Suprathreshold Pressure Pain Stimulation in Fibromyalgia

Study Overview
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Brief Summary
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The purpose of this study is to investigate the induced-pain characteristics after suprathreshold pressure stimulation at different intensities in fibromyalgia subjects, compared with healthy volunteers.

Detailed Description
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Fibromyalgia syndrome is a chronic painful, non-inflammatory rheumatic disease with a high negative impact on the quality of life, and is characterized by widespread pain, fatigue and generalised hyperalgesia on examination, symptoms that can be the consequence of central sensitization. Despite several methods have successfully addressed this increased responsiveness of nociceptive neurons in the central nervous system, there is a lack of consensus about how to systematically perform them and those that are more appropriated for different syndromes. Therefore, investigating appropriate simple methods to assess clinical manifestations of central sensitization is relevant in the assessment of fibromyalgia. The present study aims to investigate the pain response after suprathreshols pressure stimulation in fibromyalgia subjects compared with healthy volunteers.

Official Title
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Pain Response Characteristics to Different Doses of Suprathreshold Pressure Stimulation in Fibromyalgia Subjects

Conditions
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Fibromyalgia

Intervention / Treatment
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* Device: Suprathreshold pain stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age between 18 and 80 years Fullfilled the American Collegue of Rheumathology criteria for fibromyalgia. Understanding of spoken and written Spanish. Exclusion Criteria: Diagnosed psychiatric pathology. Rheumatic pathology not medically controlled.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Fibromyalgia<br> | Device: Suprathreshold pain stimulation<br>* Suprathreshold pain stimulation will be applied in the infraspinatus muscle (point equidistant between the midpoint of the spine of the scapula, the inferior angle of the scapula and the midpoint of the medial border of the scapula) with a pressure algometer (Force Ten ™, Wagner Instruments, USA). Four suprathreshold pressure stimulations (pressure pain threshold + 20%, +30%, +40% and +50%) will be made for 60 seconds, with a minimum rest of 5 minutes between each stimulation. The sequence of stimulation (ascending or descending) will be randomized.<br>|
| Healthy volunteers<br> | Device: Suprathreshold pain stimulation<br>* Suprathreshold pain stimulation will be applied in the infraspinatus muscle (point equidistant between the midpoint of the spine of the scapula, the inferior angle of the scapula and the midpoint of the medial border of the scapula) with a pressure algometer (Force Ten ™, Wagner Instruments, USA). Four suprathreshold pressure stimulations (pressure pain threshold + 20%, +30%, +40% and +50%) will be made for 60 seconds, with a minimum rest of 5 minutes between each stimulation. The sequence of stimulation (ascending or descending) will be randomized.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Referred pain induced area after suprathreshold pressure stimulation | After each stimulation (120%, 130%, 140% and 150%), the subject should draw the induced pain area on a digital bodychart using the Navigate Pain application (Navigate Pain, Aalborg University, Denmark). The size of the areas of referred pain will be extracted in pixels. | Inmediately after each stimulation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pain intensity | It will be measured with a visual analog scale (VAS) of 100 millimeters in length. The subject has to indicate the level of pain he feels, being 0 the absence of pain and 100 the maximum imaginable. | Inmediately after each stimulation | 
| Body regions afected by pain after suprathreshold pressure stimulation | The digital body chart will be divided into 15 different regions: (1) posterior head and neck area; (2) supraspinal area; (3) infraspinatus area; (4) posterior shoulder area; (5) back area; (6) posterior arm area; (7) posterior forearm area; (8) posterior hand area; (9) anterior head and neck area; (10) supraclavicular area; (11) chest area; (12) anterior shoulder area; (13) anterior arm area; (14) anterior forearm area; (15) anterior hand area. The total number of body regions afected by pain will be recorded. | Inmediately after each stimulation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Reffered pain, Pain sensitivity, Fibromyalgia, Suprathreshold, Central sensitization