Improving Walking After Spinal Cord Injury

Summary

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.

Conditions

• Spinal Cord Injury

Interventions

DEVICE

Paired Associative Stimulation

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.

BEHAVIORAL

Locomotor Training

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.

DEVICE

Sham stimulation

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.

Sponsors & Collaborators

• Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

  collaborator NIH

• Shirley Ryan AbilityLab

  lead OTHER

Principal Investigators

• Dalia De Santis, PhD · Shirley Ryan AbilityLab

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2025-11-15

Primary Completion

2026-03-30

Completion

2026-07-30

Countries

• United States

Study Locations