Can Patients with Obstructive Sleep Apnea Titrate Their Own Continuous Positive Airway Pressure? Published: American Journal of Respiratory and Critical Care Medicine Vol 167. pp. 716-722, (2003)

http://ajrccm.atsjournals.org/cgi/content/full/167/5/716

Here is the key to this
 
 

Quote:

Clearly, for this strategy to be successful, the patient must understand when and how to change the CPAP.

 
 
So yes, its is possible, yes there was a study, no its not currently done.  (at least in the US, AND under the guidance of physicians, however there are a group of folks that advocate self treatment that have done this.  However, the ASAA does not advocate self treatment in regards to OSA as it can be a complex issue that CPAP therapy alone might not address.)  
 
Additionally, it was a single study for a short period of time with a small group.  That said, I don't doubt that a portion of the OSA population could benefit from treatment using this methodology, but I don't think it can be applied to all the OSA population.  (Especially those with other respiratory conditions.)  
 
So, in a way its misleading to say yes you can, without stating who the "you" is.
 
All that said, if an effective screening method could be devised to determine who this method would work for successfully, I think it has great promise for treating patients with OSA.