Purkin's sign (or as it is called in the literature - Purkin's symptom) was first described in 1838 by the Czech histologist Jan Purkin. At the moment, it is considered a classic sign of cerebrovascular accident. Develops as a result of a transient ischemic attack, stroke, or in patients with migraine against the background of arterial hypertension. Acute, subacute or gradual onset is observed. The clinical picture determines the ongoing vascular patency and the degree of damage to the hemisphere or brain stem.