Accountability for Conversations?

This is somewhat similar to apollo's post from a year ago, but I was just wondering if anybody had tips for dealing with the problem of the ADD partner's ability to participate fully in a conversation and yet have no memory of it.

A very benign example:  Last night my spouse asked me to make some popcorn.  I was on my way out of the room, but I started the popper and asked him to save some for me to eat later.  He said OK and I went off to do my thing.  When I came back an hour and a half later, he had not doled out the popcorn for me and had no memory whatsoever of us having that conversation.

A less benign example: We are planning a road trip vacation to visit family.  He and I sat down and talked about when we were going to leave, and agreed on a plan.  When the topic of our departure date came up again last week, he got angry with me because we were leaving on a Wednesday and came up with all sorts of excuses for why he didn't know that, or would never have agreed to it, even though we had talked about it at some length.

I'm not so much concerned about dealing with the "false memories" aspect of it - I have made my peace to a greater or lesser extent with that aspect of his ADD.  What I want to know is... does anybody have any ideas as to how to tell when the ADD spouse is not present in the conversation?  I have tried asking him to repeat things back to me (which is how I handle our four year old when she is just smiling and nodding at me) but he gets offended and says that I am patronizing him.  Any other ideas?