158 Clinical Trials for Various Conditions
The goal of this clinical trial is to learn how the FDA-cleared Q-Collar device affects brain blood flow regulation during rest and exercise in healthy adults. The main questions this study aims to answer are: 1. How does the Q-Collar affect brain blood flow when there are quick changes in blood pressure, like when standing up quickly, or when breathing against resistance? 2. How does the Q-Collar affect brain blood flow during exercise? Researchers will compare sessions where participants wear the Q-Collar to sessions where they do not wear the device to see if the Q-Collar improves brain blood flow during both rest and exercise. Participants will: * Complete two study visits, each 1 to 4 weeks apart. * Perform a series of tasks, including standing tests, breathing tests, and exercise on a stationary bike, while their heart rate, brain blood flow, and other body functions are monitored. * Wear the Q-Collar during one of the sessions and not wear it during the other session. The order of the sessions will be randomly assigned.
Cerebral blood flow (CBF) is essential for maintaining brain health and function, as it ensures delivery oxygen and nutrients necessary to support neuronal activity. Reduced CBF can impair the brain's ability to meet its metabolic demands, leading to deficits in cognitive ability. Impairments in CBF are associated with cognitive decline and neurodegenerative disease such as Alzheimer's and dementia. Many factors influence CBF, but recently lactate has emerged as a key player. Blood glucose has long been considered the primary fuel for the brain, but emerging evidence indicates that lactate may be the preferred fuel for neurons, and lactate may become even more important under stressful conditions. Individuals with obesity often have impaired lactate metabolism resulting in higher resting blood lactate concentrations and reduced ability to clear lactate after a physiological stress. At the same time, it is known that exercise is a powerful intervention for improving lactate metabolism. Thus, this project seeks to investigate the role of lactate in brain blood flow in individuals with and without obesity as well as establish if short term exercise training (individuals with obesity only) will alter circulating lactate concentrations at rest and in response to exercise.
Brain blood flow will be measured during exercise using magnetic resonance imaging.
SURVIVORS Study participants are being asked to take part in this research study called HODNIRS because the participant is a survivor of Hodgkin Lymphoma (HL) treated with chest radiation and bleomycin at St. Jude Children's Research Hospital. The study is being done to help investigators understand the link between long term effects of chest radiation and bleomycin for HL and brain function in survivors. Primary Objective To evaluate dynamic changes in CBF and oxygenation during exercise with Near Infrared Spectroscopy (NIRS) in HL survivors and non-cancer controls matched for age, sex, race, and ethnicity. . Secondary Objectives To examine the degree of CO2 clearance (DLCO/ETCO2) during rest and exercise in Hodgkin Lymphoma (HL) survivors compared to non-cancer controls matched for age, sex, race, and ethnicity. CONTROLS Volunteers are being asked to take part in this research study because they are non-first degree relative or friend of someone who received treatment for a childhood cancer or similar illness at St. Jude Children's Research Hospital or are an employee/affiliate of St. Jude Children's Research Hospital and have agreed to be a St. Jude Life Cohort Study (SJLIFE) community control.
High blood pressure (BP) is a public health problem worldwide. Nearly three-quarters of older adults (age \~60 years) in the United States have high BP. High BP links to many health problems, like stroke. Drug treatments are typically used in clinics to reduce high BP and the risk of associated health problems. However, these drug treatments may not always benefit brain health. For example, drug treatment may reduce brain blood flow, which may reduce cognitive function in older adults with high BP. Alternatively, reduced brain blood flow may cause high BP due to increased nervous system activity (the so-called "fight or flight response"). Thus, monitoring brain blood flow may help to manage high BP during drug treatment. It is unknown if brain blood flow and its control will be altered by drug treatment in older high BP patients. Therefore, study team will recruit older adults with high BP, who receive either drug treatment or a placebo for 2 weeks and will assess brain blood flow, cognitive function, and nervous system control before and after treatment. Results from this study will provide novel and clinically relevant information on the impact of drug treatment for high BP on brain health. Investigators expect these results will suggest that it is crucial to measure brain blood flow, which may be a therapeutic new target for BP control and brain health.
Twenty-six otherwise healthy adults between 18-40 years of age composed of 13 males and 13 females will be enrolled in this study to determine how sex and sex hormones influence cerebral blood flow (CBF) control in healthy young adults without confounds of age or disease. Participants can expect to be on study for approximately 16 days.
