That was one of the first tests they had me do when I started investigating the surgery, i was diagnosed in June and have been sleeping with the machine ever sense. I feel SO much better already, my moods better, I have more energy, and I'm more relaxed. Surgery is Oct 31, I hope I won't have to use the machine too long after the surgery, but I'm glad I've had it so far, it really improved my day to day life!