Background: Children with cerebral palsy (CP) have an injury to the central nervous system around the time of birth that affects the development of the brain and spinal cord. This injury leads to changes in gait neuromechanics, including muscle activity and joint kinematics. Transcutaneous spinal cord stimulation (tSCS) is a novel neuromodulation technique that may improve movement and coordination in children with CP when paired with targeted physical therapy. Research question: How does the combination of tSCS and short-burst interval locomotor treadmill training (SBLTT) affect individual gait neuromechanics in children with CP? Methods: Four children with CP (2-13 years old), received 24 sessions each of SBLTT only and SBLTT with tSCS (tSCS+SBLTT). Clinical assessments of spasticity and passive range of motion (PROM), as well as biomechanical assessments of joint kinematics, musculotendon lengths (MTLs), and muscle activity were recorded during overground, barefoot walking. Assessments were taken before and after each intervention, and 8-weeks later. Results: The combination of tSCS+SBLTT led to greater increases in hip and knee extension than SBLTT only for three participants. Three children also became more plantarflexed at the ankle during stance after tSCS+SBLTT compared to SBLTT only. While tSCS+SBLTT reduced spasticity, these changes were only weakly correlated with changes in MTLs during gait or PROM, with the largest correlation between change in gastrocnemius operating MTL during fast walking and gastrocnemius spasticity (R^2 = 0.26) and change in plantarflexor PROM and gastrocnemius spasticity (R^2 = 0.23). Significance: Children with CP used a more upright, less crouched posture during gait after tSCS+SBLTT. Large reductions in spasticity after tSCS+SBLTT were only weakly correlated with changes in kinematics and PROM. Understanding the mechanisms by which tSCS may affect gait for children with CP is critical to optimize and inform the use of tSCS for clinical care.

Chet T. Moritz serves as a clinical advisor to the company SpineX, who provided the stimulator for the study. SpineX also licensed IP generated by the team at the University of Washington, Chet T. Moritz, Katherine M. Steele, Siddhi R. Shrivastav, and Charlotte D. Caskey.

NCT04467437

This work was supported by Seattle Children′s Hospital CP Research Pilot Study Fund 2020 Award, UW Rehabilitation Medicine Walter C. and Anita C. Stolov 2021 Research Fund, and NSF Graduate Research Fellowship Program Award DGE-1762114.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The Instituational Review Board at the University of Washington gave Ethical approval for this work.

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

All data produced in the present study may be available upon reasonable request to the authors.