[Evolution of the definition of transient ischemic attack (TIA).]

The definition of TIA began with one-hour cutoff in 1950s and established with 24-hours cutoff during 1960s and 1970s. During the period when no imaging techniques could help to differentiate TIA from ischemic stroke, such definition could only contribute to clinical classification, with inevitable shortcomings. With the development of imaging technique and thrombolysis therapy, TIA has become a good opportunity for identifying and managing ischemic cerebrovascular diseases. The New TIA definition employs the one-hour cutoff with emphasis on no brain lesion evidence. The new definition may help to identify and manage ischemic cerebrovascular diseases earlier. Revision of the definition of diseases calls for the combination of the development of medical science and clinical practice.