View clinical trials related to Nervous System Diseases.
Filter by:This study is designed to use PET scans in order to measure activity of the sympathetic nervous system. The sympathetic nervous system is the portion of the nervous system that maintains a normal supply of blood and fuel to organs during stressful situations. PET scan or Positron Emission Tomography is an advanced form of an X-ray. It is used to detect radioactive substances in the body. During this study researchers plan to inject small amounts of the radioactive drug fluorodopamine into patients. Fluorodopamine is very similar to the chemicals found in the sympathetic nervous system. It can attach to sympathetic nerve endings and allow researchers to view them with the aid of a PET scan. One area of the body with many sympathetic nerve endings is the heart. After giving a dose of fluorodopamine, researchers will be able to visualize all of the sympathetic nerve endings involved in the activity of the heart. In addition, this diagnostic test will help researchers detect abnormalities of the nervous system of patient's hearts.
This study is divided into two parts. The first part of the study will use MRI technology to view the brain structure of patients with neurological disorders and normal volunteers. This portion of the study will attempt to detect specific areas of damage in the brains of patients with amnesia and dementia. It will also try to correlate the amount of brain damage with performance on tests used to measure memory. In the second part of the study, researchers plan to use MRI technology to study brain function of patients with neurological disorders and normal volunteers when they perform tasks. MRI signals during task performance will be used to record areas of the brain receiving more blood flow indicating increased activity. Researchers believe this study will help improve existing methods of evaluating patients with neurological disorders. In addition, this study may contribute information about areas of the brain involved in thought processing and motor and sensory function.
Magnetic resonance imaging (MRI) is a diagnostic tool that creates high quality images of the human body without the use of X-ray (radiation). MRI is especially useful when studying the brain, because it can provide information about certain brain functions. In addition, MRI is much better than standard X-rays at showing areas of the brain close to the skull and detecting changes in the brain associated with neurological diseases. In this study researchers will use MRI to gather information about the processes that control human movement and sensory processing. The purpose of the study is to investigate how the brain is activated when remembering, thinking, or recognizing objects. Researchers would like to determine what happens to brain functions when patients have trouble remembering, thinking, or recognizing objects following the start of disorders in the brain and nervous system. In addition, this study will investigate the processes of motor control in healthy volunteers and patients with disease.
Brain and nerve cells communicate with each other by releasing and picking up chemicals called neurotransmitters. Norepinephrine is a neurotransmitter used by part of the nervous system activated during stress called the sympathetic nervous system. The sympathetic nervous system is involved with regulating blood pressure and pulse rate. Researchers believe the level norepinephrine in the blood can be used to measure activity of the sympathetic nervous system. This study is designed to answer important questions about rates of release of norepinephrine into the blood stream, removal of released norepinephrine, and the sympathetic nervous system response to stress. Researchers will attempt to measure levels of norepinephrine and activity of the sympathetic nervous system in patients with high blood pressure, normal patients with family histories of high blood pressure, patients taking drugs that can effect levels of norepinephrine, and patients with diseases or conditions directly affecting the sympathetic nervous system.
This study will examine how the brain processes pain signals and how the different parts of the brain work with each other in response to painful stimuli. A better understanding of how people experience pain may be helpful in developing more effective treatments. Healthy normal volunteers, patients requiring third molar (wisdom tooth) extraction, and patients with persistent pain due to disease, injury or other reason may be eligible for this study. Participants will receive one or more of the following sensory stimuli, which may cause brief discomfort or pain: - Heat/Cold - applied by an electronically controlled device that touches the skin, or by temperature-controlled water baths, or by a thermally controlled brass cylinder the subject grasps - Capsaicin (active ingredient in hot chili peppers) - injected in a small volume of fluid under the skin or into a muscle - Mechanical stimulation - brushings or vibrations that do not normally cause pain - Ischemic stimulation - inflation of a blood pressure cuff on the arm or leg for up to 30 minutes These stimuli will be applied both before and during positron emission tomography (PET) scanning. This test shows which parts of the brain are active and which are not and is important for studying how different parts of the brain work together to feel and react to specific sensations. For this procedure, the subject lies on a table in the PET scanner while a series of scans are taken during different sensory conditions. At the beginning of each scan, radioactive water is injected into an arm vein through a catheter (a thin plastic tube). A special camera records the arrival and disappearance of the radiation in various brain areas, creating a picture of the brain's activity in various regions. Oral surgery patients may have PET scans both before and after their wisdom tooth extraction. Alfentanil, a commonly used narcotic pain reliever, will also be given during the PET procedure to determine how the brain responds to sensory stimuli while under the effects of a pain killer. Participants will also have a magnetic resonance imaging (MRI) scan of the brain to help interpret the PET results. MRI uses a magnetic field and radio waves to show structural and chemical changes in tissues. During the scan, the subject lies on a table in a cylindrical machine (the scanner). He or she can speak with a staff member via an intercom system. Some sensory studies may require placing an arterial and/or intravenous line. Following injection of a local anesthetic, a catheter is placed in an artery in the arm. At regular intervals during various sensory stimuli, small blood samples are drawn from the artery to measure blood gases and other substances. Samples may also be drawn from a catheter placed in a vein. Subjects may also have ultrasound monitoring to evaluate blood flow in the arteries, veins and brain. A gel is spread over the skin above the blood vessel and a hand-foot-and-mouth device is placed on the gel. The device emits high-frequency sound waves to produce a picture of the speed of blood flow in the artery and the diameter of the vessel.
