Electrical Stimulation, Neuromodulation
Conditions
Keywords
high-frequency alternating current, nerve block, somatosensory threshold, motor threshold, percutaneous electrical stimulation
Brief summary
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
Our previous studies with transcutaneous HFAC, suggest high-frequency stimulation (10 and 20 kHz) have an inhibitory effect over muscle strength and somatosensory threshold. However, in these studies the intensity needed to reach block threshold is very high. The purpose of the present work is to reduce the amount of current intensity needed using a percutaneous approach by apply two acupuncture needles near the nerve as electrodes.
Interventions
DEVICE10 kHz stimulation (Myomed 932, Enraf-Nonius)
A charge-balanced, symmetric, biphasic sinusoidal current without modulation will be delivered at a frequency of 10 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)
DEVICE20 kHz stimulation (Myomed 932, Enraf-Nonius)
A charge-balanced, symmetric, biphasic sinusoidal current without modulation will be delivered at a frequency of 20 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)
Sham stimulation will be delivered at a frequency of 10 kHz only during the first 30 seconds.
Sponsors
University of Castilla-La Mancha
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 60 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Muscle strength | Baseline at 0 minutes | Muscle strength will be measured with a dynamometer and will be expressed in Kgs. |
| Antidromic median sensory nerve action potential | Baseline at 0 minutes | 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). Negative peak latency (NPL), positive peak latency (PPL), and peak-to-peak amplitude (PPA) will be registered with a specific software (Signal software, CED). |
| Tactile Threshold | Baseline at 0 minutes | The tactile threshold will be measured with Von Frey filaments and will be expressed in millinewton |
| Oscillation Frequency of tissue assessed by MyotonPro | Baseline at 0 minutes | This outcome measure is obtained by a device named MyotonPro. The frequency of the damped oscillations characterizes the muscle tone. The muscle will be assessed is opponens pollicis muscle |
| Stiffness of tissue assessed by MyotonPro | Baseline at 0 minutes | This outcome measure is obtained by a device named MyotonPro. Stiffness reflects the resistance of the muscle to the force deforming the muscle. The muscle will be assessed is opponens pollicis muscle |
| Decrement (elasticity) of tissue assessed by MyotonPro | Baseline at 0 minutes | This outcome measure is obtained by a device named MyotonPro. The logarithmic decrement of the damping oscillations characterizes muscle elasticity which is the ability of the muscle to restore its initial shape after contraction. The muscle will be assessed is opponens pollicis muscle |
| Pressure Pain Threshold | Baseline at 0 minutes | The PPT will be measured with an algometer and will be expressed in Newtons |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Baseline flux temperature | Baseline at 0 minutes, at 15 minutes, immediately after treatment at 20 minutes, and immediately after treatment at 30 minutes | Flux will be measured using a termodoppler |
| Numerical Discomfort Rate Score | After the intervention at 35 minutes | 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) |
| Numerical Pain Rate Score | After the intervention at 35 minutes | The NRS consists of a scale from 0 (no pain) to 10 (worst possible pain) |
| Number of participants with intervention-related adverse effects | After the intervention at 35 minutes | the possible adverse effects caused by the interventions will be assess by a questionnaire |
| Blinding success | After the intervention at 35 minutes | Blinding of subjects and researchers will be assessed using the James Index |
| Baseline nerve temperature | Baseline at 0 minutes, at 15 minutes, immediately after treatment at 20 minutes, and immediately after treatment at 30 minutes | Nerve temperature will be measured using a termodoppler (Celsius degrees) |
Countries
Spain
Outcome results
None listed