Dry Needling and Patients Treatment Expectations

Study Overview
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Brief Summary
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Objectives The aim of this study is to compare the effects of inducing positive expectations against negative or neutral induced expectations on the activation of the Autonomic Nervous System and the analgesic response, after a dry needling technique in upper trapezius fibers in patients with unspecific neck pain. Summary Theoretical framework: Dry needling has proven its efficacy for the treatment of myofascial trigger points. Moreover, it has proven its effects over the Central Nervous System and the Autonomic Nervous System (ANS). Despite that previous studies have researched the role of patient's expectations and their relationship with the results of treatment, there is insufficient information concerning the effects of inducing expectations and the activation of the ANS during the application of widely used therapies, such as dry needling.

Detailed Description
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The aim of this study will be to research the effects of induced expectations combined with a dry needling technique on the activation of the ANS and on the results of the treatment. Hypothesis: The induction of a positive expectation shall cause a greater analgesic response associated with a response in the ANS compared to the induction of neutral or negative expectations. Methods: Patients with neck pain will participated in this randomized clinical trial, which will be randomly assigned into 3 groups in order to receive positive, neutral or negative expectations concerning the treatment, by means of an individual informative talk. All subjects will received treatment using dry needling in the upper trapezius fibers. The main variables measured will be the following: Analogic Visual Scale, Pressure Pain Threshold using a mechanical Force Gage (before and after) and the activation of the ANS measuring the skin conductance, skin temperature, heart rate and breathing rate (monitored for 5 minutes before the intervention, during and 20 minutes afterwards).

Official Title
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Influence of Induced Expectations on the Autonomic Nervous System During a Dry Needling Intervention for Patients With Neck Pain. A Randomized Clinical Trial.

Conditions
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Neck Pain; Dry Needling; Motivation

Intervention / Treatment
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* Other: Positive expectation AND dry needling in the upper trapezius fibers, at the most painful point
* Other: Neutral expectation AND dry needling in the upper trapezius fibers, at the most painful point
* Other: Negative expectation AND dry needling in the upper trapezius fibers, at the most painful point


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Neck pain. Hiperalgesic point in Upper trapezius muscle. Exclusion Criteria: Pain Irradiation toward upper limb Psychological disorders Whiplash. Neuropathic symptoms Cervical and / or Shoulder Spine Surgery

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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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: • Group 1. Positive expectation<br>Dry needling is a very effective tool used in the treatment of nonspecific neck pain, which we hope will reduce your neck pain. | Other: Positive expectation AND dry needling in the upper trapezius fibers, at the most painful point<br>* The subjects will received the same treatment, using dry needling in the upper trapezius fibers, at the most painful point after receiving the corresponding message.<br>|
| Active Comparator: • Group 2. Neutral Expectation<br>Dry needling is an indicated tool used in the treatment of nonspecific neck pain, but its efficacy is unknown. | Other: Neutral expectation AND dry needling in the upper trapezius fibers, at the most painful point<br>* The subjects will received the same treatment, using dry needling in the upper trapezius fibers, at the most painful point after receiving the corresponding<br>|
| Active Comparator: • Group 3. Negative Expectation<br>Dry needling is not a very effective treatment tool for nonspecific neck pain, so we expect your neck pain to increase a bit. | Other: Negative expectation AND dry needling in the upper trapezius fibers, at the most painful point<br>* The subjects will received the same treatment, using dry needling in the upper trapezius fibers, at the most painful point after receiving the corresponding<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Skin conductance (µS). | It is the measure of the variations in the electrical resistance of the skin, caused by the excitation of the sweat glands, controlled by the Sympathetic Nervous System (SNS) | Change from baseline at twenty minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Heart rate variability | This variable is defined as the variation of the heartbeat in a previously defined period in an analysis of consecutive circadian periods. It measures the time in milliseconds between the R waves of two consecutive beats (known as the RR interval) and is widely used in the field of Cardiology for the stratification of patients after an acute myocardial infarction. It has also been shown to be a useful tool in detecting ANS activation. | Change from baseline at twenty minutes | 
| Pain intensity | It will be collected through the Visual Analogue Scale (VAS). It is a continuous scale, which consists of a 100 mm horizontal straight line, so that zero is equivalent to total absence of pain and 100 to more bearable pain. | Change from baseline at twenty minutes | 
| Pressure pain threshold | The pressure pain threshold is defined as the minimum amount of pressure necessary to cause pain. It has been measured through a Force Dial FDK using a mechanical Force Gage (Wagner Instruments). | Change from baseline at twenty minutes. |