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NCT03648905
Background: The autonomic nervous system controls automatic body functions. Researchers want to improve the tests used to diagnose autonomic failure. Orthostatic hypertension is a drop in blood pressure when a person stands up. Researchers want to focus on this sign of autonomic failure. Objective: To improve testing for conditions that cause autonomic nervous system failure. Eligibility: People ages 18 and older in one of these categories: * Their blood pressure drops when they get up. * They have had a heart transplant or bilateral endoscopic thoracic sympathectomies or have had or will have renal sympathetic ablation Design: All participants will be screened with: * Medical history * Physical exam * Blood and urine tests Some participants will be screened with: * Heart and breathing tests * IV placement into an arm vein * Tilt table testing: Participants lie on a table that tilts while an IV is used to draw their blood. Participants may stay in the hospital for up to 1 week depending on their tests. Tests may include repeats of screening tests and: * Sweat testing: A drug is placed on the skin to cause sweating. Sensors on the skin measure moisture. * Lumbar puncture: A needle is inserted between the bones in the back to collect fluid. * MRI and PET/CT scan: Participants lie on a table that slides into a scanner. For the PET/CT, a small amount of a radioactive chemical will be injected with a small amount of a radioactive chemical. * Bladder catheter placement to collect urine * Skin biopsies: A punch tool removes a small skin sample. * Tests to see how the pupils react to light * Smelling tests * Thinking and memory tests * Questionnaires Participants may have a visit about 2 years later to repeat tests. ...
NCT04246437
Alpha-synucleinopathies refer to age-related neurodegenerative and dementing disorders, characterized by the accumulation of alpha-synuclein in neurons and/or glia. The anatomical location of alpha-synuclein inclusions (Lewy Bodies) and the pattern of progressive neuronal death (e.g. caudal to rostral brainstem) give rise to distinct neurological phenotypes, including Parkinson's disease (PD), Multiple System Atrophy (MSA), Dementia with Lewy Bodies (DLB). Common to these disorders are the involvement of the central and peripheral autonomic nervous system, where Pure Autonomic Failure (PAF) is thought (a) to be restricted to the peripheral autonomic system, and (b) a clinical risk factor for the development of a central synucleinopathy, and (c) an ideal model to assess biomarkers that predict phenoconversion to PD, MSA, or DLB. Such biomarkers would aid in clinical trial inclusion criteria to ensure assessments of disease- modifying strategies to, delay, or halt, the neurodegenerative process. One of these biomarkers may be related to the neurotransmitter dopamine (DA) and related changes in the substantia nigra (SN) and brainstem. \[18F\]F-DOPA is a radiolabeled substrate for aromatic amino acid decarboxylase (AAADC), an enzyme involved in the production of dopamine. Use of this radiolabeled substrate in positron emission tomography (PET) may provide insight to changes in monoamine production and how they relate to specific phenoconversions in PAF patients. Overall, this study aims to identify changes in dopamine production in key regions including the SN, locus coeruleus, and brainstem to distinguish between patients with PD, MSA, and DLB, which may provide vital information to predict conversion from peripheral to central nervous system disease.
NCT03042988
Patients with autonomic failure are characterized by disabling orthostatic hypotension (low blood pressure on standing), and at least half of them also have high blood pressure while lying down (supine hypertension). Exposure to heat, such as in hot environments, often worsens their orthostatic hypotension. The causes of this are not fully understood. The purpose of this study is to evaluate whether applying local heat over the abdomen of patients with autonomic failure and supine hypertension during the night would decrease their nocturnal high blood pressure while lying down. This will help us better understand the mechanisms underlying this phenomenon, and may be of use in the treatment of supine hypertension.
NCT04620382
The 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.
NCT02429557
Compression 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.
NCT03312556
Supine hypertension is a common problem that affects at least 50% of patients with primary autonomic failure. Supine hypertension can be severe and complicates the treatment of orthostatic hypotension. The purpose of this study is to assess whether continuous positive airway pressure (CPAP) decreases blood pressure in autonomic failure patients with supine hypertension.
NCT02897063
The purpose of this study is to learn more about the effects of midodrine and droxidopa, two medications used for the treatment of orthostatic hypotension (low blood pressure on standing), on the veins of the abdomen of patients with autonomic failure. The study will be conducted at Vanderbilt University Medical Center, and consists of 2 parts: a screening and 2 testing days. The total length of the study will be about 5 days. About 34 participants will be screened for the study.
