Adding to CCNs info.....I struggled with a diagnosis of sleep apnea for some time. Was initially told is was OSA....obstructive type. Didnt adapt well to cpap machine and just used an O2 concentrator at home for awhile. Found out thru personal research about "central" apnea. After 2 sleep studies it was determined central was my problem. Prescribed a different machine and now have consistent O2 levels and no breathing stoppage. Before it was at "severe" levels.