A stroke occurs when the blood supply to certain brain areas is disrupted. A stroke is characterized by a massive and sudden disorder of the brain function, and may lead to severe and lasting impairments or death. Strokes are caused by either a blockage of a brain artery (ischemic stroke) or by a bleeding in the brain (hemorrhagic stroke). About 85 percent of strokes are ischemic and only 15 percent are hemorrhagic.1 According to the German Stroke Foundation, about 270,000 suffer a stroke in Germany per year. Around one fifth of patients die within the first month after the incident, nearly 40 percent within the first year. About half of the surviving patients are permanently disabled after suffering a stroke, with nearly one million Germans living with the long-term consequences of a stroke.2 In some cases, a transient ischemic attack (TIA) precedes stroke. A transient ischemic attack (TIA) is often labeled a “mini-stroke.” It causes the same neurological damage as stroke, e.g. blurred vision, slurred speech and signs of paralysis. However, most symptoms of a TIA disappear within an hour, whereas the neurological deficits caused by a stroke persist longer than 24 hours. Nonetheless, a TIA should be taken very seriously as it indicates that there is something wrong with blood supply to the brain and may be a warning sign for an impending stroke. It is therefore necessary to undergo a thorough medical checkup if you or someone you know experience any of the above mentioned symptoms. In about 30 percent of all strokes a distinct cause cannot be discovered via the usual diagnostic methods. Such cases are classified as cryptogenic strokes.