View clinical trials related to Cerebrovascular Accident.
Filter by:To establish a link among Chlamydia infection, sickle cell anemia, and stroke risk.
This study will use transcranial magnetic stimulation (TMS) to identify interactions between the unaffected and affected side of the brain in stroke patients. Results from previous studies suggest that after a stroke, the motor cortex (part of the brain that controls movement) of the unaffected side of the brain might negatively influence the motor cortex of the affected side. TMS is a procedure that delivers brief electrical currents that stimulate the brain. Studies of a small number of patients have shown that TMS can cause a temporary decrease in activity of the motor cortex. Healthy normal volunteers and chronic stroke patients may be eligible for this study. Subjects may participate in up to four sessions of reaction time (speed of motor response) testing. They will perform a series of movements with the index and middle fingers of either the left or right hand in response to a signal from a computer monitor. The time it takes to do the tasks will be measured and scored. There will be rest periods during each session. TMS will be done each session to examine how the motor cortex affects recovery of function after stroke. For this procedure, an insulated wire coil is placed on the scalp. A brief electrical current is passed through the coil, creating a magnetic pulse that stimulates the brain. Depending on where the coil is placed, the stimulation may cause a muscle twitch (sometimes strong enough to move the limb), a feeling of movement or tingling in a limb, or twitching of the jaw. During stimulation, the subject may be asked to tense certain muscles slightly or to perform other simple actions. The electrical activity in the muscles activated by the stimulation will be recorded using metal electrodes taped to the skin over the muscles. Subjects will also be asked to draw a mark on a line on paper to rate their attention and level of fatigue, and how well they think they are executing the tasks. Participants will also have magnetic resonance imaging (MRI). This procedure uses a strong magnetic field and radio waves to provide detailed images of the brain. During the scanning, the subject wears earplugs to muffle loud thumping sounds that occur with electrical switching of the radio frequency circuits. The subject can communicate with the staff member performing the study at all times through an intercom system.
Recent studies have demonstrated that electrical stimulation delivered over the skin increases the muscle strength as measured by a dynamometer in chronic stroke patients. We recently also found out that such stimulation enhances the ability of healthy brains to learn faster, enhancing the beneficial effects of the motor training. The purpose of this study is to find out if this stimulation can enhance the ability of stroke patients to experience plastic changes in the brain. It may aid in the development of new strategies for rehabilitation after brain injury in the future. A clinical and neurological exam will be administered. Each patient will participate in three different sessions separated by at least 48 hours: a 2-hour peripheral nerve stimulation to the weak hand, a 2-hour peripheral nerve stimulation to the leg, and no stimulation. The sessions will be randomly ordered. A magnetic resonance imaging scan of the brain will be done as well. Nerve stimulation will be done by transcranial magnetic stimulation (TMS). In TMS, the head is immobilized within a frame. An insulated coil wire is placed on the scalp and brief electrical current passed through it. Participants may be asked to perform movements, do simple tasks, or simply tense muscles. Electrical activity of the muscles will be recorded with a computer. Some experiments may be recorded on videotape. Participants must be stroke patients who have recovered to the point of being able to make thumb movements, and the stroke must have occurred more than 6 months ago.
The purpose of this study is to better understand the role of the motor part of the brain in the recovery of motor function after stroke. The motor deficits that follow a stroke are compensated for over several months. It has been proposed that the ipsilateral motor cortex mediates these recovery processes. The results of this study will provide fundamental information on the role of ipsilateral M1 in recovery of motor function after chronic stroke. A general patient evaluation will determine the location of the lesion site and assess the degree of impairment in motor and global cognitive functioning. An assessment of motor function will also be performed. Patients will be divided into two groups: well and poorly recovered. An MRI (magnetic resonance imaging) scan may also be done if one has not been performed in the past 6 months. Two main procedures will be performed: transcranial magnetic stimulation (TMS) and test of motor performance. In the first procedure, a metal coil surrounded by a plastic mold will be placed on the head and electrical current will be pulsed through it. The electrical muscle activity will be recorded through these electrodes with a computer. The second procedure involves a reaction time test. The task will consist of reacting to a visual stimulus by performing a voluntary movement. TMS pulses will be given before each movement. This is done to determine whether this type of stimulation interferes with reaction time, which would indicated that it interferes with the brain centers executing the reaction to the visual Go-signal. Patients with single ischemic hemispheric lesions at least 12 months after the stroke who initially had a severe paralysis of the arm will be recruited for the study. Healthy normal volunteers will also be included in the study. A special effort will be made to increase the participation of women and diverse racial groups.
