View clinical trials related to Cerebrovascular Accident.
Filter by:To assess interactions between selected cardiovascular medications and genes in the incidence of heart attack, stroke, and atrial fibrillation, an irregular heartbeat.
To identify new cellular, metabolic, and genomic correlates of atherosclerotic plaque and early pathologic changes in the vascular wall and determine their consequences for coronary heart disease and stroke.
To investigate the relationship of vascular cell phenotypes to atherosclerosis.
To explore the role of insulin growth factor in cardiovascular disease in older men and women.
To investigation the association of thrombosis and inflammation genes with sub-clinical cardiovascular disease and with incident myocardial infarction and stroke in older adults.
This study will examine in healthy individuals and in patients with aphasia (a language disturbance that is usually caused by stroke, brain disease, or injury) which parts of the brain are involved in naming everyday objects. In most people, language and speech originate in the left side of the brain. When this side of the brain is damaged, language function is often impaired. Often, however, function partly recovers, possibly because the right half of the brain takes over some language functions when the left half is injured. Healthy volunteers and patients with aphasia due to stroke may be eligible for this study. All candidates must be 18 years of age and older. Patients' aphasia must have occurred as the result of a stroke that occurred more than 12 months before entering the study. In addition, their stroke must not have affected the brainstem or cerebellum. Candidates will be screened with a medical history, brief physical examination, and questionnaire about handedness. Participants will undergo the following tests and procedures: Session 1: Magnetic resonance scanning (MRI) MRI is a diagnostic and research tool that uses a strong magnetic field and radio waves to obtain images of body organs and tissues, including the brain. The subject lies in a cylindrical machine for up to 60 minutes. Loud thumping noises occur when the radiofrequency circuits are switched; this noise can be muffled by the use of earplugs. Sessions 2 and 3: Picture naming during transcranial magnetic stimulation (TMS) For transcranial magnetic stimulation, a wire coil is held on the subject's scalp. A brief electrical current is passed through the coil, creating a magnetic pulse that stimulates the brain. The subject hears a click and feels a pulling sensation on the skin under the coil. There may also be a twitch in the muscles of the arm or leg. During the TMS, subjects are asked to name pictures of common everyday objects that appear on a computer screen. They are asked to name them as fast and as accurately as possible. Their voice is recorded to determine the accuracy of their answers and the time it takes to answer. Subjects may also be asked to tense certain muscles slightly or perform other simple actions during the TMS to position the coil properly.
This study will examine the role of an amphetamine in improving the effect that electrical nerve stimulation has over brain flexibility associated with motor training in patients who experienced a stroke more than 1 year before. Chronic stroke is the main cause of long-term disability among adults. Previous studies have shown that electrical stimulation given over the skin may improve patients' recovery of motor function. Furthermore, it is known that amphetamines can improve the effects of sensory stimulation such as touch. Use dependent plasticity refers to a process in which the performance of simple, repetitive finger movements leads to encoding the details of those actions in the primary motor cortex of the brain. Plasticity in this sense refers to the capacity for change in the brain. Patients 18 years of age and older who have had a stroke, who have no history of other neurological and psychiatric illnesses, and who are able to contrite and perform simple attentional tasks and other tasks may be eligible for this study. There will also be healthy participants as a control group. Participants will have an electrocardiogram. They will also go through a practice session of about 3 hours in which they become familiar with the different tasks required in the study: motor training, pinch force, and the Jebsen-Taylor Test-which requires doing as fast as possible actions that include writing, lifting small common objects, turning pages, or lifting light or heavy objects. Then during the study, patients will be involved in a variety of sessions: - Motor training alone for about 3 hours. - Motor training, amphetamine (or placebo), and electrical stimulation for about 6 hours. - Motor training, amphetamine, and no electrical stimulation for about 6 hours. A magnetic resonance imagining (MRI) scan will be done. Patients will lie still on a table that can slide in and out of a metal cylinder surrounded by a strong magnetic field. Scanning time varies from 20 minutes to 3 hours, with most scans lasting between 45 and 90 minutes. Patients may be asked to lie still for up to 60 minutes at a time. As the scanner takes pictures, there will be loud knocking noises, and the patients will wear earplugs to muffle the sound. Patients will be able to communicate with the MRI staff at all times during the scan and may ask to be moved out of the machine at any time. During another procedure called transcranial magnetic stimulation (TMS), a wire coil will be held over the scalp. A brief electrical current will be passed through the coil, creating a magnetic pulse that stimulates the brain. Patients will hear a click and may feel a pulling sensation on the skin under the coil. There may be muscle twitches of the face, arm, or leg. Patients may be asked to tense certain muscles slightly or perform other simple actions so that the coil can be positioned appropriately. The stimulation is usually not painful, although sometimes strong contractions of the scalp muscles can cause discomfort or a headache. Patients can ask to have the procedure discontinued at any time. For the electrical stimulation procedure, three pairs of electrodes will be placed on the skin. A quite brief pulse of current will pass between the electrodes, creating the electrical field that activates the brain. Patients will feel a brief stinging around the electrodes. Regarding the amphetamine, patients will take it orally on up to four different occasions. Usually they will take 10 mg of Dexedrin before testing.
