The effect of side-alternating vibration therapy on mobility and health outcomes in young children with mild to moderate cerebral palsy: design and rationale for the randomized controlled study

BACKGROUND: Cerebral palsy (CP) is the most common cause of physical disability in early childhood. Vibration therapy (VT) is a promising rehabilitation approach for children with CP with potential to impact mobility, bone and muscle health as demonstrated by extant research. However, it is still unclear how long therapy must be conducted for and what the optimal vibration frequency is in order to gain health benefits. METHODS/DESIGN: The study is a randomized clinical trial evaluating and comparing the effects of two vibration frequency (20 Hz vs 25 Hz) and duration protocols (12 weeks vs 20 weeks) of side-alternating VT on mobility and other health parameters in children with CP. Children aged 5–12 years old with CP and GMFCS level I-III who are able to understand instruction and safely stand are eligible for the study. Exclusion criteria include bone fracture within 12 weeks of enrolment; acute conditions; the history of significant organic disease; the history of taking anabolic agents, glucocorticoids, growth hormone, and botulinum toxin injection into lower limbs within 3 months of enrolment. All participants will act as their own control with a 12-week lead-in period prior to intervention. The intervention period will consist of 20 weeks of home- or school-based VT 9 min per day, 4 times a week. After the baseline assessment, participants will be randomized to either a 20 Hz or 25 Hz vibration-frequency group. The primary outcome is mobility measured by a 6-min walking test, with analysis performed on the principle of intention to treat. Secondary outcomes include body composition, muscle strength, physical activity level, balance, gross motor function, respiratory function, and quality of life. Participants will undergo four assessment visits over the study period: baseline, at weeks 12, 24, and 32. DISCUSSION: The results of the study will provide evidence-based insights into the health benefits of side-alternating VT as a therapeutic tool in young children with cerebral palsy. The investigation of different vibration training protocols will help define the optimal parameters of intervention protocols (duration, frequency) of side-alternating VT to maximize outcomes on the health of 5–12-year-old children with CP. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ANZCTR): 12618002026202 (Registration date 18/12/2018).