A Transient Ischemic Attack or TIA is any temporary (by definition, less than 24 hours) loss of the flow of blood to any part of the brain that results in loss of brain function. Any loss of function that lasts more than 24 hours is classifed as a stroke, even if the symptoms are temporary. TIAs are usually caused by arterial plaque becoming lodged in one of the minor arteries of the brain, resulting in decreased blood flow. A TIA can be a one time event, or a recurring event.