Had sleep study – got CPAP – didn’t work. No one knew why. Got another CPAP, didn’t work. CPAP doc, sent me to ENT – he didn’t know why CPAP fails to help. Posted my issue here http://www.apneaboard.com/forums/ and someone suggested that I try a soft C Collar. I did and the CPAP works only with the C Collar on. With Collar my AHI is below 5, without the collar it’s over 10. No one knows why. I thought I’d post this in case anyone else is having no success with CPAP. Told ENT and CPAP doc and they have no idea why and just said if it works – keep using it. That was 18 months ago.