I have seen 2 neurotologists over the past 3 months for that constant rocking that I know many folks on here have. My neurotologist at Ohio State diagnosed my situation as Microvascular Compression Syndrome. I'm not real crazy about the diagnosis and he isn't quite sure either as it is controversial at best right now. However, Dr. Hain at Northwestern (Subs likes to reference this guy) has written a nice explaination. It may be one of those things that is a catch-all, but I thought others with rocking might be interested.

http://www.american-hearing.org/name/microvascular_compression.html

What is Microvascular Compression Syndrome?
In microvascular compression syndrome (MCS), vertigo, tinnitus and motion intolerance is attributed to irritation of the 8th cranial nerve by a blood vessel. It is a controversial syndrome at present.

There are many symptoms that have been attributed to MCS including disabling vertigo, severe motion intolerance, tinnnitus, and neuralgic like "quick spins". As the very existence of MCS continues to be questioned, it is understandable therefore that the symptoms of MCS are ones that could be found in other conditions, such as Ménière's disease or Migraine.

At the present writing, microvascular compression syndrome is felt to be rare. Characteristically it is a syndrome of vestibular or auditory symptoms that respond to treatment with medications for neuralgia (for example, carbamazepine), and in which other reasonable causes (such as Meniere's disease, Migraine, labyrinthitis, fistula) have been excluded. "Quick spins" and acquired motion intolerance may be characteristic clinical symptoms; however, at the present writing, studies looking at subpopulations with those particular index symptoms for response to decompression surgery have not been made (and probably they will never be done).