Improving Walking After Spinal Cord Injury

Phase 2Not Yet RecruitingNCT07223710

Shirley Ryan AbilityLab20 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Enrollment

Conditions

Spinal Cord Injury

Interventions

Paired Associative StimulationDEVICE

This new intervention consists of locomotor training in combination with paired low-intensity electrical stimulation and stimulation of the reticulospinal tract through loud sounds. Participants will receive auditory stimulation (LAS, 110dB, 500Hz, 50ms) through headphones and electrical stimulation through a pair of electrodes with 2cm inter-electrode distance positioned on the motor point over the quadriceps and the tibialis anterior muscles bilaterally. The motor point will be identified as the position of the electrodes that elicits a small visible muscle twitch or muscle contraction upon palpation over the tendon with the minimum stimulation intensity. Stimuli will be delivered with a pulse duration of 200 microseconds and will be timed to arrive at the level of the brainstem \~7ms before auditory signals.

Locomotor TrainingBEHAVIORAL

Participants will walk on a treadmill with body-weight support (ZeroG, Aretech) in the range 0-70% as needed to prevent excessive knee flexion during stance phase or toe dragging during swing phase (Finch et al. 1991). Each session will last approximately 60-min and the duration of the treadmill training will be timed to be 30 min. Subjects will be encouraged to walk at a self-selected speed at or above 0.1m/s. Speed and body-weight support will be adjusted to achieve a perceived exertion score of 4-5 (Moderate) in the Borg scale (Borg 1982). Subjects will be allowed to rest as needed during the training sessions.

Sham stimulationDEVICE

Participants will receive brief low-intensity auditory clicks (80dB, 500Hz, 50ms) through headphones and electrical stimulation through a pair of electrodes with 2cm inter-electrode distance positioned on the motor point over the quadriceps and the tibialis anterior muscles bilaterally. The motor point will be identified as the position of the electrodes that elicits a small visible muscle twitch or muscle contraction upon palpation over the tendon with the minimum stimulation intensity. Stimuli will be delivered with a pulse duration of 200 microseconds and will be timed to arrive at the level of the brainstem \~7ms before auditory signals.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 75 Years

Medical Language ↔ Plain English

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

Outcomes

Primary Outcomes

10-meter walk test (10MWT)

This standardized test assesses walking speed in meters per second over a short duration.

Time frame: baseline and day 12

Secondary Outcomes

Motor Evoked Potentials conditioned with Startle (MEP-LAS)

Motor Evoked Potentials (MEPs) will be recorded from multiple leg muscles following transcranial magnetic stimulation over the leg representation of the primary motor cortex and electrical stimulation over the thoracic spine. Loud auditory Stimuli (LAS, 110dB, 500Hz, 50ms) will be delivered 50ms before magnetic stimulation to test for cortical effects of the intervention and 80ms before the electrical stimulation to test for subcortical effects of the intervention. Stimulation intensity will be adjusted to obtain unconditioned MEPs of \~50% of the maximum MEP for each muscle.