Sleep Study titration- do they use straight pressure?

I was just wondering if anyone knew when sleep clinics are doing titration studies, if they use any sort of exhalation relief or just straight pressure?

I am not sure but I can tell you I was very comfortable during my titration night. I did wake a few time to what felt like puffs of air that were at a higher pressure than what I was feeling. Quick burts of a higher pressure. I am only at a pressure of 9 so maybe they started me out low. I did not feel uncomfortable at all!!

On mine, they started at 5 cm H2O, and went up 1 cm at a time, I was titrated at 7. No EPR, but did use a heated humidifier since I was using nasal pillows.