NCT01672255
Exercise is a cornerstone of diabetes management. It helps reduce blood pressure, promote weight loss, lower insulin resistance and improve glucose and lipid (triglyceride and HDL-cholesterol) profiles. Unfortunately, the benefits of exercise are often not embraced by diabetic individuals because of the fear of low blood sugar (hypoglycemia). My laboratory has demonstrated that Autonomic nervous system (ANS) counterregulatory failure plays an important role in exercise associated hypoglycemia in Type 1 DM. ANS responses are significantly reduced in Type 1 DM and are further blunted by antecedent episodes of hypoglycemia. Furthermore, there is a large sexual dimorphism of reduced ANS responses during submaximal exercise in both Type 1 DM and healthy individuals that is unexplained. Accumulating data are demonstrating that serotonergic pathways can regulate ANS discharge. Generally, serotonergic pathways are inhibitory but both single and longer term administration of selective serotonin reuptake inhibitors (SSRI's) such as Prozac has been demonstrated to increase basal epinephrine levels and enhance baroreflex control of Sympathetic nervous system (SNS) activity. What is unknown is whether fluoxetine can also enhance SNS responses and also override the large ANS sexual dimorphism present during sub maximal exercise. Therefore, the purpose of this study is to determine if the SSRI fluoxetine (Prozac) can improve SNS responses during exercise.
NCT04782830
The 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.
NCT01799915
Synucleinopathies are a group of rare diseases associated with worsening neurological deficits and the abnormal accumulation of the protein α-synuclein in the nervous system. Onset is usually in late adulthood at age 50 or older. Usually, synucleinopathies present clinically with slowness of movement, coordination difficulties or mild cognitive impairment. Development of these features indicates that abnormal alpha-synuclein deposits have destroyed key areas of the brain involved in the control of movement or cognition. Patients with synucleinopathies and signs of CNS-deficits are frequently diagnosed with Parkinson disease (PD), dementia with Lewy bodies (DLB) or multiple system atrophy (MSA). However, accumulation of alpha-synuclein and death of nerve cells can also begin outside the brain in the autonomic nerves. In such cases, syncucleinopathies present first with symptoms of autonomic impairment (unexplained constipation, urinary difficulties, and sexual dysfunction). In rare cases, hypotension on standing (a disorder known as orthostatic hypotension) may be the only clinical finding. This "pre-motor" autonomic stage suggests that the disease process may not yet have spread to the brain. After a variable period of time, but usually within 5-years, most patients with abnormally low blood pressure on standing develop cognitive or motor abnormalities. This stepwise evolution indicates that the disease spreads from the body to the brain. Another indication of this spread is that acting out dreams (i.e., REM sleep behavior disorder, RBD) a problem that occurs when the lower part of the brain is affected, may also be the first noticeable sign of Parkinson disease. The purpose of this study is to document the clinical features and biological markers of patients with synucleinopathies and better understand how these disorders evolve over time. The study will involve following patients diagnosed with a synucleinopathy (PD/DLB and MSA) and those believed to be in the "pre-motor" stage (with isolated autonomic impairment and/or RBD). Through a careful series of follow-up visits to participating Centers, we will focus on finding biological clues that predict which patients will develop motor/cognitive problems and which ones have the resilience to keep the disease at bay preventing spread to the brain. We will also define the natural history of MSA - the most aggressive of the synucleinopathies.
NCT06745011
Description of a method to detect Parkinson's disease or Parkinson's-like disease at an early stage (Prodromal Parkinson's Disease) where damage is still confined to the peripheral nervous system damage. Simultaneous collection of biological material to establish a biobank for use as prognostic biomarkers for the development of Parkinson's disease and other neurodegenerative diseases in which pathological alpha-synuclein deposits accumulate.
NCT03900000
Study on orthostatic Hypotension in Parkinson's disease
NCT03593512
Patients referred to neurosurgery routinely and safely undergo deep brain stimulation (DBS) for treatment of symptoms related to neurodegenerative conditions, most commonly Parkinson's disease. In the investigators experience, and published evidence shows, that stimulation has effects on the autonomic nervous system. In patients undergoing therapeutic DBS for a particular subtype of Parkinsonism, Multiple System Atrophy, the further effects on autonomic parameters such as blood pressure and bladder symptoms as well as the originally intended indications (gait and movement disorder) will be investigated. The mechanisms of any effects will also be studied by using a number of techniques such as magnetoencephalography (MEG) and Muscle Sympathetic Nerve Activity (MSNA) recording. Key goals are to: 1. Demonstrate that stimulation of the peduculopontine nucleus (PPN) improves autonomic function and has an attendant improvement on patients' quality of life 2. Investigate the role of the PPN and how it interacts with other brain areas. This translational strategy will lead to a larger efficacy study of DBS for MSA as well as revolutionizing neural-based treatments in other autonomic disorders such as orthostatic hypotension and pure autonomic failure.
