The most common form of Chiari Malformation is Type 1, it often manifests later in life (not at birth, but sometimes in children) with headaches and
cerebellar symptoms like dizziness and
memory/concentration problems. The cerebellum in the lower back of the brain starts extending down past the skull into the spine. This herniation can, and often does, get worse. If you are diagnosed with Chiari 1, you generally will be told how far the herniation extends in millimeters.