Hi Elsewhere,
The Central Sleep Apnea *sounds* like the same thing that was described to me, but I don't remember that term being used. I was having chronic throat infections, and finally after my 6th Z-pack (antibiotics) in as many months, my doctor asked if I was snoring. I said, Yes! (Very unladylike, but true.) She signed me up for the sleep study, and they said I was waking up more than 205 times per night. They said I would stop breathing, and my heart would send a warning message to the brain to rouse me out of sleep enough to start breathing again. I went for the second sleep study, in which I was fitted with the CPAP. I slept AWESOME. My CPAP cost $1700, with all the attachments, and the humidifier. The humidifier was the most important piece to me. On nights that I naturally can't breathe because of a cold or allergies, I rub a generous amount of VapoRub under my nostrils before fitting the mask on. This, combined with the warm, moist air, really helps. At first, I used the CPAP religiously every night for 9 months, now I only use it about twice a week. I notice when I don't use it, but my symptoms are just not as bad. I have not had ONE throat infection in over a year.
Of course, this is just my experience--I can't tell if you've tried the sleep study with the CPAP and it failed..?. I hope you find some relief, because having interrupted sleep for several years can cause all kinds of physical (high blood pressure, fatigue) and mental problems (brain fog, can't concentrate or focus, etc.) Have you had any luck with your second opinions yet?
BTW, they promised that I would stop gaining weight after I started using the CPAP, because weight gain is a symptom of poor sleep--THEY LIED! lol