About one-third of all strokes are preceded by one or more "mini-strokes," known as transient ischemic attacks (TIAs). TIAs can occur days, weeks or even months before a stroke.
TIAs are caused by temporary interruptions in the blood supply to the brain. The symptoms occur rapidly and last a relatively short time, usually from a few minutes to several hours, always with complete recovery within 24 hours. For instance, if you experience a sudden loss of vision, or weakness in an arm or leg that disappears, you might be having a TIA.
Because TIAs are temporary and the body soon returns to normal, it is easy to ignore them or to believe that the problem has disappeared. However, it is dangerous to ignore TIAs, because the underlying problem that caused the TIA continues to exist. TIAs are often early warning signs of more serious and debilitating stroke in the future.