Here is an example of what you are looking for in SleepyHead. In the screenshot below there are three events in succession. The first one is classed as a CA event or clear airway or central apnea. The next two are classed as OA or obstructive apnea. If you look at the mask pressure during the event you will see the trace paint a band of up and down pressure fluctuation. That is the machine increasing and decreasing flow quite rapidly to determine how the pressure responds. If the airway is clear the pressure does not fluctuate as much up and down. If the airway is blocked the blue band that is painted by the mask pressure is wider (up and down). It is not a huge difference, but there is a difference if you look closely.
Also be aware that during the ramp or autoramp the flagging of events is suppressed. So if you want the best picture of what is happening when you are going to sleep, you may want to try turning the ramp off. Then events will be flagged right from the time you turn the machine on. Once you find out what is actually happening then there is probably a strategy with the ramp and ramp pressure that could minimize it.
