Pain Inhibitory Effects of Other Pain Induced by Mechanical Pressure Compared to Electrical Stimulation and Cold Water.

Study Overview
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Brief Summary
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The objective is to estimate the effects on pain thresholds of a painful mechanical stimulus on the upper trapezius compared to a painful electrical stimulus and a diffuse noxious stimulus using the cold water hand immersion test.

Detailed Description
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The mechanical stimulus produced in manual therapy (MT) techniques elicits neurophysiological responses within the peripheral and central nervous system responsible for pain inhibition. Almost all types of MT elicit a neurophysiological response that is associated with the descending pain modulation circuit. But it has not been demonstrated whether this inhibition occurs through a conditioned pain modulation mechanism induced by painful mechanical stimulation that is carried out with manual therapy techniques.

Official Title
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Conditioned Pain Modulation Induced by Mechanical Stimulation: A Mechanism of Manual Therapy Analgesia - Study 1

Conditions
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Healthy

Intervention / Treatment
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* Other: Conditioning stimulus


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: healthy male or female between 18 and 65 years Free of pain and with no history of chronic pain Exclusion Criteria: Pregnant or having given birth within the last year

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: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Mechanical pressure stimulation<br>Mechanical compression is applied with the thumb to the upper trapezius muscle on the non-dominant side at the midpoint between the acromion and C7. The intensity of this will be regulated by the pain it causes the patient, trying to ensure that it is at all times approximately 5/10 on the numerical pain rating scale (NPRS) with 0 being no pain at all and 10 being the worst pain imaginable. The stimulation will be carried out for 2 minutes. | Other: Conditioning stimulus<br>* Pain stimulus on non-dominant side<br>|
| Active Comparator: Electrical stimulation<br>To perform this procedure a TENS will be used applying a biphasic current, since it is the most used and studied type of electrotherapy. A frequency of 100hz and a bandwidth of 150 will be used. The intensity will be increased and decreased with the patient's feeback in order to provoke a pain of approximately 5/10 in the NPRS. The stimulation will be performed for 2 minutes on the upper trapezius of the non-dominant side at the midpoint between acromion and C7. | Other: Conditioning stimulus<br>* Pain stimulus on non-dominant side<br>|
| Active Comparator: Cold pressor task<br>The non-dominant hand shall be placed in a bucket of cold water at 10.5° for 2 minutes. | Other: Conditioning stimulus<br>* Pain stimulus on non-dominant side<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from Baseline in Tibialis Anterior Pressure Pain Threshold (PPT) to immediate post-conditioning stimulus | PPTs will be assessed on the dominant side over the tibialis anterior muscle using a digital algometer (Wagner instruments, Greenwich, CT, USA). Participants will be instructed to say stop when the pressure sensation becomes painful. The average of 3 assessments on the tibialis anterior of the dominant side will be performed for analysis. The algometer pressure for assessment will be gradually increased at a rate of 1kg/second. Data will be collected in kg/cm2. | At baseline and immediately after the conditioning stimulus | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Conditioned Pain Modulation, Manual Therapy, Physiotherapy, Physical therapy