Twice in the past 18 months, I've had a problem develop in my middle ear in which fluid (or something) is lodged in the Eustachian tubes (primarily the left one), adversely affecting my hearing - I can still hear the full sound spectrum, but my ability to accurately discern pitch is severely compromised. I'm a musician with perfect pitch, so what may be a minor annoyance to some is incredibly disruptive to me.

The last time this happened, my primary care doctor referred me to an ENT specialist. She did a full hearing test, and since I can hear the full sound spectrum, my hearing was deemed "normal" (again, I can _hear_ the tones, the pitches were just "wrong"). She also couldn't see any signs of an infection. Her diagnosis was to wait and see if the problem cleared up on its own, and if it did not, to return. The problem did clear up, so I did not return.

SO, approximately 3 weeks ago, the problem reoccurred, and I've developed a theory - as of Feb. 2006, I began sleeping with a CPAP machine due to being diagnosed with a severe case of sleep apnea. I also have had a recurring problem with post nasal drip, tied to allergies. Is it feasible that the CPAP machine (which is set to about 15cm of continuous pressure) is forcing air and mucus into my Eustachian tubes?

Sorry for the long post, but I felt some background was necessary on this one.