It sounds like your mom had more age-related dementia, IMO. I'm the caregiver for both my aged parents - Dad's got the old age, atrophied brain cells version where he can remember much from eons ago, but will constantly yammer on during the entire first half of the day that he hasn't shaved yet.
Mom's more classic Alzheimers - listless, cares nothing about hygiene, confused, etc., etc.