Hi tina,
I am sorry I am so late answering your question. Your question is timely because a recent study was just released confirming that Migraines can cause brain damage. Let me explain a bit. People with a long history and/or frequent Migraine attacks are at an increased risk of what's called "silent" brain damage - brain damage without symptoms. For more information continue reading: Yes, Migraines Can Cause Brain Damage. And back in 2004, an article in the Journal of the American Medical Association that indeed, Migraine is a progressive brain disease. Read on: Is Migraine a Progressive Brain Disease?
Our Migraine with aura - The Basics article is very informative too.
Good luck
Nancy