The National Institute of Neurological Disorders and Stroke sponsors a wide range of basic and clinical research aimed at finding better ways to prevent, diagnose, and treat stroke, and to restore functions lost as a result of stroke. Preventing Secondary Brain Damage Currently, scientists are studying the risk factors for stroke and the process of brain damage that results from stroke. Some brain damage may be secondary, occurring after the initial death of brain cells caused by the lack of blood flow to the brain tissue. This secondary brain damage results from a toxic reaction to the primary damage. Researchers are studying this toxic reaction and ways to prevent secondary injury to the brain. Scientists hope to develop neuroprotective agents, or drugs that protect the brain, to prevent this damage. Animal Studies Scientists are also conducting stroke studies in animals. By studying stroke in animals, researchers hope to get a better picture of what might be happening in human stroke patients. Scientists can also use animal models to test promising therapies for stroke. If a therapy proves helpful for animals, scientists can consider testing the therapy in humans. One promising area of animal research involves hibernation. The dramatic decrease of blood flow to the brain in hibernating animals is so extensive that it would kill a non-hibernating animal. If scientists can discover how animals hibernate without experiencing brain damage, they may discover ways to stop the brain damage associated with decreased blood flow in stroke patients. Another study used a vaccine that interferes with inflammation inside blood vessels to reduce the frequency and severity of strokes in animals with high blood pressure and a genetic predisposition to stroke. Researchers hope that the vaccine will work in humans and could be used to prevent many of the strokes that occur each year in people with high risk factors. Can the Brain Repair Itself? Scientists also are working to develop new and better ways to help the brain repair itself to restore important functions to stroke patients. New advances in imaging and rehabilitation have shown that the brain can compensate for functions lost as a result of stroke. When cells in an area of the brain responsible for a particular function die after a stroke, the patient becomes unable to perform that function. However, the brain's ability to learn and change, called plasticity, and its ability to rewire the connections between its nerve cells means that it can compensate for lost functions. One part of the brain can actually change functions and take up the more important functions of a disabled part. Clinical Trials Clinical trials are scientific studies using volunteers that give researchers a way to test medical advances in humans. Clinical trials test surgical devices and procedures, medications, and rehabilitation therapies. They also test methods to improve lifestyles and mental and social skills. Clinical trials may compare a new medical approach to a standard one that is already available or to a placebo that contains no active ingredients or to no intervention. Some clinical trials compare interventions that are already available to each other. When a new product or approach is being studied, it is not usually known whether it will be helpful, harmful, or no different than available alternatives (including no intervention). The investigators try to determine the safety and usefulness of the intervention by measuring certain outcomes in the participants. Scientists are using clinical trials to - develop new and more effective treatments for stroke  - discover ways to restore blood flow to the brain after stroke  - improve recovery after stroke  - learn more about the risk factors for stroke.  develop new and more effective treatments for stroke discover ways to restore blood flow to the brain after stroke improve recovery after stroke learn more about the risk factors for stroke. Participating in a clinical study contributes to medical knowledge. The results of these studies can make a difference in the care of future patients by providing information about the benefits and risks of therapeutic, preventative, or diagnostic products or interventions. You can find more information about current stroke clinical trials at the NIH Clinical Trials Registry at www.clinicaltrials.gov. You can search for a trial using criteria such as condition or disease, medication or therapy. Each entry includes a trial description, sponsors, purpose, estimated completion date, eligibility criteria, and contact information. You can also call the NIH research study information line at 1-800-411-1222, TTY-1-866-411-1010, or e-mail prpl@mail.cc.nih.gov For more information on stroke, including research sponsored by the National Institute of Neurological Disorders and Stroke, call 1-800-352-9424 or visit the Web site at  www.ninds.nih.gov.