The purpose of this study is to examine interventions with paradigms involving upper and lower extremity cycling (A\&L cycling) with A\&L cycling with functional electrical stimulation (FES) (A\&L\_FES group), A\&L cycling with FES and transcutaneous Spinal Cord Stimulation (A\&L\_tSCS group), and control Body Weight Supported Treadmill Training (BWSTT) to potentially restore functional abilities (i.e., walking) in individuals with an incomplete spinal cord injury. The researchers hypothesize there will be improved walking function following these interventional groups.
Spinal cord injury (SCI) occurs at an annual rate of 50-60 per million in North America. Paralysis is also accompanied by drastic changes in independence and quality of life. SCI occurs mostly among younger individuals, half in people 16-30 years of age. Two-thirds of all SCIs are incomplete (iSCI), with some preserved neural connections relaying information to and from the brain. People with iSCI benefit most from improvements in walking. In addition to increasing independence, walking helps persons with iSCI remain active, with a variety of beneficial health-related outcomes. Therapy that can significantly increase sensorimotor function to these individuals living with iSCI for multiple decades would be hugely significant. Currently, the most common strategies for restoring walking after an iSCI are manually intensive, including over ground walking with weight and balance support provided by multiple therapists, or with the use of expensive robotic support with controversial outcomes. Thus, the overarching goal of this proposal is to investigate if a non-specific gait rehabilitation paradigm based on motor-assisted arms and legs cycling, motor-assisted arms and legs cycling with functional electrical stimulation (FES) to the main muscles of the legs (A\&L\_FES group), or motor-assisted arms and legs cycling with FES to the main muscles of the legs and transcutaneous spinal cord stimulation (tSCS) at the cervical level (A\&L\_tSCS group) in AIS C and D iSCI individuals generalizes to improvements in walking that outperform conventional gait specific training, e.g., body-weight supported treadmill training (BWSTT; control group) (clinical assessments). The researchers will also investigate biomechanical and motor coordination changes and adaptations tied to these functional improvements (biomechanical assessments), and the neural mechanisms that explain functional improvements and their retention over time (neurophysiological assessments). In the clinical assessments the researchers will investigate the clinically-relevant gait improvements afforded by the cycling intervention by measuring the walking gains with a battery of standard clinical tests focused on motor function, sensation, balance and spasticity. In the biomechanical assessments the researchers will focus on studying the detailed biomechanical basis for the gait improvements by using motion tracking, force plates, and EMG measurement to monitor the kinematics and kinetics of gait, and neuromuscular coordination. In the neurophysiological assessments the researchers will investigate the neuroplastic mechanisms underlying the gait improvements by conducting a battery of physiological tests to detect changes in the strength of descending and ascending spinal pathways.
Participants will complete simultaneous arms and legs cycling for 60min of active cycling. Targeted exercise intensity is 70-85% of the age-predicted maximum heart rate. Cycling resistance will be modified for continuous challenge. A target speed 10% above the highest speed at which each study participant is able to cycle voluntarily without motor, FES, or tSCS assistance will be selected during the first session and maintained throughout all training sessions. Once a participant can complete 60 minutes of continuous cycling at a specific resistance for two consecutive training sessions, the resistance will be increased to the next setting level at the mid-point of the subsequent session. Upon completion of each session, the physical therapists/researcher will complete skin checks to ensure no adverse effects have occurred. Heart rate, blood pressure, and oxygen saturation will be recorded. Participants will complete 3 training sessions per week for 12 weeks.
The physical therapists/researchers will assist the patient with donning any necessary lower extremity braces and a padded walking harness. The patient will be assisted onto the treadmill via a ramp while seated in a wheelchair or by ambulation with physical assistance, clipped into the body weight support system, assisted to stand, and provided the appropriate amount of body weight support to allow for successful stepping for 60 minutes of active walking. During BWSTT, physical therapists/trainers will adjust treadmill speed or incline and the degree of body weight support to challenge participants. Participants will be instructed to exercise with a targeted intensity of 70-85% of the age-predicted maximum heart rate. Upon completion of each session, the harness will be doffed with skin checks to ensure no adverse effects have occurred. Heart rate, blood pressure, and oxygen saturation will be recorded. Participants will complete 3 training sessions per week for 12 weeks.
Shirley Ryan AbilityLab
Chicago, Illinois, United States
Change in 10-meter walking test (10MWT)
The 10-meter walking test (10MWT) is a physical function test measuring the total time to ambulate 10 meters in order to calculate walking speed in meters per second. A shorter time indicates a better walking speed.
Time frame: Changes across baseline, after 3 weeks of training, after 6 weeks of training, after 9 weeks of training, after 12 weeks of training, and 6 months after completing training.
Change in 6-minute walking test (6MWT)
The 6-minute walking test (6MWT) is a physical function test measuring the total distance walked in a span of six minutes will be assessed. A longer distance indicates a better walking distance.
