Transient Ischemic Attacks
Just as stroke occurs when the flow of blood is blocked, TIAs happen when there is a brief blockage. The temporary loss of blood to the brain causes a brief, sudden change in brain function. This may manifest as temporary numbness or weakness on one side of the body, loss of balance, confusion, blindness in one or both eyes, double vision, difficulty speaking, or a severe headache. But these will disappear quickly and permanent damage is unlikely.
If you have ever experienced symptoms like this you should seek medical advice. A TIA can be a warning that you are at risk of stroke sometime in the future.