What is a transient ischemic attack (TIA)?

A transient ischemic attack (TIA) is characterized by a temporary decrease in blood supply to the brain, which leads to sudden and brief neurological symptoms. These symptoms can include weakness, numbness, difficulty speaking, or visual disturbances, and typically last for a few minutes to several hours before resolving completely. The key aspect of a TIA is that it does not result in permanent damage; instead, it serves as an important warning sign that could precede a full-blown stroke.

The other options represent different medical conditions. A permanent blockage of a blood vessel in the brain indicates a completed stroke, which causes durable deficits due to tissue damage. A severe headache as a warning can indicate various conditions, including a migraine or impending hemorrhagic stroke rather than a TIA. Lastly, an electrical disturbance in the brain pertains to seizure activity or epilepsy and does not reflect the ischemic nature of a TIA. Thus, defining a TIA correctly as a temporary decrease in blood supply is crucial for understanding its implications and urgency in assessing stroke risk.