch pleasantness. | Day 1 | 
| Ratings of affective touch | Touch pleasant/unpleasantness ratings will be assessed in response to each sensory stimulus (brushing, tapping, and pressure) using a Visual Analog Scale with anchors of no pleasantness to most pleasant imaginable. Affective touch perception is the difference in ratings between the affective and neutral touch conditions during the baseline testing session and will be compared between individuals with and without chronic pain. | Day 1 | 
| Ratings of Heat Pain Intensity | Pain intensity will be measured during the baseline and post-tests in the affective-Conditioned Pain Modulation blocks. Pain intensity will be assessed with a Visual Analog Scale with anchors from no pain  to most intense pain imaginable. VAS pain ratings will be compared before the cold water bath. | Day 1 | 
| Ratings of Heat Pain Intensity | Pain intensity will be measured during the baseline and post-tests in the affective-Conditioned Pain Modulation blocks. Pain intensity will be assessed with a Visual Analog Scale with anchors from no pain  to most intense pain imaginable. VAS pain ratings will be compared before and after blocks of affective touch stimuli . | Day 2 | 
| Ratings of Heat Pain Unpleasantness | Pain unpleasantness will be measured during the baseline and post-tests in the affective-Conditioned Pain Modulation blocks. Pain intensity will be assessed with a Visual Analog Scale with anchors from no unpleasantness to most unpleasant pain imaginable. VAS pain ratings will be compared before and after the cold water bath. | Day 1 | 
| Ratings of Heat Pain Unpleasantness | Pain unpleasantness will be measured during the baseline and post-tests in the affective-Conditioned Pain Modulation blocks. Pain intensity will be assessed with a Visual Analog Scale with anchors from no unpleasantness to most unpleasant pain imaginable. VAS pain ratings will be compared before and after blocks of affective touch stimuli. | Day 2 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Breathing rate | Respiration rate will be measured during the baseline and during the affective touch and pain trials. | Day 1 and 2 |