About this trial
This study looks to characterize gradients of dysfunction in the autonomic nervous system in patients with clinically diagnosed multiple sclerosis. The autonomic nervous system plays key roles in regulation of blood pressure, skin blood flow, and bladder health- all issues that individuals with multiple sclerosis typically suffer. Focusing on blood pressure regulation, the most precise metric with broad clinical applicability, the investigators will perform laboratory-based tests to probe the body's ability to generate autonomic responses. For both individuals with multiple sclerosis and uninjured controls, laboratory-based experiments will utilize multiple parallel recordings to identify how the autonomic nervous system is able to inhibit and activate signals. The investigators anticipate that those with autonomic dysfunction with multiple sclerosis will exhibit abnormalities in these precise metrics. The investigators will look to see if any substantial connections exist between different degrees of preserved autonomic function and secondary autonomic complications from multiple sclerosis. In accomplishing this, the investigators hope to give scientists important insights to how the autonomic nervous system works after multiple sclerosis and give physicians better tools to manage these secondary autonomic complications.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
18-50 years old
clinically confirmed diagnosis of multiple sclerosis -OR- uninjured control
Disqualifiers
symptoms of cardiovascular (including, but not limited to: hypertension, stroke, chest pain, etc.), respiratory, peripheral neurological or autonomic disease (particularly diabetes mellitus requiring treatment)
women who are pregnant or lactating
having a body mass index (BMI) ≥ 35 kg/m2
taking or being administered a medication known to potentially have adverse interactions with phenylephrine
Trial design
Parallel
Treatments tested in this trial
Tests of sympathetic inhibition
Diagnostic testBolus phenylephrine infusion using the Oxford technique will generate the need to inhibit sympathetic activity. Similarly, resting state Mayer waves will be assessed with regard to heart rate and blood pressure responses.
Tests of sympathetic activation
Diagnostic testCold pressor test of the hand will be used to cause sympathetic activation. Valsalva's maneuver will assess the ability to buffer against blood pressure fall (phase II).
Testing of autonomic dysreflexia
Diagnostic testCold pressor test of the foot and bladder pressor response will be tested.
Treatment groups
Trial outcomes
Primary outcomes
Valsalva Maneuver Phase II
Presence or absence of phase II on Valsalva maneuver testing, which takes approximately 15 seconds to complete. This will be repeated x3.
Secondary outcomes
Beat-to-beat heart rate
Electrocardiogram will record continuous measures with changes in R-R interval (ms) quantified and compared to baseline.
Beat-to-beat blood pressure
Non-invasive continuous blood pressure monitors will be used, with changes in systolic and diastolic pressure (in mmHg) from resting baseline measured.
Quantify autonomic dysreflexia and orthostatic hypotension
Participants will be given the Autonomic Dysfunction Following Spinal Cord Injury questionnaire (score range 0-436, with higher scores indicating more autonomic dysfunction).
Quantify secondary autonomic complications
Participants will be given the Composite Autonomic Symptom Score (range 0-100, with higher scores indicating more autonomic dysfunction).
Sponsors and contacts
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