Autonomic Effects of Spinal Cord Stimulation in Spinal Cord Injury
Orthostatic HypotensionThe goal of this interventional crossover study is to determine the effects of transcutaneous spinal cord stimulation (TSCS) on the ability to perform moderate exercise and regulate core body temperature in the chronic spinal cord injury community. The main questions it aims to answer are: What are the effects of active TSCS targeted for BP control on exercise endurance time and HR recovery during submaximal arm cycle ergometry (ACE) as compared to sham TSCS in participants with chronic, cervical SCI? What are the effects of active TSCS on Tcore responses to cool ambient exposure and on subjective reporting of thermal comfort and thermal sensitivity as compared to sham TSCS. Participants will receive sham and active stimulation while using an arm bicycle or while in a cold room. Participants are free to participate in either the exercise phase, the cold room phase, or both phases of this study. Please note that there no expected long term benefits of this study.
Spinal Cord Transcutaneous Stimulation Effect on Blood Pressure in Acute Spinal Cord Injury (SCI)...
Spinal Cord InjuriesSpinal Cord Diseases9 moreThe goal of this clinical trial is to evaluate the effect of transcutaneous spinal cord stimulation on blood pressure in individuals with an acute spinal cord injury (within 30 days of injury). Blood pressure instability, specifically orthostatic hypotension (a drop in blood pressure when moving lying flat on your back to an upright position), appears early after the injury and often significantly interferes with participation in the critical rehabilitation time period. The main questions it aims to answer are: Can optimal spinal stimulation increase blood pressure and resolve orthostatic symptoms (such as dizziness and nausea) when individuals undergo an orthostatic provocation (a sit-up test)? Optimal stimulation and sham stimulation (which is similar to a placebo treatment) will be compared. What are the various spinal sites and stimulation parameters that can be used to increase and stabilize blood pressure to the normal range of 110-120 mmHg? Participants will undergo orthostatic tests (lying on a bed that starts out flat and then moved into an upright seated position by raising the head of bed by 90° and dropping the base of the bed by 90° from the knee) with optimal and sham stimulation, and their blood pressure measurements will be evaluated and compared.
The Effect of Water Carbonation on Orthostatic Tolerance
Orthostatic HypotensionSyncope1 moreThe primary purpose of this investigation is to determine whether water carbonation can improve orthostatic tolerance in healthy control volunteers. Orthostatic tolerance refers to the ability to maintain an adequate blood pressure when standing. In some individuals blood pressure can fall when standing, predisposing to dizzy spells or fainting episodes. Drinking water can boost blood pressure and making fainting episodes less likely. However, it is not clear whether the carbonation of the water has any further impact on the blood pressure response. This is important because it may be that carbonated water expands the stomach (gastric distension), provoking an increase in sympathetic activity. The increase in sympathetic nervous system activity boosts blood pressure. Resolving this question would have important implications for patients with syncope. This study will test whether carbonated water will have any further impact on blood pressure than the already known effect of non-carbonated water.
Efficacy, Safety and Response Predictors of Adjuvant Astragalus for Cognition in Orthostatic Hypotension...
Orthostatic HypotensionIntroduction: Orthostatic hypotension (OH) increases the risk of cognitive impairment in adults. Recent big data studies have demonstrated that add-on Astragalus can improve OH state. In vitro studies have revealed that Astragalus possesses anti-inflammatory, antioxidative, and neuroprotective effects. However, the clinical effects of add-on Astragalus in improving cognition in these patients remain unclear. Therefore, this pragmatic clinical trial aims to determine the efficacy and safety of add-on Astragalus in improving cognition in patients with OH, elucidate the underlying mechanisms, identify related response predictors, and explore effective drug components. Methods and analysis: This is an add-on, assessor-blinded, parallel, pragmatic, randomized controlled trial. At least 88 adults with OH aged >30 years will be recruited. Participants will be randomized in a 1:1 ratio to receive 24 weeks of routine care or add-on Astragalus. The primary efficacy outcome will be measured by the Montreal Cognitive Assessment-Chinese version score. Secondary efficacy outcome assessment will include neuropsychological tests, blood pressure, plasma biomarkers, multimodal electroencephalograms, and neuroimaging. Safety outcome measures will include physical examinations, vital signs, electrocardiography, laboratory tests (such as hematologic and blood chemical tests), and adverse event records. Recruitment began on June 20, 2023. Ethics and dissemination: The Ethics Committee of Fujian Medical University Union Hospital has approved this study (2021KJCX040).
