Motor Cortex Plasticity and the Effect of Deep Intramuscular Needling Stimulation Therapy (DIMST) in Osteoarthritis Pain

The aim of this study is to evaluate the cortical excitability in pain of knee osteoarthritis (OA), as well as the effect of one session of a kind of electroacupuncture (deep needling intramuscular stimulation therapy - DIMST) in this pain and the cortical excitability after the intervention.

The hypothesis is that cortical excitability is altered in this condition, confirming the findings already described in other chronic pain conditions. The investigators also believe that a session DIMST can reduce pain and alter cortical excitability, restoring its previous activity will occur from chronic pain.

Recent developments in the treatment of chronic pain have shown that the primary motor cortex (M1) is an effective target for neural brain stimulation techniques, such as transcranial magnetic stimulation (TMS). Due to these promising initial results, the plasticity of M1 has also been investigated as a potential marker for chronic pain. TMS studies using single or paired pulse shown changes in M1 plasticity in neuropathic pain and fibromyalgia pain compared to healthy subjects. Thus, there is a decrease in the inhibitory activity of chronic pain that can take a state as shown uninhibited by measuring TMS indexed intracortical inhibition (ICI) and cortical silent period (CSP). Based on these experimental data and clinical studies have been focused on the effects of neuromodulation techniques in M1 excitability. The techniques used to stimulate the peripheral nervous system was investigated using different approaches. The DIMST is a therapy applied to treat peripheral chronic syndromes that may have central components such as myofascial pain. During DIMST, the needles are applied to the spinal segment associated with nerve roots dermatome corresponding to the pathology. This treatment can also be effective in the treatment of diseases that have major peripheral components such as OA. OA is a major cause of suffering and disability in the elderly, having an inflammatory component, such as a factor that contributes to the symptoms and progression of the disease. There is evidence that OA could lead to sensitization central and segmental, but these effects on M1 plasticity and other central components are not completely known.

Therefore, researchers proposed to evaluate the plasticity of M1 in this chronic pain condition and also the effect of bottom-up DIMST in pain and cortical excitability.

Eligibility Criteria:
Inclusion Criteria:

* Women with over 18 years old, with chronic pain because of primary osteoarthritis of the knee.
* Pain stable for at least three months. Score greater than or equal to 3 cm (0 cm = "no pain" and "worst possible pain" = 10cm) on VAS for pain perception at baseline.
* No contraindications to electro acupuncture or transcranial magnetic stimulation.
* Naive in acupuncture treatment.

Exclusion Criteria:

* Clinically significant or unstable disorder, medical or psychiatric.
* Presence of neurological or rheumatic comorbidity.
* Pregnancy.
* Having performed surgery in the knee to be treated in the last 6 months, or be planning surgery for the next semester.
* Having performed with corticosteroid infiltration in the last six weeks or are using this.
* Having performed with hyaluronic acid infiltration.