Alzheimer's disease is a condition marked by the deterioration of mental function. The disease usually begins in late middle life and results in death in 5 to 10 years. Patients with Alzheimer's disease typically suffer from memory loss, confusion, and disorientation. The condition has become a major medical and social problem in the United States because of the increasing number of people living beyond the age of 65. The actual cause of Alzheimer's disease is unknown. Researchers believe that Alzheimer's disease, or at least a portion of cases, may be an inherited condition. As a result, many new techniques have been developed to study the genetic causes of Alzheimer's disease and other neurological disorders. Many of these genetic techniques require blood samples and a family pedigree. A pedigree is a chart, similar to a family tree, that shows a patient's family history. The purpose of this study is to collect family and psychosocial information, blood, and biopsy samples from patients with neurological diseases, their families, and normal volunteers. This information gathered will be used to learn more about diseases that affect the brain.
This study is designed to allow researchers to use transelectrical stimulation to explore the function of the human nervous system and improve diagnosis of neurological disorders. Transcranial electrical stimulation is a non-invasive technique that can be used to stimulate brain activity and gather information about brain function. Electrical stimulation involves placing electrodes on the scalp or skin and passing an electrical current between them. When this is done, an electrical field is created that activates areas of the brain that control muscles. Muscle activity as a result of the stimulation can be recorded and analyzed.
The peripheral nervous system is the portion of the nervous system outside of the brain and spinal cord. It includes the 12 pairs of cranial nerves, 31 pairs of spinal nerves and their branches, nerves responsible for sensation and maintenance of normal body functions (sympathetic and parasympathetic nerves). Years of research using clinical examinations, microscopic examinations, and electrophysiology have made the peripheral nervous system the best-studied and most available portion of the nervous system. However, even with all of the extensive studies conducted on the peripheral nervous system, many conditions remain unclassified. The EMG Laboratory at the NIH concentrates on studying disorders of the peripheral nervous system. This protocol was designed to allow the EMG Laboratory to; I) Learn more about established diseases of the peripheral nervous system II) Identify and characterize new diseases of the peripheral nervous system III) Assess current techniques in the diagnosis of diseases of the peripheral nervous system IV) Refine old methods and develop new ones for the diagnosis of diseases of the peripheral nervous system.
This study involves sampling blood from both normal volunteers and patients with diseases known or suspected to involve body chemicals called catecholamines. The blood will be used to establish normal values for plasma levels of catecholamines and related neurochemicals; to test for abnormal neurochemical patterns in patients; and to establish a "bank" of DNA from normal volunteers and from patients to be used in future studies about possible alterations of catecholamine-related genes. Study participants will report to NIH after fasting overnight except for water or noncaloric, noncaffeinated beverages. They must not have taken Tylenol for at least 5 days. Blood will then be drawn. DNA will be extracted and stored in the freezer for future studies.
To assess the efficacy, safety, and tolerability of recombinant human nerve growth factor ( rhNGF ) in the treatment of HIV-associated sensory neuropathy. AS PER AMENDMENT 5/6/97: To compare the change in viral load between the double-blind phase baseline and week 4 in placebo and active rhNGF recipients. To ensure that rhNGF does not induce an increase in viral load compared with viral load changes seen with placebo. Up to now, treatments for HIV-associated sensory neuropathy have been symptomatic, relying on pain-modifying agents or membrane-stabilizing drugs. Because nerve growth factor is important in the development and maintenance of sympathetic and sensory neurons and their outgrowths, it is proposed that recombinant human nerve growth factor may provide a specific restorative treatment for HIV-associated painful sensory neuropathy.