Measurement of Autonomic Cardiovascular Integrity in Persons With SCI
Condition: Spinal Cord Injury
MeSH terms: Spinal Cord Injuries
Study type: Observational

Summary: 
      People with a spinal cord injury (SCI) have limited ability to move and feel sensation below
      the level of the SCI. Doctors and researchers have tests which determine the level of
      function and sensation, this test was developed by the American Spinal Cord Injury
      Association (ASIA) and has been modified over the years to improve use and sensitivity. Most
      recently, the ASIA Injury classification Scale (AIS) was modified in 2011, but this test does
      not include the evaluation of autonomic nervous system (ANS) impairment. However, people with
      SCI do have impairment of the ANS and this may adversely affect how organ systems in the body
      function. Specifically, ANS impairment tends to result in changes in heart rate and blood
      pressure that may relate to the level of the SCI, but this is not fully understood. In this
      investigation we hope to develop simple tests which will allow doctors and scientist the
      ability to measure the amount of ANS impairment to the cardiovascular system, specifically
      the heart. The first part of the study will be to determine the heart rate response to
      several tests (administration of drugs and physical challenges) which will change heart rate.
      These tests will be given to people with and without SCI and the heart rate response will be
      compared between people with and without SCI. The bigger the difference in the heart rate
      response to these test between people with and without SCI the greater degree of ANS
      impairment in the people with SCI. Once this heart rate difference is determined, several
      simple tests (deep breathing, saliva test, Valsalva) will be performed in people with and
      without SCI to again compare the heart rate response. The second part of this study will be
      to determine if the heart rate responses to the first set of tests (administration of drugs
      and physical challenges) can predict the heart rate response to these simple tests (deep
      breathing, saliva test, Valsalva). The aim of this study is to develop a simple battery of
      tests which can be easily used by doctors and scientists to determine the degree of ANS
      impairment to the heart in persons with SCI.
    


Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Forty subjects with chronic SCI and 10 age and gender matched able-bodied controls will be
        recruited. A subgroup of 20 subjects with SCI will be recruited solely for the non-invasive
        portion of the study. These patients will not undergo the pharmacological/placebo
        administration or any of the manipulations being performed in the ICU. An additional 30
        subjects will complete the non-invasive portion before and after completion of an
        ambulatory training protocol. This includes subjects who have completed various protocols
        in the Cardioautonomic Program or patients referred by their physician following routine
        physical examinations. Physicians will be informed of the inclusion and exclusion criteria
        for this study and will be able to provide us with the assurance that the patient is an
        appropriate candidate for the study and that he/she was willing to speak with the study
        coordinators.
      
Biospecimen description: 
      Two catecholamine samples are collected either pre/post tilt (in the ICU) or positional shift
      (in the autonomics lab). Samples are collected once for individuals participants in the
      non-invasive testing only subgroup, twice for individuals participating in the ambulatory
      training subgroup, and on all 4 visits for individuals participating in the main group.
    
Keywords: spinal cord injury; autonomic integrity; autonomic dysreflexia; baroreceptor integrity; sympathetic integrity; vagal integrity