measurement of autonomic cardiovascular integrity in persons with sci

Conditions: Spinal Cord Injury

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.


Eligibility criteria:
inclusion criteria: for all groups: * age 18-65 years (18-89 years for non-invasive only sci subjects) * stable health for \> 6 months * non-smoker o subjects with sci: * level of injury - c1-s4 * duration of injury - ≥ 1 year * ais classification - a, b, c exclusion criteria: for main study sci group: * tachycardia (resting hr ≥ 100 bpm) * bradycardia (resting hr ≤ 40 bpm) * hypertension * known: coronary artery disease, chronic heart failure, cardiac arrhythmias, diabetes mellitus, thyroid disease, renal insufficiency, hepatic disease, autonomic neuropathy, ulcerative colitis, benign prostatic hyperplasia, hiatal hernia, glaucoma, parkinson's disease, stroke, other neuromuscular diseases, known sulfite allergy or hypersensitivity, asthma, active illness or infection, for non-invasives only sci group * diabetes mellitus * autonomic neuropathy * parkinson's disease * active illness or infection

Keywords: spinal cord injury autonomic integrity autonomic dysreflexia baroreceptor integrity sympathetic integrity vagal integrity