A couple of things...
I do believe it is a good idea to take a few notes during a therapeutic session. For one thing, it will help you remember what was being discussed...even if you don't refer to it.
For another, you CAN refer to it if you would like.
If a session is missed (because you have to miss it or the therapist does), you can get your notes out and think about what was said the previous week and still work on what needs to be done.
Sometimes it is easy to stagnate. A few notes...a few memory jogs...can be helpful.

One of the links Mrs. D sites, mentions a book called Brain Rules. I really enjoyed this book...lots of good ideas and the author is funny too!