Transcranial Photobiomodulation for Spasticity in Pediatric Cerebral Palsy: A Scoping Review of Neurodevelopmental Considerations, Treatment Protocols, Functional Outcomes, and Methodological Gaps

Background: Spasticity, affecting over 80% of children with cerebral palsy (CP), is a major source of disability. Transcranial photobiomodulation (tPBM) is a promising non-invasive neuromodulatory intervention, but evidence for its use in pediatric CP spasticity is fragmented and limited. Objective: This scoping review aimed to systematically map the literature to characterize neurodevelopmental considerations, treatment protocols, functional outcomes, and methodological gaps related to tPBM for spasticity in pediatric CP. Methods: The review followed the PRISMA extension for Scoping Reviews (PRISMA-ScR). A systematic search was performed across eight databases from January 2000 to September 2025. The PCC framework guided inclusion of studies involving children/adolescents (0–18 years) with CP and spasticity, investigating PBM with a primary focus on transcranial application. Results: From 345 records, only five primary studies (total n = 45 children) met the inclusion criteria. The evidence base is severely limited and heterogeneous, with only two of the five studies applying tPBM. A profound lack of protocol standardization was identified, with frequent reports that are internally inconsistent or contain physically implausible dosimetry reporting. Methodological quality was pre-preliminary, with no sham-controlled or adequately blinded trials. Although all studies reported reductions in spasticity and/or motor improvements, the high risk of bias prevents attribution of the effects to tPBM. Conclusions: The evidence supporting tPBM for spasticity in pediatric CP is in a pre-preliminary stage, defined by a critically small number of studies, a pervasive lack of methodological rigor, and an absence of pediatric-specific safety protocols. The field requires an immediate pivot to foundational, sham-controlled, double-blind trials with standardized dosimetry before tPBM can be considered anything other than an unproven experimental intervention.