Ksomething said (in a different thread):I get a feeling that the bed is moving, like a super-strong heartbeat, but it is not in time with my heartbeat and nobody is in bed with me, or if he is in bed I will ask my husband if he feels it and he does not (I check to see if it is his heartbeat and it is not in time with his either). Sometimes it happens when I'm just drifting off to sleep. It often happens while I'm sleeping and wakes me up, and sometimes it is so strong I feel like I am going to fall out of bed. When my dog was alive sometimes I thought it was her bumping into the bed, then I'd look for her and she would be sleeping across the room... or now I'll think one of the kids woke up but they are not in the room.
Lippman (1951) described such motion-space hallucinations in migraineurs as "The earthquake"
http://www.migraine-aura.org/content/e27891/e27265/e26585/e43013/e46075/index_en.html
It never starts when I'm fully awake, though it continues once I am awake.
As far as I can remember, this has never happened during a headache.
Seeing the 'earthquake'comments on the migraine-aura page makes me think it could be what they were talking about. It is so strange how many different kinds of auras a person can get!
Wendi