Blood Pressure Effects on Cognition and Brain Blood Flow in PD
Parkinson DiseaseOrthostatic Hypotension1 moreParkinson's disease (PD) is the second most common neurodegenerative disorder worldwide. Besides causing symptoms that impair movement, PD also causes non-motor symptoms, such as problems thinking and orthostatic hypotension (OH), i.e., low blood pressure (BP) when standing. About one-third of people with PD have OH, which can cause sudden, temporary symptoms while upright, including lightheadedness, dizziness, and fainting. People with PD and OH can also experience problems thinking that happen only while upright and not while sitting - this can occur without other symptoms, such as feeling dizzy or faint. However, the level of low BP that can affect thinking remains unknown, and no guidelines exist for treating OH when it happens without symptoms. This is significant because OH could be a treatable risk factor for thinking problems in PD, but OH is often not treated if people do not report obvious symptoms. This project's goal is to determine how BP affects brain function in PD. The proposed experiments will measure BP and brain blood flow continuously in real-time using innovative wearable technology. Persons with PD with OH and without OH will undergo repeated cognitive tests while supine (lying down) and while upright. I will study the associations between BP, thinking abilities, and brain blood flow, and will compare groups with and without OH. These findings could be important because if a certain level of BP correlates with thinking abilities, then treating OH in PD may prevent thinking problems, which would improve health-related quality of life and reduce disability and healthcare costs.
Controlling Orthostatic Hypotension in People With Cervical Spinal Cord Injury
Spinal Cord Injury CervicalHypotension1 moreA common therapeutic intervention after spinal cord injury (SCI) is prolonged standing in a standing frame. For people with SCI, standing for 40 minutes or more, three to four times weekly improves several health-related issues including well-being, circulation, skin integrity, reflex activity, bowel and bladder function, digestion, sleep, pain, and fatigue. However, a person who experiences orthostatic hypotension (OH)-defined as a decrease of 20mm hg in systolic blood pressure or a decrease of 10mm hg in diastolic pressure within 3 minutes of standing from a sitting or supine position-secondary to SCI may not tolerate positioning in a standing frame, thus resulting in a loss of access to these health benefits. OH is common for people with SCI. It results from central nervous system dysregulation causing pooling of blood in the lower extremities that can lead to dizziness, light-headedness, blurred vision, weakness, fatigue, nausea, palpitations, headache, and/or syncope. Although an array of physical and pharmacologic interventions are available to people in the general population for managing OH, few such interventions have been evaluated for use by people with SCI, especially when the level of injury is C5 or above. One possible intervention that may be effective for people with OH secondary to SCI is functional electrical stimulation (FES) because its application results in a dose-dependent increase in blood pressure. An unanswered question is whether the placement of FES electrodes on various parts of the body has differential effects. Therefore, the purpose of this study is to evaluate blood pressure responses among people with OH secondary to cervical SCI when receiving FES intervention involving the placement of electrodes in three different positions as well as when receiving no FES intervention during tilt table sessions. The selected positions for electrode placement are: (a) the calves, (b) the quads and abdominals, and (c) the quads, abdominals, and calves. The researchers hypothesize that FES intervention, regardless of placement, will result in better control of OH than no FES intervention and that no significant blood pressure difference will occur across the three FES placements.
Effects of Blueberries in Older Adults
Blood PressureOrthostatic Hypotension1 moreThis randomized, parallel-design trial will evaluate specific clinical and physiological effects of whole blueberries in adults 70 years of age or older.
Effect of Midodrine vs Abdominal Compression on Cardiovascular Risk Markers in Autonomic Failure...
Neurogenic Orthostatic HypotensionAutonomic Failure3 moreThe purpose of this study is to learn more about the effects of abdominal compression and the medication midodrine, two interventions used for the treatment of orthostatic hypotension (low blood pressure on standing), on hemodynamic markers of cardiovascular risk. The study will be conducted at the Vanderbilt University Medical Center and consists of a screening and 2 testing days, one with abdominal compression and one with midodrine. The total length of the study will be about 5 days.
Use of Accelerometer for Quantification of Neurogenic Orthostatic Hypotension Symptoms
Orthostatic; HypotensionNeurogenic5 moreThe objective of this study is to find a more objective and accurate way to assess the efficacy of the treatment for neurogenic orthostatic hypotension. For this purpose, the investigators will use an activity monitor to determine the amount of time patients spend in the upright position (standing and walking; upright time) during 1 week of placebo (a pill with no active ingredients) and 1 week of their regular medication for orthostatic hypotension (midodrine or atomoxetine at their usual doses). Total upright time (i.e. tolerance to standing and walking) will be compared between placebo and active treatment to test the hypothesis that it can be used to assess the efficacy of the treatment for orthostatic hypotension and whether this outcome is superior to the assessment of symptoms using validated questionnaires.
Hemodynamic Mechanisms of Abdominal Compression in the Treatment of Orthostatic Hypotension in Autonomic...
Orthostatic HypotensionPure Autonomic Failure2 moreCompression garments have been shown to be effective in the treatment of orthostatic hypotension in autonomic failure patients. The purpose of this study is to determine the hemodynamic mechanisms by which abdominal compression (up to 40 mm Hg) improve the standing blood pressure and orthostatic tolerance in these patients, and to compare them with those of the standard of care midodrine. The investigators will test the hypothesis that abdominal compression will blunt the exaggerated fall in stroke volume and the increase in abdominal vascular volume during head up tilt.