My wife's original diagnosis was Alzheimer's, and it only came out a couple of years on - when I questioned it because of her vascular-type progression - that they said, well she has vascular dementia as well.Could they have been wrong with the original diagnosis? This is only the second time (first time in March this year), that she has passed out briefly and I had assumed mini strokes/fainting with VD was much more frequent?
These days she has about 3-4 faints a year that are detected. In the early days she might have 8 a night at the worst [but then I was beside her and awake all night awaiting them].
As with all things, the presentation of symptoms is different for each person.
In the early days, the medics considered all sorts of possible reasons for the fainting - low blood sugar, arrhythmia, too much alcohol, etc. Of course it is always worth checking even the most unlikely out as any of them will be better than a diagnosis of dementia.