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

Universidad de Zaragoza28 enrolled

Overview

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.

Interventions

Dry needling + usual careOTHER

Participants assigned to the dry needling group will receive a weekly session for four weeks of ultrasound-guided dry needling in the inner gastrocnemius muscle with disposable stainless-steel needles, according to the depth of the muscle to be treated. For the realization of the technique, the diagnostic criteria of the Dry Needling in Hypertonia and Spasticity technique (DNHS®) developed by Herrero et al. will be applied adapted to the characteristics of the study, as well as the procedure for its application. The ultrasound guidance will be the same ultrasound device than in the assessments. This ultrasound-guided intervention allows to guarantee the safety of the approach, to have the certainty in the location of the target structure and to see the responses of local spasm. During the application of the technique, patient will not look at the ultrasound screen to ensure the blindness of the patient to the group allocated.

Sham dry needling + usual careOTHER

Participants assigned to this group will receive the same assessments, the same number of sessions, and the sham dry needling at the same site as the dry needling group, but with a sham intervention, where the needle is dropped through the guide tube and touch the skin. The patient will not feel anything, or at most that the needle touches the skin, since it does not get into the subcutaneous cell tissue, as placebo interventions were performed in similar studies. The context will be simulated in its entirety, using the same ultrasound and disposable needles for the intervention. Both groups will continue their daily motor rehabilitation treatment during the 4 weeks, which consists of strength training, balance, motor control, gait training, and mass practice oriented to tasks of intensity and duration appropriate to each patient, allowing the fastest possible clinical improvement, as recommended by clinical practice guidelines.

Outcomes

Primary Outcomes

Modified Ashworth Scale

The modified Ashworth scale (MAS) will be the main outcome of the investigation, as is one of the most studied scales in the application of dry needling in patients with spasticity in stroke population. The MAS is indicated to assess spasticity, or positive speed-dependent stretching reflex, in pathologies of the central nervous system. The scale rate muscle tone on a scale between 0 and 4. 0 is no increase in tone, 1 slight increase in tone and catch/release at end of Range Of Motion (ROM), 1+ with catch/release through 1/2 ROM, 2 more marked increased in tone through ROM, but affected part moved easily, 3 considerable increase in tone, passive movement difficult, 4 affected part rigid flexion or extension.

Time frame: Baseline (T0), after the first intervention in first week (T1), after second intervention in the second week (T2), after third intervention in the third week (T3) and after fourth intervention in fourth week (T4).

Secondary Outcomes

surface Electromyography (sEMG) - Activity at rest

The first test will evaluate the muscle activity at rest, while the subject is asked to be relaxed, the Root Mean Square (RMS) of both inner gastrocnemius will be measured for 30 seconds.

sEMG - Dynamic stretching

The second measurement will consist of a dynamic stretch to assess muscular activity during the speed-dependent stretching reflex or spasticity. For this, 10 passive stretches will be performed according to the method described and validated by Marinelli et al. 2013, that showed an easily reproducible constant speed and rhythm to avoid intra-rater bias along the study.

sEMG - Maximum Voluntary Isometric Contraction

The third test will consist of evaluating the Maximum Voluntary Isometric Contraction (MVIC) of the internal gastrocnemius muscle. To do this, the ankle will be placed in an intermediate position, with neither fully elongated nor fully shortened muscle fibers, and 5 seconds of maximum isometric contraction towards plantar flexion will be performed 3 times, leaving an interval of 60 seconds between repetitions. Then the maximum values of electromyographic activation of each repetition will be selected to obtain the mean value.

Ultrasound (US) - Muscle thickness

Muscle thickness is the distance between deep and superficial aponeurosis of a muscle, from an image of the gastrocnemius medialis obtained with ultrasound.

US - Pennation angle

The pennation angle is defined as the angle formed by the muscle fasciculus with the deep aponeurosis, from an image of the gastrocnemius medialis obtained with ultrasound.

US - Fascicle length

Fascicle length is the length of the fascicular path between the insertions of the fascicle into the superficial and deep aponeuroses, from an image of the gastrocnemius medialis obtained with ultrasound.

US - Histogram/Echo intensity

Echo intensity was defined as the brightness of the image acquired through ultrasound. It is expressed in gray scale between 0 and 255 after processing the image in an image analysis software, from an image of the gastrocnemius medialis obtained with ultrasound.

US - Grey level co-occurrence matrices (GLCM)

Grey level co-occurrence matrices (GLCM) consist of comparing pair of pixels separated by a certain distance (by default a value of 1 is used) and in an angular direction (0°, 45°, 90°, and 135°) along the entire matrix, calculating the frequency with which certain grey levels appear in the image and their relationship with each other, from an image of the gastrocnemius medialis obtained with ultrasound.

US - Run-length matrices (GLRLM)

Run-length matrices (GLRLM) represents a set of consecutive pixels having the same grey level in each of the four angular directions described across the entire matrix, from an image of the gastrocnemius medialis obtained with ultrasound.

US - Local binary pattern (LBP)

Local binary pattern (LBP) analysis compares the intensity of a central pixel, which is taken as a reference value, with the surrounding pixels, from an image of the gastrocnemius medialis obtained with ultrasound.

US - Blob analysis (BA)

Blob analysis is based on detecting areas close to each other with a similar eco-intensity called "blobs", from an image of the gastrocnemius medialis obtained with ultrasound.

Timed Up and Go (TUG)

The Timed Up and Go (TUG) test to assess functional gait, which consists of measuring the seconds it takes the individual to get up from a chair approximately 46 centimeters high, travel 3 meters, turn and sit again. This scale has showed excellent intrarater reliability (ICC\>0.95) in patients with stroke.