Dealing with my Mom's onset of dementia (Caused by Alzheimer's disease and Lewy Bodies) she slowly withdrew from friends and current affair conversations. This was over a 5-6 year period before the onset of dementia. So I would suggest checking into that first.
As an EMT I have presented the ACE survey in the field. Seniors are polite and well receptive. In conversation they are revealing more by stories than score. But the few I have interviewed have come around to admit a higher score than first revealed.
Early in my ACE development I came across an elderly person that had been treated for suicidal tendency for 25 years. Their phone alarm went off and they gave the explanation they HAD to take there meds for their condition. A lengthy conversation followed. Two family members completed suicide. After 25 years the current therapist (Being the 4th) said, "I don't know what you want me to say. I'm not going to say anything different from the last therapists." I offered the ACE survey. They scored high, but I do not remember the exact score. And what followed next is one of the driving forces for me. "No one has ever asked me these question. Not in this way." What originally brought my attention to this person was that none of us new they lived in the community. They were a recluse.
If it's not broke, don't fix it. The original 10 questions will be enough to work with. Be brave and remember. If you're not blurring the boundaries of your practice, you're not doing enough for your patient.
I hope this has helped.