Trust your instincts. That's great advice to keep in mind throughout your caregiving journey. In fact, observations from family and friends are better predictors of the early signs of memory decline than are traditional memory tests, according to a 2010 study in the journal Brain.
Your close observations will be similarly helpful as the disease progresses. After all, you know your loved one best. You see first what's new and different from day to day.
How to use your special knowledge:
Jot down changes as you see them -- what happened, what else was going on at the time. This will help you remember and notice patterns.
Bring the list of changes to routine appointments in case it's relevant to something observed or discussed.
Don't hesitate to call the doctor and mention worrisome changes if what you see is sudden or very different. Some behavioral changes can be symptoms of delirium or medication side effects, for example.
Be persistent. If something doesn't feel right in your gut, pay attention to that. It's your body's way of talking to you.