I find the comments here interesting and I can identify with a lot of them. I am new to the CPAP OR BIPAP world. I have been on BiPAP for going on 2 months now. I have found that my events have improved greatly after solving the leaky mask issue which just involved finding the right mask for me and then getting used to wearing it. I now find that my events per hour have improved greatly. I was initially at 25 the 30 events per hour. I find that most nights now I am in the range of 0,2 to 5.0 events per hour. Every once in a while, however, I jump up to 12 - 15 events per hour. Last nights was a good example; I had 12.5 events/hour. I had been to an event and was extremely tired and my legs were unusually painful from my back issues. I could not find a comfortable position on my side which is how I usually sleep. I ended up sleeping on my back. I actually woke myself up several times and was breathing very deeply which is normal for me when recovering or reacting to an apneic event. I remember thinking that I am probably going to have a high event number tonight. I was correct as it was 12.5. I think, for me, that I have confirmed that sleeping on my back may well be the culprit for me in raising my events per hour number. I will pay close attention in further evaluating going forward. Have a good sleep!! Lyle