Effects of serial casting on cardiac autonomic modulation in children with cerebral palsy: a single-blinded randomized controlled trial

To examine whether serial casting promotes autonomic nervous system adaptation in children with spastic CP, in comparison to ankle-foot orthoses (AFOs) and no intervention. Thirty children with spastic CP (aged 6–12 years) were randomly assigned to one of three groups: Serial Casting ( n = 10), AFO ( n = 10), or Control ( n = 10). Autonomic function was assessed using heart rate variability (HRV), recorded during rest, upright activity, and recovery phases over a 30-day intervention period. Changes in parasympathetic and sympathetic activity were analyzed using time-domain and non-linear HRV indices, including the standard deviation of instantaneous beat-to-beat variability (SD1). The Serial Casting group showed a significant increase in parasympathetic activity, with root mean square of successive differences (RMSSD) increasing from a baseline mean of 22.1 ms to 33.8 ms at Day 30 ( p < 0.01), and SD1 increasing from 15.6 ms to 23.9 ms ( p < 0.01). These children also exhibited a more dynamic HRV pattern across task and recovery phases. In contrast, the AFO and Control groups did not demonstrate statistically significant changes in any HRV indices over the intervention period. Serial casting may facilitate recovery of autonomic nervous system function in children with CP by reducing neuromuscular effort and supporting more efficient physiological regulation. These findings suggest that the benefits of casting extend beyond motor outcomes, highlighting the importance of evaluating autonomic markers in pediatric rehabilitation research. Brazilian Registry of Clinical Trials (ReBEC) number RBR-5ynppq, registered 23/09/2020.