Therapist-dependent Dose of Spinal TENS

Study Overview
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Brief Summary
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The intensity used during transcutaneous electrical nerve stimulation (TENS) in both, clinical practice and research studies, is often based on subjective commands such as strong but comfortable sensation. There is not consensus regarding the effectiveness dose of TENS

Detailed Description
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Twenty healthy volunteers will divide into two groups: Therapist 1 and Therapist 2. Both therapist will apply spinal TENS and sham stimulation for 40min in random order to each subject, at an intensity to produce a strong but comfortable sensation.

Official Title
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Intensity Matters: Therapist-dependent Dose of Spinal Transcutaneous Electrical Nerve Stimulation

Conditions
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Transcutaneous Electrical Nerve Stimulation, Spinal Cord Stimulation, Dose-response Relationship

Intervention / Treatment
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* Device: Spinal TENS
* Device: Sham stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy volunteers between 18 and 60 years old Exclusion Criteria: Musculoskeletal pathology of the lower limbs History of neuromuscular disease Unable to tolerate electrical current Allergy to the electrode material Pacemaker or any implanted device Epilepsy Neurotrauma Recent surgical procedures Pain affecting the lower limbs or lower back Diabetes Pregnancy Cancer

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 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
Interventional Model Description: Randomized, double-blind, placebo-controlled, crossover trial
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Spinal TENS stimulation<br>Spinal TENS stimulation: A constant voltage and a symmetric biphasic current of 200 microseg pulse-width at a frequency of 100Hz. The intensity will increase until participants report a strong but comfortable sensation, just below motor threshold. | Device: Spinal TENS<br>* Spinal TENS stimulation over back through the electrotherapy device Myomed 932. (Enraf-Nonius, Delft, Netherlands)<br>|
| Sham Comparator: Sham stimulation<br>The same procedures as experimental group, but but will be applied a sham electrical stimulation increasing the current intensity until sensory perception of the stimulus, and then decreased to zero where it will fix until the end of the stimulation. | Device: Sham stimulation<br>* Sham stimulation over back through the electrotherapy device Myomed 932. (Enraf-Nonius, Delft, Netherlands)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Baseline Current Density | Current density (mA/cm2) is obtained by a mathematical operation which reflects the applied current intensity divided by the electrode area (45cm2) | At the onset (0min) of the Spinal TENS session | 
| Final Current Density | Current density (mA/cm2) is obtained by a mathematical operation which reflects the applied current intensity divided by the electrode area (45cm2) | At the end (40min) of the Spinal TENS session | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Baseline Maximal peak-to-peak soleus H-reflex | H-reflex data are obtained by electromyography activity (EMG). The EMG electrode is fixed on triceps surae. The stimulator electrode is fixed on the peroneus nerve, in the popliteal fossa. | baseline at 0min | 
| Baseline Maximal peak-to-peak soleus M wave | M wave ddata are obtained by electromyography activity (EMG). The EMG electrode is fixed on triceps surae. The stimulator electrode is fixed on the peroneus nerve, in the popliteal fossa. | baseline at 0min | 
| Baseline Normalized H-reflex response | Normalized H-reflex response data are obtained by electromyography activity (EMG). The EMG electrode is fixed on triceps surae. The stimulator electrode is fixed on the peroneus nerve, in the popliteal fossa. | baseline at 0min | 
| During Maximal peak-to-peak soleus H-reflex | H-reflex data are obtained by electromyography activity (EMG). The EMG electrode is fixed on triceps surae. The stimulator electrode is fixed on the peroneus nerve, in the popliteal fossa. | during treatment at 33min | 
| During Maximal peak-to-peak soleus M wave | M wave data are obtained by electromyography activity (EMG). The EMG electrode is fixed on triceps surae. The stimulator electrode is fixed on the peroneus nerve, in the popliteal fossa. | during treatment at 33min | 
| During Normalized H-reflex response | Normalized H-reflex response data are obtained by electromyography activity (EMG). The EMG electrode is fixed on triceps surae. The stimulator electrode is fixed on the peroneus nerve, in the popliteal fossa. | during treatment at 33min | 
| Post-treatment Maximal peak-to-peak soleus H-reflex | H-reflex data are obtained by electromyography activity (EMG). The EMG electrode is fixed on triceps surae. The stimulator electrode is fixed on the peroneus nerve, in the popliteal fossa. | Immediately after treatment at 40 min | 
| Post-treatment Maximal peak-to-peak soleus M wave | M wave data are obtained by electromyography activity (EMG). The EMG electrode is fixed on triceps surae. The stimulator electrode is fixed on the peroneus nerve, in the popliteal fossa. | Immediately after treatment at 40 min | 
| Post-treatment Normalized H-reflex responseMaximal peak-to-peak soleus H-reflex | Normalized H-reflex response data are obtained by electromyography activity (EMG). The EMG electrode is fixed on triceps surae. The stimulator electrode is fixed on the peroneus nerve, in the popliteal fossa. | Immediately after treatment at 40 min |