This study will determine whether an electric shock to the forearm can improve hand function in patients with chronic stroke and, if so, whether the improvement is related to brain reorganization. Some studies indicate that electromyography-triggered neuromuscular electrical stimulation (EMG-triggered NMES) on the forearm improves wrist motor function in patients with chronic stroke. The shock is delivered to the wrist extensor muscle of the forearm, causing greater hand movement than the patient can make on his or her own. The study will determine if the electric shock is more effective given after the patient initiates the hand movement (EMG-triggered NMES) than at times unrelated to patient effort (NMES alone). Stroke patients with muscle weakness on one side of the body may be eligible for this study. The stroke must have occurred at least 12 months before the patient enters the study. Candidates will have a medical history and physical and neurological examinations. Participants will be divided randomly into two groups: EMG-triggered NMES, and NMES alone. For EMG-triggered NMES, two electrodes from the NMES machine and two EMG electrodes are placed on the wrist extensor muscle of the forearm. The patient relaxes the hand, then contracts the wrist extensor muscle to produce movement. This movement triggers the NMES to deliver enough electrical stimulation to produce maximum wrist extension. For NMES alone, only the two NMES electrodes are placed on the forearm. The patient relaxes the hand and stimulation is applied at an intensity to produce full wrist extension without any patient effort. At the first clinic visit, baseline hand function is measured with the following tests: - Wrist extension - wrist extension is measured with a digital instrument called an accelerometer - Pinch power - grip strength between thumb and index finger is measured with a digital pinch analyzer - Jebsen-Taylor hand function - function is evaluated through activities such as moving a can and lifting a pin - H reflex - (Note: I could not find a description of this test or its purpose in the consent or the protocol) In addition, transcranial magnetic stimulation (TMS) is done to examine brain activity. For this test, an insulated wire coil is placed on the patient's scalp. A brief electrical current passes through the coil, creating a magnetic pulse that travels through the scalp and skull and causes small electrical currents in the outer part of the brain. The stimulation may cause muscle, hand or arm twitching, or may affect movement or reflexes. During the stimulation, electrical activity of muscles are recorded with a computer or other recording device, using electrodes attached to the skin with tape. Participants will be instructed in how to use the NMES machine at the first visit. They will be required to practice with the machine at home 30 minutes twice a day every day for 4 weeks, for a total of about 56 sessions. Follow-up evaluations of hand function will be done one day after the first NMES or EGM-triggered NMES task, then after 2 weeks and after 4 weeks of performing the exercise. These evaluations include the tests described above for baseline measurements, plus TMS.
To assess the risk of incident atrial fibrillation after stopping anti-hypertensive medication including beta-blockers and ACE inhibitors. Also, to assess the role of genetics in subsequent risk of stroke among patients with atrial fibrillation.
To extend mortality followup through 25 years for two cohorts of men in the Multiple Risk Factor intervention Trial (MRFIT): the 361,662 men screened and the 12,866 men randomized, and to pursue the general aim of elucidating unresolved research issues on the epidemiology, natural history, etiology, prevention, and control of major chronic diseases, particularly cardiovascular and neoplastic diseases and diabetes.
Atrial fibrillation is the most frequently occurring cardiac arrhythmia, with 1.0-1.5 million cases annually. It is a risk factor for congestive heart failure, and stroke, 75,000 cases of the latter occurring annually in patients with atrial fibrillation. The safety of the most widely used antiarrhythmic agent for this group of patients, quinidine, has been called into question. This study seeks to determine whether two other agents, amiodarone and sotalol, are safe and effective treatments for patients with atrial fibrillation.
To determine the association between flavonoids intake and the prevention of incident cardiovascular disease (CVD).
This study will examine the effectiveness of an experimental treatment to improve hand function in patients who have had a stroke affecting one side of the body. One of the main problems of stroke patients is difficulty using the affected hand. Most treatments focus on acute (early) intervention, although special exercises may help some chronic patients. Previous studies have indicated that combining hand exercises with anesthesia (blocking motor and sensory function) of the upper arm may improve hand movement in stroke patients, even in the chronic state. This study will examine whether the exercise plus anesthesia treatment is more beneficial for these patients over the long-term than exercise alone. Patients 18 years or older who are at least 12 months post stroke, which has affected only one side of the body, may be eligible for this study. Candidates will have a medical history and physical and neurological examinations. Participants will be randomly divided into two groups: one will practice hand exercises without upper arm anesthesia and the other will exercise with anesthesia. All patients will perform two consecutive sessions of 30-minute pinch practice-forceful pinching of the thumb and index finger. Patients in the anesthesia group will have the anesthetic injected in the lower neck. Enough anesthetic will be administered to block motor and sensory function in the shoulder and upper arm, while maintaining as much function as possible in the forearm and hand. All patients will also have transcranial magnetic stimulation (TMS) testing. For this procedure, a very brief electrical current is passed through an insulated wire coil placed on the head, producing a magnetic pulse. The pulse travels through the scalp and skull and causes small electrical currents in the outer part of the brain. During the study, the patient will be asked to make movements, do simple tasks, or tense muscles, while the electrical activity of the muscles is recorded. Patients will have four sessions at 3-week intervals and three follow-up sessions at 3 weeks, 9 weeks and 24 weeks after the testing. Follow-up evaluations will include pinch power testing, TMS, sensory function test and hand function measurement.