5. Group I: Patients with dizziness, vertigo, presyncope, and light-headedness which are likely due to secondary chronic cerebral circulation impairment associated with sequelae of brain infarction, and patients for whom KETAS (IBUDILAST) was prescribed Group II: Patients without dizziness, vertigo, presyncope, and light-headedness which are likely due to chronic cerebral circulation impairment associated with sequelae of brain infarction