Photobiomodulation in the Treatment of Spasticity in Children and Adolescents with Cerebral Palsy: A Controlled, Single-Blinded, Pilot Randomized Trial

Background/Objectives: Cerebral palsy (CP) is a non-progressive, permanent syndrome of childhood, with approximately 80% of patients exhibiting spasticity. Untreated spasticity can cause pain, structural changes in bones, muscles, and nerves negatively impacting quality of life and functionality. Photobiomodulation (PBM) has demonstrated biological effects such as tissue regeneration, muscle relaxation, inflammation reduction, and pain relief. The objective of this pilot study is to evaluate the action of PBM on the spasticity of the medial and lateral right gastrocnemius muscles of children and adolescents with spastic cerebral palsy. Methods: This single-blinded, randomized, controlled trial evaluated PBM’s effect on gastrocnemius spasticity in children and adolescents with CP. The study presents pilot preliminary results from twelve children and adolescents (7–16 years) with spastic CP who were randomized into two groups: active PBM (850 nm, 100 mW, 1.5 J/point, 2 points, weekly for 8 weeks) or placebo (same protocol, device off). Both groups received standard rehabilitation exercises. Outcomes were assessed using the Modified Ashworth Scale (MAS), Pediatric Evaluation of Disability Inventory (PEDI), Gross Motor Function Classification System (GMFCS), and ankle range of motion before and after the intervention (8 weeks). Results: MAS and all outcomes improved significantly over time in both groups. No significant differences were found between groups for all outcomes. The PBM effect size on MAS improvement (ANOVA, Analysis of Vari, η2 = 0.171) suggests modest but positive benefits. PBM did not worsen spasticity, and no adverse effects were reported. Conclusion: This study represents a pioneering effort in evaluating a safe PBM protocol for the spastics gastrocnemius in children and adolescents with CP. This protocol, used as an adjunct to physiotherapy, demonstrated no short-term adverse effects and no participant dropouts. Future studies should explore this PBM protocol in patients with less severe GMFCS levels, those with minimally preserved functionality, or those with contraindications to physiotherapeutic exercises.