This study will evaluate the effectiveness of both drug and non-drug treatments in preventing depression after a stroke.
The purpose of this study is to compare liberal red blood cell transfusion therapy with restrictive red blood cell transfusion therapy in surgical patients with cardiovascular disease or risk factors.
This study will examine how dopamine, a brain chemical, affects motor training. Taken by mouth, dopamine can enhance motor training, especially during rehabilitation after brain damage. The study will also examine whether Sinemet, a drug containing a precursor of dopamine, can improve motor training. Healthy normal volunteers and stroke patients between 18 and 80 years of age may be eligible for this study. Healthy volunteers must be right-handed. Stroke patients must have had a stroke that caused weakness in one hand, from which they have recovered enough to be able to move the thumb in different directions. Participants will have up to three study sessions, as follows: Prestudy 1 (MRI, TMS with motor training) - Session 1: Magnetic resonance imaging (MRI) of the brain. This procedure uses a strong magnetic field and radio waves to show structural and chemical changes in tissues. During the scan, the patient lies on a table in a narrow cylinder containing a magnetic field. He or she can communicate with the staff administering the test at all times. - Session 2: Transcranial magnetic stimulation (TMS) - The subject sits in a comfortable chair with the right forearm held still at the side and the head held still by an aluminum frame. A magnetic coil is placed over the head, and a small probe is attached to the thumb to measure thumb movement. Magnetic pulses are occasionally delivered over the scalp, likely inducing a mild thumb movement. After this test, the subject takes a tablet of either Sinemet or placebo (a look-alike pill with no active ingredient). Fifty minutes after taking the pill, the subject undergoes motor training that involves performing brisk thumb movements at a rate of 1 movement per second. At the end of the training, TMS is repeated. - Session 3: Identical to session 2, except subjects who took Sinemet in session 2 now take placebo, and vice versa. Prestudy 2 (MRI, PET without motor training, no TMS) - Session 1: MRI of the brain if the subject has not had one within the last 12 months. - Session 2: Positron emission tomography (PET) scanning - This procedure provides information on brain chemistry and function. First, the subject is given either Sinemet or placebo. The subject lies on a bed in a doughnut-shaped machine with a custom-molded plastic mask placed over the face and head to support the head and hold it still during the scanning. A catheter (plastic tube) is placed in each arm-one to inject [11C]raclopride-a radioactive substance that competes with dopamine for binding in certain parts of the brain and can be detected by the PET scanner-and one to draw blood samples for measuring the level of Sinemet in the blood. - Session 3: Identical to session 2, except subjects who took Sinemet in session 2 now take placebo, and vice versa. Main Study (MRI, TMS, PET with motor training) - Session 1: MRI of the brain, if one has not been done within the last 12 months. - Session 2: TMS, followed by administration of Sinemet or placebo and PET scanning with motor training. The subject lies quietly during the first half of the PET session and performs brisk thumb movements during the second half. After completing the PET scan, the subject undergoes TMS again. - Session 3: Identical to session 2, except subjects who took Sinemet in session 2 now take placebo, and vice versa.