Effects of Dry Needling on Electromyographic Activity and Ultrasonographic Characteristics in Post-Stroke Spasticity

Stroke is a global health problem, with an incidence in Europe of 147/100,000 people per year. It is estimated that 43% of them present spasticity throughout the first year, causing disability, hindering mobility and functionality, which can generate comorbidity problems, which in turn hinders its improvement over time.

Recently, high quality studies have conclude that there is a moderate level of evidence with large effect size in reducing spasticity with dry needling, as well as being cost-effective in stroke patients in both the subacute and chronic phases. However, due to the limitation of manual evaluations of spasticity, and it is necessary to look for measurement alternatives that complement it, such as the analysis of the electromyographic activity and the muscular structure measured with ultrasound. These data could provide objective, useful and complementary information to clinical assessments to be more specific and effective in the treatment of stroke patients.

This randomized controlled trial aim to analyse the effect of dry needling in this parameters in patients with stroke and spasticity, as well as correlated with gait variables. Each participant will be randomly assigned to the dry needling group or to the sham dry needling group, where participants receive a total of 4 sessions of ultrasound-guided dry needling or sham ultrasound-guided dry needling in the gastrocnemius medialis over 4 weeks, one per week. Measures of spasticity, electromyographic activity and muscle structure via ultrasound will made at baseline (T0) and immediate after each intervention (T1,T2,T3,T4). Gait variables will be made at baseline and after the last intervention (T0 and T4).

The aim of the study is to analyse the effect of dry needling in stroke patients. The investigators hypothesized dry needling will decrease spasticity and electromyographic activity of spastic muscles during dynamic stretching and at rest, causing a reduction of their abnormal hyperactivity.

Secondary, dry needling will also improve the maximum muscle contraction capacity; will improve spastic muscle ultrasound variables in terms of decreased muscle thickness and pennation angle, increased fasciculus length and reduced pixel intensity measured via histogram and second order histogram parameters; as well as dry needling will improve gait parameters such as gait speed, functional gait and better spatiotemporal parameters such as a reduction of the variability, asymmetry and an improve of the stride length.

On the other hand, the investigators hypothesized that there is a correlation between the changes that will be found in the electromyographic activity, the ultrasound variables, and the clinical and gait variables. This information will allow us to make useful predictions of best responders to dry needling according to the information obtained in electromyographic and ultrasound explorations.

The study will be a randomized clinical trial with a control group. Each participant will be randomly assigned to the dry needling group or to the sham dry needling group with a 1:1 ratio, where they will receive a total of 4 sessions of ultrasound-guided dry needling or sham ultrasound-guided dry needling in the gastrocnemius medialis over 4 weeks, one per week.

After being informed about the study, all eligible patients give their written informed consent.

Eligibility Criteria:
Inclusion Criteria:

* be over 18 years old
* understand and voluntarily sign informed consent before performing the intervention
* have a medical diagnosis of ischemic or hemorrhagic stroke
* have a grade between 1-3 according to the modified Ashworth scale (MAS) on the triceps sural
* able to walk independently to perform gait test

Exclusion Criteria:

* recurrent stroke
* who have received previous treatments of botulinum toxin type A in the last 3 months
* who have received treatments with dry needling in the last month
* severe cognitive deficits
* fear of needles
* metal allergy.