The aim of the pilot study is to gain first insights into the interaction of transcutaneous spinal cord stimulation with the altered activity of intraspinal circuits associated with spinal spasticity. The main goal is to evaluate the validity of the chosen measures and to generate a data base for statistical planning of a subsequent clinical study.

Inclusion Criteria:

written informed consent prior to participation

for participants with intact CNS:

• no previous neurological or musculoskeletal disorders

for participants with spinal cord injury:

• Spinal cord injury due to trauma
• ≥ 12 months post-spinal cord injury
• complete or incomplete spinal cord injury classified as grade C or D on the American Spinal Injury Association Impairment Scale (AIS)
• neurological level of spinal cord injury: C3-T10
• preserved tendon and cutaneo-muscular reflexes in the lower limbs

Exclusion Criteria:

• other neuromuscular diseases, e.g., amyotrophic lateral sclerosis (ALS), Parkinson's disease, Guillain-Barré syndrome, muscular dystrophy
• active implants (e.g., cardiac pacemaker, drug pump)
• passive implants at vertebral level T10 or caudal (e.g., metal screws/plates for surgical stabilization of spinal fractures)
• active infections or diseases, pressure sores
• dermatological issues at the stimulation site
• malignant diseases
• heart insufficiency (NYHA III-IV)
• potential pregnancy (pregnancy test to be conducted in women of child bearing age before application of transcutaneous spinal cord stimulation)