Time frame: Changes across baseline, after 3 weeks of training, after 6 weeks of training, after 9 weeks of training, after 12 weeks of training, and 6 months after completing training.
Change in balance with the Berg balance scale (BBS)
Change in static and dynamic sitting and standing balance will be assessed using the Berg balance scale (BBS). Items are scored from zero to four. A higher score indicates better balance and decreased fall risk.
Time frame: Changes across baseline, after 6 weeks of training, after 12 weeks of training, and 6 months after completing training.
Change in walking ability with the WISCI
The Walking Index for Spinal Cord Injury (WISCI) assesses the ability of a person to walk after spinal cord injury. It consists of a rank ordering at the impairment level from most severe (0) to least severe (20) based on the amount of physical assistance required and use of assistive devices and/or braces while walking a 10-meter distance. A higher score indicates better walking ability.
Time frame: Changes across baseline, after 6 weeks of training, after 12 weeks of training, and 6 months after completing training.
Change in Modified Ashworth Scale (MAS)
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Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
40
The Modified Ashworth Scale (MAS) is a physical function test measuring spasticity on a 6-point ordinal scale. A score of 0 on the scale indicates no increase in tone while a score of 4 indicates rigidity. Tone is scored by passively moving the individual's limb and assessing the amount of resistance to movement felt by the examiner. A lower score is a better outcome.
Time frame: Changes across baseline, after 6 weeks of training, after 12 weeks of training, and 6 months after completing training.
Change in step length
Step length is the distance between the point of initial contact of one foot and the point of initial contact of the opposite foot. Typically a longer step length is a better outcome, ideally with equal measurements between left and right limbs.
Time frame: Changes across baseline, after 6 weeks of training, after 12 weeks of training, and 6 months after completing training.
Change in step time
Step time is the amount of time that passes between the point of initial contact of one foot and the initial contact of the opposite foot. Typically a shorter step time is a better outcome, ideally with equal measurements between left and right limbs.
Time frame: Changes across baseline, after 6 weeks of training, after 12 weeks of training, and 6 months after completing training.
Change in double support time
Double support time is the amount of time that passes during which both feet are simultaneously in contact with the ground in a gait cycle. Typically a shorter double support time is a better outcome.
Time frame: Changes across baseline, after 6 weeks of training, after 12 weeks of training, and 6 months after completing training.
Change in range of motion (ROM)
Joint angle and angular velocity will be computed with the anatomical neutral position as frame of reference in the sagittal plane and flexion and extension resulting in positive and negative joint angles, respectively. Range of motion will be calculated as the difference between the maximum and minimum hip, knee, and ankle joint angles. A larger range of motion is a better outcome.
Time frame: Changes across baseline, after 6 weeks of training, after 12 weeks of training, and 6 months after completing training.
Change in joint-joint cyclogram area
The area inside joint-joint cyclograms (e.g., hip-knee) will be calculated. A larger cyclogram area is a better outcome.
Time frame: Changes across baseline, after 6 weeks of training, after 12 weeks of training, and 6 months after completing training.
Change in the number of muscle synergies
Activation patterns and bipolar EMG signals of the leg muscles (gluteus medius, gluteus maximus, rectus femoris, adductor longus, medial hamstrings, tibialis anterior, and gastrocnemius medialis) and arm muscles (delta anterior, delta posterior, biceps brachii, triceps brachii) will be assessed bilaterally during walking. Muscle synergies will be identified from the EMG signals. A higher number of synergies is a better outcome.
Time frame: Changes across baseline, after 6 weeks of training, after 12 weeks of training, and 6 months after completing training.
Changes in interlimb (upper-lower limb) modulation
This will be assessed by measuring changes in the magnitude and pattern of H-reflex suppression in the soleus (ankle extensor) of the leg during arm cycling. Features closer to that of a healthy individual is a better outcome.
Time frame: Changes across baseline, after 6 weeks of training, after 12 weeks of training, and 6 months after completing training.
Changes in the strength of cortico-spinal connectivity
This will be measured using TMS of the motor cortex known to produce a motor evoked potential (MEP) in the main muscles of the leg, and peak-to-peak amplitude of the MEP and recruitment curves of MEP amplitude as a function of TMS strength will be calculated and constructed. Recruitment curves closer to that of a healthy individual is a better outcome.
Time frame: Changes across baseline, after 6 weeks of training, after 12 weeks of training, and 6 months after completing training.
Changes in strength of periphery and somatosensory cortex
This will be measured using cutaneous electrodes on the arm and leg skin surface and recording the somatosensory evoked potentials (SSEPs) over the primary somatosensory cortex using electroencephalography (EEG) electrodes; peak-to-peak amplitude of the SEP and recruitment curves of SEP amplitude as a function of stimulus strength will be calculated and constructed. Recruitment curves closer to that of a healthy individual is a better outcome.
Time frame: Changes across baseline, after 6 weeks of training, after 12 weeks of training, and 6 months after completing training.