transient ischemic attack

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A temporary blockage of the blood supply to the brain caused by a blood clot and usually lasting ten minutes or less, during which dizziness, blurring of vision, numbness on one side of the body, and other symptoms of a stroke may occur. Also called ministroke.

Wiktionary

1. n. medicine A temporary cessation or reduction of blood supply to part of the brain, resulting in brief neurologic dysfunction that usually persists for less than 24 hours.

WordNet 3.0

1. n. brief episode in which the brain gets insufficient blood supply; symptoms depend on the site of the blockage