There is a dire need to establish normative values for transcranial Doppler(TCD) derived cerebral blood flow parameters for each type of Mechanical circulatory support (MCS) device and explore the relationship between the MCS device's systemic flow dynamics and TCD based cerebral flow(CBF) parameters TCD derived cerebral blood flow parameters can then be investigated as targets used to titrate systemic flow dynamics from MCS. Having target flow rates titrated to patient specific condition using TCD may help avoid both hypoperfusion as well as the possibility of hyperemia reperfusion injury contributing to neurological morbidity. We propose a multicenter study to gather normative data on TCD derived CBF and MCS systemic dynamics for a wide range of patient demographics. Such data collection is only possible with multi-center collaboration given the small volume of patients with MCS patients in each center.
Brain blood flow will be measured during exercise using magnetic resonance imaging.
The purpose of this research study is to determine if application of near infrared energy to the forehead can change blood flow in the brains of people with depression. Near infrared energy is like light but is not visible to the human eye.
Parkinson'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.
The purpose of the proposed study is to investigate the usefulness of laser speckle contrast imaging (LSCI) compared to indocyanine green angiography (ICGA). We will collect data from a wide variety of neurovascular surgical procedures to determine when the technology is the most clinically useful. The intraoperative LSCI system provides high resolution images of blood flow in real-time without tissue contact and without the need for an exogenous contrast agent. Further study is needed to gain a better understanding of the use of the technique during surgery, but initial results suggest that the ability to identify blood flow changes with immediate feedback to the surgeon could be a significant advantage during many procedures.
This study will focus on improving brain health through dietary modification of added sugars in middle aged adults (50- 64 years old). Participants will be fed two 10-day diets (one diet containing 5% of total energy from added sugars and one diet containing 25% of total energy from added sugars) and examine blood vessel function, hippocampus structure using a MRI, and memory performance.
Rheoencephalography (REG) shows promise as a method for noninvasive neuromonitoring, because it reflects cerebrovascular reactivity. This protocol will study clinical and technical conditions required to use REG. Additionally, our goal is to study noninvasive peripheral bioimpedance pulse waveforms in order to substitute invasive SAP. A previous study demonstrated that REG can be used to detect spreading depolarization (SD), the early sign of brain metabolic disturbance. SD can be measured invasively with DC EEG amplifiers only. Our goal is to create an automatic notification function for REG monitoring indicating change of clinical conditions.
This study will analyze the influence of acute bout exercise intensities (continuous moderate and HIIT) on middle cerebral artery velocity (MCAv) to identify which intensity elicits the greatest increase in CBF in older adults (65+ yrs). Additionally, this study will help verify positive correlations between MCAv and cognitive function. These findings are important in determining the optimal exercise prescription for increased resilience against the age-related cognitive degradation.
This study is being done to better understand the influence of cardiovascular disease on brain blood flow regulation and cognitive function, determine whether exercise-based cardiac rehabilitation can lead to better regulation of brain blood flow that may help to improve or maintain cognitive function, and determine whether exercise intensity influences changes in brain blood flow regulation and cognitive function.
The purpose of this research study is to evaluate the ability of laser speckle contrast imaging to visualize blood flow in real time during neurosurgery. Real-time blood flow visualization during surgery could help neurosurgeons better understand the consequences of vascular occlusion events during surgery, recognize potential adverse complications, and thus prompt timely intervention to reduce the risk of stroke. The current standard for visualizing cerebral blood flow during surgery is indocyanine green angiography (ICGA), which involves administering a bolus of fluorescent dye intravenously and imaging the wash-in of the dye to determine which vessels are perfused. Unfortunately, ICGA can only be used a few times during a surgery due to the need to inject a fluorescent dye, and provides only an instantaneous view of perfusion rather than a continuous view. Laser speckle contrast imaging does not require any dyes or tissue contact and has the potential to provide complementary information to ICGA. In this study we plant to collect blood flow images with laser speckle contrast imaging and to compare the images with ICGA that is performed as part of routine care during neurovascular surgical procedures such as aneurysm clipping.
The purpose of this study is to assess cerebral blood flow velocity (CBFV) following regional anesthesia for shoulder surgery. The results of this study will help to further understand the physiologic effect of the interscalene nerve block on cerebral blood flow.
This study will compare the effect of three transcranial photobiomodulation (t-PBM) doses (high, middle, and low irradiance) to sham t-PBM on PFC CBF as assessed with fMRI (BOLD) in this multi-center, phase I, double-blinded, dose-ranging, controlled, crossover study of 30 subjects with MDD. All eligible participants will undergo four sessions of t-PBM during fMRI so that they experience irradiances of 50, 300 and 700 mW/cm2 as well as sham. The order of dose administration will be randomized and t-PBM will be administered with the LightForce® EXPi Deep Tissue Laser TherapyTM System, Transcranial PhotoBioModulation-1000 (tPBM-2.0).
