After 5 years of CPAP, my current doctor's hypothesis is that reliance on CPAP has weakened the muscles in the back of my throat, and that I should work with a speech pathologist to strengthen those weakened muscles.  I also took a home test and my AHI was down to around 5, which, if the home test is accurate, might be related to having lost about 30 pounds since my initial study, which had me at an AHI of ~ 18.  

My doctor's thinking is that to the extent the speech pathologist can strengthen the muscles in the back of my throat, I might be "cured" and no longer need CPAP.  Not sure i'm convinced -- i.e., I'm not convinced -- but this is certainly a new twist in my journey with Sleep Apnea that I thought I'd let you all know about.   Will keep you posted.