Percutaneous High Frequency Alternating Current Stimulation in Healthy Volunteers With 30kHz

Study Overview
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Brief Summary
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High-frequency alternating currents of greater than 1 kHz applied on peripheral nerves has been used in animal studies to produce a motor nerve block. It has been evidenced that frequencies higher than 5 kHz are necessary to produce a complete peripheral nerve block in primates, whose nerve thickness is more similar to humans.

Detailed Description
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The previous studies with transcutaneous and percutaneous HFAC, suggest high-frequency stimulation (10 and 20 kHz) have an inhibitory effect over muscle strength and somatosensory threshold. However, the 30 kHz frequency has never been applied, and the hypothesis is that it can produce a greater blockage at the sensitive level and be a more comfortable application for the patient. The purpose of the present work is to determine if a greater blockage of the sensory component of the nerve occurs with this frequency and is to reduce the amount of current intensity needed using a percutaneous approach by apply two acupuncture needles near the nerve as electrodes.

Official Title
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Percutaneous High Frequency Alternating Current Stimulation: Effects on Somatosensory and Motor Threshold in Healthy Volunteers With 30 kHz

Conditions
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Electrical Stimulation, Neuromodulation

Intervention / Treatment
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* Device: 30 kHz stimulation (Myomed 932, Enraf-Nonius)
* Device: Sham stimulation (Myomed 932, Enraf-Nonius)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy volunteers Ability to perform all clinical tests and understand the study process, as well as obtaining informed consent. Tolerance to the application of electrotherapy. That they have not diagnosed any pathology. They do not present a contraindication to puncture and / or the application of electric currents. Exclusion Criteria: Neuromuscular disease. Epilepsy. Trauma, surgery or pain affecting the upper limb Osteosynthesis material in the upper limb. Diabetes. Cancer. Cardiovascular disease. Pacemaker or other implanted electrical device. Take any drug (NSAIDs, corticosteroids, antidepressants, analgesics, antiepileptics, ...) during the study and in the previous 7 days. Presence of tattoos or other external agent introduced into the treatment or assessment area. Pregnancy

