Hi, yes, there are forms of dementia that present that way. Dementia with Lewy Bodies is one form of dementia where there’s often a significant fluctuation in impairment. Does she hallucinate at all? That’s another potential symptom of Dementia with Lewy Bodies. There could ALSO be a medical issue; perhaps she has a certain medication that is influencing this? I would recommend having a neurologist or other doctor check out her medications and see if there’s something that could be causing these big changes.