Sympathetic-Somatomotor Coupling in Human Spinal Cord Injury

April 30, 2021 updated by: Thomas G Hornby, Shirley Ryan AbilityLab

Significance: The long term objective of this study is to improve physical therapy and fitness programs in people with spinal cord injury. The results of the study will demonstrate the importance of matching blood flow to a muscle with exercise of that same muscle.

Scientific Objective: The objective of the study is to measure how the body regulates bloodflow to a muscle during exercise. We intend to study these effects by triggering blood flow changes during movement, and measuring bloodflow changes during exercise in people with spinal cord injury. We will also look at the long term effects of different exercise programs on bloodflow during exercise.

Study Populations: This study will involve people with partial spinal cord injury and age and sex matched controls without injury.

Specific Aims: Aim 1 will be to measure bloodflow during exercise of the legs (below the injury). This aim will examine the control of bloodflow and muscle contractions and how it changes after spinal cord injury. Aim 2 will then look at changes in bloodflow during exercise after training. Three different eight week exercise training programs will be tested including 1) upper body ergometry, 2) treadmill training with exertion level matched to the upper body ergometry and 3) treadmill training with heart rate matched to an initial test of upper body ergometry.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The regulation of cardiovascular systems during muscle activity is poorly understood in people with incomplete spinal cord injury (SCI). In the past, disruptions in somatomotor and sympathetic control have been investigated separately in SCI. We propose to investigate the coupling of sympathetic and somatomotor control because it is relevant to exercise training paradigms that are designed to improve somatomotor function or enhance physical fitness. Our approach will be to measure tendon tap reflexes, voluntary muscle activation, and blood flow of the knee (below injury) and elbow (above injury) before and after sympathetic stimuli consisting of cold pressor tests, mental math and an acute bout of exercise. These data will provide information about sympathetic control of blood flow during muscle activity. Plasticity of the sympatheticsomatomotor coupling will also be investigated by making measurements before and after a treadmill training exercise program. These experiments will enable us to address three aims. Aim 1 will be to characterize coupling of sympathetic and somatomotor systems below the level of spinal injury. This aim will examine spinal sympathetic and motor reflexes and their interactions. It will also examine how descending somatomotor coupling is disrupted by the spinal injury. In Aim 2, we will identify changes in the interactions of sympathetic and somatomotor systems above a spinal injury. Because of the injury and the changes that occur below the injury, the sympathetic-somatomotor coupling is also likely to be disrupted in the arm. Aim 3 will then demonstrate plasticity of sympathetic-somatomotor coupling after exercise training. Three different eight week exercise training programs will be tested including 1) treadmill training with exertion level matched to 70-80% of HRR 2)treadmill training with 30-40% HRR. The exercise training will be tested in a randomized crossover study design with one month between exercise training paradigms. We anticipate that there will be plasticity of sympathetic-somatomotor coupling and that the exercise training effects will normalize control of these systems. However, because of the injury, we anticipate that adaptations will differ from non-injured controls.

This study has implications for exercise training in human SCI. The coupling of sympathetic and somatomotor systems is expected to depend on whether exercise targets the upper or lower body. The recovery of function requires both the improvement in the control of movement as well as in the regulation of blood flow to active muscle groups. In addition, this study is important for understanding the potential impact of treadmill exercise training on cardiovascular fitness, a topic of increasing interest in people with limitations to physical activity.

Study Type

Interventional

Enrollment (Actual)

40

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Illinois
      • Chicago, Illinois, United States, 60611
        • Rehabilitation Institute of Chicago

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • incomplete SCI
  • subjects will be over age 18
  • to fit in the apparatus and to assure a mature gait pattern
  • at least 6 months post injury, and medically stable with an incomplete lesion between levels T1-T10
  • lower extremity motor score of 10 or greater
  • presence of intact stretch reflexes, detected clinically
  • no previous history or evidence of peripheral nerve damage in the lower extremities
  • Subjects must be able to step on a treadmill with no more than 40% body weight support.

Healthy controls will be age and sex matched to the subjects with spinal cord injury.

Exclusion Criteria:

  • unhealed decubiti,
  • bladder or other infection
  • severe contracture or osteoporosis
  • heterotopic ossification
  • cardiac arrhythmia
  • inability to give informed consent
  • an episode of autonomic dysreflexia in the past year
  • use of spasticity or cardiovascular medications (e.g. baclofen)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
No Intervention: One day testing
Aim 1 will be to measure bloodflow during exercise of the legs (below the injury). This aim will examine the control of bloodflow and muscle contractions and how it changes after spinal cord injury.
Experimental: Effects of long term training
Aim 3 will then look at changes in bloodflow during exercise after training. Three different eight week exercise training programs will be tested including 1) treadmill training at high intensity as defined by 70-80% of HRR or 15-17 RPE 2) treadmill training at low intensity as defined by 30-40% of HRR or <13 RPE
Other: Treadmill Training
Subjects will be randomized to a high intensity and low intensity group. The high intensity group will train at 70-80% of their HRR and the low intensity group will train at 30-40% of their HRR.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Arterial blood flow
Time Frame: 6 hours
Subject will be tested with doppler ultrasonography immediately pre and post sympathetic stressor. Testing sessions will take anywhere between 3-6 hours.
6 hours

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Graded Treadmill Exercise Test
Time Frame: 15 months
Graded treadmill exercise test will be tested at multiple intervals pre and post training paradigms.
15 months
Heart rate
Time Frame: 15 months
Heart rate will be tested continuously during sympathetic stressors and at multiple intervals pre and post training paradigms with a Finapres.
15 months
Knee torque
Time Frame: 8 hours
Knee torque will be tested with the Biodex both pre and post sympathetic stressors.
8 hours
Tendon tap reflexes
Time Frame: 8 hours
Tendon tap reflexes will be tested during one day testing pre and post sympathetic stressors.
8 hours

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Shirley Ryan AbilityLab

Collaborators

Marquette University

Investigators

  • Principal Investigator: Brian D Schmidt, MD, Marquette University
  • Principal Investigator: George Hornby, PT, PhD, University of Illinois at Chicago

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

April 1, 2014

Primary Completion (Actual)

April 1, 2020

Study Completion (Actual)

April 1, 2020

Study Registration Dates

First Submitted

April 14, 2014

First Submitted That Met QC Criteria

April 14, 2014

First Posted (Estimate)

April 16, 2014

Study Record Updates

Last Update Posted (Actual)

May 6, 2021

Last Update Submitted That Met QC Criteria

April 30, 2021

Last Verified

April 1, 2021

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • R01NS079751 (U.S. NIH Grant/Contract)

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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