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: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 30 kHz stimulation<br>Percutaneous application of high frequency electrical current at 30 kHz over the median nerve for a 20 minutes session. The intensity of the current will increase until participants report a strong but comfortable sensation, just below motor threshold. | Device: 30 kHz stimulation (Myomed 932, Enraf-Nonius)<br>* A charge-balanced, symmetric, biphasic sinusoidal current without modulation will be delivered at a frequency of 30 kHz. The stimulation intensity will be defined as that sufficient to produce a strong but comfortable sensation, just below motor threshold, over the median nerve through the electrotherapy device Myomed 932. (Enraf-Nonius, Delft,Netherlands)<br>|
| Experimental: Sham stimulation<br>Electrodes are placed over the median nerve for 20 minutes in the same manner as experimental group but will be applied a sham electrical stimulation increasing the current intensity during the first 30 seconds. | Device: Sham stimulation (Myomed 932, Enraf-Nonius)<br>* Sham stimulation will be delivered at a frequency of 30 kHz only during the first 30 seconds.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Latency of Antidromic median sensory nerve action potential | The recording electrodes were placed on the second finger and the stimulus will be applied on the median nerve (above the elbow joint). The stimulus will consist of a train of 10 pulses (100 μs width), applied at supramaximal stimulation, presented at 1 Hz (DS7A, Digitimer Ltd). Latency will be registered with a specific software (Signal software, CED) and will be expressed in millisecond. | Baseline at 0 minutes | 
| Amplitude of Antidromic median sensory nerve action potential | The recording electrodes were placed on the second finger and the stimulus will be applied on the median nerve (above the elbow joint). The stimulus will consist of a train of 10 pulses (100 μs width), applied at supramaximal stimulation, presented at 1 Hz (DS7A, Digitimer Ltd). Peak-to-peak amplitude (PPA) will be registered with a specific software (Signal software, CED) and will be expressed in millivolts. | Baseline at 0 minutes | 
| Tactile Threshold | The tactile threshold will be measured with Von Frey filaments and will be expressed in millinewton | Baseline at 0 minutes | 
| Pressure Pain Threshold | The PPT will be measured with an algometer and will be expressed in Newtons | Baseline at 0 minutes | 
| Muscle strength | Muscle strength will be measured with a dynamometer and will be expressed in Kgs. | Baseline at 0 minutes | 
| Tactile Threshold | The tactile threshold will be measured with Von Frey filaments and will be expressed in millinewton | During treatment at 15 minutes | 
| Pressure Pain Threshold | The PPT will be measured with an algometer and will be expressed in Newtons | During treatment at 15 minutes | 
| Latency Antidromic median sensory nerve action potential | The recording electrodes were placed on the second finger and the stimulus will be applied on the median nerve (above the elbow joint). The stimulus will consist of a train of 10 pulses (100 μs width), applied at supramaximal stimulation, presented at 1 Hz (DS7A, Digitimer Ltd). Latency (NPL) will be registered with a specific software (Signal software, CED) and will be expressed in millisecond. | Immediately after treatment at 20 minutes | 
| Amplitude Antidromic median sensory nerve action potential | The recording electrodes were placed on the second finger and the stimulus will be applied on the median nerve (above the elbow joint). The stimulus will consist of a train of 10 pulses (100 μs width), applied at supramaximal stimulation, presented at 1 Hz (DS7A, Digitimer Ltd). Peak-to-peak amplitude (PPA) will be registered with a specific software (Signal software, CED) and will be expressed in millivolts. | Immediately after treatment at 20 minutes | 
| Tactile Threshold | The tactile threshold will be measured with Von Frey filaments and will be expressed in millinewton | Immediately after treatment at 20 minutes | 
| Pressure Pain Threshold | The PPT will be measured with an algometer and will be expressed in Newtons | Immediately after treatment at 20 minutes | 
| Muscle strength | Muscle strength will be measured with a dynamometer and will be expressed in Kgs. | Immediately after treatment at 20 minutes | 
| Latency Antidromic median sensory nerve action potential | The recording electrodes were placed on the second finger and the stimulus will be applied on the median nerve (above the elbow joint). The stimulus will consist of a train of 10 pulses (100 μs width), applied at supramaximal stimulation, presented at 1 Hz (DS7A, Digitimer Ltd). Latency will be registered with a specific software (Signal software, CED) and will be expressed in millisecond. | Immediately after treatment at 30 minutes | 
| Amplitude Antidromic median sensory nerve action potential | The recording electrodes were placed on the second finger and the stimulus will be applied on the median nerve (above the elbow joint). The stimulus will consist of a train of 10 pulses (100 μs width), applied at supramaximal stimulation, presented at 1 Hz (DS7A, Digitimer Ltd). Peak-to-peak amplitude (PPA) will be registered with a specific software (Signal software, CED) and will be expressed in millivolts. | Immediately after treatment at 30 minutes | 
| Tactile Threshold | The tactile threshold will be measured with Von Frey filaments and will be expressed in millinewton | Immediately after treatment at 30 minutes | 
| Pressure Pain Threshold | The PPT will be measured with an algometer and will be expressed in Newtons | Immediately after treatment at 30 minutes | 
| Muscle strength | Muscle strength will be measured with a dynamometer and will be expressed in Kgs. | Immediately after treatment at 30 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Baseline nerve temperature | Nerve temperature will be measured using a termodoppler (Celsius degrees) | Baseline at 0 minutes, at 15 minutes, immediately after treatment at 20 minutes, and immediately after treatment at 30 minutes | 
| Numerical Discomfort Rate Score | the possible discomfort caused by the interventions will be assess by a numerical rate score. The NRS consists of a scale from 0 (no discomfort) to 10 (worst possible discomfort) | After the intervention at 35 minutes | 
| Numerical Pain Rate Score | The NRS consists of a scale from 0 (no pain) to 10 (worst possible pain) | After the intervention at 35 minutes | 
| Number of participants with intervention-related adverse effects | The possible adverse effects caused by the interventions will be assess by a closed questionnaire, where the presence of any adverse effect would be qualified as 1 point and the negative presence of adverse effect as 0 point. | After the intervention at 35 minutes | 
| Blinding success | Blinding of subjects and researchers will be assessed using the Bang questionary. It will be the question after the intervention, What type of treatment do you think you have received? Will be asked, with 5 items: (1) I firmly believe that I have received an experimental treatment; (2) I slightly believe that I have received an experimental treatment; (3) I strongly believe that I have received a placebo; (4) I slightly think I have received a placebo; (5) Don't know, don't answer., Index where -1 is blinded and 1 is unblinded. | After the intervention at 35 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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motor threshold, High-frequency alternating current, nerve block, somatosensory threshold, percutaneous electrical stimulation