Dural arteriovenous fistula (DAVF) is an important cause of neurological dysfunction that is often misdiagnosed, especially in elderly population. Galenic DAVFs are a subtype of the rare falcotentorial DAVFs with a high risk of hemorrhage and aggressive clinical course. In most cases, DAVFs present with pulsatile tinnitus, headache, or orbital symptoms such as chemosis and proptosis. We report a patient with DAVF of Vein of Galen presented with progressive dementia, treated by Onyx embolisation and had good clinical outcome.