My Mum says that a feeling of giddiness and everything moving around her can come over her quite suddenly, even if she is sitting in her chair not doing anything.
Her mother, my grandmother, used to say the same thing (to which my Mum would roll her eyes and dismiss it as stuff and nonsense - but that's another story!). Is this the sort of thing that often results in falls in elderly parents? Is there any treatment that you know of that can help and decrease the likelihood of falling?