Cerebrovascular diseases (CVD) and neurodegenerative diseases (NDD) are both leading causes of death in the United States. Epidemiological data have shown that increased prevalence of hypertension is related to these outcomes. However, despite the strong association of poor brain health outcomes in patients with hypertension (HTN), the understanding of cerebral blood flow (CBF) regulation and treatment options for HTN remain limited. Acupuncture treatment (AT), which is considered a promising complementary and integrative modality, has been known to reduce blood pressure and improve endothelial function in HTN. However, very few studies have investigated AT's effect on cerebrovascular function and the possible neuroprotective properties directly via regulating HTN. Exercise is used as a stimulus that increases the brain's metabolism and requires cerebrovascular responses (vasodilation) to meet the new metabolism. Therefore, the specific aim of this study is to test the hypothesis that an antihypertensive acupuncture treatment can acutely improve cerebrovascular responses in hypertensive humans during moderate exercise.
This study tests basic differences in how men and women control brain (cerebral) blood flow (CBF), at rest and under stress. The stress is low oxygen or high carbon dioxide. The investigators hypothesize that sex differences per se, plus sex hormone differences, drive different signals in blood vessels that change the way CBF is regulated. The investigators will test these mechanisms with medicine infusions during stress, and measure CBF using state-of-the-art MRI approaches. Research confounding variables like aging and disease will be mitigated by comparing younger adults (18-40 years old).
With this study, the investigators will substantiate if regional cerebral blood flow (CBF) is affected by tDCS, assess the amount of CBF change in relation to different currents, and measure differences in regional CBF under stimulation reactivity between healthy subjects and people with Multiple Sclerosis (PwMS)using Water O-15 PET (Water Oxygen-15 Positron EmissionTomography) imaging. The objective is to investigate the changes in regional CBF after transcranial direct current stimulation (tDCS) at different intensities (1 mA, 2 mA, 3 mA, 4 mA) in healthy subjects and PwMS. The design is a cross-sectional proof of principle study in 10 healthy subjects and 10 PwMS. Relative regional brain CBF (rCBF) will be analyzed semi-quantitatively using voxel-wise and region of interest-based approaches. Changes in CBF associated with tDCS-application will be calculated with a general linear model in a ramp function of the task-specific rCBF, according to previous work in our group using a glucose analogue. Exploratory statistical testing will be done using a paired samples t-test between task and rest conditions and unpaired t-tests between PwMS and healthy controls at the same intensities. With this study the investigators will be able to dose-dependently measure real-time rCBF changes after non-invasively stimulating the superficial parts of the dorsolateral prefrontal cortex (DLPFC), a commonly used target in therapeutic tDCS applications. This will provide further insight into whether tDCS is capable of inducing changes in rCBF.
Aging is the primary risk factor for Alzheimer's disease (AD), which is a rapidly growing public health concern. Understanding the mechanisms of normal brain aging may provide insight into the factors linking advancing age to increased risk for AD and thereby lead to new therapeutic targets for preventing or slowing AD progression. Cardiovascular changes, including impaired cerebrovascular function, occur with aging and may increase risk for AD; however, the mechanisms by which cerebrovascular function becomes impaired in older adults are incompletely understood. The overall goal of this project is to examine potential mechanisms of age-related declines in cerebrovascular function in humans. The investigators hypothesize that brain macro-vascular endothelial dysfunction, secondary to oxidative stress, plays an important role in mediating age-related changes in brain blood flow and cerebrovascular reactivity. The results of this pilot study have the potential to identify novel targets of cerebrovascular aging and will help guide the design of future clinical trials aimed at improving cerebral blood flow in older adults.
The primary objective of the study is to assess the safety and effectiveness of SPG stimulation with the ISS in patients with an acute ischemic stroke in the anterior circulation initiated within 24 hours from stroke onset.
Transcranial Light Therapy involves non-invasive and invisible beams of light that increase energy metabolism in the brain. Transcranial light therapy has been found to promote brain metabolism. The purpose of the study is: To asses the change in cerebral blood flow induced by the Transcranial Continuous and Pulse Near-Infrared Light Therapy in healthy subjects. To correlate with cognitive performance the change in cerebral blood flow induced by the Transcranial Continuous and Pulse Near-Infrared Light Therapy in healthy subjects. To correlate with skin pigmentation the change in cerebral blood flow induced by the Transcranial Continuous and Pulse Near-Infrared Light Therapy in healthy subjects. To assess the safety and tolerability of the Transcranial Continuous and Pulse Near-Infrared Light Therapy in healthy subjects
The purpose of this study is to learn if conversion from immediate release tacrolimus to Envarsus improves cerebral blood flow, brain blood flow response to exercise, and cognition.
