It's a symptom of a type of disturbance in the chemical-electrical activity of the brain. In the case of your daughter, in the temporal lobe - it's up here - in the lateral part of the brain. It's rare, but it does cause bizarre hallucinations and usually just before a convulsion...the shaking of the bed. It's doubtless due to muscular spasms.

Oh no. No, no. That was not a spasm. Look. I got on the bed. The whole bed was thumping and rising off the floor and shaking - the whole thing, with me on it!

Mrs. MacNeil, the problem with your daughter is not her bed, it's her brain.

So, uhm, what causes this...?

A lesion. A lesion in the temporal lobe. It's a kind of seizure disorder.

Now look Doc, I really don't understand how her whole personality could change.

The temporal lobe is very common...It could last for days or even weeks. It isn't rare to find destructive, even criminal behavior.

Hey, do me a favor, will ya? Tell me somethin' good.

Don't be alarmed. If it's a lesion, in a way she's fortunate. All we have to do is remove the scar.