How do symptoms of "vascular dementia" differ substantially from Lewy Body Disease or Alzheimers?

My mother has been diagnosed with the first two by different doctors. she has also been diagnosed with Cortical Basal Degeneration and Posterior Cortical Atrophy. Overall her disorder is mostly in movement, although she has slight memory issue and "alien hand syndrome."

How can I tell if it's "vascular dementia" or the other dementias I am seeing?

Tagged as: dementias, memory issue, posterior cortical atrophy, vascular dementia