NCT02417415
Patients with autonomic failure are characterized by disabling orthostatic hypotension (low blood pressure on standing), and at least half of them also have high blood pressure while lying down (supine hypertension). Exposure to heat, such as in hot environments, often worsens their orthostatic hypotension. The causes of this are not fully understood. The purpose of this study is to evaluate whether applying local heat over the abdomen of patients with autonomic failure and supine hypertension would decrease their high blood pressure while lying down. This will help us better understand the mechanisms underlying this phenomenon, and may be of use in the treatment of supine hypertension.
NCT04875949
Anti alfa-3 and alfa-7 ganglionic cholinergic receptors (anti-AChRs) antibodies (Abs) plasma removal by plasmapheresis (1,2) acutely improved dysautonomia symptoms in case reports with Pure Autonomic Failure (PAF) (3). We shall assess the prevalence of anti-AChRs Ab and the relationship among Ab titer, cardiovascular autonomic profile and symptoms in neurodegenerative diseases characterized by similar dysautonomia symptoms such as PAF, Amyotrophic Lateral Sclerosis (ALS) and Postural Orthostatic Tachycardia Syndrome (POTS) (4). Ab positive patients will undergo selective immunoabsorption once a week up to achievement of Ab titer lower than 65% of baseline followed by immunosuppressive therapy with prednisone. Both Ab positive and negative groups will undergo anti-AChR Abs, autonomic profile and dysautonomia symptoms assessment, every 4 months up to 3 years. Evidence of correlation among reduced Ab titer and autonomic profile and symptoms improvement may result in new effective therapy.
NCT02591173
Pharmacologic approaches to increase levels or actions of the vasodilatory peptide angiotensin-(1-7) are currently in development for the treatment of hypertension based on findings from animal models. There are limited and contradictory clinical studies, however, and it is not clear if this peptide regulates blood pressure in humans. The purpose of this study is to better understand the cardiovascular effects angiotensin-(1-7) in human hypertension, and to examine interactions of this peptide with the autonomic nervous system. The investigators propose that the difficulties in showing angiotensin-(1-7) cardiovascular effects in previous clinical studies relates to the buffering capacity of the baroreceptor reflex to prevent changes in blood pressure. Autonomic failure provides the ideal patient population to test this hypothesis. These patients have loss of baroreflex buffering and have low levels of angiotensin-(1-7) in blood. The investigators will test if angiotensin-(1-7) infusion can lower blood pressure in patients with autonomic failure, and will determine the hemodynamic and hormonal mechanisms involved in this effect.
NCT01607268
This research study will be conducted in patients with primary autonomic failure, a disabling condition that is associated with low blood pressure upon standing. These patients are also not able to control for changes in their blood pressure due to a loss of cardiovascular reflexes that are mediated within the brain. The purpose of this study is to determine whether magnetic resonance spectroscopy (MRS), a non-invasive imaging technique, can measure levels of chemicals (neurotransmitters) in the dorsal medulla, a brain area important for control of cardiovascular function, in autonomic failure patients. Importantly, this study will determine whether there are differences in brain chemicals between patients with peripheral versus central origins of their autonomic failure. The hypothesis is that the neurotransmitter profile in the medulla will be intact in patients with peripheral autonomic failure compared to those with central impairment. Overall, this study will provide insight into understanding the mechanisms involved in autonomic failure and will determine whether a single session of MRS imaging can improve the ability to make an accurate diagnosis in these patients. This would lessen the need for more extensive and invasive clinical testing.
NCT00742586
The purpose of this study is to identify 15 patients with autonomic failure and obtain blood samples for RNA from those participants and 15 control subjects within the same age range. The stabilized blood samples, along with a limited data set, will be shipped to Western Michigan University where the actual laboratory analysis (a separate study) of the samples will take place. Unique genetic inscriptions, called gene expression signatures, are currently being identified for many diseases, including neurological diseases. The secondary goal of this study is to support the research being done at WMU and they try to look for MSA-specific signs are present in whole blood samples of MSA patients at late-stages of the disease. This is a pilot study that has a long term goal (through additional studies) a MSA-specific gene expression signature for the development of a diagnostic test for this disease that can be used in the future. Other patient groups with autonomic failure, characterized by significant drop in blood pressure on standing, will also be included in this study, to look for similar genetic inscriptions. This pilot study is expected to last for 2 years. The investigators at WMU will need some de-identified health Information about the subjects, including their age at diagnosis, age (when sample drawn) and list of their medications
NCT01044693
The purpose of this study is to evaluate the effect of the antihypertensive drug, nebivolol (Bystolic), compared to metoprolol (Lopressor) and sildenafil (Viagra) on blood pressure in patients with autonomic failure and supine hypertension.
NCT01223391
The purpose of this study is to assess if abdominal binders that use pull strings to adjust compression (non-elastic) are more effective than standard elastic abdominal binders in attenuating neurogenic orthostatic hypotension.