Hi uglogirl

I know about AD in two ways.

My mother-in-law had it so my family job was to support her and my wife. In my day job I have published some papers on it, from a basic science rather than clinical perspective.

Differential diagnosis of AD compared to other dementias is not easy though a combination of MRI, CT scans and PET scans can sometimes help - this is something that you could discuss with your husband's care team.

The fluctuations in cognition that you have described are common in AD - they certainly applied to my m-i-l.

The medications (Namenda and Airacept) that you mentioned have different pharmacological bases of action. They can sometimes help but (day job investigation related to my m-i-l) the evidence is not strong. If Namenda helps your husband, that is good.

All the best.