This study will provide insight into whether a nutritional supplement, nicotinamide riboside (NR), improves memory and brain blood flow in older adults with low memory abilities. Overall, this project has the potential to identify a novel, safe and cost-effective strategy for decreasing age-related memory loss.
The purpose of this study is to learn if changing from Tacrolimus to Everolimus will improve cognitive function by having less effect on brain blood flow.
Specific Aim: Demonstrate that statins have an effect on cerebral blood flow and neuronal activity
Project Summary Metabolic syndrome (MetS) is associated with the development of diabetes and cardiovascular disease; however it is also linked with cognitive decline and dementia. The study investigators have shown that MetS is associated with lower cerebral blood flow (CBF) and memory function in late middle-aged adults at increased risk for developing Alzheimer's disease (AD). Insulin resistance (IR) is at the core of MetS, and a hallmark feature of IR is higher fasting blood glucose (FBG) as well as post prandial hyperglycemia. While the study investigators and others have demonstrated links between IR and CBF as well as cognition from an observational perspective, no studies have investigated CBF and cognition after an intervention involving exercise and a carbohydrate restricted diet (CRD) designed to improve or normalize IR and glucose homeostasis. The study investigators propose to determine the effect of improving or normalizing glucose homeostasis on CBF and cognition, through diet and exercise, in individuals with IR and at risk for the development of AD. While exercise and a CRD have been shown to improve IR and glycemic control, we have only limited knowledge of the mechanisms behind these improvements. Nutritional metabolomics, the global measurement and interpretation of metabolic profiles, assesses the interaction of diet with the endogenous gene-protein cascade and the gut microbiome. Additionally, exercise has been shown to have an impact on the human metabolome. Finally, numerous metabolites have been specifically linked to IR and impaired fasting glucose (IFG). The study investigators propose to use metabolomics to measure changes in metabolites as individuals normalize or improve IR and glucose homeostasis. Should this exploratory study reveal increased brain blood flow and improved memory in response to diet and exercise, then early treatment of these individuals at risk might offer new avenues for disease-course modification. Strategies towards early and effective risk factor management could be of value in reducing the risk of metabolic as well as cognitive decline. In addition, should this study reveal changes in metabolic abnormalities consistent with early indications of diabetes, metabolomics could be an effective approach to complement disease risk analysis in our goal toward precision care.
Elucidating cerebrovascular control mechanisms during physiologic stress may help identify novel therapeutic targets aimed at preventing or reducing the impact of cerebrovascular disease. The physiological stressors of hypoxia and hypercapnia will be utilized to elicit increases in cerebral blood flow (CBF), and intravenously infused drugs will allow for the testing of potential mechanisms of cerebrovascular control. Specifically, the contributions of nitric oxide synthase (NOS), cyclooxygenase (COX), and reactive oxygen species (ROS) to hypoxic and hypercapnic increases in CBF will be examined. The concept that these mechanisms interact in a compensatory fashion to ensure adequate CBF during both hypoxia and hypercapnia will also be tested. \~25 young, healthy men and women will be tested at rest and during hypoxia and hypercapnia. Subjects will participate in two randomized, counterbalanced study visits under the following conditions: inhibition of NOS, NOS-COX, and NOS-COX-ROS or inhibition of COX, COX-NOS, COX-NOS-ROS. During hypoxia, arterial oxygen saturation will be lowered to 80% and end-tidal carbon dioxide will be maintained at basal levels. During hypercapnia arterial carbon dioxide will be increased \~10 mmHg above basal levels and arterial oxygen saturation will be maintained. Blood flow velocity will be measured with transcranial Doppler ultrasound in the anterior (middle cerebral artery; MCA) and posterior (basilar artery; BA) circulations as a surrogate for CBF. It is hypothesized that both NOS and COX independently contribute to hypoxic and hypercapnic vasodilation in the MCA and BA, combined NOS-COX contribute to hypoxic and hypercapnic vasodilation in MCA and BA to a greater extent than either NOS or COX alone, and NOS-COX-ROS contribute to hypoxic and hypercapnic vasodilation in the MCA and BA to a greater extent than NOS-COX.