Several decades ago researchers noticed a surprising finding. Ears that were dissected after death in people with Meniere’s symptoms showed a dilation of membranes, called endolymphatic hydrops.
The inner ear membranes are so thin that they are transparent. They are filled with a fluid called endolymph. Between them and the surrounding bone is another layer of fluid, perilymph, which cushions them. In hydrops, the membranes appear stretched and dilated like an overexpanded balloon, with more endolymph fluid inside the inner ear and less perilymph outside as a cushion. However, many attempts to cure the disease by trying to drain the extra fluid or change fluid dynamics did not stop the spells. A person with Meniere’s disease still has hydrops for months or years in between attacks, so hydrops alone doesn’t explain why a spell comes on for a few hours every now and then.
Many physicians noticed that people with Meniere’s frequently also suffered from migraine headaches. Migraines are severe headaches lasting hours, often on one side of the head, and can be associated with aura—seeing flashing lights or an expanding blind spot in vision. Some people have spectacular auras, like becoming paralyzed on one side or having trouble speaking. The auras seem like a stroke, but only last up to 30 minutes and then disappear.
The time course of a migraine seems very similar to the hours-long time course of Meniere attacks, so more and more researchers became convinced that migraine was enough to cause an attack, and the importance of hydrops was discounted. A rift occurred between those who believed hydrops caused the attacks and the migraine supporters. Some migraine researchers even thought that hydrops had nothing at all to do with Meniere’s disease. Both sides could not be right. Something was missing, and I’ll discuss this in my next post.