Then again, it could have no connection to the dolls at all. Think about it; a whole room fool of dolls? I mean there are so many other possibilities aside from the stereotypical, sci-fi movie approach. The room itself could have negative energies from a past event (ie murder, rape, suicide, etc..). If there really isn't too much in the room aside from dolls, it's probably just throwing the objects from the walls and such because that could be where most of the blood was spilled during the event.
Just a theory though. Dolls have such a reputation that they could be a forum in themselves.
Like that Dead Silent movie; I hate it. I have a certain phobia against them sort-of-speak,
and I wasn't a fan. However, consider an alternative to the possession of dolls.
Pretty unlikely. And additionally, if your mom likes these dolls it could be a malicious spirit trying to get back at her.
You'll have to investigate further and get back to us on that one necessarily.