Effect of rESWT Session Frequency on Spasticity and Function Assessed by Sonoelastography in Children With Cerebral Palsy

Cerebral palsy is the most common cause of childhood physical disability, and spasticity represents one of its most prominent and disabling features. Increased muscle tone negatively affects mobility, balance, and functional independence and may lead to secondary musculoskeletal complications. Although pharmacological and surgical interventions are available, there is a growing need for non-invasive, easily applicable, and safe treatment options in pediatric neurorehabilitation. Radial extracorporeal shock wave therapy (rESWT) has gained attention as a promising modality for reducing spasticity and improving muscle properties. Previous studies have demonstrated beneficial effects of rESWT in children with cerebral palsy; however, there is no consensus regarding the optimal treatment frequency and dosing strategy. Determining the most effective session frequency is essential to maximize clinical benefit while minimizing treatment burden. By comparing different rESWT session frequencies, this study aims to define a dose-response relationship and identify the most effective treatment strategy. The findings are expected to contribute to evidence-based optimization of rESWT protocols in pediatric neurorehabilitation and to improve functional outcomes in children with cerebral palsy. This study is designed as a prospective, randomized, double-blind, parallel-group controlled clinical trial conducted at the University of Health Sciences, Sisli Hamidiye Etfal Training and Research Hospital, Department of Physical Medicine and Rehabilitation. Participants are recruited from children presenting to the outpatient clinic who meet the inclusion criteria and none of the exclusion criteria. The study follows a double-blind protocol. Except for the operator delivering the intervention, all individuals involved in the study-including participants and outcome assessors-are blinded to the session type (real versus sham rESWT). This design ensures unbiased outcome assessment and minimizes expectancy effects. All participants continue routine neurological rehabilitation consisting of conventional physical therapy for 60 minutes per session, three sessions per week for 12 weeks. In addition, during the first three weeks, all groups attend the research center two days per week for rESWT or sham procedures combined with standardized stretching. In participants with bilateral plantar flexor spasticity, the lower extremity with the highest initial Modified Ashworth Scale (MAS) score will be taken as the basis for evaluation purposes. However, to preserve functional integrity and avoid ethical concerns, rESWT will be applied equally to both lower extremities. rESWT applications will be carried out targeting the motor end-plate zones located in the proximal one-third of the gastrocnemius muscle belly and the mid-belly region of the soleus muscle. Active and sham applications were performed using the same device, in the same patient position, on the same application area, and for the same duration. In both applications, gel was applied between the applicator head and the skin, and the applicator head was kept in contact with the skin. During sham rESWT, a soft applicator head was used; the applicator was applied with minimal compression on the skin at the lowest pressure level allowed by the device, 0.5 bar. Thus, while maintaining skin contact and physical feedback similar to the active application, the therapeutic shock wave energy transmitted to the tissue was intended to be minimized.

Participants are assigned to one of three parallel groups. Group 1 (Control) receives conventional physical therapy three times per week for 12 weeks (60 minutes per session) and, during the first three weeks, attends the research center twice weekly to receive sham rESWT followed by 20 minutes of stretching on both days, for a total of six sham sessions. Group 2 receives the same conventional physical therapy and, during the first three weeks, attends the research center twice weekly, receiving one session of real rESWT combined with 20 minutes of stretching and one session of sham rESWT combined with 20 minutes of stretching each week (total of three real and three sham sessions). Group 3 receives the same conventional physical therapy and, during the first three weeks, attends the research center twice weekly to receive real rESWT followed by 20 minutes of stretching on both days (total of six real sessions). Real rESWT is delivered using standardized parameters of 5 Hz frequency, 1.5 bar pressure, and 2000 shocks per session.

All clinical and ultrasonographic assessments are performed before exercise and rESWT sessions to avoid acute treatment effects and ensure standardization. Baseline demographic and clinical characteristics are recorded prior to treatment.

Evaluations will be performed at four separate time points: pre-treatment (baseline), at the end of treatment, and at 4 weeks and 12 weeks post-treatment.

• Spasticity levels will be assessed using the Tardieu Scale, Modified Ashworth Scale (MAS), and passive Range of Motion (PROM) measurements.
• The Pediatric Berg Balance Scale (PBS) will be used for balance assessment, the Modified Timed Up and Go Test (MTUG) for functional mobility, and the 10-Meter Walk Test (10MWT) for walking speed.
• For the assessment of spasticity-related pain levels, the Revised Faces Pain Scale (FPS-R), which is appropriate and validated for children, will be used.
• The mechanical properties of the muscle will be quantitatively evaluated using the Shear Wave Elastography (SWE) method; for the evaluation of muscle morphology, muscle thickness will be measured via ultrasonography, and the Modified Heckmatt Scale (MHS) will be applied to classify muscle structural properties

Inclusion criteria

• Children aged 6-14 years diagnosed with cerebral palsy according to the Rosenbaum diagnostic criteria.
• Gross Motor Function Classification System (GMFCS) level I, II, or III.
• Modified Ashworth Scale (MAS) score >1 and ≤3 in unilateral or bilateral ankle plantar flexor muscle groups.
• Presence of a spastic gait pattern characterized by a dynamic component of ankle equinus.

Exclusion criteria

• Age younger than 6 years or older than 14 years.
• Botulinum toxin type A injection or extracorporeal shock wave therapy (ESWT) within 6 months prior to enrollment.
• Fixed contracture with passive joint range of motion (ROM) <5° in the affected extremity, or significant bone or joint deformity.
• History of orthopedic surgery (tendon release or transfer, tenotomy, muscle release surgery, arthrodesis) involving the affected extremity.
• Cognitive or behavioral disorders that would prevent participation in the intervention or assessments.
• Uncontrolled systemic disease or significant comorbid conditions.
• History of neurosurgical intervention (e.g., selective dorsal rhizotomy, neurectomy).
• Presence of significant dystonia or severe movement disorder in the extremity to be evaluated.
• Presence of contraindications for ESWT application in the treatment area, including open skin lesions, skin infection, signs of active inflammation, or history of malignancy; bleeding diathesis, use of anticoagulant therapy, or circulatory problems due to vascular pathology.