Remote Ischemic Conditioning and Spinal Reflex Modulation in Children With Cerebral Palsy

Effects of Remote Ischemic Conditioning (RIC) Combined With Balance Training on Spinal Reflex Modulation in Children With Cerebral Palsy

Remote ischemic conditioning (RIC) is a clinically feasible intervention involving brief, sublethal periods of ischemia followed by reperfusion that has been shown to enhance motor performance, strength, and balance when combined with training in healthy adults and individuals with neurological conditions. Although RIC is thought to influence neuroplasticity through neural, metabolic, and humoral pathways, its effects on spinal-level mechanisms remain poorly understood. Emerging evidence indicates that neuroplastic adaptations occur not only at the cortical level but also within the spinal cord. Moreover, altered spinal reflex excitability is associated with spasticity, balance impairments, and functional limitations in children with cerebral palsy (CP), yet the role of spinal reflex modulations in response to RIC and balance training remains under expplored in this population. Therefore, this study aims to investigate the effects of RIC combined with balance training on spinal reflex modulation in children with CP.

Remote ischemic conditioning (RIC) is a clinically feasible, non-invasive intervention that involves brief, sublethal periods of ischemia followed by reperfusion and has been shown to improve motor performance, strength, and balance when combined with training in healthy adults and individuals with neurological conditions. Evidence from animal and human studies suggests that RIC exerts neuroprotective effects through multifactorial mechanisms involving neural, metabolic, vascular, and humoral pathways, with emerging data indicating the involvement of peripheral and spinal pathways. Neuroplasticity in response to training is known to occur not only at the cortical level but also within spinal neural circuits, where altered spinal reflex excitability is associated with spasticity, balance impairments, and poor functional outcomes in children with cerebral palsy (CP). While balance and locomotor training have been shown to reduce spinal reflex excitability in this population, the effects of RIC on spinal reflex modulation remain largely unexplored. The specific aims of this study are to determine whether 1) RIC combined with balance training modulates spinal reflex excitability, as reflected by H-reflex measures, and 2) to examine whether RIC combined with balance training leads to greater improvements in balance performance compared to sham conditioning combined with training in children with CP.

In this study, 16 children with cerebral palsy (ages 8-17 years) will be recruited. They will be randomly allocated into two groups: (A) RIC and (B) Sham. The study will consist of five consecutive visits. During Visit 1, participants will undergo baseline testing of the soleus H-reflex using a DS8R stimulator. After baseline testing, they will complete the first training session, which will include one session of conditioning combined with balance training (15 trials per session) on a stability trainer (Lafayette, IN). Visits 2 to 5 will each consist of one session of conditioning and balance training (second to fifth training sessions). During Visit 5, following the training session, post-testing of the H-reflex will be conducted. The average of the first five trials of balance training on Visit 1 will be used as the pre-test balance performance, and the average of the last five trials of balance training on Visit 5 will be used as the post-test balance performance. Conditioning will be administered to the more affected lower extremity (thigh), and a pulse oximeter will be placed on the toe for monitoring.

It is hypothesized that, compared to sham conditioning, remote ischemic conditioning combined with balance training will result in greater reductions in H-reflex excitability and greater improvements in balance performance in children with cerebral palsy. This study will help clarify whether RIC induces spinal reflex modulations when paired with balance training, reflecting spinal-level neuroplasticity in children with CP. These findings may advance understanding of the spinal mechanisms underlying the therapeutic benefits of RIC and support its translation as an adjunct intervention in pediatric neurorehabilitation.

Inclusion Criteria:

• Children diagnosed with cerebral palsy (CP) between the ages 8-17 years
• Gross motor function classification system levels I-III
• Mainstream in school and has sufficient cognition to follow the experiment instructions

Exclusion Criteria:

• Children with other developmental disabilities such as autism and developmental coordination disorders
• Children with cognitive deficits such as inability to understand and follow commands, substantially lower performance at grade level in school, and/or communication problems
• Children with balance disorders such as vestibular disorders, posterior fossa tumor etc.
• Children with known cardiorespiratory dysfunctions
• Children with sickle cell disease
• Children who are receiving other adjunct therapies such as transcranial magnetic stimulation, transcranial direct current stimulation, or vagal nerve stimulation
• Presence of lower extremity condition, injury, or surgery within last three months which could compromise conditioning and training.
• Participants who are pregnant.