Transient neurological symptoms often present a difficult diagnostic dilemma. It is often difficult to tell if the transient symptoms were due to ischemia or due to something else (see Chapter 1). Usually, by the time the physician sees the patient, the neurological exam has returned to normal. On the other hand, it is critically important not to miss the diagnosis of transient ischemic attack (TIA). TIAs may provide an opportunity for physicians to intervene and prevent an ischemic stroke and subsequent disability, and must be taken seriously. The search for an etiology must be done expeditiously. Just as angina may serve as a warning for future myocardial infarction, a TIA is often a warning sign of an impending stroke.