Improving Walking After Spinal Cord Injury

Engaging Reticulospinal Inputs to Improve Walking Ability in Humans With Spinal Cord Injury

Locomotor recovery is one of the most important goals of individuals with spinal cord injury (SCI). Ambulatory deficits severely impact daily functions resulting in lower quality of life for people living with paralysis due to SCI. Although studies have shown that locomotor training improves locomotor function in people with chronic SCI, the benefits remain limited. Our overall hypothesis is that we can engage additional descending motor pathways, such as the reticulospinal tract (RST), to improve locomotor function in humans with chronic incomplete SCI.

In this study we propose to test the effects of a novel intervention that uses repeated paired loud auditory and electrical stimulation of muscle afferents combined with locomotor training on walking speed and voluntary muscle strength.

Individuals with chronic incomplete SCI will be randomly assigned to a group that will receive 10 sessions of a startle stimulus (a very brief, loud sound) and electrical stimulation combined with locomotor training or 10 sessions of a non-startle stimulus (a very brief, soft sound) combined with locomotor training.

Inclusion Criteria:

• History of traumatic or non-traumatic SCI ≥ 6 months
• International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) level at and above T10.
• American Spinal Injury Association AIS Grade C, or D
• Weakness in ankle dorsiflexors (LEMS<=3) with the ability to perform a small voluntary ankle dorsiflexion (as detected by presence of voluntary EMG activity in the tibialis anterior) with at least one leg.
• Ability to tolerate standing position.
• Ability to walk at a minimum speed of 0.1 mile/hour on a treadmill with less than 70% body weight support.
• Requires use of assistive devices (KAFO, AFO, cane, walker) or body weight support for ambulation.
• Ability to complete the 10-Meter Walk Test.

Exclusion Criteria:

• Preceding uncontrolled medical conditions including pulmonary, cardiovascular or orthopedic disease that interfere with physical performance.
• Intolerance to physical activity.
• Severe cognitive impairment that precludes the ability to participate in any of the study procedures or give verbal consent.
• Any illness or condition that based on the research team's assessment, will compromise with the patient's ability to comply with the protocol, patient safety, or the validity of the data collected during the study.
• History of stroke resulting in sensory motor deficits.
• Pregnant women.
• Participation in a high-intensity locomotor training program in the last 6 months.
• Inability to detect somatosensory evoked potentials
• Metal implant in the head
• History of epilepsy