Electrical Neuromodulation for Modifying Spinal Network Involved in Spasticity

Electrical Neuromodulation for Modifying Spinal Network Involved in Spasticity

Muscle stiffness and muscle spasms are common after spinal cord injury. They can interfere with washing and dressing, moving between the bed and a wheelchair, walking, and sleep, and they can cause pain. Oral medications are the usual first-line treatment, but many people report limited benefit or side effects.

This study examines a non-surgical method called transcutaneous spinal stimulation. Surface electrodes are placed on the lower back and on the abdomen, and an electrical current is passed between them to activate nerve fibers entering the spinal cord.

Adults who have had a spinal cord injury and have muscle stiffness or spasms in the legs may participate. Each participant takes part in all parts of the study and serves as their own comparison. Participants attend four visits at one study site, about one week apart. The first visit is for consent and a clinical examination. At each of the next three visits, the participant receives one capsule containing tizanidine, baclofen, or an inactive substance (placebo), in an order assigned by chance. One hour later, the participant receives two 15-minute periods of spinal stimulation, one at 30 pulses per second and one at 75 pulses per second, also in an order assigned by chance. Neither the participant nor the person conducting the testing knows which capsule was taken.

Leg reflexes, muscle activity, and knee movement are measured before the capsule is taken, one hour after it is taken, during each period of stimulation, and after each period of stimulation. Clinical scales for stiffness and spasms are also scored. The study compares the two stimulation rates, compares stimulation with each medicine given alone, and examines whether adding stimulation to a medicine has a larger effect than stimulation alone.

Inclusion Criteria:

• Age 18 years or older
• History of spinal cord injury (ASIA Impairment Scale grades A-D)
• Time since injury longer than six months
• The presence of at least mild spasticity (>3) in the lower limbs, as self-reported on the Numerical Rating Scale of spasticity severity from 0 (no spasticity) to 10 (spasticity as bad as you can imagine)
• Agreement to reduce antispastic medication, if needed

Exclusion Criteria:

• Neurological level of SCI below T11
• Ventilatory-dependent
• Suspected progression of SCI (e.g., syringomyelia)
• Rigidity, contraction, or passive range of motion of <40 deg in both knee joint
• Systolic blood pressure at rest <90 mm Hg
• Implanted active devices (e.g., ITB pumps)
• Passive implants (plates, screws) between T10 and L3 vertebras
• Skin conditions precluding placement of electrodes
• Skin breakdown on their sacrum, ischii or lower extremities
• Ongoing infections
• Pregnancy
• Difficulty following instructions
• Other medical risks/contraindications as determined by the study physicians.