Effects of Percutaneous Neuromodulation on Plasticity in the Somatosensory System in Healthy Subjects

Echography guided percutaneous neuromodulation is a physical therapy technique, whose main objective is the treatment of pain with direct stimulation of the peripheral nerves using a rome needle of acupuncture as an active electrode for applying currents of electrostimulation.

The neurophysiological basis and the effects on the sensory and motor systems of this technique are not characterised. The present study proposes to perform the intervention on the area adjacent to the median nerve and to apply different stimulation protocols on healthy subjects to answer those questions.

Intervention is going to be performed in the medial side of the arm, where the median nerve is accessible to the intervention. The theoretical basis of the technique is to produce specific controlled changes in the somatosensory system using synaptic plasticity, to ultimate affect the perception of pain through reduction of nociception afference. Subsequently, the protocols are based on synaptic physiology and the circuitry of the somatosensory system.

The protocols are the following:

1. - low-frequency and high-intensity of stimulation: 2hz during 16 min at an slightly annoying intensity, to induce synaptic depression on the c-fibers circuit, presumably carrying nociception.
2. - high-frequency and low-intensity of stimulation: 100 hz in 5 second trains, separated by 1 min of no current with a perceptible but mild intensity, to induce potentiation of a-beta fibers, presumably englobing mechanoreceptors which inhibit nociception through gate control in the spinal cord.
3. - placebo group has got the same intervention, but without current.

The study design is an experimental clinical trial, with randomized order of intervention with repeated measurements. This means each subject is having the three protocols at randomized order, with a gap of at least two weeks between them. The study is triple-blinded.

Somatomotor system variables, as sensory and pain pressure thresholds, grip strength, surface electromyographic activity and blood flow are evaluated on the hand of the subject. The arm to treat was also randomized for each subject The measurements are pre-intervention, post-intervention and 24 hours after the intervention for each protocol. Blood flow are measured only pre-intervention and post-intervention.

Eligibility Criteria:
Inclusion criteria:

* healthy.
* more than 18 years old
* amateur athlete.

Exclusion criteria:

* to suffer or to have suffered any pathology on the arm on the last 30 days.
* to suffer some disease discouraging current application or needle¡ing, as coagulation deficit, etc.
* to suffer some disease as diabetes mellitus, cancer, neurology disease, depression, fibromyalgia, etc.
* to consume drugs as coagulants, anti-depressant, pregabalin, etc during investigation or the first week before investigation.
* to consume nsaids the last 48 hours before investigation or during investigation.
* to consume opioids the first week before investigation or during investigation.
* belonephobia.
* professional athlete
* to be pregnant
* to suffer immunodepression