The goal of this clinical trial is to help understand spinal cord excitability in children with cerebral palsy compared to neurologically typical children. The main questions it aims to answer are: * What are the mechanisms of spinal circuit hyperexcitability in CP? * Can transcutaneous spinal cord stimulation reduce spinal circuit hyperexcitability? Participants with cerebral palsy will be asked to complete: * Movement and strength exercises * Mild, non-invasive stimulation on the back and legs that feels like a light tap. * Gentle, non-invasive tests that help us see how the brain and the spinal cord communicate with the muscles
This is a clinical trial designed to evaluate spinal circuit hyperexcitability in children with cerebral palsy (CP) and to explore the potential of transcutaneous spinal cord stimulation (tSCS) to reduce excitability and improve spasticity. The investigators will also examine the mechanisms underlying this potential reduction of spinal hyperexcitability. The investigators will non-invasively record a range of electrophysiological responses using surface electrodes while participants perform isometric tasks. These recordings will help to better understand the differences in spinal excitability between children with CP and typically developing peers and will provide early insight into how tSCS might modulate these responses. This study has two aims: The first aim is to evaluate spinal circuit excitability in Children with CP and in children without neurological conditions (controls). Several electrophysiological markers will be collected, including sensory reflex responses, reciprocal inhibition, motoneuron firing patterns, and motor evoked potential by transcranial magnetic stimulation. The second aim is to assess the impact of tSCS on spasticity and hypertonia in CP. To achieve this aim, the same electrophysiological measurements of spinal excitability will be repeated during non-invasive transcutaneous spinal cord stimulation in patient-participants (children with CP).
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
30
Transcutaneous spinal cord stimulation (tSCS) will be administered using the Digitimer DS8R Biphasic Constant Current Stimulator, an external isolated stimulator system used in human research. The DS8R delivers controlled electrical pulses with adjustable stimulation parameters. tSCS will be delivered at frequencies between 30-50 Hz with 1 ms pulse width and a biphasic waveform. Self-adhesive surface electrodes will be positioned longitudinally over the thoracolumbar region at T11-L1 (cathodes) and over the iliac crests (anodes). In children with cerebral palsy, electrophysiological and clinical assessments will be conducted before, during, and after stimulation to evaluate changes in spinal excitability, spasticity, and motor function. Stimulation is administered during supervised study visits.
UPMC Children's Hospital of Pittsburgh
Pittsburgh, Pennsylvania, United States
RECRUITINGChange in H-reflex with Transcutaneous Spinal Cord Stimulation
The primary outcome is H-reflex peak-to-peak amplitude with transcutaneous spinal cord stimulation (tSCS). Success criteria is measured as a reduction in 20 percent of peak-to-peak amplitude of the H-reflex.
Time frame: Measured during 1 of up to 3 research sessions over up to 16 weeks
Modified Ashworth Scale
The primary outcome is the spasticity measured by the Modified Ashworth Scale with and without tSCS. The Modified Ashworth Scale is used to assess muscle spasticity. The scale is as follows: 0 = No increase in muscle tone; 1 = Slight increase in tone giving a catch when the limb is moved in flexion or extension; 1+ = Slight increase in muscle tone, indicated by a catch followed by minimal resistance throughout range of motion (ROM); 2 = More marked increase in tone through most of the ROM, but the limb easily flexed; 3 = Considerable increase in tone, passive movement difficult; 4 = Limb rigid in flexion or extension; Higher scores represent greater spasticity. Success criteria is measured as a reduction of at least 1 point in average across muscles. Scores will be averaged across assessed muscle groups to calculate a mean Modified Ashworth Scale score for each participant.
Time frame: Measured during 1 of up to 3 research sessions over up to 16 weeks
TMS motor evoked potential
A reduction in TMS motor evoked potential with tSCS is expected. Success criteria is measured as a decrease in 20 percent of the peak-to-peak amplitude with tSCS.
Time frame: Measured during 1 of up to 3 research sessions over up to 16 weeks
Reciprocal inhibition between antagonist muscles with tSCS
Reciprocal inhibition will be tested by conditioning the H-reflex (elicited by stimulating at the tibial nerve) with a prior (between 1 and 5 ms) stimulation of the deep peroneal nerve. The results will be compared in CP vs control to determine its contribution in spinal hyperexcitability in CP. Additionally, the effect of tSCS in CP will be compared to determine whether tSCS can normalize hyperexcitability in CP. Success criteria is measured as a change in reciprocal inhibition of 20 percent towards the values in control participants.
Time frame: Measured during 1 of up to 3 research sessions over up to 16 weeks
Motoneuron excitability
The investigators will measure the persistent inward currents of motoneurons as a measure of motoneuron excitability . A reduction in persistent inward current with tSCS is expected. The investigators will compare the results in CP vs control to determine its contribution in spinal hyperexcitability in CP. Additionally, the effect of tSCS in CP will be compared to determine whether tSCS can normalize hyperexcitability in CP. Success criteria is measured as a change in motoneuron excitability of 20 percent towards the values obtained in control participants.
Time frame: Measured during 1 of up to 3 research sessions over up to 16 weeks
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